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Forums :: Ask Amp Tech Expert Skip Simmons

geloso g213 tube swap

1 reply [Last post]
Mon, 02/27/2012 - 04:24
K_O_E_N_J
K_O_E_N_J's picture
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Joined: 12/16/2010

Hey there,

I just got a geloso G213 http://www.radiomuseum.org/r/geloso_g213_a_g213a.html

The amp is very loud, but its sounds a bit "thin".

There are 2 12SL7GT tubes in it.
Can I swap it with a 6sl7, or maby a 12sn7?
I got 2 6sn7gtb tubes there, can I try those 2?

I read allot about 12a*7 tubes in harp amps, can i swap them? maby with a "adapter" or something.
And what brand would be the best/would you recommend

What would be the best preamp tubes to get more bass?

And it also got 2 6V6G tubes in my geloso.
I got 2 very nice tungsol 5881, Can i swap it for the 6v6g tubes?

All tips are welcome,

Greats from holland

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Tue, 02/28/2012 - 20:57
#1
Expert Skip Simmons
Expert Skip Simmons's picture
Offline
Joined: 01/18/2010
Geleso

Hello KOENJ- Thanks for writing.

6SN7 or 6SL7 tubes are not interchangeable with the 12SL7. You COULD use a 12SN7.

You could make or buy adapters that would allow you to use 12AX7 etc. but I'm not sure where to buy them.

Different preamp tubes will not add bass.

Your 5881s should be OK in place of the 6V6Gs.

Seriously, it is very unlikely your amp is running like it should. You should spend a little on service before you assume that different tubes or mods will make it sound better. The stock amp should have PLENTY of bass.

Skip Simmons

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