Search found 1602 matches
- Sat May 11, 2024 9:39 am
- Forum: Dumble Discussion
- Topic: A SSS Build
- Replies: 10
- Views: 274
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: 573
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: 368
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: 371
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: 118070
- Thu Apr 11, 2024 7:58 am
- Forum: Marshall Discussion
- Topic: Bias voltage range on JCM-800?
- Replies: 5
- Views: 417
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: 7922
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: 7922
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: 571
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: 1163
Re: 2204 build voltages are off
some 2204s had low voltages originally (around 370v)
- Fri Mar 15, 2024 8:43 am
- Forum: Technical Discussion
- Topic: Lowering B+ on Single ended amp with Choke input
- Replies: 9
- Views: 642
Re: Lowering B+ on Single ended amp with Choke input
This solution can be used on the screens together with an ordinary capacitor input on the plates but that requires two rectifiers
- Wed Mar 13, 2024 7:09 am
- Forum: Dumble Discussion
- Topic: #002 Steel String Singer - almost there
- Replies: 69
- Views: 2440
Re: #002 Steel String Singer - almost there
we need a new clip!
- Mon Mar 11, 2024 11:46 am
- Forum: Dumble Discussion
- Topic: #002 Steel String Singer - almost there
- Replies: 69
- Views: 2440
Re: #002 Steel String Singer - almost there
the speaker jacks should be grounded together with the phase inverter if you use negative feedback. correct, and it is the only truth.. people here using just random grounding for almost everything, or what they see from other people (the worst way), multiplying noise collected from the chassis dir...
- Mon Mar 11, 2024 8:27 am
- Forum: Dumble Discussion
- Topic: #002 Steel String Singer - almost there
- Replies: 69
- Views: 2440
Re: #002 Steel String Singer - almost there
When I lift R64 NFB resistor, the hum is almost gone. Did I miss a ground some where? OT secondary/speaker ground? Thats it... those damn speaker jacks got no connection to the chassis, even with lock washers. the speaker jacks should be grounded together with the phase inverter if you use negative...
- Fri Mar 08, 2024 8:39 am
- Forum: For Sale/Trade
- Topic: Marshall replica 1987 68’ super lead NOS LCR Iskras Allen Bradley mustards Erie RS Lemco Merren
- Replies: 8
- Views: 815