2. amps-preamps
  3. 1337876441

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...
wolf_garcia
batch68
27 posts
 
Jed,
If you are asking about matching the AT7s to the AX7s, then no. If you are asking if you should have matching AT7s (or AX7s), then I'd strongly recommend it (not absolutely required, though).
jedinite24's avatar
jedinite24
1,503 posts
 
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.
rleff
1,065 posts
 
Maybe Atmasphere will see this thread and post a reply;if he does you can not get any better information in my opinion;also advice so far has been pretty good.
tomcy6's avatar
tomcy6
2,597 posts
 
Back to the original question, are the 12AX7's the input tubes and the 12AT7's the driver tubes? Is it true that the input tubes have a greater impact on sound quality than the driver tubes? TIA.
batch68
27 posts
 
Jed,
You want to get matched gain. I'd recommend balanced triodes as well, but that one is not as essential. I wouldn't worry too much about the other options. And Tom is correct that the pre-amp tubes on that Jolida are the 12AX7s and they will make the biggest difference in terms of shaping the sound. The 12AT7s are driver tubes and you shouldn't spend as much on them. Get something quiet and reliable and don't worry about their supposed sound characteristics. Spend plenty of time listening to the amp with what's in there now & decide what you want to change regarding the sound -- post that here & you'll get loads of recommendations. I have some Jolida gear as well, they're great bang for your buck amps.
Batch
More to discover