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HP8903B 27th November 2010 05:32 AM

Which tube does my amp use? 12AU7 12BH7 12AX7 6CG7 others?
1 Attachment(s)

SGregory 27th November 2010 05:37 AM

What kind of amp is it?

6L6 27th November 2010 05:38 AM

Please give us more info.

Is this a commercial amp?

Is it home built?

Why are the tubes out of it?

Where did you get it?

Do you have any information at all about the amp?

Can you take more/better pictures of it?

Can you take a picture of the insides where the small tubes connect?

HP8903B 27th November 2010 05:39 AM

It is a DIY amp that I bought that came with no tubes. All the tube sockets are not labeled.

HP8903B 27th November 2010 05:47 AM

I don't have any information on the amp.

I attached pictures of the inside.

I met up with SY and he looked at the amp for me. He said that the front tube is 12AU7 or 12AT7. The middle and back tubes are 6CG7. But as I mentioned, The middle socket will not light up the 6CG7.

HP8903B 27th November 2010 05:50 AM

3 Attachment(s)
Middle picture is of the back socket.
Right picture is of middle socket.

HP8903B 27th November 2010 05:51 AM

1 Attachment(s)
Front socket picture

astouffer 27th November 2010 06:00 AM

Are you sure the 6CG7 you have is good?

HP8903B 27th November 2010 06:05 AM

Yes I am sure. I have many 6CG7.

HP8903B 27th November 2010 06:28 AM

I got the following measurement from the 3 small tube sockets:

Front: Plate is 420 VDC, Grid is unknown, heater is 7 VAC

Middle: Plate is 948 VDC (that is right), grid is 420 VDC heater is 7 VAC.

Back: Plate is 443 VDC, Grid is unknown, One heater is 7 VAC and the other is around 3 VAC.

The two wires going to the grid of both power tube is coming from the back small socket.

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