Melos Mini Fazer

Started by AS74, July 27, 2014, 12:52:05 AM

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AS74



I'd like to bring this up to unity gain.  After searching here, there and everywhere I couldn't find an answer..
I have found stuff related to the phase 90 to help with this problem, but this thing doesn't have the output stage that has..
Would messing with the mixing resistors help here?  The 22k from input to output and 33k to the switch..

PRR

My first impression is that it needs another amplifier (Gain=1.5) at the output to be unity-gain. (I have not done the math for both modes.)

My second impression is that it puts a heavy load on a guitar and in today's world we would put a unit-gain buffer on the front.
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Liquitone

Nice work AS74, that's the first readable schematic of the mini fazer I've seen. I was working on tracing mine and make a schematic but got distracted by other projects.
You're right PRR. Although I always liked this phaser, it does robs highs and is quite a bit below unity gain when on. I haven't tested it with a bypass loop.


AS74

I won't take credit for drawing that schematic, I found it online while searching for a solution..
Thinking I might put the pedal in a loop with a booster after  :-\ or before..
Wah certainly didn't like it after it..

StephenGiles

I think this was the phaser circuit which showed the square wave output from the LFO being used to drive the FETs!!
"I want my meat burned, like St Joan. Bring me pickles and vicious mustards to pierce the tongue like Cardigan's Lancers.".

PRR

> square wave output from the LFO being used to drive the FETs!!

The plan above shows the triangle-wave driving the FETs.
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AS74

Any suggestions as to what to put on the front end and output, to help with PRR's impressions of this cicuit?

AS74



Anyone willing to do run through explaining the circuit above...In  sections as it goes ..
Or link to somewhere i could find similar explainations...Paticularly this scheme..

duck_arse

when in doubt, "geofex". in this case, the technology of phases and flangers, or similar.

and then to amz for buffers. links at the top of the page, every page.
You hold the small basket while I strain the gnat.

StephenGiles

#9
Quote from: PRR on July 27, 2014, 10:56:25 PM
> square wave output from the LFO being used to drive the FETs!!

The plan above shows the triangle-wave driving the FETs.
Yes I know, I wonder if I still have my original copy??

Very small!!

http://www.diystompboxes.com/pedals/uniphase.gif
"I want my meat burned, like St Joan. Bring me pickles and vicious mustards to pierce the tongue like Cardigan's Lancers.".

petemoore

 A buffered input boosts current availibility, helps to not load the guitar [hardly any current output there] which helps insure the rest of the circuit is introduced to 'the whole signal'.
Then something wired to voltage boost the output...which could be about anything, like a gain stage called 'boost' or 'recovery' or 'Stratoblaster' or 'Micro Amp' or even 'LPB'.
Put after the output cap and before the true bypass switch, the phase volume can then be adjusted at, below or above unity.
Convention creates following, following creates convention.

AS74


alparent

I have these mini SMD LPB boards I got made. They are so small they fit right on the A100k volume pot pins. Anytime I need to get more juice out of a box ( mostly to get things to unity....or above!) I just tag on one of these babies.
Should post pictures. I have like 30 of these made up. Send me your address and i'll send you one.

moose23

Bit late with a reply but increasing the 47K to ground near the output should increase the the output volume. Still need to do this to my one but same principle has worked for mein many other pedals.