Atma-Sphere in CO?

I'm looking to listen to one of Ralph's amps.  I'm in Denver and have Coincident PREs and a pair of Coincident's wonderful 300b Frankenstein's if anyone's interested in doing a comparison.  Obviously the speakers won't travel, but I'd be willing to pack up the amps and do some driving.

Will probably catch AS at RMAF, but would also love to do a home based A/B comparison...
I own both the Franks and the Atma-sphere M-60's, and use the amps to drive Coincident Super Victory II's and Coincident Triumph Extreme II's.  Let me say at the outset that I love both amps and have no desire to sell either.  Several years ago, I did a long and careful audition of the Franks driving PRE's, so I have a good feel for the combo you have. I suspect this will be a tough choice for you, and the best option is to do a long evaluation in your room with your ancillaries with both amps side by side.  You already know the virtues of the Franks.  What I can tell you is that the M-60's equal the Franks in many respects, but the amps do diverge on some attributes.  As you know, and as Ralph has pointed out on numerous occasions, 300B amps are at their best when driven gently.  Distortion rises rapidly above 1-2 W output.  For me, that is an issue.  I listen to a lot of orchestral music, so rising distortion became an issue driving the 92.5 dB efficient SVII's.  Rising distortion will never trouble you with your PREs driven by M-60's.   If you mostly listen to small scale works, with peak volumes at or below 90dB in a smallish room, rising distortion may not be a significant issue.  You will find the M-60's lack some of the wonderful sonority of the Franks, but not much, provided that you select good driver tubes to replace the awful (in my opinion) Chinese 6SN7s that are stock.  I really favor the NOS RCA 6SN7s, myself.  For me those tubes bring some of the 300B virtues to the M-60's.  The less expensive 1960's vintage 6SN7GB tubes are fine.  It is not necessary to use the uber expensive 40's and 50's vintage tubes.  Also relevant is that I ordered my M-60s with the V-cap upgrade and the power supply upgrade.   I do hope you are able to arrange a long audition with the M-60's having an appropriate driver tube compliment, and I will be very interested in your conclusions. 
@brownsfan Thanks so much for the information... super useful.  Will probably also demo a Pass XA-25, that's at least easy to get in the room for a 30 day demo and I'd love to be able to just leave the stereo on all day without concern for tube life.
@cal3713 ,  I've also thought about giving Pass or First Watt at try, and almost went that way before I bought the M-60's.  The problem is that when I like something, I don't want to give it up.  That is why I ended up keeping the Franks.  If I brought in an XA 30.8, I'd probably end up with 3 amps.  For what its worth, you can leave the M-60's in standby mode if you like.  There is no B+ voltage in standby, so I'm not sure that compromises tube life, and the amps don't generate much heat in standby.  Ralph can give you a better answer on that stuff. 
I'd love to be able to just leave the stereo on all day without concern for tube life.
If the amps are on a moderate load (and most Coincidents are) then the tube life is really really long. I leave my amps on all day and most of the night without worries, although I do put them in standby if I step out for dinner or the like.
i believe The Music Room has some M60 coming up for sale soon....Broomfield
i have no dog in fight
i have bought/sold with them...hyper good people
@tomic601 Thanks for the heads up. I sent an e-mail yesterday and just got my invoice today. Can’t go wrong with a 45-day 100% refund trial period. Very curious to hear how they compare.

And @brownsfan I do happen to have a pair of old smoked glass RCA VT-231s so hopefully they help the M60’s play nicely in the system.
@brownsfan btw, any word on which of those 6SN7s are most critical?  I think I have enough pairs of decent ones to replace the stock drivers, but only one pair of those smoked glass RCAs.
@cal3713 I think the amps you bought are MK 3s, so I am going to have to defer to Ralph.  Mine are MK 3.3, so what I know is not relevant to your amps regarding which positions are most impactful.  I can say that at least in my amp, tube rolling the drivers is noticeable.  Some like the old Sophias that were rebranded First Musics, and as I said, I found the 60's RCA GTBs to my liking. (I left the new stock Chinese tubes in the position that controls DC offset, since Ralph told me rolling that tube has little impact.  Not sure which tube in the MK 3 controls that function.)  When you get your amps, please share your thoughts on the amps per se and also anything on your preference in 6SN7s.
If its an older amp updated to Mk3, the tube layout might be different.
So, in the latest iteration, the tubes in the rear beneath the meter on either side are the most important to the sound. The one in the middle is next most important.
In the very early Mk3.0 (long chassis) the most important tube is the one in the front, followed by the one right behind it.
In older amps updated to Mk3.0 (and up to Mk3.2) that have the more rectangular power supply cover, the front left tube is most important, followed by the front right.  If updated to Mk3.3, both front tubes have equal importance.
The driver tube sits by itself on the later chassis (with the more curvaceous power supply cover). It should have either a -GTA or -GTB suffix. If the long chassis version, this is the rearmost 6SN7. In the older rectangular style, this is the rear right hand 6SN7. While this tube has less effect than the others, it is still audible.

One thing to keep in mind- you may run into intermittent operation when trying different tubes. We use the Chinese 6SN7s, which have a longer pin on the base of the tube that is also slightly larger diameter. So the socket pins might be spread a bit and have a looser contact with NOS tubes which often have shorter pins. The sockets are easily tightened without taking the amp apart. Contact me if you run into something like this and I'll walk you through the process- it only takes a few minutes. 
@atmasphere Thanks so much Ralph.  Given the proximity (on my daily commute route) and 45 day trial period, I honestly just bought the amps without even finding out which version they are.  And now they've got the ad down, so I can't check.  My visual memory is that they are are not the long chassis, but I'll find out tomorrow.  Very interested to hear. 

@brownsfan Also, I had been limping around with some old cables on my PREs due to the need for bi-wiring the bass & midrange units and finally got some proper cables in the system... it has greatly improved the situation, so it'll be a good shootout between the Franks and the M-60s.
@atmasphere Thanks so much for the information Ralph.  Given that the amps were local and came with a 45-day return period, I didn't even investigate what version of Mk3s they were.  Definitely the more recent wide chassis version though.  

@brownsfan And very curious to hear them in comparison to the Franks.  Upon getting my PREs out of storage after living away for a year, I've been limping them along with poor cabling due to the separate binding posts for the subs and head units.  Finally got new cables (I built them from the Dueland WE replica wire) and everything is sounding much better with the Franks.  Will be an interesting shootout.  
@atmasphere Also, if I'm reading your post correctly, that means that my RCA 6SN7GT VT-231s won't actually work in the amp.  Right?  I don't think I actually have any GTA or Bs, unfortunately.
The GTs will work in all but the front position. Just use the Chinese 6SN7 in that location and you'll be fine.

The fundamental difference I suspect you'll hear is that the Franks have a more lush sound while the M-60 is more neutral. The difference is that the distortion signature of the Franks is based on the 2nd harmonic while the M-60's product (like all fully differential amps) is based on the 3rd. The ear treats both the same, but amps with a 3rd harmonic have overall a lot less of *any* harmonic, starting with the 3rd which is about 1/10th or less of what you see in an SET. So while it is still smooth and relaxed like an SET, its just got less of its own 'tonality'.

I'd be interested to hear what you think.
@cal3713 ,  I looked at the Music Room ad and remember that they indicated the amps were MK 3 and were 8 years old.  @atmasphere  can probably deconvolute the history of your new amps when you have the serial numbers.  Ralph nailed it on the difference between the Franks and the M-60s.  Your preference is going to be a matter of personal taste.   I love both amps, and really enjoy having both.  The M-60s are upstairs and the Franks are downstairs.  Even if I didn't have 2 systems, I would probably keep both amps.  BTW, I am using the shortest possible run, about 2.5 ft, of the Duelund WE replica (12 G) from the M-60s to my Coincident super victory IIs.   Ralph advised keeping the speaker cables as short as possible.   I've been very satisfied with the Duelund in my set up. 
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Thanks again for all the input folks.  Will be very curious to find out how it shakes out... I pick up the amps tomorrow, so I should know more by the end of the weekend.
I've now gotten a good demo with the M-60 (it came with a nice set of VT-321s, including RCA smoked glass and Ken-Rads). I believe it improved on the Frankensteins in two dimensions: 1) bass definition & quantity, and 2) "cleanliness," the sound was super clean and I could tell there was very little distortion in the signal. Unfortunately, these improvements also came with a cost, in that I lost a degree of realness/naturalness. There was less texture or color to the sound than through the Frankensteins. I wish I could just marry the two amplifiers to get the best of both worlds, but in the end decided that bass was less important than realness, and will be sticking with the Frankensteins.  

At this point I'm starting to lean towards just keeping the Franksteins and dealing with the slightly reduced bass output. I got new cables (constructed from the 16ga Duelund WE replica wire) a couple weeks ago and that has really improved the bass situation as well. Now that they are broken in, the Franksteins do not really sound lean at all. Due to some unfortunate life situations I had been limping along with a combination of old budget MIT cables (that I'd also had to repair myself after a connector broke off) and anti-cables and it is now clear that they were actively preventing me from hearing the bass content the Franks/PRE combination was capable of.

In any case, I am growing more and more impressed with the Frankensteins. They're still in the system despite bringing in both the M-60s and the Lyngdorf TDAI-3400. I may also try the Pass XA-25, but do not really anticipate them beating out the Franks given what I've heard over the past few weeks. I may just decide to invest in getting as much as possible out of the Franks by upgrading power cables and installing Dueland capacitors.
@cal3713 thanks for the update.   I am well aware of the virtues of the Franks, which is why I am keeping them.  If I had to choose between the Franks and the M-60's, I'd probably keep the M-60's, but it would be a though choice.   Your PREs are more efficient than my SVIIs, so I can see how the balance might be tipped towards the Franks in your case. BTW, what tubes are you using in the Franks?
Its funny, I've thought about bringing in a Lyngdorf for my downstairs system, where I have significant room acoustics challenges, and returning the Franks to the upstairs system for use with smaller scale works.  But if I do that, I will not be letting go of the M-60's.
Keep us posted if you bring in the Pass.  I will be surprised if it displaces the Franks, but it would be an interesting experiment. 
I assume you are talking about installing the Duelunds in the Franks.  I haven't done that yet, but you might want to consider the PRE crossovers also.  I recently rebuilt the crossovers of my SVIIs, and the work substantially improved bass articulation among other improvements.  I don't have any actual knowledge of the PRE crossover design, but in Coincident models below the PRE, the design and parts list seems pretty consistent.  My guess is if you look you will find Solen caps and resistors, and they are not all that hard to beat. 
Just a FWIW- we've had terrible luck with the MIT and Transparent cables; we've never gotten them to play nice with our gear. No idea why, but you might want to run that comparison again if you can borrow a different set of interconnects.

Also- the amps are very transparent, but if they've been sitting a while, I wouldn't take them seriously until they have about 20-30 hours on them. Further, they need about an hour to really sound right.
@atmasphere Thanks for the information Ralph. Fortunately I was running them with my Duelund speaker cables and Ocellia interconnects. I’ll hook them up to my little desktop speakers and let them play for a couple days and then give them another shot before returning.

@brownsfan And I have the EML XLS in my Franks. I used to also have Mullards as my rectifiers, but unfortunately my tubes went bad.   I replaced them with standard NOS RCA 54Us.  Will probably give the Mullards another (3rd) shot at some point in the future. As for caps, the PREs only have one capacitor (and two induction coils) in the crossover. Isreal says its a Mundorf. I’ve seen in there and it’s wrapped so I can’t confirm whether that’s true.
@cal3713 I just recently picked up a pair of used EML XLS and also have the mullard rectifiers.  Tried the Elrogs twice, which were superb, but they failed.  Not sure if the new Elrogs are holding up in the Franks or not.  But they were to die for tubes.  As for the PREs, I'm guessing the two inductors are in series with the woofer and midrange, and the Mundorf cap is in series with the tweeter.  This is the arrangement I found in the SV IIs, except that the cap was a Solen.  The woofer had a cap and resistor in parallel, as did the midrange.  I'm guessing that like the SVIIs,  the PREs have these additional caps and resistors in parallel.  Some say replacing those parallel caps and resistors don't make a difference, but my experience was that replacing them really transformed the SVIIs.  I did not replace the inductors in my speakers.  I was told the Solens Israel uses are really good and there was no need to replace them. 
@brownsfan Actually there aren't any caps or resistors on either the woofers or midrange.  Only that one cap attached to the tweeter. 

From Coincident:  "The signal path contains only one capacitor (Mundorf – The most transparent cap for the purpose) and two inductors (proprietary 10 AWG OFC Litz - one for the midrange and one for the bass). That is it."  Due to a shipping nightmare, I've been forced to look inside my speakers to find out what got damaged (before eventually shipping to Isreal for a full repair) and can confirm that that's true...
Do let us know IF you return them to TMR
i know a guy with some ESL-63......
I'm sorry, I just have to say this.
Due to the elevation, the ATMOSPHERE in Colorado is very thin.
Please forgive me.
Well, I left the M-60s on for about a week and then compared again to my my Franks. As Ralph had intuited, they did improve and narrow the gap between the two amps.  Once again, I was impressed by the bass control and grainless sound.  As before, however, the Frankensteins performed better on 3-dimensional sound and naturalness of voices and instruments.  I wish I could just magically combine the two amps, but in the end decided to return the M-60s to The Music Room. 

 I'll probably be taking them up to Broomfield next Wednesday.  For other potential buyers, they do come with VT-231 Ken Rads and RCA smoked glass tubes  I think the 6SN7GTBs are Sylvanias.  They should really advertise that in the ad...  
It sounds like these amps were used- any idea what version they are? The current version is Mk3.3 (older versions can be updated with full warranty reactivation).
@atmasphere I never found out from TMR. They had the 6sn7s in the 2x2 configuration, but had rounded edges on the power supply cover.  

Would love to hear a fully updated version at some point in the future, but only have funds for the units themselves at this point.
If it had rounded corners on the power supply cover its a Mk3 at least.
Any idea of the condition of the tubes? The main reason we've found that people let go of our amps is that they don't realize how far downhill the tubes have gotten. The second reason is that they buy a new speaker to which the amp is not compatible. In your case, that is no worries as your speaker (or its predecessor) was designed with M-60s that Israel used to own.
@atmasphere Interesting. I do believe there is at least one bad tube in the amp. I had a channel go out and was able to flip which channel it was by switching out the tube complement. I got a new set of 4 output tubes from TMR and rectified the problem, but did not consider switching out all the tubes. I’ll see if they have a full extra set before returning...
If the 6SN7s get weak, the amp can sound a little sleepy or dead. Its worth it to make sure they are all good!
@atmasphere Unfortunately The Music Room wouldn't provide any extra tubes... they do have a tube tester, but stated:  "while we can test the tubes, that may not really give you the information you are looking for, we can test to see if it is working, and get some idea of the condition but this won't tell how it sounds or how much use they have had. In addition, this would also take quite a bit of time to test that number of tubes."  They then offered to put in an order for a new set of tubes if I wanted to pay...
@cal3713 One other thought is that you mentioned what 6SN7s you had but you didn't mention where you put them.  I have found that any given mixture of 6SN7s will give very different results depending on where the tubes are located in the amps.  In my case with the 3.3's, I have some NOS grey glass RCAs in the two most important positions, (back row, left and right).   I have a Sylvania GTB in the back center position.  This position seems to want a tube with great dynamics, sparkle and air.  When I put a third RCA in that position, everything gets kind of sleepy, almost sirupy.  But the Sylvania that works so nicely in the center position does not play nicely on the outside positions.   In those positions there seems to be a decided lack of smoothness with the Sylvania.  In the 4th position out in front, I've tried new production Sophias and Tung-Sols.  The TS was better than the Sophia, but Ralph has warned against the new Russian TS tubes elsewhere.  The best tube I've tried so far in that position out front is a 1960's RCA GTB.  I've got a pair of GE GTA tubes on the way to try in that position.  In the end, regardless of tube complement, the M-60s are not going to sound like a 300B SET.  I listen to a lot of live orchestral and chamber music, and have a good perspective on what I "should" be hearing.  After 18 months with the M-60s, I would argue the M-60s are more faithful to that live music standard, and in my case I really need the extra juice.  Ralph and others can offer guidance on how to get the best from the M-60's, but no one can tell you what you ought to prefer.   For me, choosing between these amps is a real Sophie's choice.   Its going to take a lot to pry either one from my hands.  There is no wrong choice between these two options.   They both have their own beguiling charm.  Some like blue eyed blonds, some like dark eyed brunets.  I guess that makes me an audio polygamist. 
while we can test the tubes, that may not really give you the information you are looking for, we can test to see if it is working, and get some idea of the condition but this won't tell how it sounds or how much use they have had. In addition, this would also take quite a bit of time to test that number of tubes.
What you want them to do is test the 6SN7s. If they are good, that helps a lot! They should not be borderline. Don't have them test the power tubes, instead you can do that quickly by comparing them to the photos at this link:
The reason is that if the tube is failing, quite often it knocks out the link or links in the photos. So a tester really isn't needed- the amp has a meter, if you are concerned about strength, and it can be used to get a relative merit reading of any power tube.
@brownsfan & @atmasphere great, thanks for the information. I'll do some checking, swap out some of the 6sn7s for some nos ones I've got around, and do some more listening tonight.
How does the dynamics compare from the M60 to the 300B?

On the DIY Forum someone changed the Vcaps to another brand i forgot. The sound was tonally warmer.
@phantom_av Unfortunately it's been too long for me to give any reliable information.

I've transitioned to simple source follower amplification (first watt f4 mono-blocks, only adding current to the signal) and focus on getting the warmth from my preamp (Don Sachs 6sn7).

That combination is remarkably beautiful with great tonality and an amazingly holographic soundstage.