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.
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@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.
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@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. |
@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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@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.
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@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.
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@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.
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