Search found 227 matches
- Sat Mar 30, 2024 1:37 pm
- Forum: Vox/Hiwatt Discussion
- Topic: Hiwatt DR504, looking for a little info
- Replies: 5
- Views: 1043
Re: Hiwatt DR504, looking for a little info
I suspect that DR504 is a UK-made Hiwatt made during the time Musicground owned the rights to the Hiwatt name (the Harrison clan) I doubt they sourced their iron from Heyboer (I've used many Heyboer Partridge clone transformers in Hiwatt-type builds) I believe the Harrisons sourced their Partridge c...
- Wed Mar 27, 2024 11:53 am
- Forum: Marshall Discussion
- Topic: 2204 build voltages are off
- Replies: 9
- Views: 844
Re: 2204 build voltages are off
Here is a schematic (w/voltages) of one 1983 Marshall 2204 (owned by mhuss) These are typical voltages of a 1983-era 2204 amp --- This does not mean that EVERY 1983 2204 will match these voltages exactly --- this does not mean that EVERY Marshall 2204 ever made will match these voltages (my '79 Mars...
- Sun Mar 03, 2024 1:03 am
- Forum: Marshall Discussion
- Topic: Sir 36 mod
- Replies: 10
- Views: 813
Re: Sir 36 mod
Years ago I followed some of the many SIR #36 schematics you posted (on another forum) and built many similar amps, usually 50 watt These heads were sold to musicians in my local area and were well received --- your schematics helped me to learn to modify Marshall circuits But most local musicians, ...
- Mon Feb 12, 2024 3:45 am
- Forum: Marshall Discussion
- Topic: '82 JCM800 2204
- Replies: 4
- Views: 711
Re: '82 JCM800 2204
I did some tweaking to a 25 watt 2204-type build I did recently --- I put the 470k/470pF !st Treble Peaker back in (i had a 68k in there) to give it more treble response when the MV is cranked above 5 --- this worked well, I'd gotten into the habit of building 2204-type amps without the 1st Treble P...
- Thu Feb 01, 2024 5:58 pm
- Forum: Marshall Discussion
- Topic: '82 JCM800 2204
- Replies: 4
- Views: 711
'82 JCM800 2204
I recently serviced this amp for a friend --- It is a 6550 spec amp that had EL34's installed (which biased the EL34's so cold that it barely operated at all) I quickly measured all the resistors in the amp (initially looking for the "problem" before I realized it was a 6550 amp) and I found that th...
- Fri Jan 19, 2024 3:54 am
- Forum: Technical Discussion
- Topic: Sound City L120 mk4 Biasing
- Replies: 10
- Views: 1281
Re: Sound City L120 mk4 Biasing
Here's a 100 ohm/5 Watt Metal Oxide Power Resistor that Mouser currently has in stock --- It has better specs than the other 3 similar resistors they have right now: https://www.mouser.com/ProductDetail/YAGEO/RSF500JT-91-100R?qs=sGAEpiMZZMvmQ%252BOLa8n%2FM0VaQqJq%2FX2CratbCum5YeFYTqqG54ZAZA%3D%3D Bu...
- Mon Jun 26, 2023 3:58 pm
- Forum: Marshall Discussion
- Topic: sv20h circuit question
- Replies: 3
- Views: 1855
Re: sv20h circuit question
Why not build your own Mini-Plexi ?
I just built two mini-2204's (6L6GC x 2, 25 watt scaled iron) one stock-ish and the other Hi Gain with a plate driven tone stack and other mods
You can build your mini-Plexi and make it however you want it
https://mhuss.com/Plexi6V6/Plexi6V6.gif
I just built two mini-2204's (6L6GC x 2, 25 watt scaled iron) one stock-ish and the other Hi Gain with a plate driven tone stack and other mods
You can build your mini-Plexi and make it however you want it
https://mhuss.com/Plexi6V6/Plexi6V6.gif
- Mon Oct 31, 2022 8:35 am
- Forum: Vox/Hiwatt Discussion
- Topic: Tube shield in a Hiwatt?
- Replies: 16
- Views: 4592
Re: Tube shield in a Hiwatt?
I built two DR504 clones in 2006 without heat shields ---- One I still have and it is still running fine --- The other was sold to a touring band that has been using it since then playing all over the SW USA, Mexico, and parts of South America --- They brought it back to me once for a "tune up" and ...
- Sun Aug 28, 2022 12:22 am
- Forum: Fender Discussion
- Topic: carbon comp resistors
- Replies: 49
- Views: 7086
Re: carbon comp resistors
I just saw a YT video that said Reptilian Space Aliens have a military base in Antarctica from which they fly most of the craft that people report as UFO's It went on to say that they've been having navigation problems (because they're Space Aliens) and have hired Elvis Presley to pilot their craft ...
- Fri Mar 11, 2022 5:47 pm
- Forum: Fender Discussion
- Topic: 1965 Bandmaster hum
- Replies: 93
- Views: 12373
Re: 1965 Bandmaster hum
I must agree If the OP's amp has Stray Voltage on the main Eyelet Board then no parts swapping will fix the hum problem until the Stray Voltage is eliminated I'd also take a very close look at the grounding of everything on the front panel of the amp ----- Make sure everything is Clean, Tight, and S...
- Sun Mar 06, 2022 8:49 pm
- Forum: Fender Discussion
- Topic: 1965 Bandmaster hum
- Replies: 93
- Views: 12373
Re: 1965 Bandmaster hum
No, just the rectifier diodes ---- not on the Main Board
It seems like I've seen this black paint/dye on other old BF Fender amps, too
Maybe on the many Showman/Dual Showman amps i've owned or serviced
It seems like I've seen this black paint/dye on other old BF Fender amps, too
Maybe on the many Showman/Dual Showman amps i've owned or serviced
- Sun Mar 06, 2022 5:39 pm
- Forum: Fender Discussion
- Topic: 1965 Bandmaster hum
- Replies: 93
- Views: 12373
Re: 1965 Bandmaster hum
My #2 '65 Bandmaster had the black dye/paint on the diode solder joints, too ---- I just un-soldered the joints as usual and used my vacuum pump to clean out all the old junk ---- I removed the Rectifier/Bias board and backing board and cleaned up everything before i put it all back together with ne...
- Sun Mar 06, 2022 12:42 am
- Forum: Fender Discussion
- Topic: 1965 Bandmaster hum
- Replies: 93
- Views: 12373
Re: 1965 Bandmaster hum
I installed new 1N4007's in the rectifier (Bias, too) when I got my #2 '65 Bandmaster up and running when I first got it I re-did the whole Rectifier/Bias board when I replaced the blown PT it came with When I tested this one out it sounded almost as good as my #1 '65 Bandmaster (my favorite amp) so...
- Thu Dec 23, 2021 9:10 pm
- Forum: Marshall Discussion
- Topic: output section for small venues - JCM800
- Replies: 12
- Views: 2480
Re: output section for small venues - JCM800
Years ago I built an EL84 x 2 2204 type head and ended up installing both the pre-PI MV and a PPIMV Also added a fixed Resonance/Depth circuit and added a bit of extra gain to the preamp (and cutting some low freqs in preamp to counter higher gain flubbiness) I still have this one and it is useful a...
- Mon Nov 29, 2021 12:34 pm
- Forum: Technical Discussion
- Topic: Sound City L120 mk4 Biasing
- Replies: 10
- Views: 1281
Re: Sound City L120 mk4 Biasing
I've Rebuilt/Reporposed dozens of SC 120's over the years ---- Hiwatt preamps, Modern Hi Gain preamps, Blackface/Brownface Fender preamps To help out the sometimes marginal Bias Supply, I've taken to installing 100 ohm/5 watt Cathode resistors on all six Output tubes Then building a Hiwatt DR103 typ...