I had to mention about this relatively unkown avr below, though it does not fall in the class mentioned above:
JVC DP20: The most underestimated receiver of its generation, it had so much to offer while being ignored due to lack of snob value. On the day I went to buy the Yamaha z9, a friend of fine being a relative newcomer to the world of music and HT asked a favor to buy cheap receiver for him as starter. As I shelled 4.5 grand for my z9 I saw this jvc branded dp20 selling for mere 850 dollars brand new. They had an initial retail price of 2.5 grand but due to the lack of hi end brand image the re-sellers was selling them cheap. My friend being out stationed for over three month due to shipping business, I had enough time to spend a do direct comparison with z9 and 59 txi. Lacking the hi-class WOW effect of Z9 it was enough sound wise to put smile across my face. Its defining characteristics are an unfailing smoothness through the midrange and on up through the upper midrange, a gentle touch of warmth with high-frequency transients cymbals, vocal sibilants just where you'd want them: naturally smooth, yet exceptionally detailed and convincingly non-mechanical. However, relative to z9, the DP20 comes up a little short in terms of high-frequency transparency, more of a seethrough sound and in terms of midbass punch. It had separate 5.1 and 7.1 channel inputs though lacking ilink. It had bass and distance management system that operated flawlessly and I was awed at how much this avr provided for its mere asking price. If I had to describe dp20 in short it will be like having the sound signature of denon while having the grunt of 59txi and in having a little limited feature set of lexicon rv8. In the end I gave it ten out of ten in terms of SQ, power and features relative to its asking price. No other avr can get that good relative to price other than z9.
Victor/ JVC Brand Logo
My love for Victor/ JVC brand always stood strong with the use of many Onida products in our home. More than two decades back Onida sold consumer electronic goods in our country and had a joint venture with JVC. Our Onida VCR was just a rebadged JVC with excellent product quality and performance to boot. Our Onida CRT television is over two decades old and is still in working condition with a JVC picture tube implanted on it. It is to note Victor of Japan is JVC to the rest of the world. As Victor Company of Japan they did design and produce hardware like televisions, AV amplifiers, DVD players, stereo integrated e.t.c. just like any other consumer electronics company. But they are also a software manufacturer. They have the additional ability to enhance the performance any audio/ video hardware product by implementing their own propriety software. This type of software primarily comes from their studio engineers at Victor Studio. One such world renowned sound quality enhancing software from this firm is K2 Processing technology. In this post I will once again project their AV amplifiers/ AVRs, actually their most expensive and best sounding one. As expected such beasts were born in the Uber AV amplifier era, and in this case it was 2003. In Japan it is known as Victor AX-V8000 with an estimated price of US $3,000, a pure AV amplifier. For the rest of the world, it is an AVR better known for JVC RX-DP20V retailing at US $2,500. Why AX-V8000 is more expensive than RX-DP20V will be reveled later in this post, but as of now we must go through some of Victor/ JVCs cool-stuff technologies that made AX-V8000/ RX-DP20V quite a unique product that deserved attention.
K2 Processing Technology
The monogram K2 stands for the last names of two senior engineers, Kuwoka from Victor Company of Japan and Kanai from Victor Studio. The K2 internal project primarily got initiated when studio recording engineers at Victor Studio complained about their own CD recordings in early 1980s. They claimed there was a clear degradation in sound quality when compared to analog master copy from where the recording was made. An investigation phase led to the discovery that during CD recording process electrical distortion like jitter, rippling etc. got introduced in the master digital signal created after analog-to-digital-conversion from the analog master which is then getting recorded in CDs. When these recorded CDs were played back this time being converted from digital to analog signals by DAC for us to hear, recorded sound with additional jitter & rippling in CDs made an adverse effect resulting in inferior sound quality compared to analog master. To resolve this degradation in sound quality during CD manufacturing process a joint internal project between two teams led by hardware engineer Kuwoka & studio engineer Kanai gave birth of this technology, better known as K2 processing.
K2 Technology Logo
The two main implementations of K2 processing are:
1) Maximizing sound quality during down-converted CD recordings from Analog Master Copy: An attempt led by these two engineers to improve the degradation in sound quality that occurred during recording & manufacturing time led to the original version of K2, which was named "K2 Interface". The first JVC K2 interface got introduced in 1987 for maximizing sound quality during CD recording process in the confines of the Red Book format i.e. 44.1 kHz/16-bit. During this process extremely accurate 192 kHz/24-bit ADCs (analog to digital converters) are driven by atomic clocks which are a thousand times more accurate than crystal clocks. Substantially reduction of jitter and rippling in the digital master signal is obtained from analog master. K2 software algorithms are then applied to this master 192 kHz/24-bit signal to be down-converted to 44.1 kHz/16-bit and get recorded in CDs. It is to note K2 processed CDs behave like normal ones and you do not need any specific decoder in CD players to play them. Victor/ JVC claims their proprietary K2 processing can retains almost all the sound quality of master 192kHz/24-bit digital signal even after getting down-converting to Red Book format. At first glance it looks quite an unrealistic claim but at the same time there must be some positive outcome from repeated subjective evaluations made by studio engineers in order to confirm the improvement in K2 processing algorithms. The wide use of K2 processing in mastering and manufacturing process of their renowned eXtended Resolution Compact Disc (XRCD) confirms some truth in it. After all by general consensus, XRCDs are the highest quality 44.1 kHz/16-bit recorded CDs you can ever buy.
2) Restoring sound quality of down-converted linear formats found in CD/ DVD-Video recordings as well as compressed multi-channel DVD-Video recordings to near Analog Master Copy sound quality: K2 processing belonged to Victor/ JVC Group and was quietly used in their CD recording process to have an edge over their competitors as general public new nothing about it. Meanwhile, K2 development continued in both hardware and software giving birth to Extended K2 processing Ver. 1.0 in 1997 and later Extended K2 processing Ver. 2.0 in 1999. The main objective of Extended K2 software processing is to improve the sound quality of down-converted linear audio formats like PCM and compressed multi-channel audio formats like Dolby Digital/ DTS variants found in CD/ DVD-Video recordings. An attempt was made to come closer to analog master sound quality. With this came the realization of its huge applicability in consumer electronics market. Hence decision was taken to embed the second version of Extended K2 processing in some LSI chip later giving birth to Compression Compensative Converter LSI in late 2000. This LSI is better known as CC Converter containing Extended K2 processing algorithms.
CC Converter LSI
Looked at a broad scale the two main parameters effecting sound quality of digital audio are bit-depth & sampling frequency. Say in a CD recording process an analog master copy after A/D conversion becomes 192 kHz/24-bit digital master signal. This master signal is then down-converted to 44.1 kHz/16-bit in digital domain to be recorded in CDs as per Red Book format. Following problems then arise:
1) As quantization resolution gets down-converted to 16-bit for recording in CDs, a very faint analog signal in analog master may not be accurately reproduced after D/A conversion from these recorded CDs. This leads to sound quality degradation.
2) As sampling frequency is down-sampled from master 192 kHz to 44.1 kHz in CDs, very high frequencies in the audible range say 20 kHz may not be accurately recreated after D/A conversion from these recorded CDs. A 192 kHz master signal contains multiple inaudible high order harmonics above 20 kHz to accurately produce a 20 kHz audible signal. A CD with 44.1 kHz sampling frequency is capable of 44.1/2 = 22.05 kHz max waveform. So a CD recording does not contain the added inaudible frequencies above 20 kHz that though unheard may affect the generation of a perfect waveform on high frequencies (say 20 kHz).
CC Converter Logo
Question can arise whether human ear can ever perceive such a subtle nuisance in sound quality, but theoretically it exists. This CC Converter LSI tries to counter the above mentioned deficiencies that get embedded during CD/ DVD-Video recording process through its K2 Extended processing algorithms. Below lies the block diagram of a CC Converter:
Block Diagram of CC Converter
The CC Converter is divided into three successive operating sections:
High-bit Expansion: Let us consider a CD recording which contains a linear PCM stereo audio track of 44.1 kHz/16-bit. Here the 16-bit digital signal from CD is first analyzed by K2 processing algorithms. Then K2 tries to deduce the original analog master signal before A/D conversion with its algorithms while preserving the same sound energy of 16-bit signal. After deduction K2 bit-expands the incoming 16-bit digital signal to a 24-bit signal with the help of computed results to smooth out the resultant signal waveform while preserving the sound energy. An outgoing digital signal of 44.1 kHz/24-bit is now formed. Similarly a 20-bit digital signal is also bit-expanded to 24-bit.
Block Diagram: High-bit Expansion Stage
Frequency Conversion: The second stage performs simple over-sampling with an internal digital filter. It may be two times or four times depending on the incoming digital audio signal. A 44.1/48 kHz signal is over-sampled four times to 176.4/192 kHz respectively. On the other hand an 88.2/ 96 kHz signal is over-sampled two times to 176.4/192 kHz respectively. For a CD the 44.1 kHz/24-bit signal from first stage gets frequency up-converted to 176.4 kHz/24-bit in this stage.
Range Expansion: In the final stage of CC Converter the 176.4 kHz/24-bit digital signal from the second stage is further analyzed by K2 processing algorithms. This time though K2 tries to deduce the original analog master waveform before A/D conversion containing all the added information for multiple high order harmonics required to correctly represent audible high frequencies (say, 20 kHz). It does so with its own exclusive algorithms. Then K2 processing modifies the 176.4 kHz/24-bit digital signal with its own computed results. Finally a 176.4 kHz/24-bit digital signal gets created mimicking the original analog master copy from which the actual CD recording was made. As per Victor/ JVC this processing provides optimum smoothness, reality and 'live' presence reflecting the analog master. Similarly a 192kHz/24-bit signal is treated in the same way.
Block Diagram: Range Expansion Stage
-----------
What I really appreciate here is the difference in approach taken by Victor/ JVC with CC Converters compared to other high-bit and over-sampling systems found in the market. CC Converter unlike others do not just mechanically bit-expands and add frequencies over a CD recording so as to create a bit-extended & frequency bandwidth expanded signal. On the contrary it has the power to compute the incoming digital audio signal with its Extended K2 algorithms and then re-create a bit-expanded and frequency bandwidth expanded signal on a software level. It then tries to regain the original analog master signal before A/D conversion. Thus CC Converter is a micro-computer running its own embedded K2 processing software which additionally contains a mechanical digital filter. It can up-convert various CD and DVD-Video audio formats as under:
Input -> Output
44.1kHz, 16/20/24 bit
-> 176.4kHz, 24 bit
48kHz, 16/20/24 bit
-> 192kHz, 24 bit
88.2kHz, 16/20/24 bit
-> 176.4kHz, 24 bit
96kHz, 16/20/24 bit
-> 192kHz, 24 bit
How much CC Converters succeeded in "restoring sound to its original state" is debatable. Or did they go further away from the truth? One thing for certain, Extended K2 processing algorithms in CC Converters never caught up the market the same way K2 processing algorithms did with their XRCD manufacturing process. Further furnished below is Victor/ JVC own statement regarding their CC Converters:
When an analog signal is converted into digital (A/D conversion), high frequencies -- normally those higher than 20 kHz with CDs -- are removed as dictated by the CD's sampling frequency. Absence of this high-frequency data affects the quality of sound in the audible range. The CC Converter features exclusive algorithms to restore lost signals based on the recorded digital signals of audible frequencies, those frequencies that should have been recorded in the first place. It also uses high-bit quantization to reproduce minute signals. Moreover, in order to precisely reproduce the signals that have undergone such processing, the CC Converter features a broader analog bandwidth (up to 4 times the sampling frequency) extending beyond 20 kHz. This improves the quality of the music data in the audible range. Through high-bit/high-sampling processing, the CC Converter generates expanded digital signals with a quality close to that of the original master. The algorithms of the CC Converter have been verified for their musical legitimacy by studio engineers and musicians through repeated auditions. Because the number of digital sound sources has been growing fast, the CC Converter has proved to be a much-sought-after solution for the faithful recreation of original sound. It also works with compressed data, such as Dolby Digital and DTS formats.
---------------------------------------------------------------------------------------
P.E.M. D.D. Converter
P.E.M. D.D. Converter stands for "Pulse Edge Modulation Differential linearity-errorless D/A Converter". Phew!!! It is actually an advanced variation of the conventional 1-bit DAC that should theoretically eliminate zero-crossing distortion. This JVC exclusive 192 kHz/24-bit DAC also features their own VANS (JVC Advanced Noise Shaper) circuitry which is a 4th-order noise shaper that eliminates noise by shifting it out of the audible audio range and into the inaudible ultra-high frequency range. This DAC LSI incorporates dual P.E.M. D/A converters, thus is a stereo DAC with dual layers of shielding and independent power supplies to prevent Pulse Generator interference of master clock. It is originally manufactured by Panasonic for JVC and is liberally used in all of their products. P.E.M. D.D. Converter review opinions are a mixed bag, some said they are just good while others claimed they are the best 1-bit DACs available in market, very musical and accurate. Below is a diagram revealing its internals:
Block Diagram of P.E.M. D.D. Converter
---------------------------------------------------------------------------------------
Digital Acoustics Processing (DAP)
A Victor/ JVC exclusive sound-field post processing technology very similar to Yamahas Digital Sound Field Processing. Yamahas DSP technology is just more mature and first implementation can be traced way back in 1986, while DAP is a decade behind. Thus DAP is not as vast, as dense or as accurate as Yamaha DSP technology but is still a much better option than any third part conventional post processing technology used by other AV hardware manufacturers. Both Yamaha & JVC have one thing in common; they both have sound engineers which gives them a subjective edge. So they both sent their engineers worldwide to measure the acoustics of famous concert halls and theaters. Later they both implemented vast amount of DSP computed data taken from actual venues for creation of sound-fields in their AV amplifiers/ AVRs.
---------------------------------------------------------------------------------------------------------------------------------
The Beginning
I can think of Victor/ JVC brand being famous for making televisions, VCRs, camcorders, DVD players/ recorders, CD players/ recorders/changers and automobile AV entertainment. But I can never recollect them to make a foray in AV amplifiers/ AVRs and earn a HiFi pedigree. Their AV amplifiers/ AVRs at best catered low to mid-end segment; priced lower than equivalent models from the big four (Denon, Pioneer, Onkyo & Yamaha). Feature wise they were able to match the big fours offerings, but in terms of sound quality and product quality they lagged a bit behind. With the advent of Uber AV amplifier era from 2000 onwards, the mindset of every electronic consumer companies changed from pole to pole. As market got ready for truly expensive AV amplifiers, their marketing departments started pushing for an expensive model instead of curbing the idea at very inception. It was a hardware engineers dream come true to have free reign to select the best parts from their inventory and produce the best sounding AV amplifier they can ever conceive. Victor/ JVC also followed suite during this Uber wave and gave birth to Victor AX-V7000 in 2001. Retailing at 230,000 yen (excluding tax) in Japan it was their first high-end AV amplifier to justify Top-Of-The-Line [TOTL] status; ready to go head on with big fours TOTLs.
Victor/ JVC sketched a completely new technical design for AX-V7000 which needed some time to smooth its rough edges. It had the sound quality and power output on par with big fours TOTLs but turned out to be a bit down on product quality requiring frequent repair. Victor/ JVC understood this and their lower brand value in AV amplifier market, pricing AX-V7000 significantly lower than TOTLs from other respected brands. For example Yamaha DSP-AZ1 was retailing for 300,000 yen (excluding tax) on the same year AX-V7000 got released. With two additional years of experience they fine tuned this product with additional refinements and improved product quality & reliability significantly and thus Victor AX-V8000 was born in late 2003. This model is generally regarded as their best sounding AV amplifier ever and also their most expensive one, retailing for 350,000 yen (excluding tax) in Japan which currency converted was roughly US $3,000. Knowingly with AX-V8000; Victor/ JVC went to an unchartered territory with performance that matched the TOTLs from the big fours and this time with equal product quality to boot. Unfortunately for them Denon, Pioneer, Onkyo & Yamaha by then had already decided to shift to the next level, the Uber level of AV amplifiers costing 525,000 yen (excluding tax) and above. So AX-V8000 remained at best a great TOTL, I will say in the same level of Yamaha DSP-AZ1 or Denon AVC-A11SR (TOTLs) which by itself was a great achievement for Victor/ JVC. Ubers like Denon AVC-A1SRA, Pioneer VSA-AX10Ai-S, Onkyo TX-NR1000 and Yamaha DSP-Z9 were on a different league though.
Victor AX-V8000
For the rest of the world Victor AX-V8000 is better known as JVC RX-DP20V. There are slight differences between the two; firstly RX-DP20V is an AVR. Lets be frank here, no one will be willing to pay an equal amount of money for a top of the line JVC branded AVR which one can easily dish out for a Denon, Pioneer, Onkyo or Yamaha. The basic human instinct to link these big four as HiFi brands while JVC as just another electronic consumer company at least in AVR category will surely bug your mind even if all of them had identical performances. JVC must have understood this disparity and thus slightly down-graded the over engineered Uber level chassis of AX-V8000, lower quality speaker terminals and omitting the additional touch screen remote that came with it. Hence the RX-DP20V retailed for five hundred dollars less at US $2,500. No compromises where made to internal electronic components and sound quality which gives us a sigh of relief. RX-DP20V got region wise further divided into two sub-models. Europe got the identical specs and same silver finish of AX-V8000 with just a tuner added in JVC RX-DP20VSL (SL -> Silver). In contrast North America had to live with usual black version in JVC RX-DP20VBK (BK -> Black) but it came with added goodies like Zone 2 support and added RF (Radio Frequency) rod antenna in the AVR. As the supplied main remote supported both IR (Infrared) and RF signals, wall penetrating RF signals from other Zones can be easily sent by this remote to the AVR at a distance of even 50 feet!!! No doubt it was a handy feature for Zone control. To complicate matters even further there came a down-graded version of RX-DP20VBK, this time with lower quality internal components while keeping the specifications intact. The chassis was further down-graded and some functions removed. Known as JVC RX-DP15, it was the cheapest THX ULTRA 2 certified AVR known to man at just US $1,900. For the rest of the post let us concentrate on the top version, the Victor AX-V8000.
--------------------------------------------------------------------------------------
Victor AX-V8000/ JVC RX-DP20V
An AV amplifier/ AVR when looked upon from AV separates point-of-view happen to be an amalgamation of a separate AV processor with a multi-channel power amplifier on a single chassis. Henceforth I have put my views under similar headings and tried to compare "TOTL" Victor AX-V8000 with an Uber Yamaha DSP-Z9 implementation.
Chassis
Victor AX-V8000
Beautifully crafted solid aluminum Front Panel
Silver finish solid aluminium side panels for up-market feel and greater chassis strength
Beautifully crafted Top Panel
Back Panel
One of the main distinguishing feature of Japanese Uber AV amplifiers are their un-parallel chassis quality. First the internal chassis is made from heavy gauge reinforced steel sheets for utter strength. Such tough chassis are required when dealing with some ten kilos of mains transformer!!! With further treatment this chassis came fully copper plated or black anodized. This ensured maximum heat dissipation and reduced chassis impedance. These are not just a single box as found in now-a-days AV amplifiers; and have fully insulated multiple chambers to prevent internal interference between internal digital & analog circuits. This internal chassis is further complemented with beautifully crafted brushed aluminum finish front, side and top panels. This not only provides an up-market feel but most importantly further strengthens the internal chassis for maximum strength and vibration damping. General statements from Uber manufacturers were
It would take a meteor to wipe this out asserting the titanic strength of the chassis. A notch below, TOTLS from the same manufacturers never enjoyed this level of chassis quality bar few. Victor AX-V8000 is one such TOTL to enjoy near Uber level chassis quality which is simply astounding. The other TOTL I can think of is Yamaha DSP-AZ1. To start with AX-V8000's internal thick chassis is fully copper plated. It is further divided into five main chambers to prevent internal interference.
JVC RX-DP20VSL: Internal View [Europe model]
1 -> Analog Power supply chamber
2 -> Analog 7-channel Power amplifier chamber
3 -> Analog Video and Audio Chamber
4 -> Analog Audio Chamber
5 -> Digital Audio Chamber
One notable feature is the inclusion of a solid 1.6 mm thick transformer base plate to which the three power transformers are mounted. Due to their combined weight of over 9 kilos; special attention was required for stress concentration in the chassis. The other notable feature is in the use of three feets instead of conventional four in the chassis base. Quite unique as it was, it does provide the perfect balance with no wobble as the ends of the three feet always form a plane. In a completely flat plane though the four feet base will have an advantage as center of gravity will be shifted further inside providing better stability. This internal chassis is then complemented with silver finished aluminum front, top and side panels. They are not as exquisitely crafted as Ubers but still definitely provided an up-market feel with added chassis rigidity. Another quite noteworthy feature of AX-V8000/ RX-DP20V is the fully motorized front panel door that opens in two stages. As the power is turned on, the front panel door will automatically move down a little to reveal the source selection buttons. If you turn it off the front panel door moves up automatically to close!!! During operation the door can be further opened by pressing the door down button situated at its right side to revel additional control buttons.
Step-1: Front Panel Door Closed
Step-2: Front Panel Door is half opened to reveal source selection buttons
Step-3: Front Panel Door is fully open to reveal all buttons for operation
The paramount chassis quality of AX-V8000 took a slight dip in sister JVC RX-DP20V models. Two internal copper braces running from back to front just below the top panel to provide additional rigidity and flex control was removed. The aluminum top and side panels were replaced with a single cheaper steel cover as found in other TOTLs. The combined effect was a less costly chassis but with some added flex & less rigidity. Mind you the RX-DP20V is still rock solid AVR by todays standards, but it was not lucky enough to receive the over-engineered chassis of AX-V8000. These measures were one of the main reasons why RX-DP20V models retailed five hundred dollars less. But it did have four feet.
Victor AX-V8000: It had additional copper braces for rigidity
Victor AX-V8000: Third feet
JVC RX-DP20VSL: A simple silver finished steel cover
JVC RX-DP20VSL: Europe model had four feet, note the fully copper plated chassis
-----------------------------------------------------------------------------------------------------------------------------------
AV Processor
Audio
Multi-channel Inputs (Analog/ Digital): I am truly overwhelmed by how much AX-V8000/ RX-DP20V has in offer for its asking price. A Yamaha DSP-Z9 in 2004 would cost you US $4,500 brand new while a JVC RX-DP20VBK comes for as little as US $2,500. It was truly a value-for-money TOTL. As expected I found huge differences between an Uber and TOTL implementation in regards to electronic components used which creates the performance difference, there must be one at an US $2,000 price gap. Uber DSP-Z9 follows a more pure and holistic approach, an excessively over-engineered product with top-spec electronic components. The total focus on sound quality, the sheer number of components used and their detailed implementation to retain audio fidelity or video quality will make your jaw drop with awe. TOTLs on the other hand take a different approach and are well engineered products using components in the audio/ video path as and when required, it is as per needs basis with some cost cuttings being evident. AX-V8000 falls in such a group of TOTLs along with competitors like Yamaha DSP-AZ1 and Denon AVC-A11SR. A TOTL will always have selective performance per channel type, the fronts getting maximum attention with higher quality components while center, surrounds, surround backs & subwoofer gets secondary treatment to save hardware cost. Such differences in audio fidelity per channel type is understandable and are followed by every AV amplifier manufacturer now-a-days. The AX-V8000s audio chain from EXT 7.1 channel analog inputs to 7.1 channel pre-outs will contain 24 op-amps, 3 ADCs, 1 DSP micro-computer with 2 memory modules, 4 DACs, 4 volume controllers and 8 muting transistors. These are quite respectable numbers for a 7.1 channel audio chain. For the same channels DSP-Z9 kills AX-V8000 with its sheer numbers of components used by implementing 52 op-amps, 4 ADCs, 9 DSP micro-computers with 10 memory modules, 6 DACs, 9 volume controllers and 22 muting transistors!!!
Victor AX-V8000
All Gold plated Digital, Analog and Video Inputs/ Outputs
Full Copper plated 5-chambered internal chassis
Upon comparing with the league of other TOTLS of its time AX-V8000 contains a better AV processor section in terms of both additional functionality and flexibility. I am not here to fall in the subjective domain of sound quality; let it rest until I hear an AX-V8000. To start with all audio and video input/outputs terminals in AX-V8000 are gold plated like DSP-Z9. The co-axial/ Tos-Link digital audio inputs first pass through an AKM AK4112B digital audio interface receiver (DIR) for source selection. This DIR is capable of handling digital audio signals of 96 kHz maximum sampling frequency at up to 24-bits. So nothing over 96 kHz/24-bit gets supported. The selected input signal from DIR then reaches a 32-bit Aureus TMS320DA610 (DA610) DSP micro-processor from Texas Instruments. As I remember this DSP chip used to be the most powerful of its kind back in 2003 ~ 2005 and AX-V8000 was the first AV amplifier in the world to implement it. While other well known DSP chips like SHARC Melody Ultra ADSST-21161 from Analog Devices had their cores running at 100MHz churning out 600 MFLOPS, this DA610 was capable of 225MHz having a computing power up to 1200 MFLOPS. Being two times as powerful as a SHARC, only one was good enough to perform both audio decoding as well as post processing activities in AX-V8000. Implementing such a powerful DSP allowed AX-V8000 to attain Uber level DSP processing at 96 kHz sampling frequency while its competitors were still limbering at 48 kHz. As processors need memory to work; DA610 used 8 MB of RAM from Samsung (K4S641632F) and 2 MB ROM from SST (SST39VF160) in order to perform various decoding from Dolby & DTS, post-processing and JVC Digital Acoustics Processing (DAP). No auto acoustic calibration was supported which should have required another DSP micro-processor.
A single Texas Instruments Aureus TMS320DA610 (DA610) DSP micro-processor is used
Turning back the attention to DSP-Z9; the digital audio inputs first pass through a DIR from Sanyo (LC89057W-VF4-E) for source selection. This DIR is capable to handle digital audio signals of 192 kHz maximum sampling frequency at up to 24-bits. The selected input signal from DIR then reaches a 32-bit SHARC Melody Ultra ADSST-21161 DSP micro-processor for audio decoding. It has its own memory of 8 MB of RAM (Winbond W986432DH) and 2 MB ROM (Fujitsu MBM29LV160BE). Next followed a swarm of YSS-930s; a Yamaha exclusive DSP micro-processor for their own Yamaha Digital Sound Field Processing and YPAO (Yamaha exclusive auto-acoustic calibration). Four YSS-930s tied to four 512 KB static RAMs (Cypress CY7C1041CV33) teamed up to perform post-processing activity. The final result is then acoustically calibrated by a second team of four YSS-930s with another four 512 KB static RAMs (Cypress CY7C1041CV33). In the end the DSP-Z9s DSP implementation does look monstrous in comparison to AX-V8000 or for the matter any TOTL. In my knowledge it is still the most elaborate, powerful and expensive implementation of any Uber from 1st and 2nd generations. [
Note: In one of my previous posts I wrongly quoted DSP-Z9 to use 16 MB of static RAM for post-processing and 16 MB for auto acoustic calibration. I was wrong as it actually uses 2MB for post-processing and another 2 MB for auto acoustic calibration. Similarly I wrongly quoted DSP-Z11 to use 32 MB of RAMs for post-processing and 16 MB for auto acoustic calibration. It is actually 4 MB RAM (twice of DSP-Z9) for post-processing and another 8 MB for auto acoustic calibration. But the end result after correction still remains the same, DSP-Z11 used twice as powerful DSP micro-processor with twice the memory of DSP-Z9 for post-processing activities.]
Victor AX-V8000
Victor AX-V8000 had two Remotes [Optional touch-screen remote]
JVC RX-DP20VSL came with a single Remote
JVC RX-DP20VBK came with a single Remote
Victor AX-V8000 did perform normal decoding of Dolby Digital/ DTS on both their 5.1 and 6.1 channel variants. It is also THX Ultra 2 certified which to me is real deal. This implies paramount importance to sound quality was provided during development phases of this AV amplifier to meet the highest THX standard aka Ultra 2. An additional bonus of such a certification is assurance of real grunt from all those seven equally powered audio channels. Speaking of flexibility AX-V8000 has two multi-channel analog inputs instead of one. You can easily connect a BD player to EXT 7.1 channel analog inputs while any other 5.1 channel analog source can be connected to its DVD-IN 5.1 channel analog inputs. If the EXT 7.1 channels are used then the eight analog input voltage signals are first filtered by four JRC NJM5532 dual op-amps in single-ended configuration. These are renowned op-amps known for their audio quality and as we will find out later AX-V8000 uses them liberally.
In a single-ended configuration (abbreviated as single-ended) a single discrete stereo ADC/ DAC/ Volume Controller/ operational amplifier (op-amp) is used to handle two audio channels, which tends to be the simplest and cheapest implementation. On the other hand if DVD 5.1 channel analog input is used then these six analog voltage signals are treated with two NJM5532 (single-ended) for the fronts and center/ subwoofer channels while surrounds had to deal with a lower quality JRC NJM4580 dual op-amp (single-ended). In the next step both multi-channel inputs merge to a single lane where the front two channels gets an additional pre-conditioning by two JRC NJM4580 in differential configuration.
In a differential configuration (abbreviated as differential) a single discrete stereo ADC/ DAC/ Volume Controller/ operational amplifier (op-amp) is configured to handle a single audio channel rather than two, which tends to produce better performance at the cost of design complexity and price. Now comes the biggest shock to find even though AX-V8000 fully supported 7.1 channels analog inputs, DSP processing is only performed over 5.1 channels!!! This means the rear surround analog channels from EXT 7.1 input never reaches the digital domain where DSP micro-computers reside, thus no post-processing or bass management is performed over it. Instead the surround back channel remain in analog domain and continues its path towards the pre-outs and then to power amplifier. Why Victor/ JVC refrained from a full blown 7.1 channel DSP processing is a big mystery to me. It required just an ADC for surround backs, the implemented DA610 micro-processor is fully capable of 7.1 channel processing over 96 kHz/24-bit. All I can think of is maybe Victor/ JVC thought there were no 7.1 channel formats like DTS-HDMA or Dolby True HD as of today and at those times DVD/ SACD players had only 5.1 channel analog outs. Thus only 5.1 channels from both inputs (EXT 7.1 & DVD-IN 5.1) get analog to digital converted. As with all TOTLs primary importance is provided to the front channels where a high quality 192kHz/24-bit Cirrus Logic CS5361 stereo ADCs (single-ended) does duty delivering 114 dB dynamic range. The rest four channels (center, two surrounds and sub-woofer) have to be content with two 96kHz/24-bit Cirrus Logic CS5333 stereo ADCs (single-ended) capable of only 98 dB dynamic range. Mind you all ADCs are pre-configured to work at a constant rate of 96 kHz/24-bit to feed the DSP micro-computer.
JVC (JCV8006) CC Converters are used
JVC MN35505 DAC
It is truly satisfying to see Ubers like DSP-Z9 does not budge on audio quality for any of its eight analog audio input channels over EXT 7.1. In first phase these eight analog input voltage signals are filtered by eight JRC NJM2068 dual op-amps (differential). These are renowned op-amps and can be found to be liberally used in others Ubers as well, Denon AVC-A1SRA, Pioneer VSA-AX10Ai-S to name a few. A second phase filtering is then performed by four NEC uPC4570 dual op-amps (single-ended) followed by a third phase of filtering by four NEC uPC4574 quad op-amps (differential). Notice the multiple phases of filtering by DSP-Z9 to retain the incoming signal purity on all its 7.1 channels at the same high level. Then it uses the same high quality 192kHz/24-bit Cirrus Logic CS5361 stereo ADC (single-ended) on all 8 channels which AX-V8000 reserves for the fronts only. Thus 114 dB dynamic range is maintained throughout the 8 channels, all pre-configured to work at a constant rate of 96 kHz/24-bit to feed the nine DSP micro-computers. Coming back to AX-V8000 the six analog audio channels (except for rear surrounds) after analog to digital conversion reaches the DA610 micro-processor where post processing activities like THX Ultra 2, bass management, parametric equalization and Digital Acoustics Processing (DAP) are performed. AX-V8000 also come with some additional merits while using such a powerful DSP micro-processor. One such is the memory settings against each input source (say a DVD source or a CD source, etc) where you get the opportunity to set up each input source with its own set of parametric equalizers settings, default volume level, default DSP mode, which type of input source is to be used for that source (analog or digital), etc. It is truly a remarkable feature as different audio sources have different characteristics and intended use, so the user have complete control to set it up accordingly. Audio delay up to 200 ms is provided when watching movies. AX-V8000 has no auto acoustic calibration which is quite understandable as at those times only Pioneer and Yamaha had the knowledge and wealth to develop the software required for it. Next comes the famous implementation of JVCs own Compression Compensative Converters (CC Converter) to improve sound quality. The eight digital audio channels from DA610 are used to feed four of these stereo CC Converters (JCV8006) in single ended configuration. These CC Converters depending upon the incoming sampling frequency from DA610 up-converted audio signals to 176.4 kHz or 192 kHz at a constant bit depth of 24-bit. Finally the up-converted eight channel signal from CC Converters is fed to four of their own P.E.M. D.D. Converters in (single-ended) for digital to analog conversion. These are 1-bit stereo DACs capable of 192 kHz/24bit resolution, better known for JVC MN35505. Even though the CC Converters were introduced with much fanfare by Victor/ JVC in their AV amplifiers and a lot was expected out of them, during THX Ultra 2 certification process on AX-V8000/ RX-DP20V these converters were found to introduce a negative impact on the final sound quality when measured objectively. Thus THX negated the use of CC Converters when any THX mode gets engaged. Questions still pertains regarding use of such converters and their real advantages for improving the sonic experience. Some claim to obtain a more natural sound field with them from any source. I feel the improvement in audio fidelity if any has to be measured subjectively with CC Converters as the whole concept of K2 processing technology is based on subjective evaluation. Until I hear an AX-V8000/ RX-DP20V I personally cannot comment any further. The DSP-Z9 on the other hand kept it simple and neat after DSP processing with no discrete digital filters or converters on board to improve sound quality. It just used the most expensive and performance oriented DAC from Burr-Brown lineup. Six 192kHz/24-bit Burr-Brown PCM1792 stereo DACs line up for its eleven audio channels as the center channel gets differential mode while the rest are in single-ended configuration.
Victor AX-V8000
Four CC Converters team up with four P.E.M. D.D. Converters (DACs)
P.E.M. D.D. Converters (JVC MN35505)
Next in line comes a very important stage of the audio signal chain which can dent the sound quality considerably if not handled correctly by proper designing. I am talking about the current to voltage conversion (I/V Conversion) from DACs and their subsequent filtering phases. The I/V conversion stage of AX-V8000 included the use of four NJM5532 (single-ended) for the eight analog audio channels from JVC MN35505 DACs. Note the difference here as DSP-Z9 being an Uber not only uses more expensive and better performance oriented dual op-amp by the name OP275 from Analog Devices for this stage but it also drops the cheapish single ended for more performance oriented differential configuration. The center getts an even more exclusive treatment in dual-differential setup. The Denon AVC-A1SRA also uses this renowned op-amp for the same purpose.
In a dual-differential configuration (abbreviated as dual-differential) two discrete stereo ADC/ DAC/ Volume Controller/ operational amplifier (op-amp) are configured to handle a single audio channel rather than four, which tends to produce even better performance at the cost of design complexity and higher price. Thus twelve OP275 are implemented by DSP-Z9 for its eleven audio channels. Returning back to AX-V8000 for the next filtering phases after I/V conversion, two higher quality NJM5532 (differential) for fronts are used along with a NJM5532 (differential) for center. The surrounds and surround backs gets two cheaper NJM4580 (single-ended). Subwoofer channel gets a NJM4580 (differential). In the second phase fronts get further treatment from a NJM5532 (single-ended) while surrounds and surround backs had to do deal with two cheaper NJM4580 (single-ended). In the third phase it is only the fronts that get a final treatment with a NJM5532 (single-ended) before all eight channels head towards the digitally controlled analog volume controllers. So the selective precedence of AX-V8000 or for the matter any TOTL for fronts followed by center & surrounds gets clearly evident from its implementation. On the contrary DSP-Z9 again provides equal treatment to all its eleven channels in its first phase of filtering after I/V conversion stage by using nine NJM2068 dual op-amps mainly in differential configuration. Only the two presence and two subwoofers channels have a NJM2068 (single-ended) each. In the second filtering phase the fronts have a pair of high quality OP275 (differential) and presence a NJM2068 (single-ended) all heading towards the volume controllers.
The volume controllers used in AX-V8000 are four stereo Toshiba TC9459F (single-ended) for the eight audio channels. This controller does volume control in 1 dB steps which are ok for general use, but an even fine grained control of 0.5 dB steps would have been a welcome. DSP-Z9 does just that at a much higher level in differential implementation of volume controllers to cease minute distortion generated by these attenuators. Seven of their own Yamaha YAC520 stereo volume controllers does duty for the main seven channels (differential) while the rest two presence channels and stereo subwoofers gets a YAC520 each (single-ended), making it nine in total. If you are reading still now, you have already traveled the path where analog EXT 7.1 channel inputs signals being filtered are fed to ADCs to step up in digital domain where they gets processed by DSP micro-processors and later gets fed to the DACs so as to return to analog domain only to be voltage converted and again filtered and then sent to volume controllers. Phew!!! How far are the pre-outs then? For AX-V8000 they are quite close as a final set of four NJM5532 (single-ended) takes care of the eight analog output signals from TC9459F. The fronts receive an additional treatment from a NJM4580 (single-ended) and then all seven channels are passed through seven Sanyo 2SC3576 muting transistors while the subwoofer gets an unknown Rohm 2SD2144 before submitting to 7.1 channel pre-outs. For DSP-Z9 there is still some way to go as some additional extra efforts are made to retain the audio fidelity as much as possible from the inputs. In the first batch four OP275 (single-ended) for the eight channels are used. The remaining center channel and two presence channels get an OP275 (differential) and a uPC4570 (single-ended) respectively. It even has a second phase of filtering here, an indication of excess engineering. Here four NJM2068 (single-ended) are used for the same eight channels. The remaining center channel and two presence channels get a NJM2068 (differential) and a uPC4570 (single-ended) respectively. Again crunching the numbers DSP-Z9 uses not one but two Toshiba 2SC3326 muting transistors per channel, twenty two in total for the eleven channels before submitting to 9.2 channels pre-outs!!! For both the AV amplifiers the main seven channels (plus two additional presence channels for DSP-Z9) from the pre-outs then takes the journey towards the power-amplifier domain.
Other notable mentions are the rotary optical encoders and electrolytic capacitors used in these AV amplifiers. These rotary encoders are electro-mechanical devices that sits behind the big volume knobs of these AV amplifiers. There are no analog potentiometers here; we are dealing with digital data produced by these encoders as we turn the volume knob clockwise or anti-clockwise so as to digitally control the analog volume controller ICs situated in the circuit boards. AX-V8000 uses an Alps rotary encoder (unknown part number QSW0867) to control its four Toshiba TC9459F, while DSP-Z9 comes with a Noble REB162 to control its nine Yamaha YAC520. The REB162 is a top of the line rotary encoder from Nobles lineup, comes with a metal shaft rather than plastic one with resolution of 24 pulses per 360 degree spin and a minimum rotational life of fifty thousand cycles. This means during operation if you rotate the volume knob of DSP-Z9 full 360 degrees three times a day which is roughly equivalent to some 50 volume adjustments done per day (we hardly move the volume knob past 20 degrees at a time for volume up or down); then the REB162 have a minimum rotational life of half a century!!! Regarding the use of electrolytic capacitors in DSP-Z9, it uses Nichicon MUSE series throughout. These are the highest grade audio electrolytic capacitors offered by Nichicon and are the most expensive. Different variants of MUSE series can be found throughout the DSP-Z9 like Fine Gold, Gold Tune and Super-through variants having different intended use. As these complex AV amplifiers use a hell lot of capacitors, the total hardware cost of the product is greatly affected by them. On the other hand Victor AX-V8000 being a TOTL selectively uses the highest grade Nichicon MUSE audio capacitors in few places where absolutely necessary and can significantly affect the audio fidelity. Elsewhere all medium grade Nichicon capacitors are used.
Rotary optical encoders
Victor AX-V8000
Yamaha DSP-Z9
Pure Direct/ Analog Direct: Analog lovers may also rejoice as these AV amplifiers takes utmost care with two channel analog audio in the most direct way from the analog inputs to the power amplifier. Fewer the number of components used in the chain the better it is. The most minimalistic 2-channel analog audio chain I can ever think of contains an analog input to the stereo volume controller followed by two muting transistors leading to the power amplifier with some op-amps thrown in. The AV amplifiers with so many different types of supported inputs use many solid state transistor switches acting as relays to route their signals. These transistor switches may induce little noise or distortion to the analog signal, so for these direct chains they try to avoid them as much as possible ending with one or two at maximum. From pure performance point of view, these cheap transistor switches can even be replaced with mechanical relays with gold contacts (generally found in high-end stereo amplifiers) but this increases the cost exponentially. Victor/ JVC calls this kind of direct analog chain as Analog Direct in AX-V8000. Considering any two channel analog source (say CD input) in AX-V8000, this analog input is first filtered by a NJM5532 (single-ended) followed by two transistor switches (JVC QSK0112) one after the other. Now a stereo volume controller Toshiba TC9459F (single-ended) is then used followed by a second and third phase filtering by a NJM5532 and a NJM4580 respectively. Finally a pair of Sanyo 2SC3576 muting transistors are used leading to the pre-outs and then to power amplifier. Ubers like DSP-Z9 takes analog stereo even more seriously and has a special 2-channel Pure Direct analog input dedicated for this purpose. For Pure Direct mode they are also able to reduce the number of switches to just one and then used an expensive mechanical relay with internal contact material made of silver alloy with gold alloy overlay. Op-amps and volume controllers are implemented in a more expensive way by following differential configuration. Thus in DSP-Z9 stereo analog signal from Pure Direct input is first filtered by a pair of NJM2068 (differential) before passing through a NEC EC2 mechanical relay. The selected output of this relay switch is fed to a pair of Yamaha YAC520 volume controllers (differential). After this a second & third phase of filtering takes place with an OP275 followed by a NJM2068. Finally a pair of Toshiba 2SC3326 muting transistors are used per channel leading to the pre-outs and then to power amplifier.
Headphone: The headphone treatment in Victor/JVC AX-V8000 is not up to the mark as it is clear from very onset that the headphone application is treated as a secondary aspect. This is a common concept most AV amplifiers. As such it makes use of the cheapest implementation possible by taking the amplified power output from power amplifiers and then apply a pair of 470 ohms resistors to drive the headphones. So the only shield between those tiny speakers of your headphone and over 100 watts of power per channel is the aforementioned resistors. If these resistors go berserk you end up with a pair of fried headphones. On the other hand DSP-Z9 being an Uber at least tries to give a proper headphone amplifier treatment. Here the front analog channel is taken up just before they meet the muting transistors and goes to pre-outs. The front channels then follow up to a separate discrete headphone amplifier circuit board where a pair of Toshiba 2SC2878 muting transistors for headphones is used. The signals then head towards the headphone power amplifier section. At first some capacitance is provided to deal with the peaks at very high headphone listening levels and then a JRC NJM4556A dual op-amp in single-ended configuration is used as the headphone driver. The NJM4556A is built for audio applications while specifically keeping headphones in mind. It is a high current output op-amp capable to deliver 70 mA of current per channel and good for headphones up to 150 ohms load. Having heard the sound of DSP-Z9 over a pair Sennheiser HD518, I must admit the sound is smooth and pleasant to listen, very detailed and by no means harsh.
Video
Victor AX-V8000 has composite, S-Video and component video inputs/ outputs, limited to video switching capabilities. Any video received through composite or S-Video will be converted and sent to the component monitor outs. The components are also HDTV complaint and are able to pass 720p/ 1080i max. DSP-Z9 does just that but adds another dimension to it by including video up-scaling feature, so a 320i video from composite will be converted to 320i component video format and then up-scaled to 720p via component outs.
------------------------------------------------------------------------------------------------------------------------------------
Power Amplifier
Victor/ JVC went to great lengths in order to unsure sound quality remains as pure as possible with AX-V8000. In an AV amplifier there are generally three kinds of signals namely: analog audio signal, digital audio signal and video signal. Problem arises when these three different kinds try to interfere with each other degrading sound as well as video quality. One way by which AX-V8000 countered this is by providing five isolated internal chassis chambers for different kinds of signals. Then it takes a step further and uses independent power supplies for each of them. So the power supply chamber of AX-V8000 contains three independent EI-Core power transformers with their own rectifier circuits. The transformer dedicated for analog audio signals weighs roughly 8.5 kilos to provide the juice required running the analog boards and more importantly the THX Ultra 2 certified seven channel power amplifiers. The use of a thick 1.6 mm copper plated base for these three transformers only affirms their massive combined weight which must be over 9 kilos. Frankly I never expected such a level of dedication for audio fidelity from a US $2,500 AVR, but Victor/ JVC opened my eyes. Result: better sound quality. Another noteworthy mention is the rectifier circuit design for the power amplifier. AX-V8000 follows a drastically different approach which I have never encountered on any other AV amplifier. If you look at DSP-Z9, its massive toroidal transformer dedicated to power amplifier is complemented with a single rectifier circuit containing a pair of Nichicon Super-through power capacitors with combined capacitance of 56,000 uF, 80V. Each of the main seven powered channels of DSP-Z9 (omitting the two powered presence channels as of now) is fully dependent to this common rectifier circuit and its provided capacitance. Victor/ JVC tried to take this concept a step higher by implementing channel independent rectifier circuits with their own capacitance to counter any interference between multiple channels. So the seven powered channels of AX-V8000 ends up with seven independent rectifier circuits and their own pair of Nichicon 3,300uF, 80V power capacitors. This comes up to 6,600uF per channel and 46,200uF of total capacitance. Though a more pure concept it comes with its own advantages and disadvantages. Theoretically this approach should provide better channel separation. But now as each channel is bound to its own 6,600uF of capacitance or 13,200uF for stereo operation it will never contain the boundless dynamic power or bass power that DSP-Z9 can provide for a speck of a second during stereo playback at extremely high volumes with its common 56,000 uF of reserve. But then again we are talking about a rare scenario. In the end Victor/ JVC deserves appreciation for at least trying something different to elevate sound purity. I personally give them full marks for this effort.
Victor AX-V8000: Top Internal View revealing 7 pairs of power capacitors for 7 powered channels
JVC RX-DP20VSL
Mains Power transformer can be seen
Power Capacitors: A pair of Nichicon 3,300uF, 80V per channel
For the analog Class-AB power amplifiers of AX-V8000, Victor/JVC implemented their Dynamic Super-A technology. This technology is related to their power amplifiers. Class-A power amplifiers requires their power output transistors to be always on. This result on very low efficiency & high production cost. But the sound is unmistakably smooth with very low distortion. Class-AB amplifiers found in most AV amplifiers/ AVRs behave like this when they are in Class-A mode for the first few watts. But as they switch to Class-B mode in need of higher efficiency and greater power output, they constantly start to switch the power transistors on & off. This sometimes leads to increase of distortion resulting in a metallic & harsh sound. To counter this all AV amplifier manufacturers at least on their TOTL models apply some constant idling current on the power output transistors to prevent them from completely switching off. Thus the sound remains smooth even in high power Class-B mode having less switching distortion than pure Class-B. But it comes in expense of some efficiency which is manageable with the huge power supplies implanted in TOTLs. Victor/ JVC call their take on this type of technology as Super-A. For this they use their own IC chip known as Super-A chip. Dynamic Super-A further extends the Super-A concept and provides additional refinements to manage the vast dynamic range of new digital audio formats like DVD-Audio & SACD. When the seven analog audio signals from AX-V8000s pre-outs reach the power amplifier chamber from below they feed the four separate driver circuit boards for the seven channels of the power amplifier. Each driver board takes care of (front left/ surround back left), (front right/ surround back right), (surround left/ surround right) and (center) channels. It is in these driver boards a JVC VC5022 (Super-A IC chip) per channel is implemented.
JVC Super-A IC
Victor AX-V8000
THX Ultra 2 certified Power amplifier view from below, note the 1.6 mm thick base provided for the triple power transformers
The four Driver Circuit Boards for the Power Amplifier
In the end of the power amplifier chain a pair of Sanken 2SA1494/ SC3858 power transistors are used per channel on +/- 63 volt rails. These are 200 watt devices in single configuration. AX-V8000 is manufacture rated to produce:
@ 8 ohms:
120 watts X 2 [@ 20Hz ~ 20kHz @ 0.02%THD]
@ 6 ohms:
150 watts X 2 [@ 20Hz ~ 20kHz @ 0.03%THD]
So even under 6 ohms load while delivering 150 watts per channel in stereo, it just has 50 watts of overhead. In contrast DSP-Z9 uses two pairs of Sanken 2SA1492/ 2SC3856 on +/- 65 volt rails. These are 130 watt devices in dual configuration, 260 watt in total per channel. At 6 ohms load while delivering 200 watts in stereo it has just 60 watts of overhead. This again signifies the mindset of Japanese manufacturers targeting a minimum loudspeaker impedance of 6 ohms with limited overhead left to spare to decently perform at 4 ohms load. That said I have seen DSP-Z9 to pull nine hulking Axiom Audio towers (4 ohms rated) all around at extremely high volume levels for sustained amount of time without breaking a sweat. I assure AX-V8000 to be no different. In this entire post you may have found me to repeatedly sing praise regarding the purity in design concept of AX-V8000. This continues in power amplifier domain too as all the seven power transistors with negative polarities (Sanken 2SA1494) are bolted to one heatsink while the other matching seven power transistors with positive polarities (Sanken 2SC3858) are bolted to the other heatsink. This separation of positive and negative voltages on power transistor level is made to improve channel separation and provide better sound purity. The dual solid aluminum heatsinks used here are huge by any AV amplifier standards while being black anodized for maximum heat dissipation. This being a THX Ultra 2 certified internal power amplifier can only mean good and comes with high quality banana-plug speaker terminals for AX-V8000. The total heft of AX-V8000 at 25 kilos further confirms its high current power output capability.
Victor AX-V8000
High Quality Speaker Terminals
Victor AX-V8000: Angular View
Conclusion
I find both Victor AX-V8000 and JVC RX- DP20V to be tremendous value for money TOTLs. They are great sounding AV amplifiers/ AVRs with good flexibility and gobs of power. Since I have not personally heard them in action I will end by post with a link to the review page of RX-DP20V performed by Sound&Vision. This review will provide you a measure of its sound quality and capabilities.
Link:
Sound&Vision Review: JVC RX-DP20V
Enjoy!!!