Search found 1607 matches
- Fri May 31, 2024 8:03 am
- Forum: Marshall Discussion
- Topic: My first experience with Mullard reissue 12AX7’s
- Replies: 8
- Views: 358
Re: My first experience with Mullard reissue 12AX7’s
the mullard RI has limited voltage gain but delivers quite a bit of current. I like it in the phase invert (or cathode follower sometimes), not in v1
- Fri May 31, 2024 7:34 am
- Forum: Technical Discussion
- Topic: Taming amp gain in single channel deluxe reverb build
- Replies: 78
- Views: 3219
Re: Taming amp gain in single channel deluxe reverb build
grid resistors also help minimizing blocking distortion. and be careful with .1uf coupling caps in the PI combined with 220k bias splitters On my project, I was able to experiment some yesterday with knocking back the PI input using a voltage divider (the 220K + an added 250K pot to ground) & made ...
- Thu May 30, 2024 7:19 am
- Forum: Technical Discussion
- Topic: Taming amp gain in single channel deluxe reverb build
- Replies: 78
- Views: 3219
Re: Taming amp gain in single channel deluxe reverb build
add grid resistors downstream and reduce the values of the coupling caps to reduce low bass, esp. early in the circuit. see if the filtering is sufficient I messed a little bit with coupling caps, but preferred what the smaller cathode caps did in this circuit. There is a nice clear bass that I can...
- Wed May 29, 2024 7:13 pm
- Forum: Technical Discussion
- Topic: Taming amp gain in single channel deluxe reverb build
- Replies: 78
- Views: 3219
Re: Taming amp gain in single channel deluxe reverb build
add grid resistors downstream and reduce the values of the coupling caps to reduce low bass, esp. early in the circuit. see if the filtering is sufficient
- Sun May 26, 2024 9:03 am
- Forum: Technical Discussion
- Topic: LAR/MAR PPIMV bypass pop noise?
- Replies: 9
- Views: 362
Re: LAR/MAR PPIMV bypass pop noise?
those who have switched between two larmars have simply used two 500k stereo pots in parallell, which gives about the same resistance as single 250k stereo pot. Instead of the 2m2 security resistors on the 250k you may need to adjust the value of the security resistor. but don't be too mechanincal, ...
- Sat May 11, 2024 9:39 am
- Forum: Dumble Discussion
- Topic: A SSS Build
- Replies: 54
- Views: 2496
Re: A SSS Build
Looks great. and reminds me that I have a cab and chassis and lots of NOS 7581as waiting (need transformers)
- Mon Apr 29, 2024 6:38 am
- Forum: Technical Discussion
- Topic: Add an HT Fuse?
- Replies: 10
- Views: 911
Re: Add an HT Fuse?
I've tried running a superlead with a 500ma ht fuse instead of the normal 1a. it ran for many hours without blewing
- Sun Apr 21, 2024 1:47 pm
- Forum: Technical Discussion
- Topic: '63 Selmer Treble n bass dilemma..
- Replies: 4
- Views: 480
Re: '63 Selmer Treble n bass dilemma..
do these amps draw more current than a jtm45?
- Mon Apr 15, 2024 7:24 am
- Forum: Technical Discussion
- Topic: Measuring filter caps performance.
- Replies: 4
- Views: 483
Re: Measuring filter caps performance.
This is delving into hazardous testing, which you may not have done before, in which case imho you should work with a competent person to raise your experience. The commonly used technique is to insert a 1kΩ resistor in series with the filter cap and clipping a handheld multimeter across the resist...
- Sat Apr 13, 2024 4:30 pm
- Forum: Dumble Discussion
- Topic: My take on Eric Johnson's Steel String Singer #005
- Replies: 220
- Views: 126322
- Thu Apr 11, 2024 7:58 am
- Forum: Marshall Discussion
- Topic: Bias voltage range on JCM-800?
- Replies: 5
- Views: 945
Re: Bias voltage range on JCM-800?
I’m working on a JCM-800 and I find that the bias voltage ranges from -58VDc to -42VDC. I have tried the EL-34’s that the amp came in with and a new set. I find with a new Marshall branded set if EL-34’s the maximum they will pull is 27mA. The bias circuit is incredibly simple. A diode, two resisto...
- Thu Apr 11, 2024 7:57 am
- Forum: Trainwreck Discussion
- Topic: Where to find Trainwreck Logos?
- Replies: 58
- Views: 9062
Re: Where to find Trainwreck Logos?
[Franchesca (Express "85") had Clarostat PC style pots throughout where both Ingrid (Express "92") and the Liverpool from Funks images have a mix of Clarostat, PEC and Mil-spec AB's but in similar layouts. The 1megs used for volume appear different than those used for treble etc. I would be interes...
- Wed Apr 10, 2024 7:57 am
- Forum: Trainwreck Discussion
- Topic: Where to find Trainwreck Logos?
- Replies: 58
- Views: 9062
Re: Where to find Trainwreck Logos?
[Franchesca (Express "85") had Clarostat PC style pots throughout where both Ingrid (Express "92") and the Liverpool from Funks images have a mix of Clarostat, PEC and Mil-spec AB's but in similar layouts. The 1megs used for volume appear different than those used for treble etc. I would be interes...
- Mon Apr 08, 2024 6:26 am
- Forum: Speakers and Cabinets
- Topic: who makes vox cabs these days?
- Replies: 4
- Views: 743
Re: who makes vox cabs these days?
the problem is with the grill cloth
- Tue Mar 26, 2024 7:07 am
- Forum: Marshall Discussion
- Topic: 2204 build voltages are off
- Replies: 9
- Views: 1953
Re: 2204 build voltages are off
some 2204s had low voltages originally (around 370v)