Driver/Input tubes


I need somebody to either explain or steer me to an explanation of the 12AX7/12AT7 tube's purpose in my Jolida JD502P power amp. I get preamp tubes in a preamp, but I've found it difficult to find a clear explanation of what the "driver" and "input" tubes are actually doing, and their relative importance to the sound of the amp. The 502P seems to have a typical compliment of these tubes, sharing its basic design with a lot of apparently similar power amps. Brain trust...hep me...hep me...
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Showing 2 responses by jedinite24

Stupid questions coming up. Does this mean that it is a must for the 12AT7 and 12AX7 tubes to be matched (each triode of the preamp tube has matching gain) and balanced (when the plate current draw of each triode is the same)for the Jolida 502P? I found that some tube sellers add a surcharge for this service.
Hi Marakanetz and Batch68

From seeing the tubes that came with the Jolida 502P I see I don't have to have matching 12AT7 and 12AX7 tube brands. It came with EH 12AT7 tubes and Tung Sol 12AX7 tubes. I normally like having uniformity all around but hey if it is ok for Jolida it should be ok for me.

I was wondering about the necessity of matching the gain of each triode of the preamp tube as well as the plate current draw of each triode being the same.

Here are some examples. Please see the Options check boxes

http://www.dougstubes.com/preamp-tubes/12at7-ecc81/penta-12at7.html

http://www.dougstubes.com/preamp-tubes/12ax7-ecc83-7025/penta-12ax7.html

If matching isn't necessary I was just going to go to the music shops by me and get the Groove Tubes equivalent of these tubes. They aren't matched at all from what the associates tell me.

Thanks again for the help.