The Amp Garage

I agree with loverocker, I've tried the hotplate but prefer the Weber MASS. I've never had a chance to try the airbrake. I have the MASS with tone controls and line out, and my favorite way to use it is to put it on full attenuation with no speaker attached and run the line out to rack fx and to a s...

Back to my amp's issues. First, it's got a huge hiss with the volume control up high. It doesn't need a guitar plugged in to do it, and it did it even with my Les Paul. Weirdly, the hiss would reduce when I did NOT touch the strings, and it hissed more when I did. It wasn't noticeable when playing,...

Hi Mark, Thanks for the info. I just gave it a try and I have to agree with your assessment. Smoother distortion and nice sustain (I had notes feeding back at a low volume), but you loose the Marshall crunch. I also loose my favorite semi-clean tones (Hendrixy clean with a little hair). Interesting ...

Well I gave it a try and got complete havoc. I think the standard JTM design is more forgiving of layout. Also rather than reconfigure the cathode follower, I cascaded to two inputs and used the standard wreck values: v1a (1k5/22uf) -> v1b(2k7/22uf) -> hpf -> v2a (10k) -> cathode follower I had some...

LeftyStrat, Yeah, you got it right. That was exactly what I meant. Let me know if you try it and your results. I was curious how this small mod would sound in a Marshall ... and I wondered what Ken Fischer did with his marshall mods and thought maybe this was one of them. Yeah that was what I found...

so change V2a from 820 to 2.7K and V2b from 100K to 10K ? It is slightly more complicated. Change v2a from 820 to 2.7k and add a 22uf bypass cap in parallel with the 2.7k resistor. Then you'll need to modify v1b from being a cathode follower (with the signal coming off the cathode) to a standard ga...

Interesting, I'll give that a try.

Hey David,
What is the value of the cap across the plates of the PI? Is it 50uf or 50pf?
That's one thing I've never seen in any of the other schems.

Thanks,
Thomas

I've been chomping at the bit to build a wreck, but I promised myself I would build a JTM45 first. Though I've built a couple of AX84 designs and have been doing fx builds for many years, I wanted to get my experience level up. Well, my JTM45 turned out fantastic. It is the quietest amp I've built t...

Hey Moose,
I'd be interested in a set also. My order of preference:

1) Dual primary
2) 5k
3) 6.6k

Those pics are awesome, snide. Thanks!!

On the files page under "Schematics and Layouts" / "Main schematics", the second link "Trainwreck Rocket by Mark Abbott" is linked to wreckxpr.pdf, the main express schematic.

Just wondering if Mark had sent you an update from the hand drawn schem listed further down the page.

Thanks.

I wonder what he sold it to them for.

I emailed them and they are asking $23,500.

Hi Mark, I don't have any info, but your description has me intriqued enough to attempt a Rocket build at some point. I have an old dynaco OT w/ a primary of 4.3k that I thought about using, which seems the normal range for 4xEL84. I can share my experience on alternate primaries with my most recent...

That's great. Glad you didn't fry anything. Now you have to post some clips.