original bluesbreaker pedal

[jschwalls]

I got this in yesterday on trade at the store i work at... cost $0...
it doesnt sound to good, i was wondering if there were any cool mods available to make this pedal come to life.... currently it sucks the tone , bad. and has NO low end at all...

also on the board there are parts labeled C4 and C17 (for example), that look like resistors.. i would love to find an original schematic with the correct placement of things and rebuild it... even as it is, it sounds kinda cool.


thanks in advance.
JON

[jschwalls]

i now have an original Marshall schematic, still no clue as to why some of the spots labeled for Caps have resistors on them.....the board appears to be untouched the solder looks original.....

thanks Scott Kiraly for the schematic.....

[Gus]

Some caps are axial

A stock bluesbreaker can sound good into a tube amp that is turned up.

[jschwalls]

yeah, these aren't the axial type.... they look EXACTLY like resistors...they even have the colored rings....
I got the pedal from the original owner and he says it has never been touched.... really weird

[slacker]

They're axial ceramic caps, I think all the Marshall pedals use them, certainly my Shred Master does. It has 2 sorts in it, the first are mustard coloured and are the larger values, the second look like light blue resistors complete with coloured bands and are the smaller values. If you check the bands you should find they match up to the values on the schematic.

[frankclarke]

If you don't like the sound of it, the neatest mod is to sell it on eBay for $150, and buy something you like. Otherwise google "bluesbreaker mods". Changing a couple of diodes and caps isn't likely to turn a pig's ear into a silk purse, regardless of the current (Floyd Rose my '57 Strat please) fashion for mods.
I reworked my GV-2 to sound like a Morley JD-10 (OK, I'll go and write that up, and fix my Bluesbreaker mods page), but I wouldn't mod an original Guv'nor for example.
Edit: update done.

[jschwalls]

well, i have ALOT of pedals ,thanks to the fact that i work at a music store and get them for next to nothing when they come in on trade.... i just like having alot of toys that never get used i guess... hahha
My OCD is king of the hill now....

the main problem with the pedal is the muddy lifeless tone, the original owner said it sounded fine, them it started sounding bad...
like i said i got it for $0, and just want to tinker with it to see what results i can get.... i am sure that better caps will help the sound ALOT.

thanks for all the info guys...


JON

[Gus]

It might be worth more stock.

Look in schematics link at the top of the page



I would first find out what happened to the sound
First the simple stuff
check the switch with a DMM set to ohms
check/clean  the input and output jacks



The way the gain is controlled is clever.  The pot changes the gain in both stages.

[DougH]

Bluesbreaker may not be your cup of tea, but it shouldn't have a "muddy lifeless tone". Sounds like something is wrong with it.

As Gus mentioned, it's a good sounding pedal through a cranked up amp, as most "overdrives" don't really come to life until you get some air moving through the speakers. Bedroom pedals they are not...

[slideman82]

Well, certainly, there must be some mods to be done. I'm not really familiar to its schematic, but, y first impression is changing that horrible TL072 for a socket, and then try a JRC4558D or maybe a Rail-to-rail opamp, like the TL2272, maybe this has some change in the sound. It has happened to me that the opamp really affects the sound, try a TL072 in a TS, it becomes fuzzier, really harsh. The JRC4558 gives you those good mids in the TS circuit. Also, try replacing those 4 1N4148 for a pair of leds, and c4 for something bigger (maybe 100p)... well, those mods are what I have in mind right now. Becareful with PCB tracks whem modding!

[DougH]

Nothing wrong with TL072's in those Marshall pedals. Bluesbreaker, Guv'nor, etc, all sound good with it IMO. The Bluesbreaker is not a "mid hump" machine like a TS. Nothing wrong with TL072's in general, really. Most of the time I prefer them over a 4558.

[DougH]

If you don't like the sound of it, the neatest mod is to sell it on eBay for $150, and buy something you like. Otherwise google "bluesbreaker mods". Changing a couple of diodes and caps isn't likely to turn a pig's ear into a silk purse, regardless of the current (Floyd Rose my '57 Strat please) fashion for mods.

I'm going to get a bunch of Bad Monkeys and do the LarryCurlyMoe mod where I change the filtering cap and polarity diode. Probably get about $20k a piece on Ebay I would guess...

[GibsonGM]

I used green LEDs for clipping in my build of a BB, much better than stock, IMHO.  More output, a lot grittier, and tons of low end!   Could be a problem in the tone stack area, a bad cap in there or something.   I'd audio probe thru that area and see what changes and where, that might point out the trouble spot.  The thing should sound pretty good stock...

[Gus]

There is nothing wrong with a TL072 if used correctly.

The blues breaker does not tax the output stage of the 72.

The bluesbreaker might be one of the effects that changing parts in it can often make it sound worse.  Changing the gain because of the interaction of the pot on both parts of the gain stages

If you have read posts of mine over the years iI have posted about not likeing ceramics: However effects are producers of sound and sometime ceramics are what you want.

[DougH]

The only mod I might make to a Bluesbreaker would be a small brite cap on the gain pot (the stg 2 variable series resistance section). It will roll the highs off slightly as you turn the gain control down. A small cap can be used to compensate and keep the frequency response fairly even at different gain levels.

[slideman82]

Nothing wrong with TL072's in those Marshall pedals. Bluesbreaker, Guv'nor, etc, all sound good with it IMO. The Bluesbreaker is not a "mid hump" machine like a TS. Nothing wrong with TL072's in general, really. Most of the time I prefer them over a 4558.

Yes, maybe 072 are better than 4558, with theirs JFET input, but, how they sound on overdrives is another thing...

Oh, I'll have to mod a Bad Monkey, is its schemo on the net?

[jschwalls]

when the pedal is off it has a real muddy sound to it, when switched on it sounds nice but has very little low end....

Im gonna rebuild it back to stock with newer parts....

we shall see...

thanks guys.

[wampcat1]

Nothing wrong with TL072's in those Marshall pedals. Bluesbreaker, Guv'nor, etc, all sound good with it IMO. The Bluesbreaker is not a "mid hump" machine like a TS. Nothing wrong with TL072's in general, really. Most of the time I prefer them over a 4558.

Oh, I'll have to mod a Bad Monkey, is its schemo on the net?

Yes... it is just a tubescreamer with a sim inductor after that.
bw

[analogmike]

I got a few of those in for repair, it was just a half-dead chip. Pop any decent op-amp in there and I bet it will sound fine.

[jschwalls]

i will try replacing the chip.. thanks MIKE