2359glenn | studio
Sep 6, 2021 at 9:39 AM Post #39,122 of 39,425

bcowen

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I still have FOMO for Tung Sol 7802's. @L0rdGwyn bought the last several pairs on the planet. :unamused:
I'd never even heard of that tube type...until now. Looks like it plays in the same ballpark as a 5998?
 
Sep 6, 2021 at 10:15 AM Post #39,123 of 39,425

L0rdGwyn

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I'd never even heard of that tube type...until now. Looks like it plays in the same ballpark as a 5998?

It's a pretty rare one, highest gm tube of the 6AS7G / 5998 family! 20K micromhos vs. 14K micromhos for the 5998. They are pretty much extinct though, I don't think many were made in the first place.
 
Sep 6, 2021 at 10:36 AM Post #39,124 of 39,425

Tjj226 Angel

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It's a pretty rare one, highest gm tube of the 6AS7G / 5998 family! 20K micromhos vs. 14K micromhos for the 5998. They are pretty much extinct though, I don't think many were made in the first place.

Another one of interest is the KT90. Sadly it's not a dual triode, so you would have to buy more of them, but they have a transconductance of 15K micromhos and they are WAYYYY more linear than any tube in the 6as7 family.

But I still prefer super triodes over normal OTLs.
 
Sep 6, 2021 at 11:08 AM Post #39,125 of 39,425

bcowen

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Another one of interest is the KT90. Sadly it's not a dual triode, so you would have to buy more of them, but they have a transconductance of 15K micromhos and they are WAYYYY more linear than any tube in the 6as7 family.

But I still prefer super triodes over normal OTLs.
Have several of the Type 3's in the stash. Big, ballsy, dynamic sound (compared to 6550's and KT-88's). Never tried them in a 5998/6AS7 app though.

KT90 Ei.jpg
 
Sep 6, 2021 at 11:17 AM Post #39,126 of 39,425

triod750

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What can these tubes be used for? Hearing aids?

1630941410461.png



Available with metal base too.

1630941628574.png


Up for sale, matched pair - TELEFUNKEN EL3010 - power pentode

The EL3010 made by Telefunken is claimed to be the most advanced tube ever made. Designed to be used with transistor drivers. The EL3010 has an extremely high transconductance of 90 mA/V.

Made in Ulm - West Germany

Purchased from EADS ( European Aeronautic Defense and Space Company ) on their liquidation action in 2014 - tubes were very well taken care of

NSN p/n 5960-12-152-1672

Metal base

Low noise

Long lifespan

Data sheet is available on the following link: HTTPS://frank.pocnet.net/sheets/128/e/EL3010.pdf


BRAND NEW IN BOX - NEW OLD STOCK

What you see is what you get

Note: It would be great replacement tube for your audio amplifier based on EL34 6CA7 KT77 - converter / adapter is available for purchase from various vendors ( please check on eBay or conduct google search )
 
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Sep 6, 2021 at 11:42 AM Post #39,127 of 39,425

leftside

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What can these tubes be used for? Hearing aids?

1630941410461.png


Available with metal base too.

1630941628574.png

Up for sale, matched pair - TELEFUNKEN EL3010 - power pentode

The EL3010 made by Telefunken is claimed to be the most advanced tube ever made. Designed to be used with transistor drivers. The EL3010 has an extremely high transconductance of 90 mA/V.

Made in Ulm - West Germany

Purchased from EADS ( European Aeronautic Defense and Space Company ) on their liquidation action in 2014 - tubes were very well taken care of

NSN p/n 5960-12-152-1672

Metal base

Low noise

Long lifespan

Data sheet is available on the following link: HTTPS://frank.pocnet.net/sheets/128/e/EL3010.pdf


BRAND NEW IN BOX - NEW OLD STOCK

What you see is what you get

Note: It would be great replacement tube for your audio amplifier based on EL34 6CA7 KT77 - converter / adapter is available for purchase from various vendors ( please check on eBay or conduct google search )
Nice https://www.ebay.co.uk/itm/202978181379
 
Sep 6, 2021 at 2:24 PM Post #39,129 of 39,425

heliosphann

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It's a pretty rare one, highest gm tube of the 6AS7G / 5998 family! 20K micromhos vs. 14K micromhos for the 5998. They are pretty much extinct though, I don't think many were made in the first place.
Apparently. I was hitting up people in Europe, contacting all the big tube dealers I knew of. Most of them had never even heard of it!
 
Sep 13, 2021 at 7:01 PM Post #39,133 of 39,425

bcowen

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Speaking about tubes, it appears to me that new tubes generally run hotter in the beginning of using them, compared to when they are burned in.
Did anybody notice this?
Is there an explanation for it?
I've never really noticed this, but then I haven't been paying attention to it either.
 
Sep 13, 2021 at 11:09 PM Post #39,134 of 39,425

mordy

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I've never really noticed this, but then I haven't been paying attention to it either.
Well, I have noticed it and yesterday my finger reminded me of it lol! I am burning in a tube and it was much hotter than I thought - 77C. After a few more hours of use and cooling off overnight it now measures 64C under the same conditions.
 
Sep 14, 2021 at 6:35 PM Post #39,135 of 39,425

bcowen

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Well, I have noticed it and yesterday my finger reminded me of it lol! I am burning in a tube and it was much hotter than I thought - 77C. After a few more hours of use and cooling off overnight it now measures 64C under the same conditions.
When was your finger last calibrated? :smile::sweat_smile:
 

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