B&W 804s + Atma-Sphere M60 MkIII.2

Lewinskih01- you make a good point, although many people report excellent results running them single-ended either w a conventional RCA termination (w shorting pin in the XLR jack) or w an XLR-terminated (aka pseudo-balanced) connection.
Not to get too far off point, but can you tell us whether you are running stereo subs or dual mono subs. If the latter, do you think that the same "rules" apply to stereo subs.

Lewinskih01, you are right on real balanced connection, that’s another parameter I’ve been considering. Let’s see what Ralph is going to suggest.
For subs, your comments sound very professional and I am sure you spent a lot of time on setting the subs. I wish I had your skills and patience. I came across this article which is very interesting. I changed my mind on Subwoofer size. I guess it’s better to move toward a 12” sub. I am not really obsessed with a lot of bass in the music. I do love attending live music performances and the thing I noticed is that the bass in live music does not shake the salon, classical music to Jazz/Blues and even semi-metal group like OM! A good compromise on bass and the whole setting is the key! Besides finding a good subwoofer especially built for music is another challenge, because most subs are made for HT!

http://www.soundstage.com/maxdb/maxdb200101.htm

Besides finding a good matching amp, my plan is to get one good sub and perhaps later on move toward a second sub. Rythmik subs looks nice and well-built. There is not too much reviews on those subs, I was wondering how do you compare Rel Storm vs. Rythmik subs? I mean uniquely for music usage.

Michel

The link didn't go through?!

http://www.soundstage.com/maxdb/maxdb200101.htm

Per the B&W web site the impedance goes down to 3 ohms. Power wise the M60 sounds like it would be fine. However, the 3 ohm impedance could be a problem. The way around this would be a Zero auto former (anti cables.com) which is placed between the speaker and amp and allows the amp to "see" a higher impedance with easily selectable choices of 2x, 3x and 4x the speakers impedance. So, as an example, if you choose the 3x option the M60 would see a speaker impedance of 9-24 ohms which on paper sounds about perfect but you can easily switch between the options and see which sounds best. It come with a 60 day in home trial so there's lots of time to find out which works best for you. Another benefit, the M60 will put out 80 watts/ch at 16 ohms up from the 60 watts/ch at 8 ohms.

It may sound strange to have an OTL amp only to have but a transformer between the amp and speaker but the Zero autoformer is not like the transformer in a traditional tube amp which has both primary and secondary winding. The Zero only has primary and just enough windings to do the impedance adjustment so it much more transparent than the typical output transformer
.
BTW, the Zero is not just for OTL's. Virtually all tube amps will sound better into a higher impedance. For instance, the MC275 mentioned by Lewinski above, IMHO, would benefit from the Zero by not having to play into the impedances below 6 ohms with lower distortion, better bass etc. Some of the biggest users of the Zero's are Magnepan owners with their 4 ohm impedance driving them with tube amps.

Check out anticables.com. Hope this helps.
BTW, my own setup has an Atmasphere S30 driving the 16 ohm Zu Superfly's.

It asked Ralph (@atma-shere) about this issue and he responded even though his busy schedule, he is in RMAF show. That’s very impressive and shows how dedicated he is toward the customers.
Franck thanks for your suggestion. It is very interesting that even Ralph mentioned the same alternative of using Zero Auto T. I looked at several reviews too and it seems it is a valuable solution to resolve mismatch impedance issues between Tube-Amps and Speakers. There is some compromises but bottom line if one cares about OTL, that’s the solution to move toward! The other alternative is to change speakers! I was wondering with your speakers having 16ohm input impedance, you wouldn’t really need any Zero Auto T. Based on your experience, does this solution makes any changes (good or bad!) on matronymics and details?
Michel.