Search found 34 matches
- Sat May 04, 2024 1:04 am
- Forum: Technical Discussion
- Topic: JTM45 Build, looks alive but no sound,
- Replies: 7
- Views: 244
Re: JTM45 Build, looks alive but no sound,
Are you plugged into the main speaker jack and not the extension jack by accident? You must plug into the main jack for the amp to produce sound. Also make sure that you are not plugged into the limiter when biasing and trying to play through the amp. Edit: Looking at the schematic, it appears that ...
- Fri Apr 12, 2024 12:02 am
- Forum: Marshall Discussion
- Topic: Bias voltage range on JCM-800?
- Replies: 5
- Views: 281
Re: Bias voltage range on JCM-800?
I have often needed to drop the value of the resistor that is inline with the bias pot. If it is a 47k or 56k, lower it down to the next value and try again.
- Mon Dec 18, 2023 2:41 am
- Forum: Marshall Discussion
- Topic: soliciting input re: resistor brands for my first Marshall build
- Replies: 9
- Views: 6202
Re: soliciting input re: resistor brands for my first Marshall build
I got caught up in the same situation as you when planning my first Marshall style builds ten years ago. I went down the rabbit hole buying Piher resistors, mustard caps, Lemco silver mica and many other NOS parts that were used by Marshall. The two amps turned out fine but after building many other...
- Fri Oct 06, 2023 12:45 am
- Forum: Marshall Discussion
- Topic: SLO100 AC-DC HEATERS?
- Replies: 10
- Views: 2780
Re: SLO100 AC-DC HEATERS?
The original SLO ran all AC heaters but the newer models produced by BAD are using DC on the first couple of tubes.
- Sun Feb 05, 2023 3:26 am
- Forum: Marshall Discussion
- Topic: 2204 chassis deminsions
- Replies: 11
- Views: 3465
Re: 2204 chassis deminsions
These are some of the other Metro layouts that one of the members saved,
https://drive.google.com/drive/folders/ ... 549g-K1iDA
https://drive.google.com/drive/folders/ ... 549g-K1iDA
- Sun Feb 05, 2023 3:25 am
- Forum: Marshall Discussion
- Topic: 2204 chassis deminsions
- Replies: 11
- Views: 3465
Re: 2204 chassis deminsions
This is the old Metroamp layout that I used for my 2204. This should help you along with your build.
https://drive.google.com/drive/folders/ ... jBAObvpf2g
https://drive.google.com/drive/folders/ ... jBAObvpf2g
- Tue Jan 17, 2023 12:46 am
- Forum: Technical Discussion
- Topic: Octal preamp 2204 build questions
- Replies: 25
- Views: 11226
Re: Octal preamp 2204 build questions
Any chance that the oscillation is being caused by reversed primary wires on the OT? Have you tried swapping them? If they are reversed and causing positive feedback, that could be messing with the presence pot.
- Tue Sep 27, 2022 11:06 pm
- Forum: Marshall Discussion
- Topic: 2203/2204 plate fed tone stack layout?
- Replies: 2
- Views: 2079
Re: 2203/2204 plate fed tone stack layout?
I was going to suggest the Splawn schematic also. I built one last year from that schematic and the plate fed tonestack definitely adds a ton of gain.
- Sat Jun 25, 2022 1:03 am
- Forum: Marshall Discussion
- Topic: JMP 50 Popping Sound
- Replies: 48
- Views: 6443
Re: JMP 50 Popping Sound
It may be a long shot but several folks over the years have reported issues with those black silver mica caps. Some have been faulty right from the get go and others have been damaged from excessive heat while soldering. I have gone to using quality ceramic caps these days because of this. I also wo...
- Fri Jan 21, 2022 2:21 am
- Forum: Technical Discussion
- Topic: Best way to start learning about amps? And in what order?
- Replies: 9
- Views: 1612
Re: Best way to start learning about amps? And in what order?
Robrobinette has some good basic, beginner info on one of the most simplest circuits. Aiken's sight also has some good info. Both of these are geared specifically towards guitar amps. As suggested above, learning the basics of AC and DC should be your main priority in the beginning. https://robrobin...
- Fri Jan 14, 2022 8:02 pm
- Forum: Technical Discussion
- Topic: Framus mid control?
- Replies: 24
- Views: 3542
Re: Framus mid control?
I recently completed a Tweed ODS build that was posted here on the forum several years ago by a fellow member. I included the Framus mid control in the OD section of this amp and it does work fairly well. With the pot on 10, the gain loss is very minimal. When dialing down the pot, you do loose a ti...
- Wed Oct 06, 2021 11:46 pm
- Forum: Marshall Discussion
- Topic: Dirty Shirley Build
- Replies: 21
- Views: 12004
Re: Dirty Shirley Build
I purchased one of Burger's boards last year for a JJ jr build. The board and documentation were top notch and having two foot switchable channels with separate MV's is a nice upgrade. His board also offers a cathode bias/fixed bias circuit option should you decide to build it that way.
- Fri Jul 31, 2020 12:21 am
- Forum: Marshall Discussion
- Topic: BE Boards
- Replies: 5
- Views: 1819
Re: BE Boards
I used one of Burger's boards in a JJ jr style build just a few months ago. Excellent service after the purchase and the board was top notch!
- Sun May 03, 2020 2:52 am
- Forum: Marshall Discussion
- Topic: Split Cathode vs Shared with same values
- Replies: 10
- Views: 2115
Re: Split Cathode vs Shared with same values
This may help you.
http://forum.metropoulos.net/viewtopic.php?f=26&t=15719
The boards changed slightly over the years but this should have the info you need.
http://forum.metropoulos.net/viewtopic.php?f=26&t=15719
The boards changed slightly over the years but this should have the info you need.
- Sat Feb 22, 2020 2:54 am
- Forum: Marshall Discussion
- Topic: HOW DOES THE MOJO 18 W TMD LAYOUT LOOK TO YOU? EXPERT OPINIONS NEEDED.
- Replies: 36
- Views: 9479
Re: HOW DOES THE MOJO 18 W TMD LAYOUT LOOK TO YOU? EXPERT OPINIONS NEEDED.
I would think think that swapping those carbon comp resistors in the preamp stages for carbon film, or better yet, metal film would help to alleviate some of the hiss.