Final Photos and Final Testing, stereo 6005 SE DC amp from 2021

[RtoR King]

MY REPORT : The 6005 tube itself, ( as I am running it ), is far superior to any other output tube I have experienced in all of my listening, such that I do not mind paralleling three ( matched and balanced ) tubes in the output stage. ( VS one single 6005 output tube, which plays purer . )

Have you run calculations for the design of this new triple 6005 amp? You have preached that paralleling even twin tube sections is no good. Even in rectifier tubes! Not all of us agree with that but when it comes to parallel output tubes, there are new design problems to deal with beyond just matched tubes. Just on the surface, miller capacitance goes up and output impedance goes down. Your OPT's are probably going to need a custom wind.

There are some traditional good tube choices for 8-12 watt SET, like the 300B. And as you like trying new things how about looking at TV horizontal sweep tubes. Some have impressive power dissipation capabilities with low plate voltages to boot. Now they are class C devices but can be biased into class A with some reduction in dissipation which you like to do anyway.

 

[Dr.Gary]

03-09-2022 .........................................What is wrong with this picture below ??????..........................................


View attachment 67854


( Note, Posting software stuck on BOLD, ....sorry .)


No need for others to copy implementation errors shown above. There are two things wrong in the photo. Can you spot them ????

FIRST ERROR :


The fancy high end German three way crossover build should NEVER have used two tie wraps to bundle the twelve lead wires - coming out of it.

It truncates the high end, a sense of air, and it reduces the lower harmonics ever so slightly. Maybe a 1% to 2% subjective system degrade.

Within 20 minutes of arriving, I had my friend cut the tie wraps off, and throw them away.

He neatly spread the twelve wires 1/8th an inch or more apart from each other - so that they did not touch and their fields would no longer interact.

The German Manufacturer - should have done this !!!


SECOND ERROR :


My friend should have never ever twisted those red and black wires, from the German crossover leading to the tweeter.

In a sensitive high efficiency speaker ( only IF you happen to have an amp designed to play the high end well ), you are ruining the high end system's response.

In such a wide-band system, ANY time the speaker wire polarities touch..........just once.......it degrades the entire top end, down into into the mids and lows.

This is due to resultants that travel down the frequency range into the lower ( and easily heard ) areas of sound reproduction.

An E.E. type would know that the two speaker wires touching each other increases their total capacitance, what ever the heck that means . Note : I don't personally much care about the theoretical reason, only the subjective listening result matters to me !

In such a system, ( such as what I run ) one can not have the speaker wire polarities touch each other, for the entire amp-to-crossover, distance, and crossover to drivers distance,..... even one time !!!

Polarities touching can become up to a subjective 3 to 5% system degrade. A lot less real sounding !!! Harmonics, timbres, sense of air, and dynamics, all suffer. I just named it, and it all gets degraded . No FUN !!

My friend tells me he has Dueland speaker wire, and he will replace the twisted lengths.

I hope he remembers to cut the new wires to 57 1/8th inches, a Bob Fulton discovered compromise length. He might likely have to adjust the tweeter's signal level down some, but maybe not, when using his 300B ( midrange playback primarily ) conventional SE amplifier.

It may be very difficult to hear what I am describing, with conventional SE amplifiers, that do not play wide band . Don't blame me. What was described exists !!

Can any audio system play back cymbals in a drum kit faithfully ??? That certainly is one of my system design goals ( eg : the CD, Solo Druns - Clarke ). This is not easy for anyone, myself included, to accomplish.

Have fun listening !

Jeff

You asked "Can any audio system play back cymbals in a drum kit faithfully" The answer is yes, but in order to do so both the recording and playback need to be done using binaural technology. That's because faithful reproduction requires more than just the accurate reproduction of signals that are recorded by one or more microphones. It it requires a recording technique that is able to provide and recreate all of the information that is necessary to put the reporduced sound in the same three-dimensional environment in which it existd.

 

[reubensm]

this is amazing!

 

[Dr.Gary]

this is amazing!

Indeed.........regardless of what the "this" is to which you are referring.

 

[drlowmu]

3-11-22 ............... basic TOPOLOGY SCHEMATIC................................." Triple 6005 " SE DC audio amplifier


.................
...................................................................................................................................................................................................( Ef D.C. Biasing- filaments )


Jeff

 

[Dr.Gary]

3-11-22 ............... basic TOPOLOGY SCHEMATIC................................." Triple 6005 " SE DC audio amplifier


.................View attachment 67928
...................................................................................................................................................................................................( Ef D.C. Biasing- filaments )


Jeff

You often talk about the detrimental effect of modulated power supply lines, but your proposed design, which uses three paralleled 6005s at the output (instead of one) actually increases power supply line modulation by a factor of three and only exacerbates that problem. That leads me to ask why do you not use a separate B+ power supply for the 6E6P-E input/driver which would totally prevent the modulation of the power supply line that is produced by the high-current output stages from even being seen by the input/driver stage?

 

[Hari Iyer]

@drlowmu - Adding a constant current source - A choke of around 2H just before the driver plate resistors will prevent driver tubes from struggling for peak current on demand.

 

[grindstone]

Well, you'd be more up-to-date than I am on these styles of builds @Hari Iyer , but one of the things Dennis seemed to do ages ago was basically bleed one PS-section away from the front end about as hard as the back-end pulled so that one stage didn't "pedal" the other's rail. I think that's sort of what Jeff seems to be doing lately (?). The semantics vary, but I think the upshot is that the bleeding is so much more dominant that the requirements of the voltage amplifier stage are basically "noise" to the total demand. I've not looked at any specifics and never got time to look hard at the last amp. Brute force always works, it just costs some heat. What I (think I?) remember is that the harder you bleed and the higher overall demand, the higher the ripple. I'm about-certain that the lower-storage and lower-resistance filters ring in-band, but haven't looked at specifics and value-judgments are less-useful. In my dotage, I have come-around to trusting listening reports more than I used to. It's just that it's all a system and it's possible that some sort of compression/expansion from a ringing supply rail could dovetail with falling primary inductance, etc--and about anything else without even considering the load. I've looked pretty hard for impedance and phase curves for that flavor of A7 and have struck-out so far. It may just be that the "damping" ordinarily provided by higher resistance or active regulation is served in the form of overpowering the demand by "shunts". I will cheer-on anyone building Anything and hanging it out there for the world to see

And maybe now a comment I thought of too late for the last one. I wonder why -- during early layout -- the "old school" methods of locating/orienting iron aren't used? Specifically, put some (low level/safe) AC across one and put your scope across another piece of iron and orient for min induction--and _that's_ where it goes and how it's oriented, etc. I know it's not on it's steel chassis yet (another strong influence), but perhaps it could be done then before the layout is designed fully.

 

[drlowmu]

Well, you'd be more up-to-date than I am on these styles of builds @Hari Iyer , but one of the things Dennis seemed to do ages ago was basically bleed one PS-section away from the front end about as hard as the back-end pulled so that one stage didn't "pedal" the other's rail. I think that's sort of what Jeff seems to be doing lately (?). The semantics vary, but I think the upshot is that the bleeding is so much more dominant that the requirements of the voltage amplifier stage are basically "noise" to the total demand. I've not looked at any specifics and never got time to look hard at the last amp. Brute force always works, it just costs some heat. What I (think I?) remember is that the harder you bleed and the higher overall demand, the higher the ripple. I'm about-certain that the lower-storage and lower-resistance filters ring in-band, but haven't looked at specifics and value-judgments are less-useful. In my dotage, I have come-around to trusting listening reports more than I used to. It's just that it's all a system and it's possible that some sort of compression/expansion from a ringing supply rail could dovetail with falling primary inductance, etc--and about anything else without even considering the load. I've looked pretty hard for impedance and phase curves for that flavor of A7 and have struck-out so far. It may just be that the "damping" ordinarily provided by higher resistance or active regulation is served in the form of overpowering the demand by "shunts". I will cheer-on anyone building Anything and hanging it out there for the world to see

And maybe now a comment I thought of too late for the last one. I wonder why -- during early layout -- the "old school" methods of locating/orienting iron aren't used? Specifically, put some (low level/safe) AC across one and put your scope across another piece of iron and orient for min induction--and _that's_ where it goes and how it's oriented, etc. I know it's not on it's steel chassis yet (another strong influence), but perhaps it could be done then before the layout is designed fully.

Superb post. You really have a decent handle on what is going on. Bravo !!!

You are totally correct on the SHUNTING ( bleeding ) of currents. In the early decades, there was about 43 mA. drawn in the 2A3 Finals stage. The front-end stage was typically a 7B4 ( symmetrical ) triode , mu of 100, running at a low plate current. Lets say about 0.7 mA. at idle. This was possible with a DC amplifier. There existed a powerful driver stage B+ SHUNT resistor, drawing about ten milliamperes of current to ground. So there was a ratio of about 14.28 times more current in the shunt, than in the driver tube. Yes, that is brute force !!!

In addition, Dennis would have one of his own " Final Filters " , a L/C in the form of a one Ohm or less hash choke, and a carefully bypassed bank of high quality film caps of varying values ( to play full bandwidth in the highs ) , located " zero lead length ", right at the point-of-use ( The Plate Resistor of the Driver tube.) This all worked very well back then.

In more recent years, 2019, Dennis had me build a KT88 amplifier, with a 12BZ7 Driver tube pulling 1.1 mA. My earliest audio design background was with Bob Fulton being my mentor. Bob would have me build separate supplies in an amp and actively DOUBLE regulate the B+ to each use point. Such amps were impractical, six chassis for stereo, and 400 + pounds total weight. See one channel, from 1982-88 :


This above, was my first totally-from-scratch amplifier build, with help from Bob Fulton and Bob Goodman, circa 1982.

In the 2019 KT88 stereo amp, I used double ( two shunts in series ) shunting for the first time, in a DC SE amplifier. It is similar to what Bob Fulton would like. But this is KISS " double passive " in 2019 .................instead of " double active " in 1982. Simplicity rules. I also used double 5U4GB tube rectifiers for the first time in 2019, somewhat like vintage McIntosh MC-60 monoblocks did. ( Easily THE best sounding McIntosh amps of that vintage era in Dennis' highly experienced opinion ).

In 7-2019, we did an audio amplifier testing trip, driving from Kansas City to Montana, about 2,000 miles each way., We learned a LOT from the KT88 amp. The $41.00 each Electro Harmonix KT88 tubed amp out-performed in most ways, a pair of monoblock 2A3 DHT amps running VAIC mesh plates. It outperformed the DHT mesh plate 2A3s in terms of having noticeably more clarity, resolution, and dynamic contrasting. Since that visit, Dennis ( my audio mentor ) and I have been experimenting with the use of various combinations of doubled rectifiers, non DHT Finals, SHUNTS, and Dennis Fraker Final Filters.

As people can see in the topology schematic above, I am using a total of FOUR different filter sections, to both the B+ to the Driver's Plate Resistor, and the B+ to G2 of the 6005 tetrode. In each case there is Double ( in series ) SHUNTING ( lowers impedances ) and Double Dennis Fraker Final Filters ( L1/C1/L2/C2 ) to both the Ra and G2, for B+feeds.

Anyone who studies tube amp schematics should recognize, this quadruple passive filtering is singularly unique.

No one I am aware of in audio, except Dennis and I , uses this quadruple filter topology.

If you want the best possible audio resolution and definition, the B+ to the driver tube must be far far cleaner that what is currently the norm.

For over a century, amps use a single B+ series dropping resistor, and a capacitor to ground, to feed the next earlier audio stage. Audio design people seldom question this common-use topology. 99.999% of the schematics are this way !! In modern times, they will add complex ( and forced sounding ) current sources, or active tube regulation, as a band aid for what could have been done far better sounding, passively.

Grindstone, since 2021 we have a new " big plus". When I insert a 6005 into the Finals slot, it outperforms my 2019 KT88 SE DC amp easily by at least 20 %.. This is due to the design of the 6005 tube itself, and an inherent / far better transfer efficiency VS : all other tubes I have worked with . Also : the fact that ( after four 6005 builds since 2014, at Dennis' urging ) I finally figured out how to do it. It is the single 6005 stereo amp of 2021 ( on HFV ), and the upcoming " triple " 6005 amp of 2022, topology above. The first ( stereo single ) is three Watts, and the triple monoblocks will be 9 Watts per channel, give or take a Watt.

I have been waiting for someone like you, to post back to, and to have a cogent discussion.. Thank you !!!! If there is any area I have not explained satisfactorily to you, feel free to post again.

Best wishes,

Jeff

 

[Hari Iyer]

My

Well, you'd be more up-to-date than I am on these styles of builds @Hari Iyer , but one of the things Dennis seemed to do ages ago was basically bleed one PS-section away from the front end about as hard as the back-end pulled so that one stage didn't "pedal" the other's rail. I think that's sort of what Jeff seems to be doing lately (?). The semantics vary, but I think the upshot is that the bleeding is so much more dominant that the requirements of the voltage amplifier stage are basically "noise" to the total demand. I've not looked at any specifics and never got time to look hard at the last amp. Brute force always works, it just costs some heat. What I (think I?) remember is that the harder you bleed and the higher overall demand, the higher the ripple. I'm about-certain that the lower-storage and lower-resistance filters ring in-band, but haven't looked at specifics and value-judgments are less-useful. In my dotage, I have come-around to trusting listening reports more than I used to. It's just that it's all a system and it's possible that some sort of compression/expansion from a ringing supply rail could dovetail with falling primary inductance, etc--and about anything else without even considering the load. I've looked pretty hard for impedance and phase curves for that flavor of A7 and have struck-out so far. It may just be that the "damping" ordinarily provided by higher resistance or active regulation is served in the form of overpowering the demand by "shunts". I will cheer-on anyone building Anything and hanging it out there for the world to see

And maybe now a comment I thought of too late for the last one. I wonder why -- during early layout -- the "old school" methods of locating/orienting iron aren't used? Specifically, put some (low level/safe) AC across one and put your scope across another piece of iron and orient for min induction--and _that's_ where it goes and how it's oriented, etc. I know it's not on it's steel chassis yet (another strong influence), but perhaps it could be done then before the layout is designed fully.

My 2019 KT88 has this double shunt bleeding resistors before the DFFF. They bleed close to 14mA, but the driver plates require < 1 mA. Hope my assumptions are correct. So adding a CCS at the driver plate won't benefit much in this design. Removing PS noise / ripple becomes more important due to a current drain in the previous stage. Last week added a flourcent tube choke which is 1H, 75 ohms replacing the DFFF - can't say which sounds better though. Atleast the new choke don't sound bad either.

 

[drlowmu]

My
My 2019 KT88 has this double shunt bleeding resistors before the DFFF. They bleed close to 14mA, but the driver plates require < 1 mA. Hope my assumptions are correct. So adding a CCS at the driver plate won't benefit much in this design. Removing PS noise / ripple becomes more important due to a current drain in the previous stage. Last week added a flourcent tube choke which is 1H, 75 ohms replacing the DFFF - can't say which sounds better though. Atleast the new choke don't sound bad either.

Your assumptions are almost correct, 14 mA. to 4.5 MA. in your amp. ( 6FQ7 @ 4.5 mA. is 3.1 times ).

It is nice to see you experimenting and I commend you for doing so.

Dennis and I like to keep the DCR of the DFFF ( Dennis Fraker Final Filters ) low, about a single Ohm or so for each choke, as per the Dr. Halijak letter ( Dean of E.E., his 1989 letter to me was posted in full, in the previous thread - to Yogibear ).

This low DCR filtering to the Driver ( and G2 in the case of our tetrodes -- your KT88s, my 6005s ) is per direct experiences that Dennis has had, over many many amps, in maybe a 40 year time period. Your 2020 KT88 amp is your very first and only tube amp build.

Hari : Dennis has a larger budget, and far more direct tube amplifier experiences, to do things in audio, than either you and I.

He nicely became my Audio Mentor, after Bob Fulton's death in 1988. I have only known you since 2020, when you contacted me and requested amplifier design help. As much as I find you an interesting and lovely person, and I am happy to have your friendship - no end , I will tend to give Dennis my most serious attention in things audio. So, I do not " jump " at trying out each and every system change you make.

Three weeks ago, you experimented with the small low DCR chokes .... in the Dennis Fraker Final Filters to Ra and G2. That change theoretically FITS with the Dr. Halijak power supply letter, and my own understanding of power supply design.

I WILL try those choke types out . Not in the new Stereo single 6005 amps ( Chassis #1 and #2 ) which sounds good to me, but in the upcoming "triple". I will have room in the " triples' " mono blocks, to A-B this, over time. I have purchased 16 chokes of this new type, and they are now in hand.

Specification-wise, the two filter chokes in a " double " Dennis Fraker Final Filter, will change from presently, a combined total of 2.2 Ohms DCR and 0.94 mHY,..................... to ........only 0.28 Ohms DCR and 12.0 mHY. Orders of magnitude lower in DCR and higher in mHY ( inductance ). Nicely, both of the inductive specifications are changing in the right directions.

That certainly has my personal interest to try out and HEAR what it does - on my reference music playback material. Give me 4 to 6 months to fully evaluate these changes on music playback. I must build both of the " triples " first !!

Always remember, I use an ALTEC two-way front horn loaded speaker system, about 101 dB. No crossover on the 515B fifteen inch driver. Obtaining a maximum in dynamic playback resolution in amp builds - is one of the key design focuses ( along with wide bandwidth, and reliability of design, etc. )

Best wishes always, have fun.

Jeff

 

[drlowmu]

3-12-2022 .................. Mini Report ............. How to dissipate POWER in the Final's Cathode Resistor

In a two stage DC tube amp, the plate voltage of the Driver tube, is " stacked " or added to the voltage of the Output tube's Cathode, along with the bias voltage required by the Finals tube.

So, with a 6005 Output ( Finals ) tube, the cathode in a DC amp will be at about a 225 VDC potential, rather than at 13 VDC as in a conventionally designed tube amplifier. ( cap or interstage transformer coupled ).

Yes, in a way, the entire amplifier rests or references to - the DC amplifier's Cathode resistor ( Rk ). It better be a good one !!!!

In a "triple " 6005 monoblock, with each tube drawing 32 mA., we have 96 mA. at 225 VDC potential, at the top of this Rk, going to ground when using a single, shared Rk.

Ohm's Law, 0.096 A. times 225 VDC means the shared Rk must dissipate a whopping 21.6 Watts of power, continuously. THAT is a lot of power for a resistor to dissipate.

The entire DC amp depends upon this resistor, and it's 225 VDC result, in a way, as a reference voltage.

I design for high reliability, and my resistors are often four times over rated . Besides power dissipation considerations, the resistor must also SOUND good. One choice I use is an ARCOL HS series, their 50 Watt wirewound models. The manufacturer specifically states it is designed for " High PULSE " operation. Music is pulsed in nature, and I focus on achieving maximum dynamic contrasting.

Two ARCOL HS 50 Watt resistors at the standard manufactured 4.7 K Ohmic value, will give a paralleled result of 2.350 K at 100 Watts dissipation. Easily usable at 21.6 Watts. I have a new bullet-proof DIY heatsink idea, to install - below deck. Minimum of parts to assemble, and decent cooling. The ARCOL HS series happen to have a flat surface , on the tops of their power resistors. I decided to " sandwich in " these two 4.7K 50 Watt resistors, between three flat heatsinks. Take a look at a test-fitting :





Yes, thermal grease, and sanding off the anodizing at contact areas, will be applied. I feel very comfortable putting this implementation in place, inside the " Triple ". It should sound good, loaf, and not fail.


Jeff

Datasheet : http://www.arcolresistors.com/wp-content/uploads/2014/03/HS-Datasheet.pdf

 

[drlowmu]

04-09-2022 ....................................... PROGRESS REPORT

The obligation is fulfilled. The amp is destined to power Lowther Beauhorn Virtuosos.

My personal- use stereo 6005 amp, is performing consistently well. I am in awe of what a single 6005 tube can do on ALTEC VOTT A7-8s, when using this latest circuit.

I have been working lately on the first monoblock of the new 2022 amp's chassis, carefully laying it out and drilling, tapping, and chassis- punching it's 14 gauge welded steel chassis. It is destined to be named the "PFA 6005 TRIPLE"

The output stage will be Single Ended Parallel - with three carefully matched ( and circuit-balanced ) 6005 tubes.

This newest design, IMHO, deserves a separate DIY build thread of it's own. Coming up, if that is acceptable here.

Thanks for visiting.

Jeff

 

[drlowmu]

The 2022 continuation of this above thread, and the " PFA TRIPLE 6005 " design and build, can be accessed in the following thread :

The " PFA TRIPLE 6005 "..... DIY tube amplifier of 2022.

This .................... is a never-before designed and never-before built tube amplifier circuit. It is being built to be subjectively evaluated, by listening on high efficiency, large-radiating-surface loudspeakers, such as ALTEC or GPA models. Up until now, ( in my estimation and...

www.hifivision.com

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

The initial and original HFV thread, on a stereo 6605 amp's 2021 development, starting on January 8th, 2021, can be accessed here :

New Design, SE 6005 Directly Coupled Audio Amplifier

This is a current design and build project, a DIY hobby of mine for many years. It uses a 6005 FINALS tube, which has a 10 Watt (correction - 12 Watt) plate dissipation, and was introduced in the 1950s. Used in car radios and TVs as the FINAL stage, in the USA and in Russia ( an equivalent )...

www.hifivision.com

Jeff

 

[drlowmu]

Follow - Up to March 5, 2022 Post ......................." The last 1% " ................ Someone - finally DID something !!!

email exchanges...... on 05-08-2022, as follows :

Jeffrey​	1:40 PM (0 minutes ago)
to Louis,

After Hari Iyer lived with his 6FQ7 - KT88 SE DC amp design for about a year, I FINALLY got him this past week to AC orient all the individual AC feeds, inside each monoblock, by EAR, systematically. IE :

1) the main amplifier AC feed
2) The filament of the Driver tube
3) The High Voltage secondary feed to the rectifiers
4) The filaments for the two 5U4GB rectifier tubes
5) The filaments for the Finals tube.

I wrote this up on our HFV Forum here :

https://www.hifivision.com/threads/...o-6005-se-dc-amp-from-2021.88263/#post-993132 See the whole thread that followed.

I privately estimated to Hari last week, that if he followed my AC orientation post, he could become ( probably ) the second person in the entire world, to do this and reap any resultant benefit. ( I was trying to ENCOURAGE him to experiment and get his mono DC KT88 amps better optimized !!! ) It worked, Hari took the bait and he did the AC orientations by ear !!!!!!

As you can see below, he reports to me today - " a 15 to 20% improvement in sound quality ( SQ ) overall for his Hi Fi system. "

Now, I have to get him to write additionally on the HiFi Vision Forum, so that others will " open their minds " and perhaps learn and benefit from this now-corroborated result !!!

<deleted by mod>

How long will it take, for the rest of the world, to " wake up " to the first report ever ( likely ) of internal AC orientation , as outlined on Hi Fi Vision 3-5-22, and referenced to above ?? Maybe never !!!

Ohh well, Hari and I will certainly have listening FUN at home !!! Hari, care to tell others how pleased you are now ??


Jeff

---------- Forwarded message ---------
From: Hari Iyer <XXXXXXXX @gmail.com>
Date: Sat, May 7, 2022 at 10:31 PM
Subject: Re: You OK
To: Jeffrey , <XXXXXXXX @gmail.com>

Yes, I am fine. It took me 8+ hours to fix the AC orientation of both the monoblocks. The results are very obvious and conclusive on my turntable and not very much on my Marantz UD-7007 Blueray player.
Left monoblock only the 400vac+400vac was swapped.
On the Right monoblock the driver filament, the 400vac+400vac and the rectifier 5vac required swapping.

I think the AC orientation gives around 15% to 20% of SQ improvement and not the final 1% as mentioned in your post. Large benefits in center image focus by removing phase errors (if any), holographic and detailed sound stage and transparency is very obviously noticed on turntable.

Thanks once again for the tip and more so for continuously following up with me for that

.

BR,



On Sat, 7 May 2022, 23:52 Jeffrey, < XXXXXXXXX @gmail.com> wrote:

Hari :

It's about 1 AM your time so you may be sleeping. Had not heard back from you. Knowing the VACs are LETHAL, are you OK ????

Jeff

 

[Hari Iyer]

Yes Jeff. I am more than 100% satisfied with the outcome. I wasted 1 year of my audio life being lazy not doing this before. How stupid i could be. Better late than never. Those who believe this is snake oil are either lying or don't know anything. Period.

 

[drlowmu]

Yes Jeff. I am more than 100% satisfied with the outcome. I wasted 1 year of my audio life being lazy not doing this before. How stupid i could be. Better late than never. Those who believe this is snake oil are either lying or don't know anything. Period.

Dear Hari,

It is not good to be so harsh, " are either lying or don't know anything ".... is too harsh. ' Not a way to win friends, or make your point, I have learned.

I would rather use softer terms like " unimaginative, or unwilling to trust their ears, or maybe most of all ..... - unwilling to experiment. "

FYI, prior to mid-2019, I honestly do not think anyone even knew about the Multiple Internal AC Polarity Orientation . Today, I bet you easily...... 99.9 percent in audio are fully unaware.

Multiple Internal AC Polarity Orientation is a sonic result which was initially heard - with a newly made SE DC KT88 amp. I brought this new SE DC amplifier to Livingston, Montana, USA ( a 4,000 mile round-trip drive ) in 7-2019. This was an amplifier A-B session - for my audio Mentor to hear, and several other very nice audio friends.

You state : " Wasted 1 year ". ..... I do know how you feel right now.

In 2015-2017 I feel I wasted two years of my audio life building Type 45 ST tube SE DC amps.

But ....... I discovered something quite obvious and valuable to know - that the 45 ST tube itself, despite being highly touted, is simply not ever good enough, when playing speakers full range. We live and we learn !!!

Thank you for reporting to HFV F.M.s of your new listening results !!

Jeff

 

[drlowmu]

This..............


Then.........this


A Classic Example of "Oxymoron"

Hello Kannan,

Well thank you - for reproducing my entire first quote, which I feel was balanced.

I seek to comment, to your above post.

Equally, in both quotes, I was describing / expressing things that I have many times experienced. These topics are well known to me personally.

YMMV. ..... Very fine. ........Thanks for expressing your perception, and doing your post. " Esse est percipi. "

Honestly to everyone reading this, I erred in my judgement, by specifically bringing up Gary's name. I apologize to all.

This was hard to resist. Especially after knowing him for 44 years, having him post onto HFV as he does, and with him being found 100% wrong ( independently corroborated on HFV - last week ) .

Enough of this personal stuff !! I am through discussing the post by R to R, which well-served his intent to discredit me.


- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

What is very positive here .... in audio and on HFV ??

We just have been shown a way, now have brand NEW knowledge, in SE tube amps, and in Push Pull, to further optimize their music playback performance. How ? By systematically listening to individual internal AC polarity connections, ( which are typically haphazardly attached at the time of manufacture.) This new optimization technique is done by aligning all of these various internal AC connections, individually by ear.

Almost free ! Tools required - a soldering iron, two well insulated clip leads.

CAUTION, most of these AC feed points and voltages below deck in a tube amplifier truly are " instantly lethal ". The UTMOST in safety and care must be taken.

This work is best left to the most experienced DIYers or experienced technicians. A lesser experienced tube amplifier owner should ideally attend the session, and DO partake in the A vs: B music listening evaluations, for each connection.

Quite an enlightening listening experience..... as Hari and I will both attest to.

As usual, hearing is believing.

Continue optimizing your amps, and keep on doing positive things !! If I can assist any, call upon me.

Kindly refer to my " The Last 1% " HFV post of 3-5-22, and Hari Iyer's direct experiences. FYI, Individual Internal AC Polarity Optimization ( " IIACPO " ) can subjectively result in quite a bit more, than a 1% listening improvement

Jeff

 

[RtoR King]

Enough of this personal stuff !! I am through discussing the post by R to R, which well-served his intent to discredit me.

Don't try to make me the bad guy here. The moderators reinstated your membership here as well as allowing you to start this thread on the promise there would be no more bashing of people or established theory. You have no scientific research to back up your claims. The fact that one of your loyal and devoted followers tried your suggestions and reported positive results does not rule out placebo effect.

It's quite OK to announce what you hear and for others here to do the same. But to use that as a ticket to belittle 100 years of formal electrical engineering knowledge is not OK. As you admittedly lack the electronics theory to thoroughly evaluate this phenomenon you hear, the next logical step is for you to embrace the knowledge of the engineering community to study further and potentially find a plausible clause. Instead you would rather claim we are narrowly educated idiots because we ask for scientific data to support YOUR findings. That's not a good way to enlist our help.

 

[Gudebrod audio]

Follow - Up to March 5, 2022 Post ......................." The last 1% " ................ Someone - finally DID something !!!

email exchanges...... on 05-08-2022, as follows :

Jeffrey​	1:40 PM (0 minutes ago)
to Louis,

After Hari Iyer lived with his 6FQ7 - KT88 SE DC amp design for about a year, I FINALLY got him this past week to AC orient all the individual AC feeds, inside each monoblock, by EAR, systematically. IE :

1) the main amplifier AC feed
2) The filament of the Driver tube
3) The High Voltage secondary feed to the rectifiers
4) The filaments for the two 5U4GB rectifier tubes
5) The filaments for the Finals tube.

I wrote this up on our HFV Forum here :

https://www.hifivision.com/threads/...o-6005-se-dc-amp-from-2021.88263/#post-993132 See the whole thread that followed.

I privately estimated to Hari last week, that if he followed my AC orientation post, he could become ( probably ) the second person in the entire world, to do this and reap any resultant benefit. ( I was trying to ENCOURAGE him to experiment and get his mono DC KT88 amps better optimized !!! ) It worked, Hari took the bait and he did the AC orientations by ear !!!!!!

As you can see below, he reports to me today - " a 15 to 20% improvement in sound quality ( SQ ) overall for his Hi Fi system. "

Now, I have to get him to write additionally on the HiFi Vision Forum, so that others will " open their minds " and perhaps learn and benefit from this now-corroborated result !!!

Gee, Dr. Gary ( Sokolich ) with both an EE degree and PhD degree, chided me on HFV by writing there would be absolutely no difference at all. Narrowly educated people such as EEs often do highly unimaginative and lousy jobs in audio design, in their personal home set ups and in their own system implementations. Some certainly do not !!! I often giggle to myself, at what some of them will sometimes will tell me.

How long will it take, for the rest of the world, to " wake up " to the first report ever ( likely ) of internal AC orientation , as outlined on Hi Fi Vision 3-5-22, and referenced to above ?? Maybe never !!!

Ohh well, Hari and I will certainly have listening FUN at home !!! Hari, care to tell others how pleased you are now ??


Jeff

---------- Forwarded message ---------
From: Hari Iyer <XXXXXXXX @gmail.com>
Date: Sat, May 7, 2022 at 10:31 PM
Subject: Re: You OK
To: Jeffrey , <XXXXXXXX @gmail.com>

Yes, I am fine. It took me 8+ hours to fix the AC orientation of both the monoblocks. The results are very obvious and conclusive on my turntable and not very much on my Marantz UD-7007 Blueray player.
Left monoblock only the 400vac+400vac was swapped.
On the Right monoblock the driver filament, the 400vac+400vac and the rectifier 5vac required swapping.

I think the AC orientation gives around 15% to 20% of SQ improvement and not the final 1% as mentioned in your post. Large benefits in center image focus by removing phase errors (if any), holographic and detailed sound stage and transparency is very obviously noticed on turntable.

Thanks once again for the tip and more so for continuously following up with me for that

.

BR,



On Sat, 7 May 2022, 23:52 Jeffrey, < XXXXXXXXX @gmail.com> wrote:

Hari :

I’ve also learned the exact same thing from Jeff. Weird, but it’s true this on my KT120seul mono block build. I then proceeded to do the same testing on my preamp that has 3 transformers in it. Simply amazing at which the clarity and stage became so much more accurate, everything Hari describes is true a solid adjustment. Thanks Jeff for sharing! Others just need to try it and listen.