• New Sponsor: ShipNerd, Ship Your Gear with Us... for less! Click Here.

Tubes - Matched dual or quad?


Senior Member
I am cheap, so I bought a matched set of 2 tubes for my DSL 100 and I pulled the 2 other old tubes so I could run the amp with 2 power tubes. But I changed my mind, I want to run it with 4 power tubes. So should I buy 2 more tubes or 4 more tubes - remember I am cheap.

Seems like when you bias the DSL you are biasing two tubes at a time. For the DSL you bias the right side then the left side. So, it seems like, if I buy another matched set of tubes, I should install them together on the right side and then the other matched set on the left side.

Then I suppose I could bias the amp to be the same for both sides.


You are correct. Keep the matched pairs together. No real need to buy matched quads, IMHO.

Heady Jam Fan

Just make sure you know which two tubes are paired within the amp.

In my experience, amps with 4 power tubes usually pair the middle two and outer two rather than left two and right two.

Also, depending where you bought the matched pair, I wonder if they could send you another pair that would be close enough to make a quad... But seems that doesn't matter in your case.

Oh yeah. Do both bias pots work the same? I know, for example, its a popular mod on SFTR's to add a bias adjustment pot to the bias balance pot that eventually became the stock format for the amp.

Trending Topics

Top Bottom