Dennis Had Inspire Amps

[FloridaBoy]

Originally Posted by pstrisik

I've tried both and moved on, though it has been some time. Dennis is not enamored with the KT120's due to what he refers to as hard clipping. My understanding is that makes distortion sound harsher.

He included KT150's with my amp as it was the tube he made that amp for (it is called an Inspire KT150).

*I* believe that although these amps can use just about any pentode they sound best with just a few combinations. I think I have found what works best for me in my rig and will just enjoy the music.

[pstrisik]

Originally Posted by FloridaBoy

*I* believe that although these amps can use just about any pentode they sound best with just a few combinations. I think I have found what works best for me in my rig and will just enjoy the music.

You asked.

[FloridaBoy]

Originally Posted by pstrisik

You asked.

I was thinking about someone else.

[Musica Amantem]

Originally Posted by pstrisik

I've tried both and moved on, though it has been some time. Dennis is not enamored with the KT120's due to what he refers to as hard clipping. My understanding is that makes distortion sound harsher.

He included KT150's with my amp as it was the tube he made that amp for (it is called an Inspire KT150).

Interesting ... This throws my "theory" down the drains . I would expect an optimal group of output tubes for your amp design to be a distribution about the KT120 / KT-150 specs, but you prefer the 6V6, I believe. It seems there's more to the synergies involved in the entire rig than to the amp's output tube design characteristics . .. I have the opposite results relative to the 6V6 in my KT-88 amp. Go figure! Thanks for the feedback.

[pstrisik]

Originally Posted by Musica Amantem

Interesting ... This throws my "theory" down the drains . I would expect an optimal group of output tubes for your amp design to be a distribution about the KT120 / KT-150 specs, but you prefer the 6V6, I believe. It seems there's more to the synergies involved in the entire rig than to the amp's output tube design characteristics . .. I have the opposite results relative to the 6V6 in my KT-88 amp. Go figure! Thanks for the feedback.

Hard to know given different systems and tastes. I'd say, at this point, that my favorite power tubes are the Visseaux 6V6 or Mullard EL34 Xf2, the latter I have been playing for a few weeks now (with early "fat bottle" British GZ37/CV378/53KU and 1975 Voskhod "rocket" 6N23P driver). I seem to be settling in to a preferred combo.

Another experiment on the way though. I have vintage Amperex EL84's coming along with adapters. While this won't turn my SEP into a SET, I did have a chance to try the Wolf Ear Kitoki EL84 based SET on a recent amp tour. The sparkly highs made it seem like a worthwhile experiment. We'll see if they get traction or ruled out.

[Musica Amantem]

As you guys know, most of our Inspire amps are Triode-strapped Pentodes or Tetrodes, so, theoretically, these should be SET's, as one or two (depending on which output tube) of the pins have been eliminated. An amp can also run a Tetrode or a Pentode output tube in single-ended configuration, but not strapped as a Triode. There are sonic implications involved. People talk about the specific qualities of a "true" Triode output tube, especially in the midrange frequencies, but I guess this also depends on the design of the amp.

I've never heard the EL34 or EL84. The Super Zen EL84 amp from Decware comes to mind, deemed as a "purist" nice little amp. It's nice to see how large a range of output tubes your amp can handle, from the specifically designed-for KT-150 to even the EL84 ... Talk about robustness!

[FloridaBoy]

Originally Posted by Musica Amantem

As you guys know, most of our Inspire amps are Triode-strapped Pentodes or Tetrodes, so, theoretically, these should be SET's, as one or two (depending on which output tube) of the pins have been eliminated. An amp can also run a Tetrode or a Pentode output tube in single-ended configuration, but not strapped as a Triode. There are sonic implications involved. People talk about the specific qualities of a "true" Triode output tube, especially in the midrange frequencies, but I guess this also depends on the design of the amp.

I've never heard the EL34 or EL84. The Super Zen EL84 amp from Decware comes to mind, deemed as a "purist" nice little amp. It's nice to see how large a range of output tubes your amp can handle, from the specifically designed-for KT-150 to even the EL84 ... Talk about robustness!

No, they are not single ended triodes because the output tubes are pentodes. They can only be single ended pentodes or single ended pentodes wired/strapped in triode. The 45, 2A3, 300B etc. are directly heated triodes.

[FloridaBoy]

Originally Posted by pstrisik

Hard to know given different systems and tastes. I'd say, at this point, that my favorite power tubes are the Visseaux 6V6 or Mullard EL34 Xf2, the latter I have been playing for a few weeks now (with early "fat bottle" British GZ37/CV378/53KU and 1975 Voskhod "rocket" 6N23P driver). I seem to be settling in to a preferred combo.

Another experiment on the way though. I have vintage Amperex EL84's coming along with adapters. While this won't turn my SEP into a SET, I did have a chance to try the Wolf Ear Kitoki EL84 based SET on a recent amp tour. The sparkly highs made it seem like a worthwhile experiment. We'll see if they get traction or ruled out.

That should be fun. Be careful with rectifiers. *Most* EL84 amps use an EZ81/EZ80 rectifier. You may want to check with Dennis.

[Musica Amantem]

Originally Posted by FloridaBoy

No, they are not single ended triodes because the output tubes are pentodes. They can only be single ended pentodes or single ended pentodes wired/strapped in triode. The 45, 2A3, 300B etc. are directly heated triodes.

So how come Dennis calls all of them "SET"?

From Wikipedia: "The phrase directly heated triode single-ended triode amplifier (abbreviated to DHT SET) is used when directly heated triodes are used"

The ones you mentioned as "true" Triodes (45, 2A3, 300B, etc) are what here are referred to as directly heated Triodes, which makes the amp become a DHT SET. A Pentode or Beam-Tetrode output stage with the tube strapped as a Triode (three elements) works as a SET. When not strapped as a Triode, these woud be SEP, IMO.

[pstrisik]

Originally Posted by Musica Amantem

So how come Dennis calls all of them "SET"?

From Wikipedia: "The phrase directly heated triode single-ended triode amplifier (abbreviated to DHT SET) is used when directly heated triodes are used"

The ones you mentioned as "true" Triodes (45, 2A3, 300B, etc) are what here are referred to as directly heated Triodes, which makes the amp become a DHT SET. A Pentode or Beam-Tetrode output stage with the tube strapped as a Triode (three elements) works as a SET. When not strapped as a Triode, these woud be SEP, IMO.

He has made a few SET designs, but has not referred to the pentode designs as SET or SEP that I have seen (or recall anyway). In the ebay ad for mine, he talks about single ended, but not T or P:

NEW INSPIRE TUBE AMPLIFIER by DENNIS HAD FEATURING THE NEW KT-150 "FIRE-BOTTLE" BEAM POWER VACUUM TUBE AMPLIFIER IN A SINGLE-ENDED CLASS A DESIGN.