MXL timing belt. Stereo LADDER Volume Control.
DEFECTING,........ from Digital .............back to TUBE / ANALOGUE / LPs
- Thread starter drlowmu
- Start date
- Status
MXL timing belt. Stereo LADDER Volume Control.
TEENY TINY Update ..... 5-07-2023
Over this past week I doubled - up on Caddock TF-020s at almost ALL the critical circuit locations. The result is positively stupendous.
The 0.047 uF GROSS and INADEQUATE - sounding-cheap Sprague " OrangeDrop ", as the first-to-second stage coupling cap, was replaced with a well-chosen REL Teflon and Tinfoil expensive high-quality coupling cap, much to anyone's listening delight.
New and updated below-deck photos will be taken and posted here, of the many doubled-up TF-020 Caddock resistors.
An updated present - listening description, is to be reported on, in a day or so.
Over this past week I doubled - up on Caddock TF-020s at almost ALL the critical circuit locations. The result is positively stupendous.
The 0.047 uF GROSS and INADEQUATE - sounding-cheap Sprague " OrangeDrop ", as the first-to-second stage coupling cap, was replaced with a well-chosen REL Teflon and Tinfoil expensive high-quality coupling cap, much to anyone's listening delight.
New and updated below-deck photos will be taken and posted here, of the many doubled-up TF-020 Caddock resistors.
An updated present - listening description, is to be reported on, in a day or so.
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Listening report I will delay, to be sure I do not overstate this new unit's capability, and what I am hearing. Hint : It initially is sounding superb.
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Three month update, 6-2023
I am very pleased to have stopped using digital sources these last several months, in favor of my L.P. collection.
I am today at another " PIVOT POINT ". Among the changes attempted, I went through about THREE changes of resistor-types in this Trevor Lees PAS preamp modification project during the last few months. By the third resistor iteration, I ended up " losing " circuit continuity in one of the two stereo RIAA EQ channels.
I proceeded with my recent mods in a rushed and sloppy way, eagerly listening after each change.
I am a human being, I was always ANXIOUS to hear the next change's effect. I was proceeding in an orderly and progressive way, albeit rushing. L.P. playback was getting better and better, almost every other day. It was audiophile-addictive.
But NOW I have likely either an OPEN or a SHORT on the printed circuit board. Only one channel plays, one stereo channel of an L.P.
Guess what, the channel that IS working, sounds fabulous to me. I have spent many hours enjoying my Hi Fi, personally listening to music.
I've had the preamp's circuit board on an oscilloscope, as recently as yesterday, and I do not have the patience, skill, or ability to effect a repair.
Here is the PIVOT POINT :
I am embarrassed at my sloppy mod work, ( especially by the THIRD Resistor - P.C . Board change-out ) - such that I do not want to show it to Technical friends, who are offering to FIND and FIX the circuit problem gratis.
*** I have to decide to give or not give the preamp over, ....... for a repair. ***
If I keep the preamp at home now, I will MAINTAIN most of it, and " simply " rip-out the audio's four tubes on two printed circuit boards. I'd more neatly build the circuit Point-For- Point with silver-like content Percy Wonder Wire, on Keystone 817 Terminal strips and brass flat-stock tube socket rails.
My overriding intent is to KEEP this Cascode 12AX7 preamp circuit, and use it henceforth, happily. .
To keep the sloppy mod job, or redo all four tubes point to point, ( a LOT more work ),
is the PIVOT to be decided NOW !!.
One path I'd be proud of, the other, not so much.
I'd like to inform you all, that these unique Mods I elected to do : the BRASS PYRAMIDS, doubled Caddock TF-020 resistors, the Cardas Silver 18 AWG and Mil Spec wire mods, Ladder Precision Wirewound Volume Control ..............are some of THE most effective phono playback LISTENING / circuit improvements - I've ever experienced. ' Am pleased about it.
I also LIKE the fact that the unit is housed in such an UNASSUMING - looking DYNA PAS chassis, a true wolf in sheep's clothing - for future use.
" PIVOT POINT " Time...............is here. ........ What to do ?????
Jeff
I am very pleased to have stopped using digital sources these last several months, in favor of my L.P. collection.
I am today at another " PIVOT POINT ". Among the changes attempted, I went through about THREE changes of resistor-types in this Trevor Lees PAS preamp modification project during the last few months. By the third resistor iteration, I ended up " losing " circuit continuity in one of the two stereo RIAA EQ channels.
I proceeded with my recent mods in a rushed and sloppy way, eagerly listening after each change.
I am a human being, I was always ANXIOUS to hear the next change's effect. I was proceeding in an orderly and progressive way, albeit rushing. L.P. playback was getting better and better, almost every other day. It was audiophile-addictive.
But NOW I have likely either an OPEN or a SHORT on the printed circuit board. Only one channel plays, one stereo channel of an L.P.
Guess what, the channel that IS working, sounds fabulous to me. I have spent many hours enjoying my Hi Fi, personally listening to music.
I've had the preamp's circuit board on an oscilloscope, as recently as yesterday, and I do not have the patience, skill, or ability to effect a repair.
Here is the PIVOT POINT :
I am embarrassed at my sloppy mod work, ( especially by the THIRD Resistor - P.C . Board change-out ) - such that I do not want to show it to Technical friends, who are offering to FIND and FIX the circuit problem gratis.
*** I have to decide to give or not give the preamp over, ....... for a repair. ***
If I keep the preamp at home now, I will MAINTAIN most of it, and " simply " rip-out the audio's four tubes on two printed circuit boards. I'd more neatly build the circuit Point-For- Point with silver-like content Percy Wonder Wire, on Keystone 817 Terminal strips and brass flat-stock tube socket rails.
My overriding intent is to KEEP this Cascode 12AX7 preamp circuit, and use it henceforth, happily. .
To keep the sloppy mod job, or redo all four tubes point to point, ( a LOT more work ),
is the PIVOT to be decided NOW !!.
One path I'd be proud of, the other, not so much.
I'd like to inform you all, that these unique Mods I elected to do : the BRASS PYRAMIDS, doubled Caddock TF-020 resistors, the Cardas Silver 18 AWG and Mil Spec wire mods, Ladder Precision Wirewound Volume Control ..............are some of THE most effective phono playback LISTENING / circuit improvements - I've ever experienced. ' Am pleased about it.
I also LIKE the fact that the unit is housed in such an UNASSUMING - looking DYNA PAS chassis, a true wolf in sheep's clothing - for future use.
" PIVOT POINT " Time...............is here. ........ What to do ?????
Jeff
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DECIDED today, to do a Point To Point REBUILD, ......... 6-8-2023
The DYNA PAS preamp chassis is not ideal , and my home's entire audio system will be disabled as I re-do the Phono RIAA EQ. I have chosen to rip out the two PC boards and TRY to rebuild the circuit Point To Point.
By applying a re-do without use of the 1970's Trevor Lees P.C. boards, my audio friends who would seek to precisely copy the circuit in the future can hopefully do so. Using commonly available ( albeit expensive - top quality ) parts.
I will have to figure out a parts layout - inside a compromised space. I have NEVER ever built an RIAA EQ before, only audio amplifiers from scratch - the last 42 years. It can't be ideal. But I already know this will be OH SO GLORIOUS to experience, once operating.
I've heard enough, with one working channel, to easily be 100% confident. Phono playback took on a whole new meaning, which L.P. people have not-yet to ever experience, so I believe!
' Will need some build time. Stay tuned.
This HAS to be heard.
Jeff
The DYNA PAS preamp chassis is not ideal , and my home's entire audio system will be disabled as I re-do the Phono RIAA EQ. I have chosen to rip out the two PC boards and TRY to rebuild the circuit Point To Point.
By applying a re-do without use of the 1970's Trevor Lees P.C. boards, my audio friends who would seek to precisely copy the circuit in the future can hopefully do so. Using commonly available ( albeit expensive - top quality ) parts.
I will have to figure out a parts layout - inside a compromised space. I have NEVER ever built an RIAA EQ before, only audio amplifiers from scratch - the last 42 years. It can't be ideal. But I already know this will be OH SO GLORIOUS to experience, once operating.
I've heard enough, with one working channel, to easily be 100% confident. Phono playback took on a whole new meaning, which L.P. people have not-yet to ever experience, so I believe!
' Will need some build time. Stay tuned.
This HAS to be heard.
Jeff
Last edited:
DISCOVERED JUST TODAY, Oh my GOODNESS . 6-09-23
There are many E.E. design people who know all the Formulas on how to calculate a RIAA EQ. ( Not me !! )
Many audio industry people whom I knew, or still know, have worked DECADES during their lives to get good sounding Phono EQs for their own use.
I would guess someone could today spend $30,000 USD on a phono EQ. ' Seems excessive.
From what I have heard the last few weeks ( with only one channel playing ) I have a strong suspicion that possibly no phono EQ existing, will outperform the subject of this Hi Fi Vision thread.
You see, people who are E.E. experts will apply their talents to (1) accurate RIAA equalization, or (2) multiple L.P or 78 RPM equalization curves, or (3) luxury convenience features, such as remote controls of Volume, Source Selections, and Phase Switching from one's seated position.
The people who put out these product types, will build them with decent parts, or course. BUT to my guess, none of these Phono EQs will get built, in matters pertaining to their unit's ultimate SOUND, with the very BEST parts and approaches they need to have.
Almost always, today's E.E. trained individuals never build a pure vacuum tube circuit. ......"Oh no, lets add a set of solid state diodes, and get rid of any inefficient tube rectifier. Lets use a solid state Constant Current Source. It " specs " and looks on a scope, ohh so much better. "
We won't even have to seriously and aurally compare things, to any earlier technologies
The new numbers speak for themselves. And my modern use of tubes is so far theoretically improved, no need to consider listening to prior archaic circuits.
Nicely - and in almost ALL cases, we do not have to use the VERY best parts, the cost is unwarranted. ( Even more so with a DIYer. ) We just need to make sure " it is good enough " VS the competition. What do people expect for $30,000 ? "
- - - - - - - - - - - - - - - - - - - - - - - - - - -- - - - - - - - -
So there we are. Why aren't Manufacturers building and offering the best sounding equipment possible to own ????
Today, 06-09-2023, I spent some time on-line to see what was written about " doubled resistors " ( two resistors, each exactly double the needed value, connected in parallel with each other. ) This thread's preamplifier ultimately uses this technique, in every resistor location. So I have LISTENED to what that doubling did, in every circuit spot, the last few months. In a brief search today, I found nothing, but I am guessing a write up exists.
Doubled paralleled resistors everywhere, and other tricks, turned my phono playback into a DYNAMICS MONSTER unlike anything maybe anyone has ever heard before in all of audio. Not JUST that all-doubled resistor treatment, but in conjunction with all MY MOD decisions - already described. ( Brass Rigid Pyramids, a 10 Ohm Choke Input Filter, doubled Caddock TF-020s wherever possible, Cardas 18 AWG Chassis Wire, and ( likely ) the world's FIRST Bourns Ladder Precision WireWound volume-control system ) ...... all make this build effort unique. Concentrating on sound and great parts, I am hoping to develop this build to be - sonically without peer.
Below is a post from 2011, found this afternoon, which makes me feel good that I was mentor-advised to TRY some of the resistor iterations I had tried. Realize, unlike the article above from 12 years ago, Jeff himself ended up " having " to have, a MUST HAVE after hearing it, DOUBLED Caddock TF-020s, something not discussed in the Audiogon Thread back in 2011. Here is 2011 , I uncovered today :
------------------------------------------------------------------------------------------------------------------------
I'm bumping up this thread as I just completed a comparison of resistors in the gridleak position of a tube pre-amp.
The contenders:
Vishay S102C
Tc TX2575
Dale RN65
Takman Rey
Shinko Tantalum
Holco (old stock)
Caddock USF340 (TF020)
Generic Metal Film
PRP
This was quite an interesting undertaking as I was not expecting to hear drastic differences. In the past I heard
differences between resistors but mainly in the high frequencies (cartridge loading application).
The Shinko Tantalum was by far the most inaccurate resistor of the lot. Dale RN had the most bass and midrange
warmth. TX 2575- the biggest disappointment of the lot. A laid back/bland/lifeless sound. S102/PRP/Takman/- not
worth the time of day. Holco- now this is an interesting part. Very lively/dynamic/textured presentation with great
inner detail and prat. Unfortunately it adds a fullness to vocals and mid-bass that ultimately becomes distracting.
And the winner......by a w-i-d-e margin is the Caddock USF340 (TF020). Clearly the most
transparent/musical/involving resistor I've had the pleasure to hear.
- - - - - - - - - - - - - - - - - - - -- - -- - - - - -- - - - - - - - - - - - - - - - --
I personally, alone, have spent about 200 hours listening to one operating channel, over the last several weeks of modding.
These independently-chosen added parts are only - beginning - to get broken in. Looks like I settled on the above fellow's number one favorite sounding resistor, Caddock TF020, .........but only if DOUBLED-UP.
I can not wait until audio friends and some serious listeners experience these DYNAMICS - and music's playback.
Do any of the $30,000 Phono Preamps have all-doubled-up Caddock TF-020s, and Rigid Brass Pyramid mounts in 2023 ? Fabulously good-sounding Precision wirewound 10K LADDER Attenuator Volume Controls ? Nope So sad for them all, particularly their owners. I alone personally WILL have the circuit, and like my 6005 circuit, those SOTA TRIO speaker wires, I share it gratis, here on HFV.. Time and priority is NOW to build and rebuild this, precisely as described herein. The music lover's " end - game " Phono Stage .
Jeff
There are many E.E. design people who know all the Formulas on how to calculate a RIAA EQ. ( Not me !! )
Many audio industry people whom I knew, or still know, have worked DECADES during their lives to get good sounding Phono EQs for their own use.
I would guess someone could today spend $30,000 USD on a phono EQ. ' Seems excessive.
From what I have heard the last few weeks ( with only one channel playing ) I have a strong suspicion that possibly no phono EQ existing, will outperform the subject of this Hi Fi Vision thread.
You see, people who are E.E. experts will apply their talents to (1) accurate RIAA equalization, or (2) multiple L.P or 78 RPM equalization curves, or (3) luxury convenience features, such as remote controls of Volume, Source Selections, and Phase Switching from one's seated position.
The people who put out these product types, will build them with decent parts, or course. BUT to my guess, none of these Phono EQs will get built, in matters pertaining to their unit's ultimate SOUND, with the very BEST parts and approaches they need to have.
Almost always, today's E.E. trained individuals never build a pure vacuum tube circuit. ......"Oh no, lets add a set of solid state diodes, and get rid of any inefficient tube rectifier. Lets use a solid state Constant Current Source. It " specs " and looks on a scope, ohh so much better. "
We won't even have to seriously and aurally compare things, to any earlier technologies
The new numbers speak for themselves. And my modern use of tubes is so far theoretically improved, no need to consider listening to prior archaic circuits.
Nicely - and in almost ALL cases, we do not have to use the VERY best parts, the cost is unwarranted. ( Even more so with a DIYer. ) We just need to make sure " it is good enough " VS the competition. What do people expect for $30,000 ? "
- - - - - - - - - - - - - - - - - - - - - - - - - - -- - - - - - - - -
So there we are. Why aren't Manufacturers building and offering the best sounding equipment possible to own ????
Today, 06-09-2023, I spent some time on-line to see what was written about " doubled resistors " ( two resistors, each exactly double the needed value, connected in parallel with each other. ) This thread's preamplifier ultimately uses this technique, in every resistor location. So I have LISTENED to what that doubling did, in every circuit spot, the last few months. In a brief search today, I found nothing, but I am guessing a write up exists.
Doubled paralleled resistors everywhere, and other tricks, turned my phono playback into a DYNAMICS MONSTER unlike anything maybe anyone has ever heard before in all of audio. Not JUST that all-doubled resistor treatment, but in conjunction with all MY MOD decisions - already described. ( Brass Rigid Pyramids, a 10 Ohm Choke Input Filter, doubled Caddock TF-020s wherever possible, Cardas 18 AWG Chassis Wire, and ( likely ) the world's FIRST Bourns Ladder Precision WireWound volume-control system ) ...... all make this build effort unique. Concentrating on sound and great parts, I am hoping to develop this build to be - sonically without peer.
Below is a post from 2011, found this afternoon, which makes me feel good that I was mentor-advised to TRY some of the resistor iterations I had tried. Realize, unlike the article above from 12 years ago, Jeff himself ended up " having " to have, a MUST HAVE after hearing it, DOUBLED Caddock TF-020s, something not discussed in the Audiogon Thread back in 2011. Here is 2011 , I uncovered today :
------------------------------------------------------------------------------------------------------------------------
I'm bumping up this thread as I just completed a comparison of resistors in the gridleak position of a tube pre-amp.
The contenders:
Vishay S102C
Tc TX2575
Dale RN65
Takman Rey
Shinko Tantalum
Holco (old stock)
Caddock USF340 (TF020)
Generic Metal Film
PRP
This was quite an interesting undertaking as I was not expecting to hear drastic differences. In the past I heard
differences between resistors but mainly in the high frequencies (cartridge loading application).
The Shinko Tantalum was by far the most inaccurate resistor of the lot. Dale RN had the most bass and midrange
warmth. TX 2575- the biggest disappointment of the lot. A laid back/bland/lifeless sound. S102/PRP/Takman/- not
worth the time of day. Holco- now this is an interesting part. Very lively/dynamic/textured presentation with great
inner detail and prat. Unfortunately it adds a fullness to vocals and mid-bass that ultimately becomes distracting.
And the winner......by a w-i-d-e margin is the Caddock USF340 (TF020). Clearly the most
transparent/musical/involving resistor I've had the pleasure to hear.
- - - - - - - - - - - - - - - - - - - -- - -- - - - - -- - - - - - - - - - - - - - - - --
I personally, alone, have spent about 200 hours listening to one operating channel, over the last several weeks of modding.
These independently-chosen added parts are only - beginning - to get broken in. Looks like I settled on the above fellow's number one favorite sounding resistor, Caddock TF020, .........but only if DOUBLED-UP.
I can not wait until audio friends and some serious listeners experience these DYNAMICS - and music's playback.
Do any of the $30,000 Phono Preamps have all-doubled-up Caddock TF-020s, and Rigid Brass Pyramid mounts in 2023 ? Fabulously good-sounding Precision wirewound 10K LADDER Attenuator Volume Controls ? Nope So sad for them all, particularly their owners. I alone personally WILL have the circuit, and like my 6005 circuit, those SOTA TRIO speaker wires, I share it gratis, here on HFV.. Time and priority is NOW to build and rebuild this, precisely as described herein. The music lover's " end - game " Phono Stage .
Jeff
Last edited:
RtoR King
Active Member
Equalization is equalization. A phono RIAA circuit is no different functionally than bass and treble controls or a graphic equalizer. Except for one important thing. The RIAA equalizer is not adjustable as traditionally built nor should it be.
In theory you could build a flat full bandwidth phono preamp and apply the RIAA equalization via a graphic equalizer at the line level. Probably even with bass and treble controls. You might even be able to do it in the speaker crossover? The point is that equalization is equalization. You can apply the RIAA curve any place in the chain.
The problem with RIAA equalization by "soldering iron" is that you do not have a reference point for a flat response. And unless the circuit is swept, you have no idea of the filter (equalizer) response. I guess you could reverse calculate it from the "chosen by ear" components back into a response curve. But if you can do that, why not build it right in the first place?
If you don't like what you hear, then add a defeatable tone control circuit or graphic equalizer. But first make sure your speaker and associated crossovers are as close to a flat response as practical. Now you have a flat reference point and the ability to manually alter the response as required for recordings that don't suit your personal listening preferences.
That is how audio engineers do it! Produce a flat frequency response based on industry standards, RIAA, NAB, but provide the user with optional tone control to use as deemed needed by the listener.
Your comments above are simply your opinions, nothing more. There is no data to back up any of your claims. It's only what you think you hear. And that's prefectly fine. But it's hardly a proven path for all to blindly follow.
In theory you could build a flat full bandwidth phono preamp and apply the RIAA equalization via a graphic equalizer at the line level. Probably even with bass and treble controls. You might even be able to do it in the speaker crossover? The point is that equalization is equalization. You can apply the RIAA curve any place in the chain.
The problem with RIAA equalization by "soldering iron" is that you do not have a reference point for a flat response. And unless the circuit is swept, you have no idea of the filter (equalizer) response. I guess you could reverse calculate it from the "chosen by ear" components back into a response curve. But if you can do that, why not build it right in the first place?
If you don't like what you hear, then add a defeatable tone control circuit or graphic equalizer. But first make sure your speaker and associated crossovers are as close to a flat response as practical. Now you have a flat reference point and the ability to manually alter the response as required for recordings that don't suit your personal listening preferences.
That is how audio engineers do it! Produce a flat frequency response based on industry standards, RIAA, NAB, but provide the user with optional tone control to use as deemed needed by the listener.
Your comments above are simply your opinions, nothing more. There is no data to back up any of your claims. It's only what you think you hear. And that's prefectly fine. But it's hardly a proven path for all to blindly follow.
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There is an update from drlowmu on this thread which is as below and am updating on his behalf. I hope mods wont have an issue with that,
Very exciting audio news.
The Trevor Lees cascode phono circuit should be very satisfying Kees for you to build. I have recently DISCOVERED HOW to get almost any tube phono preamp to REALLY perform - with new extremes of resolution, realism, and dynamics.
All the single-steps I have taken in the last several weeks, has provided me with an undeniable GREAT way to execute a decent vacuum tube phono circuit. This ALL involves improving the Power Supply... of course.
A phono's supply needs to be built like that of an ultra-high-quality 20 Watt power amplifier !!!
I just measured a DYNA PAS3 Transformer's HV secondary,... and the DCR is HUGE. Despite this too-high transformer DCR, I was able to get the very best sound I personally have ever heard from ANY Phono set up, any time in my life, ....
by paying complete attention to details of the entire Power Supply B+ chain, that feeds the phono circuit. Important things that most people ignore.
Start your phono unit design with a superb AC Plug, use a DIY 12 AWG m22759/11 Power Cord, 114 1/4 inches long, ( raised OFF the floor or rug !! ). For an IEC, only use a 20 A. unit, NEVER ever those typical 15 A. rated ones. HUBBLE brand's 20 A. IEC can be sourced from Michael Percy, through me. The Hubble 20A. IEC sonically "destroys" all the others !!! Use a SPDT 15 A. rated ON-OFF heavy duty toggle switch, with dual contacts, parallel - wired, to act as 30 A. contacts.
On the drawing board, (hopefully to be made by Shilchar Q1-2024), is a new R-Core 5.7 pound Power Transformer, that will have only 40 Ohms end-to-end DCR, 630 VCT, with lovely lead-out wires. Dennis Fraker assures me, my transformer DCR re-design is absolutely the correct thing to do, and it will result in yet another huge sonic improvement. I 100% agree. 40 Ohms end to end !!
( Dennis Fraker has owned / used as low as 23 ohms DCR - with his Phono's power transformer - it, weighing 16 pounds! This was a dual-chassis Phono Preamp with an 85 pound Power Supply chassis. That preamp ( in the 1970s? ) retailed for $28,000 USD, a one-of, all octal tubes. He bought it used for $10 K, had $14 K in it with his mods, and sold it when he got offered $22 K USD. Next, he bought a dual chassis ARC SP-10, ... which D.F. also extensively modded ).
Besides, use of low DCR power XFRs ( 20 DCR for any amp, 20 DCR for Phono ) I've PRECISELY learned to do the following ( as a phono implementation ) :
Use a single 5V4GA ( RCA ) vacuum tube rectifier, powered with a separate 2 A. 5 VCT Ef XFR. Always a choke input ! A Stancor C-2708 10 Ohm 320 mHY L1 choke, leads upgraded, into a 35 uF 370 or 440 VAC GE " 97F " oil cap as C1. For L2, same Stancor type with improved leads, into a 80 uF GE " 97F " as C2, into a THIRD Stancor C-2708 as L3, leads upgraded, feeding a final 35 uF GE " 97F " capacitor as C3. Simple.
12 AWG Mil Spec m22759/11 wires for grounds, and m22759/11 14 AWG Mil Spec wire, as B+. This topology is notated as:
L1 / C1 / L2 / C2 / L3 / C3
PSUD2 it. Not seen, but easily heard, C1, C2, and C3 : three GE " 97Fs ", uniquely provides a phono playback with extreme-wide-band DYNAMICS. These nicely replace 2016-2023's use of 5 uF Arcotronics GTO bypass caps. Triple-series-connected L1, L2, L3 Stancor 10 Ohm chokes sound very good - and provide EXTREME resolution for high mu 12AX7 tubes. We do NOT hear any phono preamp, all we hear are superbly defined, ultra-dynamic music notes. The stock preamp's Trevor Lees filtering of B+ follows, used after this new " TRIPLE L/C " B+ filter - herein described.
This basic topology, as the start of ANY decent tube phono stage, performs phono playback IMHO, as - worth its' weight in gold !
My involvement with analogue phono playback changed from being bored / seldom listening - to being totally involved mentally with my L.P.s in December 2023. Easily, I am drawn-into each L.P.'s music performance and sound aspects. I own over 10,000 L.P.s. This was subjectively a magnificent 15 % improvement / and audio system change. No one (who I know of) has designed a
phono stage supply - quite like this.
(Additional Note: My Trevor Lees test preamp uses doubled (paralleled) Caddock TF 020 resistors, Rel TFT Audio Cap 0.047 uF / 600V. teflon and tin foil .047uF coupling caps, and a highly favored four Bornes 3-turn Precision Pot / 10 K LADDER Volume Control. These parts each, are ultra transparent. ) And expensive.
A similar as-above " TRIPLE L/C Power Supply " topology will be applied to a Softone MODEL 4 ( 12AX7 - FET follower ) phono circuit by me, early in 2024. That build should become my own personal long-term phono EQ.
PSUD2 simulations of this Power Supply topology shows B+ ripple is reduced to nanovolt AC levels - for the 12AX7 input tube. How's that!!
( Millivolt, microvolt, and nanovolt are units of measurement for alternating current (AC) voltage. Millivolt is equal to 0.001 volts, microvolt is equal to 0.000001 volts, and nanovolt is equal to 0.000000001 volts.)
This nanovolt filtering level produces special-to-hear results, with music's inner details and sweetness remaining intact.
Use of " 97Fs " provides unsurpassed and WILD dynamic contrasting - addictive once heard (particularly, on my SE parallel - 6005 powered ALTEC A7-8 VOTT speaker.) A speaker that plays back over 104 dB sensitive, one Watt, one Meter.
Truly FUN stuff. Surely, there is positively NO " going back " from this new topology, once experienced / heard, and lived with. I am so pleased and happy now. ... NO parts OR value substitutions are allowed. Got that? I hope so. Be prepared to be quite amazed. This is an exciting-to-hear, reasonable to implement, newly found phono playback topology!!!
You've been provided with my latest - developed, precise phono supply recipe. In addition to everything above, I also SHUNT passively regulate each B+ circuit node individually, drawing often several times the stage's current to ground, through four-times load over-rated HIGH QUALITY / good sounding wirewound power resistors. (e.g. : Ohmite Series 20s, Mills MRA-12s, and ARCOL HS series.)
In the end, we ALL listen to music - modulated Power Supplies...... Just how GOOD are they???
DIY.
Do I need to say " YMMV " ?? and " IMHO "?? LOL, OK, ... sure.
Very exciting audio news.
The Trevor Lees cascode phono circuit should be very satisfying Kees for you to build. I have recently DISCOVERED HOW to get almost any tube phono preamp to REALLY perform - with new extremes of resolution, realism, and dynamics.
All the single-steps I have taken in the last several weeks, has provided me with an undeniable GREAT way to execute a decent vacuum tube phono circuit. This ALL involves improving the Power Supply... of course.
A phono's supply needs to be built like that of an ultra-high-quality 20 Watt power amplifier !!!
I just measured a DYNA PAS3 Transformer's HV secondary,... and the DCR is HUGE. Despite this too-high transformer DCR, I was able to get the very best sound I personally have ever heard from ANY Phono set up, any time in my life, ....
by paying complete attention to details of the entire Power Supply B+ chain, that feeds the phono circuit. Important things that most people ignore.
Start your phono unit design with a superb AC Plug, use a DIY 12 AWG m22759/11 Power Cord, 114 1/4 inches long, ( raised OFF the floor or rug !! ). For an IEC, only use a 20 A. unit, NEVER ever those typical 15 A. rated ones. HUBBLE brand's 20 A. IEC can be sourced from Michael Percy, through me. The Hubble 20A. IEC sonically "destroys" all the others !!! Use a SPDT 15 A. rated ON-OFF heavy duty toggle switch, with dual contacts, parallel - wired, to act as 30 A. contacts.
On the drawing board, (hopefully to be made by Shilchar Q1-2024), is a new R-Core 5.7 pound Power Transformer, that will have only 40 Ohms end-to-end DCR, 630 VCT, with lovely lead-out wires. Dennis Fraker assures me, my transformer DCR re-design is absolutely the correct thing to do, and it will result in yet another huge sonic improvement. I 100% agree. 40 Ohms end to end !!
( Dennis Fraker has owned / used as low as 23 ohms DCR - with his Phono's power transformer - it, weighing 16 pounds! This was a dual-chassis Phono Preamp with an 85 pound Power Supply chassis. That preamp ( in the 1970s? ) retailed for $28,000 USD, a one-of, all octal tubes. He bought it used for $10 K, had $14 K in it with his mods, and sold it when he got offered $22 K USD. Next, he bought a dual chassis ARC SP-10, ... which D.F. also extensively modded ).
Besides, use of low DCR power XFRs ( 20 DCR for any amp, 20 DCR for Phono ) I've PRECISELY learned to do the following ( as a phono implementation ) :
Use a single 5V4GA ( RCA ) vacuum tube rectifier, powered with a separate 2 A. 5 VCT Ef XFR. Always a choke input ! A Stancor C-2708 10 Ohm 320 mHY L1 choke, leads upgraded, into a 35 uF 370 or 440 VAC GE " 97F " oil cap as C1. For L2, same Stancor type with improved leads, into a 80 uF GE " 97F " as C2, into a THIRD Stancor C-2708 as L3, leads upgraded, feeding a final 35 uF GE " 97F " capacitor as C3. Simple.
12 AWG Mil Spec m22759/11 wires for grounds, and m22759/11 14 AWG Mil Spec wire, as B+. This topology is notated as:
L1 / C1 / L2 / C2 / L3 / C3
PSUD2 it. Not seen, but easily heard, C1, C2, and C3 : three GE " 97Fs ", uniquely provides a phono playback with extreme-wide-band DYNAMICS. These nicely replace 2016-2023's use of 5 uF Arcotronics GTO bypass caps. Triple-series-connected L1, L2, L3 Stancor 10 Ohm chokes sound very good - and provide EXTREME resolution for high mu 12AX7 tubes. We do NOT hear any phono preamp, all we hear are superbly defined, ultra-dynamic music notes. The stock preamp's Trevor Lees filtering of B+ follows, used after this new " TRIPLE L/C " B+ filter - herein described.
This basic topology, as the start of ANY decent tube phono stage, performs phono playback IMHO, as - worth its' weight in gold !
My involvement with analogue phono playback changed from being bored / seldom listening - to being totally involved mentally with my L.P.s in December 2023. Easily, I am drawn-into each L.P.'s music performance and sound aspects. I own over 10,000 L.P.s. This was subjectively a magnificent 15 % improvement / and audio system change. No one (who I know of) has designed a
phono stage supply - quite like this.
(Additional Note: My Trevor Lees test preamp uses doubled (paralleled) Caddock TF 020 resistors, Rel TFT Audio Cap 0.047 uF / 600V. teflon and tin foil .047uF coupling caps, and a highly favored four Bornes 3-turn Precision Pot / 10 K LADDER Volume Control. These parts each, are ultra transparent. ) And expensive.
A similar as-above " TRIPLE L/C Power Supply " topology will be applied to a Softone MODEL 4 ( 12AX7 - FET follower ) phono circuit by me, early in 2024. That build should become my own personal long-term phono EQ.
PSUD2 simulations of this Power Supply topology shows B+ ripple is reduced to nanovolt AC levels - for the 12AX7 input tube. How's that!!
( Millivolt, microvolt, and nanovolt are units of measurement for alternating current (AC) voltage. Millivolt is equal to 0.001 volts, microvolt is equal to 0.000001 volts, and nanovolt is equal to 0.000000001 volts.)
This nanovolt filtering level produces special-to-hear results, with music's inner details and sweetness remaining intact.
Use of " 97Fs " provides unsurpassed and WILD dynamic contrasting - addictive once heard (particularly, on my SE parallel - 6005 powered ALTEC A7-8 VOTT speaker.) A speaker that plays back over 104 dB sensitive, one Watt, one Meter.
Truly FUN stuff. Surely, there is positively NO " going back " from this new topology, once experienced / heard, and lived with. I am so pleased and happy now. ... NO parts OR value substitutions are allowed. Got that? I hope so. Be prepared to be quite amazed. This is an exciting-to-hear, reasonable to implement, newly found phono playback topology!!!
You've been provided with my latest - developed, precise phono supply recipe. In addition to everything above, I also SHUNT passively regulate each B+ circuit node individually, drawing often several times the stage's current to ground, through four-times load over-rated HIGH QUALITY / good sounding wirewound power resistors. (e.g. : Ohmite Series 20s, Mills MRA-12s, and ARCOL HS series.)
In the end, we ALL listen to music - modulated Power Supplies...... Just how GOOD are they???
DIY.
Do I need to say " YMMV " ?? and " IMHO "?? LOL, OK, ... sure.
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