Search found 170 matches
- Mon Aug 15, 2022 9:13 am
- Forum: Fender Discussion
- Topic: Summer project troubleshooting
- Replies: 15
- Views: 2225
Re: Summer project troubleshooting
Now I have moved all the grounding as suggested, but it did (next to) nothing with the hum at idle. The hum when gaining up is maybe a tiny bit better But wait... If I connect the negative feedback the hum pretty much disappears :) It's still present, but it's at a "normal" level for a tube amp I g...
- Mon Aug 15, 2022 8:57 am
- Forum: Fender Discussion
- Topic: Summer project troubleshooting
- Replies: 15
- Views: 2225
Re: Summer project troubleshooting
Now I have moved all the grounding as suggested, but it did (next to) nothing with the hum at idle. The hum when gaining up is maybe a tiny bit better
- Mon Aug 15, 2022 7:25 am
- Forum: Fender Discussion
- Topic: Summer project troubleshooting
- Replies: 15
- Views: 2225
- Mon Aug 15, 2022 4:18 am
- Forum: Fender Discussion
- Topic: Summer project troubleshooting
- Replies: 15
- Views: 2225
Re: Summer project troubleshooting
Thanks @Stevem, @pdf64 and @bepone. Here's an updated layout, does this correspond with the tips you provided?
- Sun Aug 14, 2022 7:34 am
- Forum: Fender Discussion
- Topic: Summer project troubleshooting
- Replies: 15
- Views: 2225
Re: Summer project troubleshooting
There's a center tap for the heaters on the PT..
(edit) and the CT is grounded
https://www.tube-town.net/info/datenbla ... -v2020.pdf
- Sun Aug 14, 2022 7:27 am
- Forum: Fender Discussion
- Topic: Summer project troubleshooting
- Replies: 15
- Views: 2225
Re: Summer project troubleshooting
Thanks, I'll give that a try later today
- Sun Aug 14, 2022 7:19 am
- Forum: Fender Discussion
- Topic: Summer project troubleshooting
- Replies: 15
- Views: 2225
Re: Summer project troubleshooting
Yes, it's norwegian :) It's actually, well kind of, wired that way. The bottom/filter board ground is not grounded like that, it's connected to the same ground point as the ground bus. I think you can see it in the pictures. But I can try to wire the cathode bypass directly to the filter cap negativ...
- Sun Aug 14, 2022 6:58 am
- Forum: Fender Discussion
- Topic: Summer project troubleshooting
- Replies: 15
- Views: 2225
Summer project troubleshooting
Hello :) I have had this project this summer where I've built this Fender-ish amp from scratch. A friend of mine was interested in an amp with one good clean channel that looked like a Mesa. I figured I'd give it a go and I have spent lots of hours this summer bulding the headshell and the amp. Anyw...
- Tue Jul 26, 2022 7:53 am
- Forum: Marshall Discussion
- Topic: JMP 50 Popping Sound
- Replies: 48
- Views: 6571
Re: JMP 50 Popping Sound
I dont know if its relatable, but I had a similar issue a while back that turned out to be a faulty output transformer. https://ampgarage.com/forum/viewtopic.php?f=6&t=33621
- Thu May 26, 2022 9:24 am
- Forum: Technical Discussion
- Topic: Relay noise/hum
- Replies: 3
- Views: 591
Re: Relay noise/hum
I might be overthinking this whole project. But is the easiest solution to either skip the cathode follower and wire it as two individual normal gain stages (plate driven eq) or preferably add another tube and leave the marshall-ish pre amp and eq alone and make the fender-ish pre amp and eq like it...
- Thu May 26, 2022 8:52 am
- Forum: Technical Discussion
- Topic: Relay noise/hum
- Replies: 3
- Views: 591
Relay noise/hum
I am currently re-building an amp that I have run into some issues with. I think there's a post around when I tried to sort out some issues with a Mesa DC-2 that I finally gave up on. The person owning it wanted me to rip out everything and build something new and a bit different in the chassis (and...
- Thu Apr 21, 2022 8:59 am
- Forum: Marshall Discussion
- Topic: 2204 1R bias problem
- Replies: 26
- Views: 3248
Re: 2204 1R bias problem
voltages at the supply are very low.. i never seen that in marshall.. something is missing in this story, 1R doesnt matter if is connected or bypassed.. where are those electrolytic caps and are you sure that you return all the connections ok? recheck all the grounds (- poles) and other what you to...
- Thu Apr 21, 2022 8:56 am
- Forum: Marshall Discussion
- Topic: 2204 1R bias problem
- Replies: 26
- Views: 3248
Re: 2204 1R bias problem
I did not see a couple of messages, sorry.martin manning wrote: ↑Tue Apr 19, 2022 10:54 am BTW, it looks like the bias supply is connected directly to the PT secondary and not through the standby switch, so you have bias voltage when in standby, correct?
That seems to be correct (though, I dont have the amp at the moment)
- Thu Apr 21, 2022 8:55 am
- Forum: Marshall Discussion
- Topic: 2204 1R bias problem
- Replies: 26
- Views: 3248
Re: 2204 1R bias problem
Where are you grounding the cathode to make the noise go away? If you can short it to the chassis at the tube socket and stop it, the existing ground must be bad. I did not see a couple of messages, sorry. I dont ground to "ground" :lol: , I just short pin 1 to pin 8 (since the 1R is between 1 and ...
- Wed Apr 20, 2022 6:18 pm
- Forum: Marshall Discussion
- Topic: 2204 1R bias problem
- Replies: 26
- Views: 3248
Re: 2204 1R bias problem
It's enough to bypass the resistor with a wire from pin 8 to 1 (as the resistors now hang between 8 and 1). That 1 ohm shouldn't make any difference. Maybe the socket is not making good contact with the tube pins? Have you cleaned and adjusted the socket tension? I cleaned but forgot to adjust tens...