50 Watt Modded Marshall

[gldtp99]

One of the recording engineers from the studio across the hall from my workshop picked up this 50 watter I built---- he records lots of heavy bands so the amp should be put to good use---- here he is playing his new amp:

http://youtu.be/CLvvqisrA2o

[xtian]

MULE! Awesome sauce!

[M Fowler]

The Mule kicks Ass

GJ2 guitar rep was in the store this morning trying to promote the Lerxst amps $2995 but my buddy Dave walked him over to my Fowler HRP 100w #39 and fired that baby up.

We won't be replacing my HRP with Lerxst anytime soon. But maybe we should stock the Mule.

Mark

[gldtp99]

Thanks guys !!! This one is a plate driven tonestack design---- Hell, just get a Quick Rod schematic and then tweak it to your ear----- that's what this is-----I'm not even sure the schematic was correct but it worked out in the end-- Magnetic Components iron.
Mule Amps is definitely a part time hobby---- I can only build @10 amps a year so I'm not looking for distribution.
All the #39/#36 amps I've built have rocked but all have had a good deal of backround hiss------I'm building a 50 watt 3 and 4 gain stage amp now that is near stock JCM 800 on the Lo input and adds the extra gain stage on the Hi input---inputs not wired as stock JCM 800 so real time switching (with A/B/Y box on this 1st one) is possible-----still tweaking it out.
It would be nice to be able to sell amps for @$3k------then maybe I could make a little money with my hobby (obsession ?)
This red 50 watter was used at another local studio, in an earlier tweak, to record an album by an up-and-coming local band------ they loved it and offered me $400 to buy it--I declined---I got more than that for it when it sold to the recording engineer at this studio, but not a huge amount more--- maybe I need to meet more rich people------ most musicians I know don't have a lot of extra $$$.....................gldtp99

PS---- think of it----- getting $3k/amp for mostly ripping off someone else's ideas---- gotta love it

[M Fowler]

I had to knock V1 down with a 5751 tube otherwise the amp was absolutely nuts and still is. Love the harmonics the #39 circuit produces. Maybe I should build #36 next.

I'm convinced I could build and sell bass amps to the young guns around my town rather then guitar amps. They click to the neck position pup, crank the bass knob, roll back the mid/treble knobs and your speakers better handle it or your going to flub out. If I hear one word about tone I give them a lecture on tone because they don't know tone.

Perhaps Hiwatt and Orange 100w-150w beasts. Something that will stay clean and powerful. A Fender twin doesn't stand a chance with these guys.

Mark

[gkelm]

Nice work! And sounds like you're fairly local.

[gldtp99]

Thanks !! I'm in Arlington.

[gldtp99]

I had to knock V1 down with a 5751 tube otherwise the amp was absolutely nuts and still is. Love the harmonics the #39 circuit produces. Maybe I should build #36 next.

I'm convinced I could build and sell bass amps to the young guns around my town rather then guitar amps. They click to the neck position pup, crank the bass knob, roll back the mid/treble knobs and your speakers better handle it or your going to flub out. If I hear one word about tone I give them a lecture on tone because they don't know tone.

Perhaps Hiwatt and Orange 100w-150w beasts. Something that will stay clean and powerful. A Fender twin doesn't stand a chance with these guys.

Mark

I know what you mean----- I live in Arlington, TX---- the home town of the late Dimebag Darrell Abbot of Pantera----- his style is still a big influence on many younger players here------ so this means that any mid-to-high gain amp I build will be subjected to sometimes extreme low tunings, sometimes with 7 or 8 string guitars.
It used to be frustrating when I'd build a mildly modded 2204 clone, tweaked it out so it sounded wonderful in standard tuning--- and then have it turn into an audio pile of mush when one of the low tuned players plugged into it.
Last night a friend was over testing out the 3/4 gain stage 2204 based amp i'm building now----- using both a 7 string and a 6 string in many different low tunings------the amp handles down to B Standard and Drop A tuning quite well--- but it was built to be able to do this (200uF 1st stage filtering, NFB resistor is 100k taken from 8 ohm OT tap)------ doubling the Screens filtering will also go a long way to keeping the low end tight at low tuning levels but it will also make clean tones sound too stiff/shrill, to my ear ( I have a Laney AOR 50 that I gutted and built a SLO/Dual Rec based circuit into, with massive filtering, that handles heavy gain/lo tunings very well---but forget about any usable clean tones).
The idea for this amp was to provide a very wide range of great sounding tones from Marshall cleans to full on High gain in a single channel 2204 based amp with real time switching (with A/B/Y box on this one) between the Lo and Hi guitar inputs-----on this one the Lo input runs the near stock 2204 3 gain stages and the Hi input adds the 4th gain stage---- the switching works very well but i'm still balancing the gain levels/voicing of the 3 stage and 4 stage modes------later similar amps will have internal relay switching between the two modes.
And all of this has to happen without nasty noise problems, of course----- another experiment with this amp was to use a common, less expensive PT--- this one is powered by a Fender replacement Vibrolux Reverb/Tremolux PT ( http://www.tubesandmore.com/products/P-TF22723 )-I get mine from CE but it's the same p/n-----compare the specs of this PT to a 50 watt Marshall PT--------it works very well and the 4A heater winding powers two EL34's and four 12ax7's without any undue heat problem--------the amp was pushed hard last night and the PT performed well-------- it also has 30mA more HT current capacity than a 50 watt Marshall PT.
This amp will also have a Metro FX loop for delay, gate, etc----- but that will be added after I finish up the rest of it.
It is easier to build an amp that handles low passages if one starts with a high wattage amp, that's true------ but lower wattage amps can do it, too if they are built for it----- anyway, these are the kinds of things I do for fun...............................gldtp99

[M Fowler]

Good write-up.

I'm going to have to get serious about designing a local amp or just forget about it and let them shop Musician's Friend for junk throw away amps.

Mark