MesaBoogie ODS Revoicing

[Pacosipulami]

Hi there

new user....my name is Paco, I'm a bedroom player, composer and technician (mostly for pro lighting gear today, ..ever saw a DMX port in a guitar amplifier? Nah, me neither....but who knows, someday maybe? ). Regarding my nickname, I'm a huge Marsupilami fan over 20yrs, some friends used to call me "Pacosipulami".....

I'm very lucky to own myself two MesaBoogie StudioPreamps in great shape, so I thought it might be a cool idea to add some "fresh vibe" to one of 'em....

As a fan of the d-style concept and a long term mesa/boogie mk3/EVM12L user, I modded the Boogie drive circuit a bit, will turn the clean tonestack into a skyliner and rework the clean stage.

Today I revoiced the OD circuit....here are some guts shots

[img:640:480]http://www.pacocasanovas.ch/P1000851.jpg[/img]

right after the mod

[img:640:480]http://www.pacocasanovas.ch/P1000853.jpg[/img]

the front

and here is a short demo (just with the reworked overdrive stage, no HRM, no skyliner mod - here with the original boogie tonestack and clean gain stage - I have to rework this later on.....I'm not going for the holy grail d-style tone - I got my own ideas! But the basic concept goes in the same area....

http://www.youtube.com/watch?v=s9cKcP7esY4

playing over a pair of active nearfield speakers in bedroom volume.....no harmonic feedback possible here!

PS: The same little tune was recored 18 months ago - with the axefx standard - almost the same tone
http://www.youtube.com/watch?v=6E4IaWU-qyg

Cheers
Paco

[Ang3lus]

amazing tone man, and amazing playing, very D-style and awesome.

[da Geezer]

amazing tone man, and amazing playing, very D-style and awesome.

Agreed........very nice tone and playing.

Have any schematics showing your tweaks, or can you give some details of what you did to revoice?

Geezer

[Ang3lus]

how many gain stages does that boogie have ?

i want to mod this 4 tube gain stage preamp i have here to be a "d-style" voicing.

[Pacosipulami]

@ all: much thanks!
@ Ang3lus: the boogie studio preamp basic circuit is made of five gain stages - input stage with pre volume tonestack (RCA type) with Mid-Boost option, followed by another clean gain stage - then two gain stages (one of them is a cold bias gain stage) feed into a fifth gain (which is a linear type gain stage) stage before passing the solid state EQ (five band LCR active graphic EQ) circuit and the fx-loop then into a stereo output dual gain stage with the speaker simulator or main-output jacks

We've got five tubes in there - 4x12AX7, 1x12AT7 (used as a reverb driver).

I've reworked the overdrive circuit - the V3 tube in the boogie circuit - attached is a handwritten copy, since I did that all direct from mind). Hope you can read it! Maybe I find an app for my mac to redraw the schematics...

the Mesa schematic can be found here:
http://www.freeinfosociety.com/electron ... reamp1.gif

PS: I got another little mod in there - LDR 4 puts another 200k between the signal path and ground when switching to overdrive - it slightly lowers the master volume in the lead channel, because the Lead Master is now located before the fifth gain stage (V2a)....

overall, this would never be a real d-style amp, but it's some nice dynamic fat overdrive, as I like it!

[ToneMerc]

Welcome aboard, that sounds real nice there. I would not change a thing.

TM

[Reeltarded]

Paco! Welcome!

Now, go! Go on! Git! We don't need Randall Smith suing us for looking at his registered patents, even if you did change everything.

Great tone and feel! I love that first vid, gonna check the second right now. Thanks for the happy face on your fingers!

I don't mind the fake thing but the real thing sounds better.

[Pacosipulami]

Paco! Welcome!

Now, go! Go on! Git! We don't need Randall Smith suing us for looking at his registered patents, even if you did change everything.

should I delete the pdf and the link? ....mmh, confused. I found the manual with google.....

[Reeltarded]

Just joking.. sort of. Randall Smith patents everything we have ever done or seen.

Your amp sounds great, and your playing is too happy not to notice! Good deal buddy.

[ampdoc1]

Fine job!! You are an excellent player, and have nailed that Dumble type feel and response. Randall just wishes his designs sounded like that!!!

a'doc1

[roberto]

Awesome sound and playing!
The midrange complexity is clear even through youtube!

[10thTx]

Sounds incredibly smooth! Very creamy tone. Thanks for sharing.

Nice playing too.

with respect,10thtx

[Pacosipulami]

Many thanks to everyone!

Successfully added the skyliner tonestack mod today - with a few small changes to the Mesa topology. After all - it's still a revoiced MesaBoogie Preamp, not a Dumble ODS . I had the words of ToneMerc in my mind all day, but couldn't resist - but the skyliner mod with PAB switch worked out just great and had a very positive effect on the drive circuit.

The clean channel was to quiet compared to the drive channel. So I changed the function of LDR4 once again - I added a 100k trimmer on the LDR4 tap parallel to the overall output A potentiometer. This lowers the volume in the drive channel - now having a better balance between clean and lead!

Last thing to do would be a revoicing of the recording out - with the new d-style tone, the recording out is a bit too scratchy - I'll increase the value of C411 and C412 a bit and hopefully I'm done! Normally I'll use the cabinet block in my AxeFx with the EVM12L impulse loaded.....


I had a lot of fun within the last few days! Now I'm the owner of a mighty cool ODS-style preamp! I'm so happy!

cheers
Paco

[Pacosipulami]

PS: My PAB just break the wire between the bass and treble pot - nothing more! This sounds most organic to my ears. On the bass pot the cw tap and wiper are shorten.....

No needs for jazz/rock voicing or deep switch option here! I'm done!

[ToneMerc]

You just could not leave well enough alone...lol. You need to just bite the bullet and use those chops to build a full blown amp now.

TM