thebes Posted March 29, 2020 Author Share Posted March 29, 2020 On 3/27/2020 at 9:29 AM, seti said: Hey Marty do you have an o-scope? This could help look around and actually see what everything is doing. Yes I do but I haven't used it in a long time. I've got various probes and stuff but really don't know how to use it in amp testing. Quote Link to comment Share on other sites More sharing options...
thebes Posted March 29, 2020 Author Share Posted March 29, 2020 On 3/27/2020 at 11:44 AM, babadono said: I just tried calling Jensen Transformer. They are shut down following the mandatory order of Governor of CA and Mayor of LA until Monday 20th of April(at minimum). Digging out a pair of cheap rca cables right know, and i have 1k resistors so I'll build a set this morning. Quote Link to comment Share on other sites More sharing options...
thebes Posted March 31, 2020 Author Share Posted March 31, 2020 So I built the plugs and used them and other than replicating the lowering of hum I noticed when I plugged a cd player in, no startlingly revelations. However, I have noticed that the hum seems to be coming from the right channel. I swapped all the tubes back and for the in pairs and the hum stayed with the right channel, so I've ruled out the tubes themselves as a source. It also decreases when I touch the amp, and while pocking around with a plastic probe the hum increases and makes weird science fiction sounds when it's around an area that includes the on/off light/ the power switch, and volume control and the balance pot. I've already disconnected the on/off light with no change, and I've replaced the volume pot with no change. I'm going to get a dental pick and tighten all the points to eliminate that as a problem. Then I have to troubleshoot the whole right circuit. What do you think, should I start with preamp or power section? Work from the outputs in, or rectifier out? Quote Link to comment Share on other sites More sharing options...
thebes Posted April 1, 2020 Author Share Posted April 1, 2020 23,000 plus views for this thread? Is this place suddenly trending? Quote Link to comment Share on other sites More sharing options...
OO1 Posted April 1, 2020 Share Posted April 1, 2020 - Quote Link to comment Share on other sites More sharing options...
babadono Posted April 6, 2020 Share Posted April 6, 2020 @thebes Marty I believe it is, man I almost forgot about this. Give me a shout @babadono So you built some dummies, basically 1K center contact to shield and plugged them into a line level input, then selected that input. And you have observed that you have a hum but only in the right channel. Is this correct? Not a "startling" revelation but it determines that in fact the problem is in the integrated itself not further upstream in your system. So you are going to or did what with a dental pick? Tighten points? Do you mean the tube socket contacts. Quote Link to comment Share on other sites More sharing options...
thebes Posted April 8, 2020 Author Share Posted April 8, 2020 Your recap is correct. Just to be clear, I've only put this in my two systems to see how bad the hum is. I already knew the rest of my gear worked properly. I also use test speakers when working on an amp. I'd rather blow them up than my Khorns! Yes, I'm making sure a poor tube socket contact is not causing a grounding problem. The dental pics I ordered should be here in a couple of days. Quote Link to comment Share on other sites More sharing options...
babadono Posted April 8, 2020 Share Posted April 8, 2020 Cool @thebes I'm just getting going out here on the left coast. Don't forget @babadono if i don't see your post after a day or two. Quote Link to comment Share on other sites More sharing options...
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