Search found 49 matches
- Wed Jan 09, 2013 9:29 pm
- Forum: Technical Discussion
- Topic: Quiet fizzy 2204 -VVR2 issue
- Replies: 10
- Views: 2798
Low B+ was caused by bad zener diode.
I had an odd problem with my 6V6 Marshall Hybrid amp. (Front end of the 2022, into the 2204 driver and Phase Inverter) I installed the VVR and it dropped the B+ from 400v to about 285 volts. I tried many things, but ended up replacing the 12v zener, and now it works from 400v down to about 50v. I sc...
- Thu Jul 09, 2009 1:00 am
- Forum: Trainwreck Discussion
- Topic: express hum issue, run out of ideas!
- Replies: 13
- Views: 2095
hum problem
Hello! Welcome to the forum. Sometimes when I have a problem with a new build, especially one with mods, I remove the mods! I guess it is like starting with a clean slate. I first try to get the "stock" circuit up and running before I start tweeking or changing things. Once I have it running, then I...
- Tue Jul 07, 2009 4:45 am
- Forum: Technical Discussion
- Topic: Ampeg B-22-X reverb tank and tremolo problem...
- Replies: 5
- Views: 1759
reverb pan
Hello! I've had good results by using the pan with the highest input impedance for Ampegs. There is no reverb transformer that takes the hi-z from the driver tube and changes it to low-z to drive the pan. If I recall the accutronics number was 4fb3c1b. It was the highest input-z that they made. The ...
- Fri May 29, 2009 5:05 am
- Forum: Technical Discussion
- Topic: Smoking 7.5k grid resistors on AC30/4 build - Oh, the Stink.
- Replies: 20
- Views: 4719
Oscillation
Hello!
I would try reversing the plate wires from the primary of the output transformer to the power tube sockets. If they were reversed, then the negative feedback would become positive feedback, and it would oscillate. Of course if you don't have feedback then it would not matter.
I would try reversing the plate wires from the primary of the output transformer to the power tube sockets. If they were reversed, then the negative feedback would become positive feedback, and it would oscillate. Of course if you don't have feedback then it would not matter.
- Fri May 29, 2009 4:31 am
- Forum: Trainwreck Discussion
- Topic: Air brake problems
- Replies: 11
- Views: 3646
airbrake problems
Hello! I just finished mine a few days ago. I had no output also. Then I took my ohm meter and hooked it between the input jack "hot" and the output jack "hot", and rotated the switch. The meter showed open, or infinity. I finally tracked the problem down to the variable resistor. I had to sand the ...
- Sun May 03, 2009 7:15 pm
- Forum: Technical Discussion
- Topic: Unknown power xformer double check
- Replies: 6
- Views: 1220
xformer wiring
Hello! One thing to consider is the 6.3 wires have a center tap, and the 5 volt windings don't. (According to the schematic that is) So the secondary wires should be fairly easy to figure out. The HV windings have a much higher ohms, then by finding which winding is center tapped, you can find the 6...
- Tue Apr 21, 2009 1:07 am
- Forum: Technical Discussion
- Topic: I've got a need for a Talkbox...
- Replies: 6
- Views: 1613
Talk Box
Hello! I've built a few. If I recall, I used a nice University Sound driver. It had the standard thread that would thread on to the horn, and I used clear PVC tubing that slipped over the threads. If you can't find the correct size tubing, then get some slightly larger and use a hose clamp to secure...
- Sun Apr 12, 2009 5:57 pm
- Forum: Technical Discussion
- Topic: AM Radio Interference-How to cure?
- Replies: 22
- Views: 4850
Radio Noise
Hello Again, I remember when I was a kid, (1880??) we used to make crystal radio sets. They were what amounted to a diode (galena) and a cat's whisker (wire). To pick up strong nearby stations in an amp, it would only take a bad solder joint, that would "detect" or pick-up the station. The bad solde...
- Sun Apr 12, 2009 1:08 am
- Forum: Technical Discussion
- Topic: AM Radio Interference-How to cure?
- Replies: 22
- Views: 4850
Radio Noise
Hello! I'm a ham radio operator and a musician. Perhaps you should pick up a copy of the Radio Amateur's Handbook which is put out by the ARRL. I go to "hamfests" several times a year, where I buy tubes, books, and all kinds of tube gear. In the handbook there are chapters on basic electronics, desi...
- Sat Apr 11, 2009 3:43 am
- Forum: Technical Discussion
- Topic: !5" speaker recommendations.
- Replies: 13
- Views: 2497
My Favorite 15" Speaker
Hello! My favorite one is a 15" Jensen Neo. I put one in my custom built bassman combo. (I made it with a guitar channel and a bass channel). The highs are nice and crisp, and the bass response is smooth too. I play mainly light rock style music, and I also take it to church too. The neo speakers ar...
- Thu Apr 02, 2009 8:31 pm
- Forum: Technical Discussion
- Topic: New Vox Night Train Amp
- Replies: 13
- Views: 2666
New Box
Hello!
I find it quite humorous reading the disclaimer on the rear of the amp:
"NO GUARANTEE IS APPLIED WHEN USED OUTSIDE OF JAPAN."
Perhaps that is because it is a 100V unit?
I find it quite humorous reading the disclaimer on the rear of the amp:
"NO GUARANTEE IS APPLIED WHEN USED OUTSIDE OF JAPAN."
Perhaps that is because it is a 100V unit?
- Thu Apr 02, 2009 8:21 pm
- Forum: Technical Discussion
- Topic: 1st Champ build newbie help request
- Replies: 27
- Views: 5318
Filament wiring
Hello! Congratulations on your first build! I agree with the great advise of the previous posters. I've built many small sized amps. The tweed Champ is one that I like to change the filament wiring on. I like to make the filament wiring like the silverface models. I first twist the green transformer...
- Thu Mar 26, 2009 6:16 pm
- Forum: Technical Discussion
- Topic: Ruined
- Replies: 13
- Views: 2594
Spoiled Too!
Hello and welcome! Spoiled? Yes, that is exactly how I feel now after building my Express! The Express sounds so nice I'm spoiled and don't want to play my Marshall clones, or dare I say, my Dumble clone! The Dumble is sweet, but it really uses too many parts and I have to adjust too many knobs to g...
- Thu Mar 26, 2009 3:08 am
- Forum: Dumble Discussion
- Topic: 715P caps a big no no?
- Replies: 33
- Views: 4314
Cap choice
Hello! My favorite caps are the Sozo ones. They are more "clear" sounding to me. One of the best ways to audition different caps is with a single ended amp, or should I say a "simple" one. I have a hi-fi design that uses an SRPP preamp with one coupling cap into a single 6L6 tube. The idea here is t...
- Wed Mar 25, 2009 3:24 am
- Forum: Technical Discussion
- Topic: JTM45/5F6-A pre amp into a '68 Bassman
- Replies: 19
- Views: 5583
Bassman mod
Hello! It would be a pretty involved mod. The main problem I see when I compare the two circuits is the way the tone controls are implemented. Mojo Musical Supply carries the eyelet board for the 5F6. If I were doing it, I would get the new eyelet board, and remove the existing one and perhaps keep ...