Dennis Had Inspire Amps

[Musica Amantem]

Originally Posted by FloridaBoy

Check this out: https://www.stereophile.com/interviews/399/index.html

Wow! I knew he had been leading that SET revival movement in the US but I thought he was in Radio long before starting to design amps. Anyway, that puts him in these endeavors earlier than the bulk of the Japanese in the early 70's. It is incredible how he still is so passionate about his art after all these years.

[BearCityUSA]

Originally Posted by Musica Amantem

Wow! I knew he had been leading that SET revival movement in the US but I thought he was in Radio long before starting to design amps. Anyway, that puts him in these endeavors earlier than the bulk of the Japanese in the early 70's. It is incredible how he still is so passionate about his art after all these years.

Cool interview! Interesting about the 2A3 amp. He often speaks of the first amp he built being 6v6g design.

If you think about it 2017 minus "One of the best sounding amplifiers I have designed in over 59 years of slingin solder" = 1958. He grew up in post war golden era of tubes

[FloridaBoy]

I think a 6V6 was the first amp he built. The article could be wrong.

[Musica Amantem]

Originally Posted by FloridaBoy

I think a 6V6 was the first amp he built. The article could be wrong.

It is probably the rest of the gear in Dennis's case, but I still do not understand his preference for that tube. It may sound sweet in very sensitive speakers, with the right gear, but relatively speaking the 6V6 sounds lacking soundstage, presence and even some detailing. Even the 6L6's sound better, OTBE, never mind Kink-Tetrodes and the like. Or, it may just be my setup which is not conducive to this tube's optimal range. Of course my experience with this tube does not include the most regarded NOS tubes some have cited here, which I suppose are a different kind of animal compared to the RCA GT and G ST's I have.

[pstrisik]

Originally Posted by Musica Amantem

It is probably the rest of the gear in Dennis's case, but I still do not understand his preference for that tube. It may sound sweet in very sensitive speakers, with the right gear, but relatively speaking the 6V6 sounds lacking soundstage, presence and even some detailing. Even the 6L6's sound better, OTBE, never mind Kink-Tetrodes and the like. Or, it may just be my setup which is not conducive to this tube's optimal range. Of course my experience with this tube does not include the most regarded NOS tubes some have cited here, which I suppose are a different kind of animal compared to the RCA GT and G ST's I have.

It's been quite a while, but I'm going to revisit the 6V6's - Popes and Visseaux. The latter was my favorite when I was running them. I'm beginning to weed out some tubes that I won't likely use. I have way too many!

[FloridaBoy]

Originally Posted by pstrisik

It's been quite a while, but I'm going to revisit the 6V6's - Popes and Visseaux. The latter was my favorite when I was running them. I'm beginning to weed out some tubes that I won't likely use. I have way too many!

See you at the Degenerate Tube-O-holics swap meet.

I still like 6V6ST's and the Pope GT's.

[Musica Amantem]

IME, 6V6 and 6L6 (44 mA max plate current in Triode at 250 V) sound weak, with narrower sound-stage and need all the boost these can get from the PRE. I would argue one should try "playing the gain" between PRE and AMP with those to improve body of sound.

The KT-66 has a slightly higher max plate current in Triode mode (60 mA) over the 6L6 /6V6, but lower than the EL34 (70 mA). The 6L6 and KT-66 sound proportionally better in my rig over the 6V6, but still limited (soundstage, depth, body of sound, bass, dynamics).

The EL34 and KT-77 (120 mA) are cousins, and probably share transparency traits in their midrange. Go higher into the 6550 / KT-88 (150 mA), and now the boldness is too much and this masks nuisance and transparency, offering too much body of sound and bass (ideal for rock, though). No PRE boost for these.

The reason why I need a PRE with the KT-77 to get all the body of sound I expect, is the same which makes the 6550 not need one for all that glorious body of sound (a difference of 30 mA). This correlates with my crazy theory of plate current specs. Therefore, I expect the EL34 to require the LP-27a to be at its best in my rig, although still slightly weak-sounding, but with the same transparent/airy behavior I get from the KT-77.

Note: "Playing the gain" is achieved by either using the PRE's volume dial maxed out and controlling volume from the AMP to improve body of sound in smaller output tubes (6V6, 6L6, 350B, KT-66), or, the opposite (the most common approach), maximizing the Amp's volume dial and controlling the volume through the PRE. This last mode thins out the sound of heavy-sounding recordings or larger, too bold-sounding output tubes. Playing within the in-between range of possibilities may be used to either compensate for lack of or de-emphasize (lean-out) body of sound (boldness).

[pstrisik]

Interesting. I don't have a volume control on my amp. I have the LP-2 pre and a Cambridge Audio Azur 851N streamer/DAC. Since the LP-2 doesn't have a remote, I run the streamer/DAC in preamp mode and control the volume from there with a remote. So I do the same thing, but balancing volume settings between the DAC and Pre. I typically have the volume setting on the LP-2 at about 3 O'Clock.

Can't give you specifics since it's been a while, but I've found the current production GL KT-77 preferable to both current production Mullard EL-34 and vintage Mullard EL-34 xf2 (one of the "holy grails"). The only thing close was the =C= EL-34, but I still prefer the KT-77.

We have some company, so I'm not doing my usual kind of listening and will have to give the 6V6's a listen in a couple of days. Back when I was running 6V6 though, I found the Visseaux to out do any of the others. The Pope's sounded a bit veiled in comparison.

The need for a Pre or not will also depend greatly on the speakers. I imagine speakers with greater sensitivity might allow going without the Pre even with the 6V6.

BTW, IIRC, the 5AR4 rectifier helped them along quite a bit, but with the IIPS mod, I don't think that is a tube we are supposed to be running and would make less difference anyway.

Originally Posted by Musica Amantem

IME, 6V6 and 6L6 (44 mA max plate current in Triode at 250 V) sound weak, with narrower sound-stage and need all the boost these can get from the PRE. I would argue one should try "playing the gain" between PRE and AMP with those to improve body of sound.

The KT-66 has a slightly higher max plate current in Triode mode (60 mA) over the 6L6 /6V6, but lower than the EL34 (70 mA). The 6L6 and KT-66 sound proportionally better in my rig over the 6V6, but still limited (soundstage, depth, body of sound, bass, dynamics).

The EL34 and KT-77 (120 mA) are cousins, and probably share transparency traits in their midrange. Go higher into the 6550 / KT-88 (150 mA), and now the boldness is too much and this masks nuisance and transparency, offering too much body of sound and bass (ideal for rock, though). No PRE boost for these.

The reason why I need a PRE with the KT-77 to get all the body of sound I expect, is the same which makes the 6550 not need one for all that glorious body of sound (a difference of 30 mA). This correlates with my crazy theory of plate current specs. Therefore, I expect the EL34 to require the LP-27a to be at its best in my rig, although still slightly weak-sounding, but with the same transparent/airy behavior I get from the KT-77.

Note: "Playing the gain" is achieved by either using the PRE's volume dial maxed out and controlling volume from the AMP to improve body of sound in smaller output tubes (6V6, 6L6, 350B, KT-66), or, the opposite (the most common approach), maximizing the Amp's volume dial and controlling the volume through the PRE. This last mode thins out the sound of heavy-sounding recordings or larger, too bold-sounding output tubes. Playing within the in-between range of possibilities may be used to compensate or de-emphasize (lean-out) unwanted body of sound excesses (boldness).

[Musica Amantem]

Agreed. Speakers may make all the difference in our rigs. I now believe I should eventually go into higher sensitivity terrain (mine are nominally 98 dB//m/watt). But, that may put my enjoyment of the LP-27a at risk.

I believe you could use the 5Z4 in lieu of the 5AR4, as these heat directly and both have the same Low V-Drop specs. This has become a favorite lately in my rig.

The GL KT-77 with LP-27a are my best combo. Are you familiar with this article?

http://wallofsound.ca/audioreviews/t...tubestore-com/

Seems the GL KT-77 has another contender in the 6CA7 from Shuguang, followed closely by the T-S EL34B.

[Rosco65]

Originally Posted by pstrisik

Interesting. I don't have a volume control on my amp. I have the LP-2 pre and a Cambridge Audio Azur 851N streamer/DAC. Since the LP-2 doesn't have a remote, I run the streamer/DAC in preamp mode and control the volume from there with a remote. So I do the same thing, but balancing volume settings between the DAC and Pre. I typically have the volume setting on the LP-2 at about 3 O'Clock.

Can't give you specifics since it's been a while, but I've found the current production GL KT-77 preferable to both current production Mullard EL-34 and vintage Mullard EL-34 xf2 (one of the "holy grails"). The only thing close was the =C= EL-34, but I still prefer the KT-77.

We have some company, so I'm not doing my usual kind of listening and will have to give the 6V6's a listen in a couple of days. Back when I was running 6V6 though, I found the Visseaux to out do any of the others. The Pope's sounded a bit veiled in comparison.

The need for a Pre or not will also depend greatly on the speakers. I imagine speakers with greater sensitivity might allow going without the Pre even with the 6V6.

BTW, IIRC, the 5AR4 rectifier helped them along quite a bit, but with the IIPS mod, I don't think that is a tube we are supposed to be running and would make less difference anyway.

Peter, I think there is a difference between your setup and MA's. He has a volume control at the front of the preamp which determines the amplitiude of the signal being amplified by the preamp, followed by a volume control on the amp which controls the amplitude of the signal being amplified by the amp. In this case, for a given volume level the amp is always doing the same thing. We are changing how hard we are driving the preamp by playing with the input and output volume controls. There are likely sweet spots where the preamp is happiest when driving different tubes.

OTOH, your arrangement only controls signal amplitude going into the preamp/amp system. You can play with how much gain is coming out of the output stage of your streamer, but in the end the preamp is always going to be driven at the same level for a given volume level.

I don't know if this is better or worse. I would posit that MA's setup has the potential to tweak the sound a little more and is the common arrangement in guitar amps. It is likely he is able to find a spot in the preamp's gain range that suits his preference for each tube.