diytube.com

Dynakitparts.com just came out with a upgrade kit for your Dynaco ST-70, Mark II, Mark III and Mark IV that will allow you to balance the bias between the output tubes. You no longer need to have a matched pair.

Also as your matched pair of tubes age with use, they don't "wear out" the same so one tube will pull more current than the other and they are no longer matched. With this upgrade kit, you can simply balance the bias.

No modification to your chassis is needed for the additional balance pot. I have installed this in my ST-70 and was able to balance the bias with unmatched tubes.

Go to http://www.dynakitparts.com/store/product.aspx?id=295 for more info.

Regards,
Sal

That's a neat way he mounted that pot. I've never seen any "matched" tubes actually stay matched so a balance circuit is a good idea.

Speaking of balance pots, is there a single turn pot that will fit the Diy ST70 and Poseidon boards?

I wonder if it's my circuit

That way of mounting the pots is really interesting... no drilling required.

Cheers!

TerrySmith wrote:That's a neat way he mounted that pot. I've never seen any "matched" tubes actually stay matched so a balance circuit is a good idea.

Speaking of balance pots, is there a single turn pot that will fit the Diy ST70 and Poseidon boards?

Yes its a single turn potentiometer. The DIYtube ST-70 board has a balance pot built in, not sure of the Poseidon board.

Regards,
Sal