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GM70 Triode

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finwbu

finwbu

Member
Joined 2002
Paid Member
GM70 Triode tubes Sale

have decided to make a bit of a clean out in my stock of 8 Pieces GM70 tubes. Old Military stuff. All Tubes are used but ok.
One Pieces 33€.Minimum Order 2 pieces + shipping
Walter
 

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Brett

Brett

Member
Joined 2002
NickC said:
do you have the sockets for these? looks hard to get i remember the pins are not in a square configuration i think it is trapiozedal.
Do you have the data sheet for this. Want to find out max power dissipation, rp, mu most sheets are in russian. More important is the max dissipation.
THanks
Click to expand...

Send me PM and I'll email you good datasheet in English.
Pd = 125W

Sockets are a PITA to get, so I used a cap clamp under chassis to hold them, and brass crimp on connectors pushed onto yhe pins. There is little to no opportunity to tube roll, so it was a satisfactory solution.
You'll also need good DC for the filament.

There's a Yahoo group that started with a bit of an emphasis on this tube but has broadened it's horizons

http://groups.yahoo.com/group/GM70/
 
N

NickC

Member
Joined 2001
promitheusaudio.com
brett
i can't email your email as your add is not listed in the forum and you disable emails in your particulars section
could you email instead at nickcrap@hotmail.com. That address is spam always no point hidding my account.
THanks alot brett.
Great idea about mounting the tube, plus if you get metal clamp could use as a heat transfer to heatsinks cooling the base. Real orginal
 
Brett

Brett

Member
Joined 2002
Oops, I thought I'd enabled the email again.

Anyhoo, I've sent off a pdf with data and curves as well as another set of curves.

The cap clamp type base was something I came up with out of neccessity, as the surplus sockets you see on ebay are crap or you have to drill and modify the 6C33 ones, which is also less then optimum.

Just to give you an idea, I made mine with a 600V B+, PP, cathode biassed, 120mA/tube, 6ka-a for about 12Wrms or double that peak. Lots of people use them as SETs both series and parallel fed with good results. Another common op point is 800-850V, 135mA but I didn't find they sounded a lot different wherever I tried them.
 
K

Ken L

Member
Joined 2002
Lorenzo Tang at wiwitubes In Hong Kong

Had GM70 sockets.

I bought a pair. They're porcelain, appear to be an original septar socket. Probably a recent generic version.

Air freight to the US, they were about $45 a pair.

Don't know if he still has any or if anybody is interested but I thought I would post it.

Regards

Ken L
 
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