Dennis Had Inspire Amps

[Bombadil]

Originally Posted by nhparrot

Bombadil, Dennis recommended the KT77's to me based on my system with ProAc Response 1SC's. Although I like the KT77 better than a KT88 or 6L6, the power tube set I prefer most is a 6V6GT, enough so that I have multiple makes of the tube (Pope, Visseaux, Bendix, Hytron).
.

I've tested a wide range of tubes in my system. The tubes which I've found the most forward through the mids & highs - not saying that they are overly bright but more detailed - are (in order):

1) 6P3S-e
2) 6V6GT
3) KT77

This can be a good or bad thing, depending upon one's speakers, room, system, etc.

The tube having an even more aggressive midrange is substituting a 6BL7 for the 6SN7.

The combination of a 6BL7 with 6P3S-e output tubes drives me out of the room.

[Rosco65]

While we can driver ourselves crazy trying to find the “best” tubes for our amps, being able to run a wide variety of output tubes has a number of advantages. One advantage is that it offers a relatively inexpensive way to experiment with “new” tube gear in our systems. Another is that it offers opportunity for both system and music matching. A KT77 might be a great way to add a little rock and roll drive to an Altec two way monitor, which is a little laid back. Conversely, a smoother tube (6F6? I ordered a quad to try them out) might be a better match with Omega Alnico speakers, whose whizzed cone can get a little bit of an edge if you’re not careful.

Or we can swap tubes based on music or recordings. A more forgiving output tube may make a lot of late 70’s vinyl actually sound good.

[x3workshop]

Originally Posted by Rosco65

While we can driver ourselves crazy trying to find the “best” tubes for our amps, being able to run a wide variety of output tubes has a number of advantages. One advantage is that it offers a relatively inexpensive way to experiment with “new” tube gear in our systems. Another is that it offers opportunity for both system and music matching. A KT77 might be a great way to add a little rock and roll drive to an Altec two way monitor, which is a little laid back. Conversely, a smoother tube (6F6? I ordered a quad to try them out) might be a better match with Omega Alnico speakers, whose whizzed cone can get a little bit of an edge if you’re not careful.

Or we can swap tubes based on music or recordings. A more forgiving output tube may make a lot of late 70’s vinyl actually sound good.

I agree with this statement completely. I've used different power tubes to accommodate the qualities of different loudspeakers as well as different musical genres to great success.

[x3workshop]

BTW, heard from Dennis. It looks like he has something special he's about to unleash on us. Hold onto your wallets.

[Bombadil]

The QMB-25 monoblocks which Dennis builds and sells via Moon Audio, as far as I know, run 6V6 tubes exclusively. Does anyone know differently? Could one use 6L6 tubes? EL34? Or even a lower powered 6L6-type like a 5881?

I suspect the OT's might not be spec'ed to handle the higher power of anything other than a 6V6.

[straitwire]

Originally Posted by Bombadil

The QMB-25 monoblocks which Dennis builds and sells via Moon Audio, as far as I know, run 6V6 tubes exclusively. Does anyone know differently? Could one use 6L6 tubes? EL34? Or even a lower powered 6L6-type like a 5881?

I suspect the OT's might not be spec'ed to handle the higher power of anything other than a 6V6.

Hey Bombadil, I asked Dennis the same question awhile back and he said it used 6V6's exclusively because of the output transformers impedance and power rating, and also the power transformer that was used had a 6v filament winding rated at 4 amps I think, so 6L6's or bigger would have been a bit much for that power transformer without adding filament transformers or using a power transformer with a higher amperage filament winding.
I really liked the layout of the QMB-25, no wasted space and a lot of power in a relatively small package, it was a natural progression from the SET-84 which was the first front to back oriented parallel single ended amp we built, which came from a conversation about how the EL84 tubes sounded so special, that if we could double the power and keep the same sound that it would make a really nice amp...straitwire

[Bombadil]

Thanks straitwire. I suspected as much.

I am not as familiar with the sound of the 6V6. I know I don't like them in my Inspire KT88 HO amp. They are too strident to my ears, in my system.

Perhaps in a different amp, they would be much better.

OTOH, I very much like EL84 tubes. I have both an Inspire SE EL84 amp and an old Cary Audio EL84 amp.

So perhaps this makes no sense as I have heard others compare the sound of EL84 and 6V6 as being similar. It is just that they are not similar in my system, being used in two very different Inspire amps.

[Bombadil]

Originally Posted by Bombadil

I have a pair of JJ KT77, which DH was recommending once upon a time. Don't know if that is still true. In my system they have a bit more "bite" through the midrange and highs than EL34s and my vintage Sylvania fat boy 6CA7s. Even a bit more than my re-issue Gold Lion KT88s.

Not so much that I would label them as being aggressive or forward. Just a touch more midrange detail, and perhaps a bit less deep bass definition than a KT88/KT120.

Vs EL34, the KT77 is more open with better imaging. The KT77 isn't as "lush" or warm-sounding as the EL34. I've read on guitar amp forums that people have switched from EL34 to KT77 to get a more dynamic, slightly more aggressive sound. I hear that same quality through my system when I'm playing songs with strong lead guitar riffs when using KT77s.

Replying to my own thread, am I going insane?

Before writing the above, I searched my tube cache for Golden Lion KT77s, as I thought I had some. But couldn't find them. I moved recently and packed up all of my tubes and tube gear about 3 months ago. Shortly after writing the above, I found my GL KT77s. At least I wasn't imaging that I had some.

So today I slapped them into the Inspire and compared them to the JJs. I don't fully trust such comparisons, as they are sighted comparisons with several minutes between listening sessions. Historically I have found such comparisons to be untrustworthy. I am a fan of double blind testing. But I would need two Inspire amps to pull that off.

In today's listening evaluations, it was my perception that the GL tubes brought out a bit more subtle detail and had a bit more definition in the lower bass region. That is, I think I could perceive a little more air on percussives, a little more "fingering" on background guitar, a little longer decay on piano. I noticed all of these things more in multiple songs than I did when playing the JJs. Whether I could pick out the differences in a double blind test, who knows? I've failed those before when I was confidant I would pass.

I found myself getting more into the music when using the GL. Ultimately that's how I decide what to use.

So the GL moved ahead of the JJ KT77 on my list of preferred tubes.

[decooney]

Originally Posted by x3workshop

BTW, heard from Dennis. It looks like he has something special he's about to unleash on us. Hold onto your wallets.

I asked Dennis a while back if he would consider building me a pair of higher power strapped triode mono blocks to replace/sell my current upgraded Cary V12R, and my Inspire Triode Hot Rod stereo amp I could pass long to a friend. Maybe in the future, could be fun if he'd ever consider doing it.

[FloridaBoy]

Originally Posted by decooney

I asked Dennis a while back if he would consider building me a pair of higher power strapped triode mono blocks to replace/sell my current upgraded Cary V12R, and my Inspire Triode Hot Rod stereo amp I could pass long to a friend. Maybe in the future, could be fun if he'd ever consider doing it.

I have seen older Inspire amps with a triode/pentode switch. I wonder why that has gone the way of the dinosaur?