Dennis Had Inspire Amps

[Musica Amantem]

I've read the max anode plate dissipation of the KT-88 is 42 watts, whereas the equivalent spec in the KT-66 is 50 watts. Does this mean that, other things being equal, the KT66 yields almost 20% more power? If so, why no Inspire amp comes stock with KT-66's? If so, maybe Dennis prefers the sound of the KT-88 over other kinkless tetrodes (KT-66, KT-77, etc.), but giving up an extra 2 watts or so in these amps is a tradeoff.

Yet, here's an argument which contradicts the above conclusion (from Wikipedia): "The KT88 was introduced by GEC in 1956 as a larger variant of the KT66. It was manufactured in the U.K. by the MOV (Marconi-Osram Valve) subsidiary of G.E.C, also labelled as IEC/Mullard, and, in the U.S., Genelex Gold Lion".

I'm assuming a "larger variant" means more power? Should we assume the larger the number after "KT" in their designation, the more power ceteris paribus?

Thanks for any enlightenment.

[bILLwOJO]

My Inspire amp is signed KT66, built on 3-20-14. Can run a wide variety of tubes. Out of rotation at the moment, I'm using my MC40 monoblocks on some recently purchased Valencia's, next up will be the Inspire amp.

BillWojo

[Bombadil]

Standard specs for a KT66 has their maximum plate dissipation at 25W. I've seen some which claim 30W. In my KT88 amp, I get about 2 watts less per channel when using KT66, according to Dennis.

I haven't spent many hours yet with my re-issue Genalex KT66, but what I've heard, I've liked very much.

http://www.audiomatica.com/tubes/kt66.htm

[Comzee]

I've only owned some of these tubes mere days, but here is some early initial impressions with the fire-bottle.

My tube list:
Tung Sol NOS 6550 3 hole - matched pair
Psvane kt88 - matched pair
Psvane 6SN7(cv181)
Preferred Series 274B
Electro Harmonix 6SN7 gold pin
JJ GZ34
JAN-Sylvania 5Y3WGTA
JJ matched 6v6
JJ 5U4G
Gold Lion KT88 - matched pair
RCA NOS 6SN7
Sylvania NOS 6SN7GT 2 hole black bottom getter - (x2)
RCA NOS 5v4g - (x2)
MELZ 6N8S 5 hole plate - (en route)
Mullard f31 fat base gz34
Nothern Electric 6SN7
Nothern Electric 6SL7
Sophia Electric 6SN7GTA
Sophia Electric 6SL7
Sophia Electric 274B mesh
TAD 6V6GT - matched pair
JAN NOS 6V6 - matched pair - (en route)


I got the "tung sol 3 hole" and "2 hole black bottom getter" tubes based on those Hot Rod impressions from a few pages back. Everything else has been me free wheeling it.


I know a few people have asked, the NOS Tung Sol 3 hole are the real deal. I wouldn't say they blew me away, but I'm impressed. (early impressions)

My ranking for:

Output tubes:
#1 Tied - Gold Lion KT88 / Tung Sol 3 hole NOS
#2 Psvane kt88 (for the price these disappointed me)
#3 TAD 6v6 (a close third to the Psvane KT88, at a fraction of the cost)
#4 JJ 6v6 (bad)

Input tubes:
#1 Psvane 6SN7/CV181 (this surprised me, based on my kt88 experience)
#2 Tied - RCA NOS 6SN7 / Sophia Electric 6SN7GTA
#3 Sylvania NOS 6SN7GT 2 hole black bottom getter (disappointing based on Hot Rod impression)
#4 Electro Harmonix 6SN7 gold pin

Rectifiers:
#1 Sophia Electric 274B mesh
#2 Preferred Series 274B
#3 Mullard f31 fat base gz34 / JAN-Sylvania 5Y3WGTA
#4 RCA NOS 5v4g
#5 JJ GZ34

Notes:
#1 When I say "tied" I'm not saying they sound the same, I'm saying I think they're on the same level.

#2 NOS Tung Sol 3 hole maybe not worth it price v.s. performance. GL KT88 pair is $120, if you can get a TS3hole pair for close to that, I'd say go for it. I bought the strongest matched pair I could find for $300, for that price not worth it.

#3 Sophia 274B mesh is (imo) not good enough to warrant $100 more than the Preferred Series 274B. I'm extremely impressed with the Preferred Series 274B at the price.

#4 Northern Electric 6SN7 and 6SL7 are copies of Sophia (or visa versa?) Either way they look identical, and sound identical.

#5 6SN7 tubes are noisy (I use my Fire-Bottle with headphones too, so I notice this). 6SL7 are quite, low noise. Psvane cv181 is a freak of nature, quite and crazy raw resolution + full filled out sound.

#6 I REALLY looking forward to trying the MELZ 6N8S 5 hole plate

#7 YMMV!!! I'll give deeper impression between Gold Lion KT88 vs Tung Sol NOS 3 Hole once I get a few 100s of hours into each.

EDIT:
Guess I should have mentioned, Omega Compact Alnico (with r compound) and Sennheiser HD800 are what I used for the above impressions.

[Musica Amantem]

Originally Posted by Comzee

I've only owned some of these tubes mere days, but here is some early initial impressions with the fire-bottle.

My tube list:
Tung Sol NOS 6550 3 hole - matched pair
Psvane kt88 - matched pair
Psvane 6SN7(cv181)
Preferred Series 274B
Electro Harmonix 6SN7 gold pin
JJ GZ34
JAN-Sylvania 5Y3WGTA
JJ matched 6v6
JJ 5U4G
Gold Lion KT88 - matched pair
RCA NOS 6SN7
Sylvania NOS 6SN7GT 2 hole black bottom getter - (x2)
RCA NOS 5v4g - (x2)
MELZ 6N8S 5 hole plate - (en route)
Mullard f31 fat base gz34
Nothern Electric 6SN7
Nothern Electric 6SL7
Sophia Electric 6SN7GTA
Sophia Electric 6SL7
Sophia Electric 274B mesh
TAD 6V6GT - matched pair
JAN NOS 6V6 - matched pair - (en route)


I got the "tung sol 3 hole" and "2 hole black bottom getter" tubes based on those Hot Rod impressions from a few pages back. Everything else has been me free wheeling it.


I know a few people have asked, the NOS Tung Sol 3 hole are the real deal. I wouldn't say they blew me away, but I'm impressed. (early impressions)

My ranking for:

Output tubes:
#1 Tied - Gold Lion KT88 / Tung Sol 3 hole NOS
#2 Psvane kt88 (for the price these disappointed me)
#3 TAD 6v6 (a close third to the Psvane KT88, at a fraction of the cost)
#4 JJ 6v6 (bad)

Input tubes:
#1 Psvane 6SN7/CV181 (this surprised me, based on my kt88 experience)
#2 Tied - RCA NOS 6SN7 / Sophia Electric 6SN7GTA
#3 Sylvania NOS 6SN7GT 2 hole black bottom getter (disappointing based on Hot Rod impression)
#4 Electro Harmonix 6SN7 gold pin

Rectifiers:
#1 Sophia Electric 274B mesh
#2 Preferred Series 274B
#3 Mullard f31 fat base gz34 / JAN-Sylvania 5Y3WGTA
#4 RCA NOS 5v4g
#5 JJ GZ34

Notes:
#1 When I say "tied" I'm not saying they sound the same, I'm saying I think they're on the same level.

#2 NOS Tung Sol 3 hole maybe not worth it price v.s. performance. GL KT88 pair is $120, if you can get a TS3hole pair for close to that, I'd say go for it. I bought the strongest matched pair I could find for $300, for that price not worth it.

#3 Sophia 274B mesh is (imo) not good enough to warrant $100 more than the Preferred Series 274B. I'm extremely impressed with the Preferred Series 274B at the price.

#4 Northern Electric 6SN7 and 6SL7 are copies of Sophia (or visa versa?) Either way they look identical, and sound identical.

#5 6SN7 tubes are noisy (I use my Fire-Bottle with headphones too, so I notice this). 6SL7 are quite, low noise. Psvane cv181 is a freak of nature, quite and crazy raw resolution + full filled out sound.

#6 I REALLY looking forward to trying the MELZ 6N8S 5 hole plate

#7 YMMV!!! I'll give deeper impression between Gold Lion KT88 vs Tung Sol NOS 3 Hole once I get a few 100s of hours into each.

Could you kindly remind us what amp version are you using in this tube-rolling process? Thanks for sharing your impressions!

[Comzee]

Originally Posted by Musica Amantem

Could you kindly remind us what amp version are you using in this tube-rolling process?

Hmm, I guess Dennis makes more than one version of the Fire-Bottle?
Mine is the "SE HO" version.

[Musica Amantem]

Originally Posted by Bombadil

Standard specs for a KT66 has their maximum plate dissipation at 25W. I've seen some which claim 30W. In my KT88 amp, I get about 2 watts less per channel when using KT66, according to Dennis.

I haven't spent many hours yet with my re-issue Genalex KT66, but what I've heard, I've liked very much.

The KT66 Tube

Wikipedia published Anode plate dissipation specs as per my earlier post. I'm sure the KT-88 yields more power, so I guess anode plate dissipation is not a correlator for power.

https://en.wikipedia.org/wiki/KT88

https://en.wikipedia.org/wiki/KT66

Maybe these refer to the original versions (NOS)

[Musica Amantem]

Originally Posted by Comzee

Hmm, I guess Dennis makes more than one version of the Fire-Bottle?
Mine is the "SE HO" version.

As far as I remember, Dennis has recently created the following variations so far:

EL84, 6V6, KT88, KT88 w oversized trannies, PSE KT88 and a 45 SET.

So, yes, there are differences. Mine is the KT88 strapped as Triode, w/oversized (20 watts) trannies and a long chassis.

[Bombadil]

Originally Posted by Musica Amantem

Wikipedia published Anode plate dissipation specs as per my earlier post. I'm sure the KT-88 yields more power, so I guess anode plate dissipation is not a correlator for power.

https://en.wikipedia.org/wiki/KT88

https://en.wikipedia.org/wiki/KT66

Maybe these refer to the original versions (NOS)

I believe that spec published in Wikipedia is incorrect. If you read the text of that same article, it states that the max dissipation is 25W.

[Musica Amantem]

Originally Posted by Bombadil

I believe that spec published in Wikipedia is incorrect. If you read the text of that same article, it states that the max dissipation is 25W.

I agree. Found more formal references indicating KT88's at 40 watts and KT66 at 25 watts for a 38% difference in favor of KT88 ... Apparently the designation numbering correlates with power, with KT77 rated at 25 Watts, KT90 at 50 watts; KT120 at 60 watts; KT150 at 70 watts, and so on. In our oversized transformer version, I suppose the max power would be with KT150. The sound quality is another matter, though, so I guess Dennis prefers the sound of KT88 among Kink Tetrodes and 6V6 among Beam Tetrodes.

BTW, the 6L6 GC is rated at 30 watts, so is more powerful than the KT66 and KT77, but the Russian variant, 6P3S-E is rated at just 20.5 watts, although I find them more detailed and transparent than the KT88 which has more body and density to the sound but at the cost of some transparency losses. In conclusion, some power loss would be expected from the KT66 relative to the KT88 but power gain relative to the 6P3S-E. This reinforces my expectations a good KT66 should be right on the money in my amp. Interesting to read the 6V6, 6V6G, 6V6GT are all rated at only 12 watts!


Can anybody tell if the KT66 is detailed and transparent relative to other alternatives? Thanks!