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1. First, sound quality--resolution/transparency and smoothness (= nonedginess)--are excellent, even with brand-new everything.2. Have had some problems with lack of good contact with tube sockets. Had lots of trouble getting one amp to null its DC offset. Thought it was mismatched output tubes or even bad frontend tubes. Played with 16 output tubes (hereafter OT or OTs) and several frontend tubes (FETs)--original Chinese and old Tung-Sol roundpates. Sometimes the cathode follower's filaments wouldn't glow. Eventually worked out a sequence of loading input tubes into the amp and then pairs of OTs, and all has been well in both amps for a couple days. (I experienced the problems in only one amp, I experienced NO OT-internal-fuse blowings, and Ralph was very helpful.) My lesson learned--TY, Ralph--is that the Chinese tubes have slightly larger pins, and sometimes the socket's contacts don't make good contact with my old tubes.
3. Have installed new Cardas CCGR bindingposts, new solid-silver wires to the cap terminals, new Furutech FP-901(R) RCA jacks, two 1uF SoniCap Platinum output-stage-PS bypass caps in each amp, and three strips of SoundCoat the thicker...see link...on each bottom cover. IMO the chassis rings too much, and I'll be adding more of that stuff. (IMO vibrating resistors, capacitors, wire, vacuumtubes, etc., do NOT add to the sound quality, they all diminish it.)I applied SoundCoat inside the VERY-highly-ringing transformer cover of the 2nd amp.
This cover is now DEAD!4. I THINK the first serious improvement project I'll do is to replace the inexpensive 100/350 'lytic caps in the frontend's powersupply with BlackGate VK-series 150/350s*, bypassed with 0.47uF Platinums. ... But that's a big project, and probably it'll take me weeks to start that. Then I'll replace the output-stage PS caps, and for that I have a bunch of BlackGate 470/160s*.
I've removed the feet from my amps; I'm using the 2"-square Wagner antivibration pads...
...two-high. They seem to work just finely on my carpeted concrete-slab floor.* that I've been saving for many years
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Tin-eared audiofool, large-scale-Classical music lover, and damned-amateur fotografer.
William Bruce Cameron: "...not everything that can be counted counts, and not everything that counts can be counted."
Edits: 04/23/16 04/23/16 04/23/16 04/23/16 04/23/16 04/23/16 04/24/16 04/24/16 04/25/16 04/26/16 04/30/16 04/30/16 05/02/16 05/02/16 06/19/16 06/19/16Follow Ups:
Below this paragraph is what I just posted on Audiogon. I purchased a used pair of Mark 3 M-60s'and sent them to Atma-Sphere to be upgraded to the newest 3.3 version. I also had the cu V-Caps,upgraded power supply and dual speaker binding posts installed.
Well, at this point here's an update of my opinion of the Atma-Sphere M-60's compared to my Pass Labs X350.5.
First off, the cu V-Caps have maybe 40 hours on them. I recall reading somewhere that these caps take the longest of all caps to break in. Somewhere between 250-500 hours! Ralph from Atma-Sphere indicated 140 hours is probably all they need. Also, I am still using the older mismatch tubes that came with the used M-60's. In addition, some of my favorite tweaks did not apply well with the M-60's. One of them that surprised me was the Synergistic Research carbon XOT's. The XOT's placed at the speaker cable ends had provided a nice sharpening of the image. But now with the Atma-Sphere amps the sound was limited in the frequency extremes. I think they must have had a conflict with the M-60's 4 ohm output impedance. So, I ended up selling them!
So, with all that being mentioned, I am getting some very nice sound quality even at this early point in the break in process. There is a very wide and deep soundstage. There is a smoothness that is hard to describe. It is not a veiling of upper frequencies for I have noticed so many chimes, bells and every kind of tingling sounds imaginable in familiar recordings that I did not notice before. No, it is a smoothness that makes it easy to listen to music for long intervals. The vocals are pure and true and to me very lifelike. And although I am crossing over the lower bass at 100 Hz to (2) JL Audio F-113 subs the bass notes are taking on a more definitive tone. That is, you can follow the walking of the bass lines better, very enjoyable. Evidently the bass notes do not just reside in just the lower range.
I originally thought that playing music as loud as before (compared to my high power SS amp) might be a problem. Yeah, I'm an old time rocker (64 years old). And, I have been known to crank it up to, "feel the music". All you air guitar rockers know what I mean… With the M-60's, I can still play the music quite loud with my DIY speakers and external crossover's. So, I did a good job matching the driver components to mesh well with the Atma-Sphere's. But, the weird thing is, I find myself listening at lower sound levels more than before and I don't know why.
Both of the amps (Pass Labs & Atma-Sphere) have their sonic qualities. I do however believe that my Pass Labs amp has more dynamic's and will play significantly louder, especially with lower impedance speakers like my old Eggleston Andra 2's. The Pass Labs also has more slam and startle factor, and they do have similar warmth as the Atma-Spheres.
The Atma-Sphere M-60's have a purer tone and I think reveal a little more detail. I have many audio recordings that I recorded through the decades of live performances from TV/Cable/Satellite broadcasts (the Tonight Show, Jay Leno, Grammy award shows and such) that with the M-60's I now detect distortion. Distortion that I never knew were in those TV/Cable/Satellite recordings with the Pass Labs amp.
At this moment, my preference is the Atma-Sphere M-60's over the Pass Labs for its higher sonic purity. And I love those dimly lit tubes! But, we audiophiles are a fickle bunch that changes minds often. If I change speakers or if I long for more slam and loudness the Pass Labs will be sitting on the sidelines. I don't intend to sell either product at this time.
ozzy(Audiogon moniker)
...and the left-channel speakercable patched with somewhat-better stuff. Other than that, I'm just listening and loving the sounds. Unfortunately, my hi-frequency hearing continues to deteriorate along with my ability to delight in my system's transparency.
All my nonaudiofool buddies (and wife, of course) keep saying 'hearing aides', but I'm not sure.
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March update. Finished adding SoundCoat damping material to the amps' bottom covers and a bit to the interior ceilings. The chassis now don't ring--they only 'tick--when the very mechanical switches are turned on or off.
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Tin-eared audiofool, large-scale-Classical music lover, and damned-amateur fotografer.
William Bruce Cameron: "...not everything that can be counted counts, and not everything that counts can be counted."
Edits: 02/27/17 03/12/17 03/13/17
My cockapooch and I were listening to music when WHAM!, something popped VERY loudly in the right channel and flashed brightly in the RH half of the right-channel amp. Of course we both jumped and she approached the amp, sniffing, but I called her back. The music continued playing and sounded fine, but I turned off that amp and visually checked the fuselinks in the 4 right-hand OTs. Found both fuselinks disappeared in one tube (see link below), replaced the tube with a spare, turned the amp on, rebalanced that amp after it warmed (and again hours later), and all is GOOD. In many output-transformered amps, that tube blowing would have taken with it a large resistor on the board and junked a $50 - $100 tube; my spare OTs cost about $9 each, delivered, IIRC.I've been merely listening to these amps and my system for a couple months; this summer, in spite of the desert heat in Phoenix, seems to be my season for buying, selling, and shooting pistols, punching paper and blowing up pesky waterjugs. :-)
The system sounds EXCELLENT, and I'm VERY happy I have these amps.
TYVM, Ralph!
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Tin-eared audiofool, large-scale-Classical music lover, and damned-amateur fotografer.
William Bruce Cameron: "...not everything that can be counted counts, and not everything that counts can be counted."
Edits: 07/08/16
Finally got the four Platinum bypass caps in the 2nd amp and also made another left-channel preamp-to-poweramp IC. This is of Neotec UPOCC-silver NEI-1001 (?) and KLE Innovations Absolute Harmony highest-quality solid-silver RCAs*.Also started removing the SuperSubs from the front wall.
Tonite we pulled the drivers and then the front panels which left the hollow boxes lined with 2" plastic foam. The subsequent mild damping of the rear wave from the Super-7s has improved image placement and solidity and reduced instrumental blurring, thus improving transparency.Will be building some panels combining broadband absorption and bass trapping for those about-3'-wide-by-6'-high soon-to-be-blank walls.
HOT DAMN it really sounds better!
* The KLE Innovations connectors are the successor to the Eichman plastic-bodied, low-metal-mass RCAs of years ago; see link.
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Tin-eared audiofool, large-scale-Classical music lover, and damned-amateur fotografer.
William Bruce Cameron: "...not everything that can be counted counts, and not everything that counts can be counted."
Edits: 05/14/16 06/19/16
Sound-Coated the transformer cover, moved the pair of 1uF Platinums--that amp was humming a bit because I wasn't smart enough the first time to get both caps far enough away from the AC-filament cables--and added a pair of 0.47uf Platinums to the powersupply poles supplying Vs1*.
Will get the 0.47uFs installed and the 1uFs moved in the other amp, and then they'll cook for weeks while I fool around building another equipment rack, this time with 80/20 stuff. (Can't afford the rack/s I want.)
* JIC you haven't read Ralph's note, the former V1 is now two 'N7s with sections in parallel, labeled V1a and V1b.
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Tin-eared audiofool, large-scale-Classical music lover, and damned-amateur fotografer.
William Bruce Cameron: "...not everything that can be counted counts, and not everything that counts can be counted."
Edits: 04/27/16 04/27/16 04/27/16 04/28/16 04/30/16
Hi,
Bypassing have been long term best practice for us amateurs but I'm not too sure that it's a good idea after all.
Real world capacitors are capacitors with unavoidable small inductance and resistance so we should design our circuits with that in mind that they indeed are resonators at a given frequency.
By paralleling (different values) of capacitors might interact with each others like a parallel resonant circuit. Our perception of an improvement by the added capacitors might not be an improvement after all. Verifying the implementation by measuring the circuit before and after can give us a hint.
So, I believe your intention by replacing the originally 150uF capacitors is the better approach.
For my own DIY M60 I've installed 4-pole electrolytic capacitors followed by electronic chokes followed by polypropylene capacitors. No bypassing.
It does measure excellent for sure but is it really a better implementation soundwise compared to Ralphs approach? Maybe, maybe not.
Ralphs passive PSU design is guaranteed to be long stable solution without any risk for a meltdown of the output tubes nor our beloved bass drivers.
BR.
Hello
Long time lurker and first time poster in ANY forum.
I recently completed a kit build of a pair of M60's and I am loving them. It was a project that was way over my head and with Ralph's generous/patient support I got through it. I have also been bitten by the modification bug and have upgraded signal path resistor quality (same values) to great effect. My question to jeffreybehr (and anyone else who wants to add their thoughts) is; what are the sonic benefits of all of the additional capacitance (bypass capacitors)?
If this has been covered before, please forgive and point me in the right direction.
Thanks
I won't comment on the parts swapping. But it seems to me that I see threaded recesses in the bottom of your chassis which might accommodate the threaded male ends of audiophile "footers", if you are of a mind to do that. I wonder why feet of some sort were not included in your shipment.I am sure you realize this, but go easy on the dampening materials lest you impede the cooling of the amplifier via heat transfer direct to the metal chassis. The cooling is not entirely dependent upon the slotted air vents.
I will send out your 6SN7 this week. Thanks.
Edits: 04/25/16
Yes, I understand that the chassis surfaces help cool the amp, but I suspect the bottom cover does very little of that. Probably I'll apply very little SoundCoat to the ceiling of the chassis. Since I'll add little damping to the ceiling of the chassis, I plan to add four stainless-steel bars, probably 3/4-by-2-by-4-1/2" to be cushioned with some sort of Herbies pads, placed on edge atop the chassis, one each between the rows of output tubes and two alongside the frontend tubes. It's easy for me to visualize that, but I expect a few pictures will be worth hundreds of words.
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Tin-eared audiofool, large-scale-Classical music lover, and damned-amateur fotografer.
William Bruce Cameron: "...not everything that can be counted counts, and not everything that counts can be counted."
on my first and only reading of your post, I thought you lamented the lack of "feet" and so are using your own solution to that problem.
The best, really only, way I have ever read about (but never used) to cure the "problem" (if it is a problem) of vibrating capacitors and resistors is that spray-on or paint-on compound, can't recall the name of it, that really does dampen vibrations. However, it must be a nightmare if you later want to change out parts or service the circuit. Other than that, one could use double-sided tape and other forms of goop. So what do you do?
One guru on TubeDIY actually recommended keeping capacitor and resistor leads as long as possible and coiling them up so as to allow the leads to act like a spring, in an attempt to decouple the part from the vibration of the chassis. But that leaves the part free in space to vibrate secondary to signal transfer.
I too have been fiddling around with my Atma-Spheres. It was more out of boredom than anything else. In my mind the MA-1's started out as the best I have ever owned. I also have the Tenor 75 OTL's in house.
I had to build 'risers' to accommodate my mods.
The Mundorf TubeCaps, like the Blackgates (which was my first mod) do make things a little smoother.
If you look at the bottom right corner of my picture, you'll see the Mundorf 4-pole storage supply caps. I'm not sure how 4-poles would be installed in the M60, though you appear to be more knowledgeable than I. No words can describe the elevated state of 'thereness' of my record collection.
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