Search found 16 matches
- Sun Nov 10, 2024 11:37 am
- Forum: Technical Discussion
- Topic: Clone build Tranny voltage too high
- Replies: 13
- Views: 1653
Re: Clone build Tranny voltage too high
Thought I'll drop an update on the 100 watt clone, Been working on my house and got behide. Well install the new power tranny and she came alive. It is a beast. Had a slight hum in her after finding it was some poor grounding points on the chasse, redid the ground scheme to star ground and it is dea...
- Tue Jun 25, 2024 12:36 am
- Forum: Technical Discussion
- Topic: Clone build Tranny voltage too high
- Replies: 13
- Views: 1653
Re: Clone build Tranny voltage too high
To make sure I got true readings. The tubes are old tubes I use for just things like this and also I placed 500ma fuse in which blew . I normally don't do things this way and if I was working on somebody else amp I sure would not. There is more then one way to skin a cat.
- Mon Jun 24, 2024 8:26 pm
- Forum: Technical Discussion
- Topic: Clone build Tranny voltage too high
- Replies: 13
- Views: 1653
Re: Clone build Tranny voltage too high
I do have a light bulb limiter and used it many times. they were only on for less then a second or two and I shut it down because I saw the current shooting up. The reading was what the meter said when I pulled the switch. And no I have not check the impedance of the tranny. Will look into it at a l...
- Sun Jun 23, 2024 11:30 pm
- Forum: Technical Discussion
- Topic: Clone build Tranny voltage too high
- Replies: 13
- Views: 1653
Re: Clone build Tranny voltage too high
Ordered a new tranny so when it comes in should be good to go. Thanks to you all that gave your thoughts
good night.
good night.
- Sun Jun 23, 2024 7:50 pm
- Forum: Technical Discussion
- Topic: Clone build Tranny voltage too high
- Replies: 13
- Views: 1653
Re: Clone build Tranny voltage too high
Well put in the tubes and found an issue with the bias supply. With the bias voltage set to its coldest the tube idle at 178mA. Boy did that drop the HT winding voltage Plates 472 volts and screen was 456volts so I think it would be best just get a new tranny then fighting this thing. If I try to co...
- Sun Jun 23, 2024 12:54 pm
- Forum: Technical Discussion
- Topic: Clone build Tranny voltage too high
- Replies: 13
- Views: 1653
Clone build Tranny voltage too high
Hello All, I tried searching this up but didn’t find anything. Sorry if it is related to another post. I’ve been building a Marshall 100watt clone. I use a power tranny and output tranny form a old Kern amp that was loaded with 6550s. I’m using El34s in the amp but my voltage off the power tranny (H...
- Tue Nov 30, 2021 10:20 pm
- Forum: Technical Discussion
- Topic: Sound City L120 mk4 Biasing
- Replies: 10
- Views: 2890
Re: Sound City L120 mk4 Biasing
eddiep1966 wrote: ↑Tue Nov 30, 2021 10:14 pmReread the post and there it was, I do have some good stupid moments.
- Tue Nov 30, 2021 10:14 pm
- Forum: Technical Discussion
- Topic: Sound City L120 mk4 Biasing
- Replies: 10
- Views: 2890
- Tue Nov 30, 2021 2:19 am
- Forum: Technical Discussion
- Topic: Sound City L120 mk4 Biasing
- Replies: 10
- Views: 2890
Re: Sound City L120 mk4 Biasing
Well Hello gldtp99 I don't know if you remember we had some conversations about this L120 over at the Vintage amp forum many years ago with papadog. Man I sure miss that forum. It's a shame that its a thing of the past now. Did you mod the bias circuit in your L120 when using the 100 ohm resistors o...
- Sun Nov 28, 2021 4:18 pm
- Forum: Technical Discussion
- Topic: Sound City L120 mk4 Biasing
- Replies: 10
- Views: 2890
Re: Sound City L120 mk4 Biasing
Thanks for the input guys it is very helpful. No my amp does not have the 68 and 22 ohms resisters. Form what I have read that was implemented in 1973 but who knows a lot of info has been lost on these amps over the years. But I never understood why they were different values for each side unless it...
- Sun Nov 28, 2021 5:32 am
- Forum: Technical Discussion
- Topic: Sound City L120 mk4 Biasing
- Replies: 10
- Views: 2890
Sound City L120 mk4 Biasing
Hello everyone, I have a 71 Sound City L120 MK4 that has been on the self for years, Well decided to bring some life back into this thing. Recap the power section and got her ready for new tubes. I was wondering if anyone had any suggestion on were to bias this thing at, well a good starting point. ...
- Sun Aug 08, 2021 3:04 am
- Forum: Marshall Discussion
- Topic: Marshall jcm800 bias issues
- Replies: 7
- Views: 2623
Re: Marshall jcm800 bias issues
Well got the sockets replaced and monitor each one for a few hours. The tubes are running stable. So now maybe move ahead on this thing.
Thanks
Thanks
- Sat Aug 07, 2021 1:33 am
- Forum: Garage Talk
- Topic: What're you listening to right now??
- Replies: 1212
- Views: 450445
Re: What're you listening to right now??
Kiss "Detroit Rock City
- Fri Aug 06, 2021 2:49 pm
- Forum: Marshall Discussion
- Topic: Marshall jcm800 bias issues
- Replies: 7
- Views: 2623
Re: Marshall jcm800 bias issues
Well so that explains it then pdf64 that goes with the other info were the amp was retubed by another, dated 96 so I'm sure he added the mod. Thanks the parts will be here today or tomorrow I'll post an update.
- Fri Aug 06, 2021 1:37 pm
- Forum: Marshall Discussion
- Topic: Marshall jcm800 bias issues
- Replies: 7
- Views: 2623
Re: Marshall jcm800 bias issues
Thanks for the suggestion Steven and Pdf64. No I don't have a schematic for this amp but the only thing I have seen component deference so far is it has 2.2k screen resistors. All the others I have seen were 1k. Don't know if these were stock or were placed in by someone else. But I agree if not the...