Author Topic: Model T mods/tube changes  (Read 3453 times)

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Offline James Peters

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Model T mods/tube changes
« on: August 27, 2001, 05:31:00 pm »
I have a few questions about my new Model T ("re-issue"), in regard to changing the sound of the amp--I'm hoping one of you kind souls can help me.

1) Which preamp tube does what, esp. in terms of which preamp tube provides the most gain to the lead channel.  (V1/V2/V3/V4/V5/V6)  I'm considering replacing one or more of the tubes with higher-gain varieties, and changing the phase invertor to a 12AT7 for less phase-invertor breakup.  (I'm assuming that the phase invertor would be V6.)

2) Would changing the screen resistors from the existing 470 ohm resistors to 1K ohm resistors, make a noticable change in sound?  I've been told that doing this will increase the "touch sensitivity" of the amp in a pleasant way.

3) Would it be that involved to make this amp compatible with EL34 tubes?  (I've heard that in amps that take 6L6's and their variants, all you have to do is connect pin #1 of each pentode to ground, and then set the bias properly.  Also, apparently after this "mod" is done, the amp is still compatible with 6L6's since pin 1 of a 6L6 doesn't connect to anything in the tube.)  For that matter, if this is true, can I still use the bias controls on the back of the amp to bias for EL34's, and what voltage would I set it to?

Thanks in advance to anyone who can help!