Dennis Had Inspire Amps

[Bombadil]

Nope, no Shuguang. I mean old 50s and 60s Made in the USA Westinghouse, the tall ones with yellow labels, 6SN7GTB. Which can be had for $10-$25 each. I've run into two tube dealers who have told me that these are excellent and underrated. Also comments in other tube forums which have sung their praises. Not saying they are the best out there, but they are plentiful, inexpensive and quite good.

Sometimes you can find them as EICO rebranded, as they were used in several EICO products.

ebay.com/itm/2-NOS-Matched-Westinghouse-6SN7GTB-Tall-Bottle-Tubes-USA-1961-/201720344474?hash=item2ef7782f9a:g:b2cAAOSwcUBYLMf 2

[Musica Amantem]

I see. I had no idea these could be had for such a reasonable price. Thanks for the heads up.

[FloridaBoy]

Originally Posted by Bombadil

Nope, no Shuguang. I mean old 50s and 60s Made in the USA Westinghouse, the tall ones with yellow labels, 6SN7GTB. Which can be had for $10-$25 each. I've run into two tube dealers who have told me that these are excellent and underrated. Also comments in other tube forums which have sung their praises. Not saying they are the best out there, but they are plentiful, inexpensive and quite good.

Sometimes you can find them as EICO rebranded, as they were used in several EICO products.

ebay.com/itm/2-NOS-Matched-Westinghouse-6SN7GTB-Tall-Bottle-Tubes-USA-1961-/201720344474?hash=item2ef7782f9a:g:b2cAAOSwcUBYLMf

I believe they were manufactured by Sylvania and re-labeled. No big deal.

[Bombadil]

Nope, at that point in time Westinghouse manufactured their own tubes. Their construction is quite a bit different than Sylvanias. Their tube code is 337, manufactured by Westinghouse. Westinghouse made some very high quality tubes. Their 12DF7 tubes, which are industrial 12AX7s, are rare and highly sought after, Brent Jessee sells them for $900/pair. And most people consider their 7591 tubes as the best 7591 ever made.

[Comzee]

I recently got a pair of 5932 a 6L6G equivalent.
There is three designs, from reading forums this is what I determined was the scale of best to worst:

Black double plate (I bought this design) (said to be the best)
Grey single plate with hole
Black single plate (worst by far)



I still have to get more time to fully understand these.
I can say right off the bat, they're far superior to the Bendix 6384 I had bought.
Probably more due to the closer spec to what the Fire-bottle wants, then the tubes themselves.

They're pretty bright, at least for the short time I've had them running. They might calm down after 100hr or something. I have the CV181-T because it's layed back sound meshes well with the bright 5932.

[FloridaBoy]

I had a pair of the 5932's but one died. I did not find them to be bright. More hours may help.

[Comzee]

Originally Posted by FloridaBoy

I had a pair of the 5932's but one died. I did not find them to be bright. More hours may help.

I wouldn't be surprised if one of them died on me.
One of them has loud static on warmup for around 30 seconds, until the amp normalizes. I'm not sure what this is called, coming to bias, or something else?
I even saw a spark inside it once.....

Regardless, after warmup it's crystal clear, if it dies it dies c'est la vie.

[Bombadil]

Those 5932s are interesting. Haven't run across any of those. A mil-spec 6L6, eh? I may have gone right past this in tube bin searches and never noticed them.

[Musica Amantem]

Originally Posted by FloridaBoy

I had a pair of the 5932's but one died. I did not find them to be bright. More hours may help.

Is there anything in the greater realm of the 6L6 family you haven't tried? Any favorites so far? I find the KT-66's to improve on the good old 6L6's, and I'm starting to lean towards the special KT-77 / EL34 family (the EL34 I have not tried yet). For some reason (probably max current plate specs), these seem better than anything else I've tried so far in my particular setup. Therefore, only input tubes for me from now on ... I'll follow Bombadil's tip with the WE 6SNT GTB (GTB's seem more suited in my system than the slightly brighter GT, at least after testing my equivalent Sylvania's) and FloridaBoy's CV-181 Z current preferences. It is a crazy hobby! It was a nice surprise to uncover the synergies of the Sylvania NOS 6SN7 GTB with the KT-77, a very neat-sounding pairing. So now I'm again open to try affordable NOS input tubes. CV-181 new production are still good options, though.

[Musica Amantem]

My Inspire came originally from Dennis with a current production Tung-Sol 6SL7. When I replaced that with a NOS 6SN7, with a slight gain loss, the sound improved tangibly. I know this does not mean the 6SL7 cannot make this amp sing, it probably will depend on the tube complement set.

Could I ask if anyone has had good results using a 6SL7 (or equivalent) in their Inspire amp, and if so, what the complement was and the type of amp (Pentode or Triode configuration)?

I have on hand a JAN Phillips 5691 (6SL7-equivalent) and several other Sylvania and GE 6SL7's, and will be trying those for the first time since I replaced the original Tung-Sol I sid not care much for. The output tube is going to be the GL KT-77.

I will be also trying a Shu Guang 6N8PJ, which is a 6SN7 variant, and a Radiotron VT-231 (6SN7). Thanks for any feedback on 6SL7 results!