Search found 2982 matches

by Mark
Sat Apr 13, 2024 2:02 pm
Forum: Marshall Discussion
Topic: Raspy treble from 2203 amp
Replies: 6
Views: 316

Re: Raspy treble from 2203 amp

Mystery double post.
by Mark
Sat Apr 13, 2024 2:02 pm
Forum: Marshall Discussion
Topic: Raspy treble from 2203 amp
Replies: 6
Views: 316

Re: Raspy treble from 2203 amp

bepone wrote: Sat Apr 13, 2024 1:50 pm Speaker is v30? Change the speaker?
Some other guitar problem?
I used a EVH MIM guitar, and I also used my Strat. The box is a Fender Bassman box with Kendrick Blackframe speakers in it. I have previously used the box with a 1959 and it sounded fine. The speakers aren’t overly bright.
by Mark
Sat Apr 13, 2024 11:56 am
Forum: Marshall Discussion
Topic: Raspy treble from 2203 amp
Replies: 6
Views: 316

Raspy treble from 2203 amp

I plugged into my friends 2203 and it sounded dreadful. It was overly compressed and the treble is raspy. The compression was due to the 100K cathode follower resistor measuring 880K. I replaced it and the amp sounded much better. The amp still has raspiness which goes away when I turn the volume up...
by Mark
Sat Apr 13, 2024 11:27 am
Forum: Marshall Discussion
Topic: Bias voltage range on JCM-800?
Replies: 5
Views: 237

Re: Bias voltage range on JCM-800?

Thanks for your advice I appreciate that.
by Mark
Thu Apr 11, 2024 7:04 am
Forum: Marshall Discussion
Topic: Bias voltage range on JCM-800?
Replies: 5
Views: 237

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 resistor...
by Mark
Wed Apr 10, 2024 8:51 am
Forum: Trainwreck Discussion
Topic: Where to find Trainwreck Logos?
Replies: 58
Views: 7451

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...
by Mark
Wed Apr 10, 2024 3:54 am
Forum: Trainwreck Discussion
Topic: Where to find Trainwreck Logos?
Replies: 58
Views: 7451

Re: Where to find Trainwreck Logos?

Malou is a very interesting example. The pots themselves are a great source of consideration for me as they each appear to have been selected for a reason. Either that or they were just sourced from a box of various pots! I know that Marshall used the "hot shield" regularly in their cascaded amps i...
by Mark
Tue Apr 09, 2024 4:49 am
Forum: Trainwreck Discussion
Topic: Why did it take me 15 years to try a 12ay7 in my Liverpool?
Replies: 8
Views: 951

Re: Why did it take me 15 years to try a 12ay7 in my Liverpool?

Did you try the vintage/fast switch. That reduces the output from the second stage. I tried a few of those sorts of things over the years. To be honest I can't remember exactly the values I played with in that spot but I did have a switch on it. I think I mostly put the preamp back to stock now... ...
by Mark
Tue Apr 09, 2024 4:47 am
Forum: Trainwreck Discussion
Topic: Where to find Trainwreck Logos?
Replies: 58
Views: 7451

Re: Where to find Trainwreck Logos?

Yes those photos were on Dave funks website maybe thunderfunk.com but cant seem to find it. Dave was a authorized Trainwreck repair shop and after ken passed Dave decided to spill the beans that he had built Trainwrecks for ken. Would send ken the chassis and ken would tweak them, serial them, head...
by Mark
Tue Apr 09, 2024 4:46 am
Forum: Trainwreck Discussion
Topic: Where to find Trainwreck Logos?
Replies: 58
Views: 7451

Re: Where to find Trainwreck Logos?

Interesting that Funk would have been involved in the Liverpool with the extra cap and 10 turn variable resistor. I wonder which amp that is and whether it is one of the more known or not. Also wonder if there was just a great deal of Mil-spec pots in stock for the Mids or if there was something ab...
by Mark
Tue Apr 09, 2024 4:41 am
Forum: Trainwreck Discussion
Topic: Where to find Trainwreck Logos?
Replies: 58
Views: 7451

Re: Where to find Trainwreck Logos?

Malou is a very interesting example. The pots themselves are a great source of consideration for me as they each appear to have been selected for a reason. Either that or they were just sourced from a box of various pots! I know that Marshall used the "hot shield" regularly in their cascaded amps i...
by Mark
Tue Apr 02, 2024 5:05 am
Forum: Trainwreck Discussion
Topic: Why did it take me 15 years to try a 12ay7 in my Liverpool?
Replies: 8
Views: 951

Re: Why did it take me 15 years to try a 12ay7 in my Liverpool?

Did you try the vintage/fast switch. That reduces the output from the second stage.
by Mark
Tue Apr 02, 2024 5:03 am
Forum: Trainwreck Discussion
Topic: Where to find Trainwreck Logos?
Replies: 58
Views: 7451

Re: Where to find Trainwreck Logos?

One mod that doesn't get any love is the Maloo picture where there is a small ceramic cap in series with a ten turn pot across the 100K plate resistor of the second triode stage. It was for high output pickups, but I noticed (depending on the cap value) it can boost bass after the tone controls. I h...
by Mark
Wed Mar 27, 2024 11:33 am
Forum: Technical Discussion
Topic: Knight 600 valve emissions tester thoughts?
Replies: 5
Views: 442

Re: Knight 600 valve emissions tester thoughts?

Stevem wrote: Wed Mar 27, 2024 9:53 am Give me your mailing address and I will send you a few!😊
:lol:

I’m sure they will eventuate.
by Mark
Wed Mar 27, 2024 9:14 am
Forum: Technical Discussion
Topic: Knight 600 valve emissions tester thoughts?
Replies: 5
Views: 442

Re: Knight 600 valve emissions tester thoughts?

I have using it for a couple of days and I have yet to see a bad valve. I was wondering what is going on.