Voxman-Plus Abomination

Started by punkin, July 05, 2009, 12:53:00 PM

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punkin

Hello All,

I had a pile of left over parts laying around so I put some stuff together on the breadbaord. I'm calling it the VoxMan-Plus Abomination.

Simply put, all I did was build the Mockman 2, the Vox 2 Knob Tone stack shows in the Duncan calulator and a simple JFet booster. Connected them in that same order and voila! Sounds pretty darn good. The tone stack really adds some flexibility to the Mockman. I can get a brutally brittle bright sound or a very sweet hollow Vox sound. This is a tasty and useable package IMHO.

Before I added the booster, I was really really happy with the sound. After the booster well, it still sounds quite good but when I turn the trebble up it tends to get just a little fizzy. To bias the FET I simply adjust the trimmer to where it sounds best and the make up gains sounds about right. This too is where the light fizz is at it's least objectionable. If I were to further describe the sound, it seems to almost have a bit of a gating sound to it. But again, this combo, it's a keeper...sound pretty darn cool. Once I get this polished I'm going to add a switchable fuzz section...I digress.

I did draw this all out using PCB123 but I can't figure out how to export it to a postable picture. As soon as I figure it out I will do so.

Anyways, if anyone is familiar with these circuits and have advice on how to tame the sizzle I'm getting from the booster stage, much appreciate it.

Here are the schematics I merged together;
Mockman 2;http://www.runoffgroove.com/mm2.html
Vox 2 Knob Tonestack;http://ozvalveamps.elands.com/electravox/ac30tonestack.jpg
Jfet Booster;http://www.muzique.com/images/jfet3.gif

Comments, suggestions always welcome and encouraged. :icon_wink:
Ernie Ball Music Man - JPM, THD Univalve, Grace Big Daddy, PepperShredder, BSIAB2, FireFly Amplifier.

punkin

I've redrawn the schematics. I continue to tinker with it. All in all as I said before a very tasty package. If anyone would like to comment on the schematic please feel free. As I mentioned in my earlier post, when I added the JFet booster stage, when the tone knobs are set for more trebble, things get slightly fizzy and has almost a gated sound. I question weather or not the last section is a good impedance match.

Currently I'm working on a fuzz section. In the end I envision a complete bypass switch a fuzz on/off switch and a tone stack only mode (so the thing will work more like a standalone EQ).

http://home.comcast.net/~spl-studios/pwpimages/VoxManAbomination.bmp
Ernie Ball Music Man - JPM, THD Univalve, Grace Big Daddy, PepperShredder, BSIAB2, FireFly Amplifier.

petemoore

Anyways, if anyone is familiar with these circuits and have advice on how to tame the sizzle I'm getting from the booster stage, much appreciate it.
  Maybe it's getting a very hot input signal, is there a volume control on the Mockman or after the tone section ?
  Maybe not...you could us LP filter caps to reduce HF response /gain, before during or after the Jfet.
  Perhaps you can tell I don't know exactly what you mean by sizzle.
  And wander...with suggestions perhaps you can find the experiment for...like...do you use all the gain the Jfet has or do you run the last volume control say less than 60%, you could consider reducing the gain of the Jfet, does the Jfet have an AC source bypass cap ? 
Convention creates following, following creates convention.

punkin

yep...i've got a volume control between the mockman and the latter tone stack and the recovery booster. The J201 booster also has a 10k trimmer on the source. curriously, when I make adjustments, about the only thing that happens is an adjustment in volume out except at wide open where I get kind of a tremolo effect as a sustained note fades out. kinda cool but not enought to make it desireable.

Ernie Ball Music Man - JPM, THD Univalve, Grace Big Daddy, PepperShredder, BSIAB2, FireFly Amplifier.