PPX3 Question

[andrewz]

Hi guys! I'm new here and have a question.

I just jumped into the tube world and bought a PPX3. And after a few dilemmas of it not working, I now love it!

However, I do have a question.

Out of the left channel I can hear some static and distortion. It almost sounds like vinyl cracks and pops/surface noise. (No, I'm listening to SACD not vinyl lol) Is that normal?

 

[Pete7]

Sounds like you have a case of microphonics with at least 1 of your tubes. I don't know the technical specifics of the causes, but I do know what you describe are the symptoms. It's an easy fix, though- not a problem with the amp itself. Just need some tube dampers like the ones found on this site. you just need to order the right size (6SN7).
Herbie's Audio Lab: Tube Dampers

 

[sacd lover]

Quote:

Originally Posted by andrewz /img/forum/go_quote.gif Hi guys! I'm new here and have a question. I just jumped into the tube world and bought a PPX3. And after a few dilemmas of it not working, I now love it! However, I do have a question. Out of the left channel I can hear some static and distortion. It almost sounds like vinyl cracks and pops/surface noise. (No, I'm listening to SACD not vinyl lol) Is that normal?

Is this a used PPX3? If so, you very likely have a bad tube; although sometimes even unused nos tubes can be bad. Cracks and pops are not normal. Switch the output tubes and see if the noise follows the tube or remains in the same channel. If the noise moves you have found the bad tube. If the noise does not move the input tube is probably bad. Replace the bad tube and all should be well.

 

[Pete7]

Sorry for the bad advice. I thought the problem sounded like microphonics. My bad.

 

[sacd lover]

Quote:

Originally Posted by Pete7 /img/forum/go_quote.gif Sorry for the bad advice. I thought the problem sounded like microphonics. My bad.

No problem ... you could be right. Descriptions of noise can be hard to decipher sometimes.

 

[diego]

It could also be dirty pins on the tube, particularly if the noise is just after the amp is turned on.

 

[mrarroyo]

Quote:

Originally Posted by diego /img/forum/go_quote.gif It could also be dirty pins on the tube, particularly if the noise is just after the amp is turned on.

I was about to post the same. I guess the first thing I would do is to check the pins and the sockets are clean. Then I would check if the sockets grab the pins tightly. I would do the tube swapping to see if it moves so you can identify a bad tube. A simpler test is to get a pencil and using the eraser end tap the tubes lightly, if you hear more noise then microphonics are likely the source.

Good luck.

 

[andrewz]

OK thanks for the advice guys! I really appreciate you explaining easily, because I'm new at this tube thing and still have lots to learn.

OK - so I did the microphonics test with the pencil, and if I tap it hard enough I do hear something, but this is different from what I'm hearing. It's more of a static noise. I also switched the middle and rear tubes and it's still in the same channel.

So my guess it's a bad tube?

And I ordered this new from Single Power...but the tubes came in plain white boxes, so I just assumed they were NOS. I could be wrong however.

But I think I'm gonna order some more tubes and see if that fixes the problem. Wish me luck!