Regrettably, I am once again in the unpleasant position of having to correct yet another litany of your incorrect assumptions and insults. For starters, I would like to point out that the "Bravura solid state early IC preamp" as you call it, is the exact same Tuttle-designed, Fulton-modified dual-mono version of the Bravura that you have been using and in love with for the past forty years. Secondly, my HK430 receiver, which has independent power supplies for the right and left channels, is highly modified, Specifically, every stage in the power amp sections of the HK430 is hard regulated. That's a total of twelve independent voltage regulators and associated filtering for the two channels. Because of the use of multiple regulators, there is no inter-stage coupling in the HK430 via the B+ and B- lines. Additionally, because of the independent power supplies and the hard regulation that is used in the Bravura as well as in my modified HK-430, it doesn't matter how the two-prong AC plugs are installed in wall outlet,
New Design, SE 6005 Directly Coupled Audio Amplifier
- Thread starter drlowmu
- Start date
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RtoR King
Active Member
MapleShade Audio?
I remember that quack!
He sold RCA connectors made from Home Depot copper tubing.
He made bi-wire bypass jumpers, you know, those brass straps that are attached to speaker bi-wire terminals if you are not bi-wiring. Anyway he sold two copper strips clearly hand cut from a tarnished piece of copper with arrows drawn on with a Sharpie pen indicating proper "audio" direction and which one was "optimized" for (+) or (-).
https://shop.mapleshadestore.com/Clearview-Biwire-Jumpers_p_1187.html
More alarming though, he sold AC power cords with plugs made from wood blocks and the "hand crafted" prongs just sticking out of the wood. His cord material was copper strips spaced apart on cellophane tape. There was enough outcry about the safety of his AC products that he finally had to drop them from his product line - if you can even call it that!
Figures you would worship an audio charlatan like that.
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Apparently, you haven't recently checked out the Mapleshade Audio web site which is quite amusing, For example the following is at the top of their list of bizarre and nonsensical recommendations:
� Lift all speaker, power, and interconnect wires 8" off any carpet or plastic tile. Use string, wood, cardboard, or 20 ounce Styrofoam cups for temporary props. You�ll think you�ve pulled horse blankets off your speakers.
https://www.mapleshadestore.com/upgrades_cable.php
https://web.archive.org/web/20220104011353/https://www.mapleshadestore.com/upgrades_cable.php
You mean sanity vs lunacy. eg "an inch of bad wire can ruin the musical experience"
RtoR King
Active Member
Regulated vs non-regulated power supplies in audio equipment have many pros and cons. An interesting engineering study as audio power amplification is one of the few areas of electronics that don't necessarily always benefit from power supply regulation. Even line level gear can have issues with regulator output impedance at higher audio frequencies. That would be a great discussion if we can keep the junk science out of it.
You too, just like RtoR King today, are getting weaker and weaker in your posting. But nicely, you were not too rude above, this time. GREAT !!
Laugh out loud, it matters NOT if a piece is regulated or unregulated, AC plug polarity, and how it effects the power transformers windings and field alignments, is a factor always in play. Only a AUDIO ( not electronics ) NOVICE would ever write the last sentence in your above post. BEAUTIFUL !!!
Ohh no, I am wrong, besides an audio novice, a BSEE and PhD, ( you ), would also foolishly author that.
A perfect example of you NOT knowing basic audio set up, oblivious, as has been the case with you, for the 42 years or so I have known you.
Allow me to address the Bravura dual mono preamplifier, that at least twice, you write " I was in love with ". Yes, in the late 70s, early 80s, it was a very nice unit. I never had the extra funds, in the 90s, 00s, 10s or 20s, to replace the unit. Also, it was originally worked-upon / modded, by my beloved mentor, Mr. Fulton so there was a sentimental attachment there.
In about 2021, you were shipped my non-working Bravura, and got it fixed, at you home lab. You did not charge me, one audiophile, helping another. Thank you Gary. You even replaced, at my request, several RCA jack sets . The problem was a solder glob had landed on the PC board, from someone else's work ( Not mine ). You had all the B & K measuring equipment and knowledge to fix it, Thank YOU . On your bench :
![GARYs LAB 20191112_162200[1] (1).jpg](https://www.hifivision.com/data/attachments/52/52975-7586a97090c78cc049989d3eebd6450f.jpg?hash=dYapcJDHjM "GARYs LAB 20191112_162200[1] (1).jpg")
In mid to late 2021, I happened to A-B my Bravura, against a 12AX7 Trevor Lees Cascode Phono Preamp. On my reference baritone male voice, for the first time in 40 years, the baritone's voice sounded like a real human being, and not fake in any way. Nicely, another good audio friend, GAVE me that same Trevor Lees preamp, to use for as long as I wanted.
The Trevor Lees preamp, built in a DYNA PAS-3 chassis, can be easily duped and upgraded by me. I actually have designed a different tube phone / line stage unit, and my intent in mid 2022 is to build an all-out tube preamp, using most of the design techniques applied to this 6005 amp build, highlighted in this thread.
Yes, I loved the Bravura, and I was cheap, so I never tried to replace it. That one A-B of the baritone's voice, has caused me to park the solid state Bravura unit on my shelf, and I will never use it again. That is the correct full story.
- - - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - -- - - - - - -- - - - - - - - - - -
There is one other lovely example, of you being good at EE, and terrible at audio set up and design. Every part you add to a circuit, has a sound and a sonic effect. The best sounding amps and speakers, often will have a simple circuit. You have added 12 solid state regulators ( I imagine basic three terminal devices ) to your power amp. Each and every one of them, besides regulating, had a sonic signature, added to the final result No free lunch. You obviously do not consider this. Of course hard regulation is ideal, but HOW does the active regulation sound ?
The EE theoretical side in you, got the best of the need to consider sonics, which you seemingly never ever considered. Like AC plug polarity, you may automatically say about ACTIVE regulators " No one can hear that ". Did you try ? Of course not. The BSEE in you, erased that from your mind, your EE mindset totally screwed you Gary, from the very ONSET. It is all there, written, plain to see, in your post at the top of this discussion.
My 1982-85 built huge TRIODE MUSIC AMP, was double actively regulated. Twelve active solid state B+ regulators, for stereo. There was a small audible sonic thumbprint, and the discreet regulators were not 100% reliable. I learned from practical experience, never again THAT way !! The SHUNTING is just three parts, two resistors and a film cap, carefully, artfully chosen, by listening !! Live and learn.
- - - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - - - - -- - - - - - - - -- - -- - - - - -
I am so happy you did the above post. An EE is not always good doing audio !! Give certain people enough rope, and they will hang themselves. Well done Gary. Now go away, stop interfering in this thread, with your non productive trolling. Get a life, now that you are retired, find something else to do, rather than logging onto HFV all day long.
Back to Chassis two, Its going slowly today.
Jeff
Laugh out loud, it matters NOT if a piece is regulated or unregulated, AC plug polarity, and how it effects the power transformers windings and field alignments, is a factor always in play. Only a AUDIO ( not electronics ) NOVICE would ever write the last sentence in your above post. BEAUTIFUL !!!
Ohh no, I am wrong, besides an audio novice, a BSEE and PhD, ( you ), would also foolishly author that.
A perfect example of you NOT knowing basic audio set up, oblivious, as has been the case with you, for the 42 years or so I have known you.
Allow me to address the Bravura dual mono preamplifier, that at least twice, you write " I was in love with ". Yes, in the late 70s, early 80s, it was a very nice unit. I never had the extra funds, in the 90s, 00s, 10s or 20s, to replace the unit. Also, it was originally worked-upon / modded, by my beloved mentor, Mr. Fulton so there was a sentimental attachment there.
In about 2021, you were shipped my non-working Bravura, and got it fixed, at you home lab. You did not charge me, one audiophile, helping another. Thank you Gary. You even replaced, at my request, several RCA jack sets . The problem was a solder glob had landed on the PC board, from someone else's work ( Not mine ). You had all the B & K measuring equipment and knowledge to fix it, Thank YOU . On your bench :
In mid to late 2021, I happened to A-B my Bravura, against a 12AX7 Trevor Lees Cascode Phono Preamp. On my reference baritone male voice, for the first time in 40 years, the baritone's voice sounded like a real human being, and not fake in any way. Nicely, another good audio friend, GAVE me that same Trevor Lees preamp, to use for as long as I wanted.
The Trevor Lees preamp, built in a DYNA PAS-3 chassis, can be easily duped and upgraded by me. I actually have designed a different tube phone / line stage unit, and my intent in mid 2022 is to build an all-out tube preamp, using most of the design techniques applied to this 6005 amp build, highlighted in this thread.
Yes, I loved the Bravura, and I was cheap, so I never tried to replace it. That one A-B of the baritone's voice, has caused me to park the solid state Bravura unit on my shelf, and I will never use it again. That is the correct full story.
- - - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - -- - - - - - -- - - - - - - - - - -
There is one other lovely example, of you being good at EE, and terrible at audio set up and design. Every part you add to a circuit, has a sound and a sonic effect. The best sounding amps and speakers, often will have a simple circuit. You have added 12 solid state regulators ( I imagine basic three terminal devices ) to your power amp. Each and every one of them, besides regulating, had a sonic signature, added to the final result No free lunch. You obviously do not consider this. Of course hard regulation is ideal, but HOW does the active regulation sound ?
The EE theoretical side in you, got the best of the need to consider sonics, which you seemingly never ever considered. Like AC plug polarity, you may automatically say about ACTIVE regulators " No one can hear that ". Did you try ? Of course not. The BSEE in you, erased that from your mind, your EE mindset totally screwed you Gary, from the very ONSET. It is all there, written, plain to see, in your post at the top of this discussion.
My 1982-85 built huge TRIODE MUSIC AMP, was double actively regulated. Twelve active solid state B+ regulators, for stereo. There was a small audible sonic thumbprint, and the discreet regulators were not 100% reliable. I learned from practical experience, never again THAT way !! The SHUNTING is just three parts, two resistors and a film cap, carefully, artfully chosen, by listening !! Live and learn.
- - - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - - - - -- - - - - - - - -- - -- - - - - -
I am so happy you did the above post. An EE is not always good doing audio !! Give certain people enough rope, and they will hang themselves. Well done Gary. Now go away, stop interfering in this thread, with your non productive trolling. Get a life, now that you are retired, find something else to do, rather than logging onto HFV all day long.
Back to Chassis two, Its going slowly today.
Jeff
Active regulation on each amplifier stage, which is what I have, is light years and orders of magnitude better than what your build has which is no regulation at all. You frequently say that we all listen to modulated power suppliesy. But, the fact of the matter is that your build is the embodiment of that very shortcoming. So, the next time that you comment about listening to modulated power supplies, realize that you are referring to your build and your listening and not to mine.
In order for a power supply in an audio amplifier to provide a low impedance over the entire audio frequency range, a two-state solution is needed. That solution involves the use of an active regulator to provide a low impedance at the lower frequencies and the use of appropriate combination of capacitors to provide a low impedance at the higher frequencies.'' Capacitors alone can't do the trick because large capacitors, which would be needed to provide a sufficiently low impedance at the low frequency end have low self-resonant frequencies and turn inductive at the higher frequencies.
RtoR King
Active Member
Agreed! And based on post #330, it would be nice to have some deeper discussion as to why without all the non-ancillary voodoo!
surfatwork
Well-Known Member
What started out as a build thread has now descended into a morass of name calling, allegations and counter allegations. Maybe it's time the mods stepped in. It's car crash entertainment, no doubt, but reflects poorly on our forum, I think. The basic point that subjectivists and objectivists won't agree has been established many pages back in any case.
1-18-2022 ................. MINI Photo UPDATE...............RECENT BUILD PROGRESS...................................Chassis # 2
Above, on 1-14, this above chassis was missing a DF FF ( Dennis Fraker Final Filter - B+ ) for the G2 requirement on the left side of the photo. Notice the blank space, VS the right side. The double B+ Final Filter has been installed since then, and is working OK.
Above, arrows denoted wiring ( of the 6005 Cathode ) that is doubled up 19 AWG Wonder Wire, available from Michael Percy Audio in the USA..
Below, Two added film caps, ( encircled below in double yellow ) are used to bypass each 6005's Cathode resistor. The two small value caps are located closer to the actual Rk ( or Cathode Resistor ), to minimize lead length for wide bandwidth, yet maintain a certain distance from the HOT heatsink.
These two caps assist in the proper high frequency playback of musical instruments. These are connected in parallel to the three film caps denoted ( Main, Mid-bass and Midrange ) bypasses, shown in the very first photo.
The use of five film caps total, of differing values and types to bypass a Cathode Resistor, is done only by my audio mentor, and me, to my best knowledge. Our technique is pretty much unique . Typical amplifiers just use a "quality" electrolytic, which I subjectively find does not favorably compare.
Regards to all.
Jeff
Above, on 1-14, this above chassis was missing a DF FF ( Dennis Fraker Final Filter - B+ ) for the G2 requirement on the left side of the photo. Notice the blank space, VS the right side. The double B+ Final Filter has been installed since then, and is working OK.
Above, arrows denoted wiring ( of the 6005 Cathode ) that is doubled up 19 AWG Wonder Wire, available from Michael Percy Audio in the USA..
Below, Two added film caps, ( encircled below in double yellow ) are used to bypass each 6005's Cathode resistor. The two small value caps are located closer to the actual Rk ( or Cathode Resistor ), to minimize lead length for wide bandwidth, yet maintain a certain distance from the HOT heatsink.
These two caps assist in the proper high frequency playback of musical instruments. These are connected in parallel to the three film caps denoted ( Main, Mid-bass and Midrange ) bypasses, shown in the very first photo.
The use of five film caps total, of differing values and types to bypass a Cathode Resistor, is done only by my audio mentor, and me, to my best knowledge. Our technique is pretty much unique . Typical amplifiers just use a "quality" electrolytic, which I subjectively find does not favorably compare.
Regards to all.
Jeff
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Tie WRAPS & WIRE-BUNDLING - removal :
An October 30, 2020 THANE, INDIA F.M.'s ACTUAL listening experience & report :
Two " hands-on " D.I.Y. HFV Forum Members are posting below . ( Susnick is USA based. Florida. )
Jeff
An October 30, 2020 THANE, INDIA F.M.'s ACTUAL listening experience & report :
Two " hands-on " D.I.Y. HFV Forum Members are posting below . ( Susnick is USA based. Florida. )
Jeff
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1-20-2022 .................... A Positively STUNNING new AUDIO DISCOVERY .......................... GTOs on the Rk bypass
Earlier in this thread, I described how in 2017, I became what I THINK is the first person in the USA to ever use GTO caps in an audio amplifier. ( I bought GTOs from a European eBay seller, who told me he had them in his 300B DIY amplifier, and others in Europe used them primarily to build TESLA COILS. )
Since 2017, I have always been using GTO caps as a "bypass" across my main power supply caps ( C1 and C2 in a L1/C1/L2/C2 B+ filter ) to the Output tubes. The output tubes are being supplied B+ by the Output transformer's Primary leads .)
As previously described, my subjective view is " no other cap, in ALL of audio, can define the leading edge of transients, crystal clear, razor sharp, on-time, or as precisely, as can the use of these imported 5uF GTOs.
GTOs performed similarly, subjectively, in the crossover of my ALTEC VOTT A7-8 speakers. Just wonderful to hear.
Two nights ago, while lying in bed, thinking about tube amps and their design, I got a bright idea. Why, since 2017, have I been confining my use of GTOs to the B+ power supply and to my A7-8 crossovers ? WHY NOT TRY IT on the OUTPUT TUBE'S CATHODE RESISTOR BYPASS, in addition to the "usual" 5 film cap Rk bypass bundle / bypass module ?????????????
Last night, I clip leaded in two GTOs, one for each channel, into the Rk ( Cathode Resistor ) bypass Module, of each 6005 Output tube. VIOLA !!!!!! Just as I theorized, the results, my subjective listening improvement was positively STUNNING !!!
I am pretty sure, no one has ever done, or heard this result in an audio amplifier before. The caps are awfully large ~!!
So audio history was made in my own apartment's living room, last night .
For this 6005 stereo amp, ( unless very neatly installed top-side, and carefully umbilicaled to the below-deck Rks ), there is NO under-chassis room to fit these two extra GTO caps to this build.
Also, I am very sure the Input stage, where MOST of the amp's gain is derived, will ALSO greatly benefit from a separate GTO across it's cathode resistor bypass Module !!! Notice my wording please........ " I am very sure " !!!! Yes.... of course !
The discovery of what I heard last night, leads me to the very next DIY amp build.
If I build 6005 monoblocks, there will be enough chassis room for four GTOs per mono chassis. Do you understand how they will be employed. ??
Two as a C1 and C2 bypasses in the ( L1/C1/L2/C2 ) power supply. A third GTO across the cathode resistor of the 6005 output tube, and a fourth GTO across the Input tube's Rk bypass bundle !! This I know will be world class fidelity, that no one I am aware of in audio has ever thought of ( or knew ) to do !! ( Or has ever heard ). One must think out of the box.
Am I arrogant?? I don't think so. This is my unique audio discovery. I will make the new monos a TRIPLE 6005 output stage, to "open"- up it's use to below 101 dB speakers. I will also use a different triode Input tube.
The new triode Input tube will have far more drive, excellent linearity, and even more detail retrieval than the lovely 6N23P-EV, currently used !!! A unique large gold - plated frame-grid Input tube !!! Amp will have perhaps 9 Watts out, instead of 3, but dynamics and audio resolution - like no one in this world has ever heard. Two 6 Ohms chokes - LOL. I wish you all reading, could have heard, precisely what I heard last night!! Hearing is believing.
Stay tuned. let us finish this stereo 6005 thread / project first, with less of this silly trolling !!!
Jeff
Earlier in this thread, I described how in 2017, I became what I THINK is the first person in the USA to ever use GTO caps in an audio amplifier. ( I bought GTOs from a European eBay seller, who told me he had them in his 300B DIY amplifier, and others in Europe used them primarily to build TESLA COILS. )
Since 2017, I have always been using GTO caps as a "bypass" across my main power supply caps ( C1 and C2 in a L1/C1/L2/C2 B+ filter ) to the Output tubes. The output tubes are being supplied B+ by the Output transformer's Primary leads .)
As previously described, my subjective view is " no other cap, in ALL of audio, can define the leading edge of transients, crystal clear, razor sharp, on-time, or as precisely, as can the use of these imported 5uF GTOs.
GTOs performed similarly, subjectively, in the crossover of my ALTEC VOTT A7-8 speakers. Just wonderful to hear.
Two nights ago, while lying in bed, thinking about tube amps and their design, I got a bright idea. Why, since 2017, have I been confining my use of GTOs to the B+ power supply and to my A7-8 crossovers ? WHY NOT TRY IT on the OUTPUT TUBE'S CATHODE RESISTOR BYPASS, in addition to the "usual" 5 film cap Rk bypass bundle / bypass module ?????????????
Last night, I clip leaded in two GTOs, one for each channel, into the Rk ( Cathode Resistor ) bypass Module, of each 6005 Output tube. VIOLA !!!!!! Just as I theorized, the results, my subjective listening improvement was positively STUNNING !!!
I am pretty sure, no one has ever done, or heard this result in an audio amplifier before. The caps are awfully large ~!!
So audio history was made in my own apartment's living room, last night .
For this 6005 stereo amp, ( unless very neatly installed top-side, and carefully umbilicaled to the below-deck Rks ), there is NO under-chassis room to fit these two extra GTO caps to this build.
Also, I am very sure the Input stage, where MOST of the amp's gain is derived, will ALSO greatly benefit from a separate GTO across it's cathode resistor bypass Module !!! Notice my wording please........ " I am very sure " !!!! Yes.... of course !
The discovery of what I heard last night, leads me to the very next DIY amp build.
If I build 6005 monoblocks, there will be enough chassis room for four GTOs per mono chassis. Do you understand how they will be employed. ??
Two as a C1 and C2 bypasses in the ( L1/C1/L2/C2 ) power supply. A third GTO across the cathode resistor of the 6005 output tube, and a fourth GTO across the Input tube's Rk bypass bundle !! This I know will be world class fidelity, that no one I am aware of in audio has ever thought of ( or knew ) to do !! ( Or has ever heard ). One must think out of the box.
Am I arrogant?? I don't think so. This is my unique audio discovery. I will make the new monos a TRIPLE 6005 output stage, to "open"- up it's use to below 101 dB speakers. I will also use a different triode Input tube.
The new triode Input tube will have far more drive, excellent linearity, and even more detail retrieval than the lovely 6N23P-EV, currently used !!! A unique large gold - plated frame-grid Input tube !!! Amp will have perhaps 9 Watts out, instead of 3, but dynamics and audio resolution - like no one in this world has ever heard. Two 6 Ohms chokes - LOL. I wish you all reading, could have heard, precisely what I heard last night!! Hearing is believing.
Stay tuned. let us finish this stereo 6005 thread / project first, with less of this silly trolling !!!
Jeff
Attachments
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The "what" which is clearly your only concern, is not just important. It really is the bottom line. However, the "why" is also important. And, that's because the "why" could provide knowledge that might lead to the identification of a part that is as good and possibly better and that is the size of your little toe instead of the size of your foot, and with a commensurate reduction in cost. That said, your experiment involving the use of the GTO capacitor as a cathode bypass clearly refutes your repeated assertions that its peak current capability is responsible for the sonic improvement that you claim that it provides.1-20-2022 .................... A Positively STUNNING new AUDIO DISCOVERY .......................... GTOs on the Rk bypass
Earlier in this thread, I described how in 2017, I became what I THINK is the first person in the USA to ever use GTO caps in an audio amplifier. ( I bought GTOs from a European eBay seller, who told me he had them in his 300B DIY amplifier, and others in Europe used them primarily to build TESLA COILS. )
Since 2017, I have always been using GTO caps as a "bypass" across my main power supply caps ( C1 and C2 in a L1/C1/L2/C2 B+ filter ) to the Output tubes. The output tubes are being supplied B+ by the Output transformer's Primary leads .)
As previously described, my subjective view is " no other cap, in ALL of audio, can define the leading edge of transients, crystal clear, razor sharp, on-time, or as precisely, as can the use of these imported 5uF GTOs.
GTOs performed similarly, subjectively, in the crossover of my ALTEC VOTT A7-8 speakers. Just wonderful to hear.
Two nights ago, while lying in bed, thinking about tube amps and their design, I got a bright idea. Why, since 2017, have I been confining my use of GTOs to the B+ power supply and to my A7-8 crossovers ? WHY NOT TRY IT on the OUTPUT TUBE'S CATHODE RESISTOR BYPASS, in addition to the "usual" 5 film cap Rk bypass bundle / bypass module ?????????????
Last night, I clip leaded in two GTOs, one for each channel, into the Rk ( Cathode Resistor ) bypass Module, of each 6005 Output tube. VIOLA !!!!!! Just as I theorized, the results, my subjective listening improvement was positively STUNNING !!!
I am pretty sure, no one has ever done, or heard this result in an audio amplifier before. The caps are awfully large ~!!
So audio history was made in my own apartment's living room, last night .
For this 6005 stereo amp, ( unless very neatly installed top-side, and carefully umbilicaled to the below-deck Rks ), there is NO under-chassis room to fit these two extra GTO caps to this build.
Also, I am very sure the Input stage, where MOST of the amp's gain is derived, will ALSO greatly benefit from a separate GTO across it's cathode resistor bypass Module !!! Notice my wording please........ " I am very sure " !!!! Yes.... of course !
The discovery of what I heard last night, leads me to the very next DIY amp build.
If I build 6005 monoblocks, there will be enough chassis room for four GTOs per mono chassis. Do you understand how they will be employed. ??
Two as a C1 and C2 bypasses in the ( L1/C1/L2/C2 ) power supply. A third GTO across the cathode resistor of the 6005 output tube, and a fourth GTO across the Input tube's Rk bypass bundle !! This I know will be world class fidelity, that no one I am aware of in audio has ever thought of ( or knew ) to do !! ( Or has ever heard ). One must think out of the box.
Am I arrogant?? I don't think so. This is my unique audio discovery. I will make the new monos a TRIPLE 6005 output stage, to "open"- up it's use to below 101 dB speakers. I will also use a different triode Input tube.
The new triode Input tube will have far more drive, excellent linearity, and even more detail retrieval than the lovely 6N23P-EV, currently used !!! A unique large gold - plated frame-grid Input tube !!! Amp will have perhaps 9 Watts out, instead of 3, but dynamics and audio resolution - like no one in this world has ever heard. Two 6 Ohms chokes - LOL. I wish you all reading, could have heard, precisely what I heard last night!! Hearing is believing.
Stay tuned. let us finish this stereo 6005 thread / project first, with less of this silly trolling !!!
Jeff
View attachment 66384
........................ A HANDY GUIDE ............................ 01-22-2022
Jeff
Jeff
I had lots of time today to do this,
1. Monoblock1 was 2.6v and reverse 5.6v
2.Monoblock2 was 2.4vand reverse 6.1v
Corrected the wiring of the both to show 2.6v
The field coil power supply showed 13v and always had a micro hum when i put my ear on the speaker cone. I connected the -ve rail to earth via a 0.1uF, 400v polyester film capacitor and the voltage dropped to 1.2v. Now the hum from the field coil has vanished to zero after this mod.
The blueray player did not show any difference by reversing the power terminal - perhaps due to the SMPS power supply used.
Did not do any critical listening to check the outcome.
Dear Hari,
After you do critical listening of familiar source material, it would be very nice to have you report subjectively, as to what you heard, IF anything at all.
The above procedure I posted above in #330 treats each audio piece as a SINGLE entity, AC orientation wise .
However, each of your KT88 SE DC mono blocks has SEVERAL AC feeds in it, and these orientations should be listened to individually, BOTH ways, and wired optimally, NOT from overall measured hum as one feed can mask the other, but subjectively, each as to what way EACH sounds best to you. Its OK to use digital source, and a remote to replay say a one minute stretch of complex music, back and forth, back and forth. ( I use Steve Clarke CD, " Solo Drums " ) Use clip leads. DECIDE what sounds best. and neatly solder THAT orientation into the circuit !!!
I personally tend to prefer aural orientation, over looking at scope wave forms, ( another valid approach ) because in the end, how it SOUNDS the best, is really what matters the most.
Here is how I would optimize your amp, each mono block, in this precise order :
1) Driver tube 6.3 VAC Filament's feed ( sensitive , its high gain )
2) Main Power Transformer's High Voltage SECONDARY ( ~800 VAC....do PRACTICE SAFETY 100% + !!!!!!!! )
3) The 5 VAC feeding your double 5U4GB directly heated rectifiers ( can be sensitive )
4) The 6.3 VAC feeding your Output tube's filament ( KT88 ). Least sensitive.
How many Audio Manufacturers take the time to do this?? Any ?? I really don't know, other than my Mentor.
Anyone can review the initial descriptions of this, in relationship to this thread's DIY 6005 Amp Build, by reviewing Page 12, Posts 226, 229 and 231.
New Design, SE 6005 Directly Coupled Audio Amplifier
Joe Roberts also prefers using a Altec 414 as full range with a Altec 802 in a WE 32 horn. No crossover. I think just one simple cap.
www.hifivision.com
Jeff
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So, how about making the above-described measurements on your previously beloved Tluttle-designed Fulton-modified dual-mono Bravura preamp as well as on your newly-beloved Trevor Lees preamp, and posting the measurement results?
RtoR King
Active Member
About AC Line RFI capacitors:
In transformer powered gear, a legacy practice was to connect around a .01uf from one side of the AC line to the chassis or signal ground, sometimes also paralleled with a high value resistor, 1 meg ohm or higher. This was to short out any RFI present on the AC line. RFI could be a strong AM radio station or a house vacuum cleaner or other appliance utilizing a brush motor. This technique was effective.
In the 1960s and prior, this capacitor was typically a wax paper 600vdc, As we know over time paper capacitors develop high leakage and this creates a safety hazard. In vintage component circles that is often referred to as the "death capacitor" and must always be replaced. In later generation gear this was changed to a mylar or polyester 600vdc capacitor. However while these caps do not suffer from aging leakage, they can fail shorted thus again creating a shock hazard by putting one side of the AC line to the signal ground at full short circuit current availability. Consumer gear still used this simple RFI filter well into the 1990s on audio and video products.
Because of this type of capacitor failure, shorting, UL and other world safety agencies stepped in and today we have type X and type Y capacitors.
Type X is for line to line connection and type Y is for line to ground connection. These caps are designed to always fail open. Listed devices now require capacitors with these ratings if connected to the AC line.
This simple AC line RFI filter has become obsolete in my observation. Modern gear use switch mode power supplies and these require a balanced Pi filter to block their own RFI and of course the capacitors used are of the XY rating. Newer 50/60hz transformer powered gear will also often omit this crude RFI filter. Especially fine audio gear where they know about the hum pitfalls that can arise.
So if your gear does have this capacitor or resistor capacitor combination from one side of the AC line to the chassis, the readings Hari presented are logically explained. And yes, flipping the plug in this case can reduce hum in the system. If the device does not have this crude AC line RFI filter or uses a balanced PI filter, flipping the plug will make no difference as Hari noted on his BluRay player which no doubt uses a switch mode power supply. A grounded three wire plug should force a proper neutral connection. However this assumes the wall outlet is wired properly and quite often they are reversed neutral and hot.
As for flipping the AC on every tube filament I can't say either way. If there is some heater to cathode problem and/or the filament buss has one leg grounded, it might make a difference. However in most tube circuits it would not. Many manufactures also made sure the same tube pin was on the same phase when tubes had the same pinout. Again I think this was just good engineering practice versus any true benefit. Note too that in tube RF circuits which would include consumer radios and TVs, one side of the filament buss was grounded by necessity.
Personally if I had a hum problem due to these crude RFI filters, I would just snip the capacitor out. If I then had AC line RFI problems, I would use a grounded Pi filter power strip which is the proper solution. But that's just me.
Hope this better explains why in some cases flipping the AC plug does make a hum level difference.
In transformer powered gear, a legacy practice was to connect around a .01uf from one side of the AC line to the chassis or signal ground, sometimes also paralleled with a high value resistor, 1 meg ohm or higher. This was to short out any RFI present on the AC line. RFI could be a strong AM radio station or a house vacuum cleaner or other appliance utilizing a brush motor. This technique was effective.
In the 1960s and prior, this capacitor was typically a wax paper 600vdc, As we know over time paper capacitors develop high leakage and this creates a safety hazard. In vintage component circles that is often referred to as the "death capacitor" and must always be replaced. In later generation gear this was changed to a mylar or polyester 600vdc capacitor. However while these caps do not suffer from aging leakage, they can fail shorted thus again creating a shock hazard by putting one side of the AC line to the signal ground at full short circuit current availability. Consumer gear still used this simple RFI filter well into the 1990s on audio and video products.
Because of this type of capacitor failure, shorting, UL and other world safety agencies stepped in and today we have type X and type Y capacitors.
Type X is for line to line connection and type Y is for line to ground connection. These caps are designed to always fail open. Listed devices now require capacitors with these ratings if connected to the AC line.
This simple AC line RFI filter has become obsolete in my observation. Modern gear use switch mode power supplies and these require a balanced Pi filter to block their own RFI and of course the capacitors used are of the XY rating. Newer 50/60hz transformer powered gear will also often omit this crude RFI filter. Especially fine audio gear where they know about the hum pitfalls that can arise.
So if your gear does have this capacitor or resistor capacitor combination from one side of the AC line to the chassis, the readings Hari presented are logically explained. And yes, flipping the plug in this case can reduce hum in the system. If the device does not have this crude AC line RFI filter or uses a balanced PI filter, flipping the plug will make no difference as Hari noted on his BluRay player which no doubt uses a switch mode power supply. A grounded three wire plug should force a proper neutral connection. However this assumes the wall outlet is wired properly and quite often they are reversed neutral and hot.
As for flipping the AC on every tube filament I can't say either way. If there is some heater to cathode problem and/or the filament buss has one leg grounded, it might make a difference. However in most tube circuits it would not. Many manufactures also made sure the same tube pin was on the same phase when tubes had the same pinout. Again I think this was just good engineering practice versus any true benefit. Note too that in tube RF circuits which would include consumer radios and TVs, one side of the filament buss was grounded by necessity.
Personally if I had a hum problem due to these crude RFI filters, I would just snip the capacitor out. If I then had AC line RFI problems, I would use a grounded Pi filter power strip which is the proper solution. But that's just me.
Hope this better explains why in some cases flipping the AC plug does make a hum level difference.
Last edited:
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