BIAS AMP 2 CRACKLING CRACKED
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There's no need to make negative comments because you feel someone's asking you for something you're not willing to give, just don't give. There are plenty of people here that don't mind helping anyone no matter who they might be. If you don't want to help, that's absolutely fine, but no need to berate someone for asking for help just because they are doing it for a paying customer instead of a hobbyist. I don't really understand the tone of this reply, but it seems a bit rude/hostile. for diy no problem i have unlimited time and help but for other cases.

BIAS AMP 2 CRACKLING FREE

I'm missing something if i'm reading 'client' here who will be charged for service? and we are providing free repair here? The other socket had already been replaced before the client purchased this amp. What should I be looking for for voltages?Īlso, while I don't think I can rule out a lead dress issue, I'm not sure what else I could do with that that I haven't already tried.Ĥ90 is a little high for a plate voltage, isn't it? I know it's still within the limits for an E元4, but I was expecting something more like 460Ĭassiddidy wrote: ↑ Fri 1:19 am. I wasn't sure what to expect from the other pins, so I left that alone. I also haven't checked voltages aside from the plate voltage (490V). I also don't have canned air, so I might wait to finish the cap job before I go out to buy some. I haven't checked for arcing inside the tubes (definitely no arcing inside the amp). Dang, I did a lot now that I'm writing it all down. I've also tapped EVERYwhere with a chopstick, nothing. And I've shortened the NFB lead, rerouting that to avoid the transformer leads. I've rerouted the leads running from board to power tubes so that they run over the board instead of alongside the transformer leads.

Still had the same 70-50% ratio no matter which sockets I put them in. I've also checked tubes in different sockets. I've basically resoldered this amp a few times. I cleaned the contacts on the socket and resoldered it. Seems like there was some corrosion around that socket, the old one might've had a short, might've burned out. I replaced one of the power tube sockets when I did the transformers (the pins seemed loose so I decided to be preemptive). In addition to reflowing the solder joints on the board, I did all the joints on the sockets and pots as well. I did leave some things out of my initial post. The primary on the OT failed, as did the heater winding on the PT I've built a tester that utilizes a 30V neon bulb lit by the voltage kickback from 'charging' a transformer with a <5V DC supply. The transformers both failed a shorting test. I then tried a pair of properly matched 6CA7s, biased them to 70%, and got the same exact distortion. I oddly enough have a spare pair of tubes that comes out to the same difference, so I tried putting 2 of the 'hotter' tubes (and then the 2 'colder' tubes) together and ended up with the same distortion. Working with a pair of matched E元4s, and it turns out one only comes up to 50% of tube's capacity when the other is at 70. I've biased them to 70% (well, one of them. The question I have, while I wait for these new caps to show up, is do you all think that this could be caused by bad caps? Or am I going to replace these things and find the sound still there? I've been looking around for a solution to this, and some posts have led me to believe this could be a cold bias issue. No idea about the age of the amp, but I highly doubt it's younger than 10 years old. One of the filter caps (half of a multicap) showed a high reading (over 2 ohms), while the others seemed to be just a little higher than they should. Then I got an ESR tester and checked the capacitors.

BIAS AMP 2 CRACKLING CRACKED

I've even gone through and resoldered the entire board in case there were any cracked solder joints. Sound was consistent with the fact that the presence knob is essentially a tone control for the NFB, reintroducing high frequencies back into the main signal. The sound is still there, although different. I thought maybe it was the NFB, so I tried disconnecting it. I've tried swapping with known good tubes, the sound is still there.

Which I really think is unrelated to the transformers, it just didn't show before.

Bias amp 2 crackling