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Old 28th November 2004, 07:48 PM   #1
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Default CJ MV55 triode mode

I just purchased a used Conrad Johnson MV55 amp. I have read a lot about the tride mode mod CJ can perform. Since I ALWAYS have to open up everything, I had a look inside and found what I think are simple jumpers to switch the mode from ultralinear to triode! Can anyone confirm this? Here is a pic:

Click the image to open in full size.

Here is a hi-res pic if you need it:
BIG jumper pic

There is another pair of jumpers for the other channel. The dealer I bought the amp from was willing to do the mod for a charge, but I would rather be able to experiment. Somewhere I have some info for doing this to the old EICO amp I used to have.

Thanks,
David
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Old 29th November 2004, 07:44 AM   #2
SHiFTY is offline SHiFTY  New Zealand
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Get yourself a basing diagram for an EL34 (remember it is viewed from underneath.)

You will find in ultralinear mode, G2 is connected to a winding on the output transformer. In triode mode, it is connected to the anode via a low value resistor (100 ohm or so).

Check that this is the case and then break out your soldering iron. Should take you 15 minutes at the outside...
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