Improved some parts in my Atma-Sphere M-60/3.3 poweramps

Dec 16, 2018
57
30
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76
Phoenix, Arizona USA
#1
After determining a few weeks ago, with Atma-Sphere's Ralph Karsten's help via e-mail, that both my M-60s work just finely after I replaced a fuse, I've had them driving my Quad 2905s for a couple weeks. They've sounded plenty powerful enough and plenty good enough.

Now that they were running, it was time to get and install some 5-star-quality coupling caps--2 per amp--and power-supply-bypass caps. I had the latter, Sonic Craft's SoniCap Platinums (Teflon-film and tinfoil) in 1uF and 0.47uF. Sonic Craft's Jeff Glowacki recommended the (Polish) Miflex KPCU, a copperfoil/paper/polypropylene/oil cap...

https://www.hificollective.co.uk/components/miflex-kpcu-01-copper-foil-capacitors.html

...that is similar to Jupiter's Copper Foil Paper & Wax cap. I ordered them this week, they arrived Thursday, and I got all five caps per amp--two Miflex coppers and three Platinums--installed Friday and Saturday. Because my arthritic hands and back get tired and sore fairly quickly and often, I did a lot of getting up and stretching and walking around every half hour or so.

Here's the first completed amp.
Full bottom_1500w.jpg

...and here's the amp perched temporarily and carefully atop a BHK300.

The BHKs are now out of the system thanx to my goodbuddy Pat's help--each weighs 84-some pounds and I can't lift them.


Being as much a tin-eared audiofool as a golden-eared audiofile, I didn't expect to hear any change in sound character this evening, especially with only single-digit hours on the new caps. But WOW! Either I'm deluding myself or these five caps in each amp really are making a difference...cleaner, less-harsh treble (violins and trumpets), a slightly warmer balance to the lower frequencies, and perhaps more spaciousness. I'm VERY happy so far and look forward to getting lots more hours on the amps.
 
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tima

Industry Expert
Mar 4, 2014
1,792
1,291
390
the Upper Midwest
#2
They are likely making a positive sonic difference. I had Ralph upgrade the caps in my MA-1 to copper foil VCaps and was quite happy with the results. Resistors can make a genuine sonic difference as well.
 

Sablon Audio

Industry Expert, VIP Donor
May 22, 2015
898
508
283
#3
Good work and no surprises about the uptick. Is also worth doing iec inlet / rca jacks / binding posts and teflon tube sockets.
 
Dec 16, 2018
57
30
20
76
Phoenix, Arizona USA
#5
Good work and no surprises about the uptick. Is also worth doing iec inlet / rca jacks / binding posts and teflon tube sockets.
TY.. Have replaced the binding posts with hi-end Cardas and the no-longer-used RCAs with Furutechs, but that corner of the chassis is way too jammed with stuff for me to replace the power inlet, and I will never go to the trouble of replacing tube sockets.

I've also applied a good amount of SoundCoat the thicker to the chassis ceiling and the transformer cover that used to ring like the proverbial bell.
2016Apr23_SoundCoat inside T-cover, posts, and RCA_1800w.jpg

I use Herbies Sound Labs tube-damping rings on the Tung-Sol oval-plate 6SN7GT Voltage-gain tubes and, now, on half the output tubes, and Tall Tenderfoots for footers.. Atop the transformer cover is a VPI Magic Brick and two small steel blocks, all with Herbies GrungeBuster footers.
MagcBrks, HerbiesTubeDmprs_1500w.jpg
 
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Sablon Audio

Industry Expert, VIP Donor
May 22, 2015
898
508
283
#6
Resistors next then Jeff! Takman metal foils are both cheap and great sounding.
 

DaveC

Industry Expert
Nov 16, 2014
3,134
1,040
390
#7
If those green resistors are those Kiwame carbon, they sound awful. Slow and warm. I'd go vintage Riken or Takman carbon if they're gridstoppers. Otherwise for PS I often use Mills wirewound, Takman metal are good too.

Also, I'd replace the electrolytic caps, especially at the last stage of the power supply, with Clarity TC caps or film caps intended for wind turbine applications. These can be large but are well worth finding a place for. Massive difference vs electrolytics.
 

bazelio

Well-Known Member
Sep 27, 2016
1,384
654
200
California
#10
I've often wondered if those Miflex are OEMed and resold marked up by Jupiter. I've never tried them.

Agree with the advice to ditch Kiwame resistors. They are awful. Those might be Mills in your amp, though. I can't quite tell. Mills would be fine. These Vishay/Mills are very good in fact. I just swapped some into a First Watt F5. And I second the Audio Note tants if you want some "magic" as well nude foils (or wirewound) for neutral transparency. Not a fan at all of carbon based resistors, though I do like Clarity caps in the PSU. :)
 
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Jul 22, 2019
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#14
So I saw the M60s next to Quads in one photo. I just got a used pair of M60s to drive ESL63s, but the amount of bass energy is WAY more than any other amp, and also the amps don’t impart extra bass to any other speaker. Is that just the way those amps are with Quads?
 
Dec 16, 2018
57
30
20
76
Phoenix, Arizona USA
#15
So I saw the M60s next to Quads in one photo. I just got a used pair of M60s to drive ESL63s, but the amount of bass energy is WAY more than any other amp, and also the amps don’t impart extra bass to any other speaker. Is that just the way those amps are with Quads?
Don't know; never had '63s. The '2905s didn't sound that way with the M-60s; those amps simply didn't have enough power for the '2905s.
 
Jul 22, 2019
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#16
Thanks for your update. You did a lot of work on those M-60s to not be able to use them with the Quads. They've been enough power in my small listening room - I can hardly push the ESL-63s before the protection kicks in. I've been getting some good hints from Ralph at Atma-Sphere and it's a work in progress, but on most music there's still too much bass.
 

Atmasphere

[Industry Expert]
May 4, 2010
949
157
455
St. Paul, MN
www.atma-sphere.com
#17
So I saw the M60s next to Quads in one photo. I just got a used pair of M60s to drive ESL63s, but the amount of bass energy is WAY more than any other amp, and also the amps don’t impart extra bass to any other speaker. Is that just the way those amps are with Quads?
A friend of mine had ESL 63s and we had plenty of opportunity to play them with M-60s. His speakers were about 5-6 feet out into the room. What we all noticed is that the Quad was essentially playing bass for the first time but not in a way that was overblown- its just that most amps can't drive the higher impedance that the 63 has in the bass region. But we've had a number of people try out the M-60s after running solid state- and we had to convince them that getting the speaker further from the wall behind them was important.

BTW the green resistors seen in the photos are not carbon composition. We don't use any carbon resistors- they are entirely metal film with the exception of some wirewound devices.
 
Dec 15, 2018
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#18
I'm using M-60 with Quad ESL 2912, MP-1 and Lampizator Big7. Previously I was using Ear V12 and Quad II Eighty amplifiers. Only Atmas are able to make Quads speakers go down to 30Hz. Neither EAR V12 or Quad Eighty were able to do it. It's actualy the first time with Atmas that I've heard a powerful and well shaped bass from my ESL speakers. No need for subwoofer any more. If you have "too much" bass in your room with your Quads 63 and Atmas, the problem is most certainly not in your amplifier, neither in your Quad 63 speakers, but in your room acoustics. People are used to have very light low end with Quads as very few amplifiers can deliver low ends on quad speakers. So you may be surprised to have "that much" bass in your room after purchasing Atmas. If you feel like now you have "too much bass", the right way of dealing with this issue would be to do some acoustic treatement. In my case I have installed 12 tube-shaped bass traps in room corners, which was very beneficial. Also, quad speakers must be placed 1,5m away from the wall, with 3m distance between them, in perfect triangular position toward the listening chair. In that configuration, the impact of low end back-waves are less audible and speakers totally dissappear. In small rooms listening 30 hz from large panels will be problematic. 30 Hz wave is 12m long or more. So you may need to invest significant amount of efforts to find the best acoustic treatement for your room (sound diffusers right behind the pannels, sound absorbers on ceiling, floor and lateral walls, tube traps in corners and middle of each wall). Atmas with Quads are fantastic match. There's no better combo as far I know. So if you are a Quad lover, go for Atmas, you'll not regret.
 
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