Well, the ZMA is back in the stable and new caps are burning in.  Obviously not ready to fully comment, but three things were immediately apparent.  

#1) I did not destroy the ZMA in this process...  Hallelujah!!  
#2 & #3 to come later.  But I will say, these caps are not coming out.  No way, no how.

I deleted a post from yesterday....because I'm rethinking this..... .

I do look forward to your posts Jeff....I'm just apprehensive about actually doing it. I have a competent soured to do it...however, I might keep my ZMA as is and turn my attention to an UFO Rachel. I don't like the current stock/& going the way of the Dodo bird - of 6P15P's and reg tubes. Having a Rach' gives me Pentodes back in Triode...plus, the mighty nuanced ZMA.

Jeff....but still, look forward to your next post about your mod. I have obviously been intrigued since the beginning of this Thread... .

Sound advice Jeff, thanks.

At this point, I have done enough listening to form my conclusion on this modification project.  While I spent about $1700 in various upgrades (connections, wiring, Type II caps, etc.) to my ZMA just prior to this power capacitor experiment, the marginal improvement from that effort is a mere fraction compared to the evolution in sound this power capacitor modification accomplished.  

I am still floored by the difference.  The improvements in imaging, detail, and realism put this ZMA in a new class.  I have to rename it “ZMA²”.   It cost me about $680 in parts and another $300 in labor, but my satification with its SQ has doubled.  So, the ROI was more than recovered.  Honestly, I am still shocked by what I am hearing.  Not subtle.  And as far as scrapping the six 47uF electrolytics for the Mundorf TubeCaps, I can detect no apparent consequences or losses - only marked improvements (coupled with the large capacitor replacement).

Witnessing what can be accomplished by tinkering with the power chain in this amplifier, there is no doubt in my mind whatever route Steve decides to take with his approach, it will yield a marked improvement in the amplifier’s performance.  How will it compare to the performance of my amplifier?  Who knows.  The large 4400uF capacitors I installed were 4 times the cost of the stock ZMA capacitors which are no match when it comes to ESL and ESR performance ratings.  These are Mundorf capacitors with design and testing specific to audio.  Even with keeping the 47uF electrolytics and bypassing them with film caps, there still may be improvements to be had replacing the large caps with a higher quality, better performing option.  But they are not cheap.  Just something to think about.  

But I still assert that if your amplifier is under warranty, I would not make any moves until Steve has had an opportunity to perform his R&D on the power supply chain.  This amplifier has more to give, I am certain of that.  So, if you could achieve those gains from the “factory” and keep the valuable lifetime warranty intact, that is the route I would absolutely consider first.  

Without a shred of uncertainty, what I am getting out of this amp now has cemented my promise to never part with my beloved ZMA - of course until I must hand it down to some worthy recipient when that time in life comes.  

Well, that’s a wrap folks!

Jeff,

Thanks for sharing your news on the ZMA modifications.  While I am enamored with the 25th Anniversary amplifier Steve has built, I really love my ZMA.  I hope you will provide Steve an opportunity to hear the modified amp and let him decide if an upgrade path is warranted from a business stand point.

If the Mundorf capacitors and additional electrolytics bring the ZMA close to the anniversary amp, that would be wonderful.  I for one would definitely be interested in purchasing this upgrade from Decware, if priced around $1K or so.  

At this juncture in life, it's just hard for me to justify having two amps for my dedicated two-channel system.  Anyway, just wanted to share my thoughts FWIW.  Enjoy your modified ZMA.

HK

......I should have had Steve add Balanced inputs when I had her in last year for backlit meters & bullet proof resistors. ....so, come late summer or fall and Steve feels the ZMA could benefit from an power supply and/or bypass enhancement.....I'm springing for the XLR's too. The voltage output/RCA, BY DESIGN of my ZDSD drives into my ZMA exquisitely. However, I want to drive some other DAC'S/Pre, DIRECTLY into my ZMA via Balanced. (ZBIT, has not been forgotten providing adjustability. However, I will have adjustability in the DAC'S analog domain output, then, running through the added XLR gain/direct to ZMA as I prefer).

Being a Kimber Select Dynamic contrast & Tonal color's member/I could never go back to anything else.....I need to budget for too (XLR IC)!

Till then, let's get this 25th, Mono 3/25th & CSP3 upgrade done DAMMIT , so I can get my ZMA in for my enhancements/late this year.




Listening Room:



Room Treatments from Michael Green & my Home Brew


Sony as Transport (DVP-NS57P)
Illuminati D-60 Digital Coax IC ~.5 meter


Shunyata Research Zitron Alpha Digital Power Cord to ZDSD {Significant}


Decware ZDSD DAC / Recorder
***************************************************************
W/Steve's Output Transformer's/kicking to the Curb quite a few superb DAC'S
***************************************************************
(@ -20 Ref Level, 0.0 Input volume and @ 16/192)



WBT-0102Ag RCA Kimber Select KS1030 ~.75 meter


Decware Zen Mystery Amplifier
~BIASED at *56* mA~
NOS/Platinum/Mullard E188CC/7308's in my A12 an B12 Input positions Cryogenic~NOS/Platinum/Telefunken 6922/E88CC for Inverter Tubes~NOS RCA 0A3's & matched Quad/Tung-Sol KT66's or 6P3S-E's




***************************************************
Kimber Select KS6063 Speaker Cable 8ft WBT-0681-Ag Spades
***************************************************



Acoustic Zen Adagio - Black Pearl (Modified)
.....enjoying from 8 ohm ZMA Taps


Caintuck Audio Eminence Alpha 15" OB BASS Unit
at 43Hz, with my Velodyne CHT 130 watt plate amp and 0 degree phase
Plate Amp....regen'd clean ~ plugged into P3
Auralex Subdude (a must)
(NOTE: Only needed when the recording calls for...Open Baffle Bass has been the best integration I have witnessed when needed and called on)







Acoustic Zen Adagio's x-over's Modified/Full Range with Mundorf MCap Supremes-single Cap to each Tweeter/4.5k cross
(Gutted: 3kHz/18dB/Octave, Linkwitz/Riley Crossovers....with all crappy parts = gone)


ZMA, updated with robust Western Electric Bias/Balance Meter's and new Resistor's ~ Feb/17

XLO Pro Power Cord to ZMA
Shunyata Research Zitron Alpha Digital Power Cord to ZDSD {Significant}
PS Audio P3 Power Plant / Pangea AC-9SE from wall to P3
(Transport and ZDSD, Regenerated/*120*~ Multiwave off...ZMA on High Current Output)
System configured on Floor ~ Townshend Audio CD Seismic Sink deployed.

I remember asking Steve about adding balanced jacks to my ZMA but he thought the ZBIT was a better way to go.  Of course, with the high dollar interconnects Stone uses, that may not be the case always.

I'm interested in your progress, Jeff, and I'm really glad the caps didn't speed it up to the point of being harsh. Knowing what caps you used I wasn't expecting that - I said what I said previously just as an anecdote. Sometimes you *can* have too much of a good thing.

I posted when those giant caps went on sale a year or two ago, and was tempted to pull the trigger - but these big red nuclear power plant caps were difficult for me to give up!

I'm still tempted to do this upgrade, I'm just kind of concerned that if I do these mods, and Steve comes up with something different, it's just going to be gutted for whatever he comes up with.

I can't really afford to do this mod twice...hell, I can't afford to do it once.  :)  

Yes, I was so torn.....having Jeff PM or email the mod pics, et al. Go ahead here and have done.

However, not just to keep my warranty.....I want the Zen Master's journey with her...and maybe those resistor's in the 25th Thread Steve speaks of (as an option/if applicable), can end up in the ZMA (the limited quantity he can obtain)? Or, a better alternative-meeting diminishing returns.

What other discoveries, he might implement (as I eluded to over in the 25th Thread as well)?  

Sounds fun Jeff. I look forward to hearing about these highly respected resistors burnt in!

Seems we are a similar track. Resistors are amazingly influential little things, so wanting to get to know them I finally bought quite a few popular samples to compare, though didn't go there on the new version Audio Notes. Probably should have gotten a few.

My last resistor foray was basic, maybe a year and half ago in the Torii. I tried Takman metal and carbon films, Kiwame carbon film, Arcol carbon, and PRP metals, .5 and 1 and 2 watt. I like the carbon caps Steve uses, but wanted to see what other resistors could do. The areas I was working then, stock metal films were nicely upgraded with TC50 PRPs from soniccraft, quick and easy. Jeff at soniccraft said they are better sounding than more typical TC100s, and having done a little test a long time ago, I recall agreeing. I find the PRP a straight forward and natural sounding metal film resistor. The rest from that test I found interesting, but more demanding due to having more obvious “signatures,” and whether I liked them depended on location and often on mixing them in series to get value while combining sonic traits. But the PRPs were innocuously clear, dynamic, extended and neutral, with a smooth and not overstated warmth… easy.

Then the last few months, having improved CSP3 connectors and volume, found bypass synergy for the power supply, and bypassed the coupling caps, I finally dug in to wires (signal and power), a challenging balancing act, ending up with variations of OCC silver, pure silver and copper, and OCC silver gold. Then I started in on resistors, the CSP3 a good place to explore being simple and lightweight!

I now have a small selection of Shinkohs, two types of Amtrans, two types of Caddocks, Vishay naked Z-foils, TDK 2W metal, and PRP along with the Takmans and Kiwames I found interesting, but generally a little too “flavored.” Speaking of which, .75 Amtran's Carbon Films are quite “flavored” too, but pretty compelling in moderation. Quite warm, even dark in the wrong settings, or with too many, the balancing toward bass can cause the top to sound "rolled off." But with more open company, they show really nice fine detail complexity in space, so far making their dark character worth adjusting around. We'll see. I wonder (hope) the bass, fine detail, and all will more fully resolve as it does with many things with burnin.

Experiments are mostly the same resistance, a Mills 12W replaced a Dale 6.5W between the 2 - 47uF power caps, .5W carbons changed to .75W Amtrans Carbon Films (AMRG) to the input grids, .5 carbon to .75W Caddock MK-132s to the input plates (also wired to G2 of the output tubes), an 840R series combo (PRP 510R + 330R Shinkoh) from input cathodes to ground (was 920R marked metal film measuring 900). I wanted to open the input tube a touch and get in the clear and complex Shinkoh sound with resistors I had, so made one. 2W TDKs replaced .5W carbons to the output tube P2s (also the coupling caps), a Takman 1W 160R metal film replaces parallel .5W 330R carbons (165R) between output tube cathode and plate, and a Shinkoh .5W 12K replacing a 10K carbon between the silver/gold output signal wire and the WBT nextgen copper/gold RCAs out. I seem to like a little more resistance there than stock. I think I do like slightly bigger wattage resistors, and maybe much bigger (2W) at least with those I am trying, but not sure yet on this one. With wires, bigger can clarify and solidify, but within a given balance can shift things toward bass also, and this seems a factor here too. Lots of variables.

Anyway, with a few of them having only 10 hours on them, others with just 30 or so, and some ~50, they sound good. Though clearly green, better in ways than previous subtler departures from stock that I thought were improvements. Too dark/dense for me now, but we'll see in time. As with bypass caps, I think I am finding that a synergistic blend of nice resistors may more fully give complex beauty than one or two. This may not be the ultimate, but a good way to explore the traits of a number of choices. Once they settle I will do some resistor rolling.

First impressions as these went in….the Amtrans, quite warm/dark, spacious and complex; Caddock 132, BIG, deep and dynamic, a little dark...too pressurized and dense at first, but intersting enough to want to clarify with others; TDK also big, but seemed neutral and transparent in this postion; Takman metal, not liking it as much as PRP in general, in this cathode to plate job it is pleasantly warm and nicely complex; Shinkoh, really nice balance, space and micro detail...revealing and transparent, making all the rest sound more complete...But then...they all need time I suspect to really hear them. The Amtrans Carbons are pretty big resistors, in an aluminum tube, and with gold plated copper wires...a lot or material, and they have refined over a couple weeks. As I listen today the blend is becoming more clear, complex and defined, together creating a nice balance that I suspect/hope will get a lot better.

Anyway, since you have moved to resistors, thought this might be intersting.

BTW, we have speculated about the efficacy of film power caps versus bypassed electrolytics. Trying Jenson electros in the Torii now, clearly not all electros are the same, nor are bypass caps, or no doubt film power caps. And combinations of bypasses and any of these clearly change the story in a big way....making it a little tricky to guess for me. Soooo, since the CSP3 has only two 47uF electrolytics, I decided to try and settle the questions to some degree. I got two Mundorf electros (same look and case as Jensons) to try in place of the stock F&Ts. And I got some 45uF Clarity TC films to try also, though they are bigger than spec, and with the bolt connectors, bigger! So I hope I can figure a way to get them in there. I will start burnin on the caps with my Frybaby to make the evaluation easier. They always need music time to sort out, but the burnin rig gets them through the hardest parts of burnin.

So I am hoping to try the Mundorf with the bypasses I now like, the Clarities by themselves, and Clarities with bypasses.

Hi Will,
Great information.  It has been fun following your resistor journey in this thread.  So far, my experience with the tantalums I have installed confirms what you are saying in terms of how flow and mitigation of signal degradation will in fact amount to improvements spanning multiple categories, speed being one of them.  

Most pronounced for me is the amount of finite detail in the music.  I would say that more nuances which were previously below the noise floor have now risen above and are quite noticeable.  It is stunning and even startling at times.  One of the most significant improvements in my ZMA with this resistor swap is in the overtones.  With piano and strings in particular, the harmonic series is longer and lingers more than it ever has.  It is beautiful.  Even reverb and resonance takes on a different life.  Incredibly present subtleties and nuances is the most notable improvement out of the gate.  

I am going to try some non-magnetic, non-inductive Mills wirewound resistors at the input & inverter tube plates in lieu of the Audio Note tantalums.  Wirewound are the best for noise since they are not susceptible to contact or shot noise.  Since these Mills are non-inductive, they won't suffer from the typical high-frequency handicaps of lesser/traditional wire wounds.  And if they suck, I switch 'em back.  

And you are exactly right Will on my 2W resistor choice for the control grid of the output tube.  It only requires a 1/2 Watt but on those Audio Note tantalums, 2W is often placed due to improved sound quality.  

Keep us posted as you continue the journey and Ill do the same.  Looking forward to more updates as they continue to burn-in.  

On your previous post, you picked up some 47uf Mundorfs to try in place of the F&Ts.  I was hoping you would try the TubeCaps un-bypassed so we have another opinion here on these caps  :)  There's always another time...

Sounds like those resistors are doing beautifully, the sound even now implying they are great resistors. Your caps seem likely to be resolving still also, so makes sense to let everything burn in and enjoy! I had the feeling the Shinkohs are special, and the ANs being based on them, your initial choices may well be exactly right!

My resistor complex is still opening and clarifying and becoming amazing. Like yours, the fine detail complexity and spacial information is really gorgeous.

I recently posted in another thread how fine detail and space are primary evaluation tools for me. Though this was always important to me, when I got my Tranquility DAC some time ago, Eric Hider taught me more. When they were developing the Tranquility, they explored loads of iterations of layout, caps, wires, connectors, damping, clocks, chips, solders, etc, and found that specifically reading decay, harmonics, ambience etc...was a relatively easy first step to see what was worth exploring further....not to mention how beautiful the music can become with this information present and in balance, and what was missing when it wasn’t!

I have found this invaluable as I do modifications. It appears that if the fragile fine information is better, other parts of the signal are generally less damaged also. Not perfect necessarily, as a cap (or whatever) may be good at nuanced fine detail, but lacking in other areas... But if the micro detail and micro dynamics are not there in a clean setup, you know quite quickly if a new part is truncating, masking, or simply not able to reveal all that is possible.

Then synergy. As I waited for my “signal” resistors to wake up, I tried (for maybe the 10th time) a resistor between the CSP3 IEC ground and the nearby connection node where the ground cap and main ground wire from the rest of the CSP3 circuits meet. I got this idea from Steve's CSP3 mod. Not being very techy, I may have this wrong, but it seems like adding resistance to this primary path to ground may power up everything a bit? Sounds that way. I tried a 10R Xicon 5W like Steve used, and found it created too much density for me, but the clarification and solidity were compelling. Then I tried a 6R2, then a 3R. Pretty close now, but the lower value Xicon sound was too tinselly/distorted for me.

So I tried a Mundorf M-cap Supreme 3R3 I had used on my speakers. Cut off the leads and soldered on soft/pure 20 gauge silver leads and Wow...nicely solid and refined...smoother, bigger, not lacking definition, but also having a bit much of what I hear with a lot of Mundorf things, a sort of "affected" "warmth" and smoothness that to me overly emphasizes "smooth warmth." The best of them I have are Silver Oil Supreme caps, and they are good at fine detail, but I still think they need help to more fully reveal fine detail and space. But probably more, what I think of now as the Supreme density gives a thickened quality to the mids and mid bass, tending to "mask" fine detail. So the very refined, but not quite my style Mundorf M-resistor came out too (again!!!).

But also, even a cleaner 3R3 may be too much in my arrangement of mods. Though exploring similar ideas and approaches, Steve and I ended up with different combinations of parts, and I am guessing I had already increased density and clarity from connectors, wire, power supply bypass choices, etc. And perhaps most influential, to tighten, balance, and solidify the Jupiter HT coupling caps, and to get a bit more clarified punch, I decided to try bypassing the 0.47 Jupiters with 0.1 Jantzen Sliver Z-caps. I think this combination has held up as "a truly great cap" in every iteration of the CSP3 I have explored since the Jantzens went in about a year and a half ago. They contributed a lot to signal coherence, density and balance while integrating open fine detail of the HTs.

So at this point the primary ground resistor is overstated for my CSP3 configuration, though I expect to try more, perhaps smaller value Mills or Ohmites. BTW, the 12 W Mills I put in the power supply did seem to clarify things nicely on first impressions. I have an Ohmite Gold to try there, and also some Mills and Ohmite Golds to compare to the Dales currently powering the power tubes cathodes.

So this is about resistors, but I told this part of the story in part to explain why I have been reticent to try the Mundorf Tube Power caps. That said, I am happy to find I like the Silver Oils bypassing the CSP power supply, and I did not love them in speakers. And the regular Supremes I tried in the Torii power were better there than in speakers too, though I was still relieved to replace them...subtler, but still that "Mundorf thing." The Silver Oils are still in the CSP3 and they are bypassed by a 0.01 Mundorf Evo Silver/Gold Oil that seems to be sticking too. These experiments help me think more positively about trying the Mundorf Tube Caps, especially if I can't fit in the 45uF Clarity TC films when the time comes! Knowing me, I may need to try both anyway! Toward the end of ultimate sound, this is a less costly place to explore with just two 47uF caps rather than 8 in the Torii! And your impressions are compelling!

Don't know if it will work, but I will try my Frybaby2 on resistors. Though I was hoping otherwise, enough people serious about resistor exploration seemed to think 100 hours or so is necessary for several nice resistors. I am reluctantly agreeing at this point. But I am trying too many types and sizes at once to clearly comment. And some resistors, like .5W PRPs, seem to adapt quickly compared to some of the bigger, more complex ones I am trying.

All that said, the sound today is becoming pretty incredible. It started to really wake up yesterday evening, and now...exciting! Guess the pokier resistors are coming in (and the Torii power caps?) ….immediacy, textures, space, amazing clarity across the spectrum without hardness, at least right now!@#$%^ ...Complex clarity and speed have been primary all along, but now it is starting to shake me up!

Jeff,

I noticed in your resistor upgrade you called out the four control grid resistors as 330K when you meant 330 ohms.

Steve