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6SN7, 6CG7/6FQ7, and 6SL7 in Elekit amps?

ebrandon

Member
2019-09-19 7:29 pm
I have an Elekit TU-8200DX amp which takes 12AU7 driver tubes, and an Elekit TU-8600 amp which takes both 12AX7 and 12AU7 driver tubes.

I was hoping to try 6SN7 tubes instead of the 12AU7 using this adpater 6SN7 To ECC83 12AX7 12AU7 Vacuum Tube Amplifier Convert Socket Adapter ( 6.3V ) | eBay

I was also hoping to try 6CG7/6FQ7 tubes instead of 12AU7 using this adapter 1pc gold plated 6CG7 6FQ7 instead ECC82 12AU7 tube adapter 6.3V heat | eBay

Finally, I was planning to try using a 6SL7 tube instead of the 12AX7 using the same adapter I would use for 6SN7 in a 12AU7 socket.

Is any of this a bad idea? Don't want to damage my amp.

Thanks!
 
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6A3sUMMER

Member
2016-06-07 6:50 am
Filaments:

6SN7 6.3V 0.6 Amps
12AU7 wired for 6.3V is 0.3 Amps

6FQ7 6.3V 0.6 Amps
6CG7 6.3V 0.6 Amps

6SL7 6.3V 0.3 Amps

Will the power transformer take another 0.3 Amps per tube filament?

As to using adapters, and various tubes:
You need to check the pinout of the various Octal tubes you are interested in and see if they are all the same.
And check the pinout of the various 9 pin tubes to see if they are all the same.

This information is is all available in your friendly tube manual, which lists the Base connections, i.e. 8BD, etc.
or check at Franks Tubes:
Frank's electron Tube Data sheets

As far as tube rolling, there are lots of manufacturers of 12AU7 tubes, some are inexpensive, some are expensive, some are old, some are new production, etc.
The same goes for 12AX7.

You may have trouble finding new production of some of the tube types you mentioned, i.e. 6FQ7 and 6CG7.

Even the 6SN7 and 6SL7 have limited new production companies.

You may also find that some various models require a little adjusting of resistor values for optimal operating conditions.
 
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6A3sUMMER

Member
2016-06-07 6:50 am
azazello,

6CG7: Gm = 6,700 to 7,700 uMhos; u = 20; rp = 2,985 to 2,597 Ohms
6N30P: Gm = 18,000 uMhos; u = 15; rp = 833 Ohms

Those 2 tubes are less alike than a string bean, versus a pod-full of peas.

If you use one of those 2 tube types in a circuit that is optimal for it,
then the same circuit will not be optimal for the other tube type.
 

6A3sUMMER

Member
2016-06-07 6:50 am
azazello,

I bet your amplifier that you interchangeably use 6N30P / 6CG7 tubes:
1. Have self bias cathode resistors with bypass caps.
2. Have current sources in the plates.
3. Have both.

4. Or, have current sources in the cathodes.

Right?
 
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