Modified Pharaoh

[rocket88]

so i have a real pharaoh in my collection (one of the first boutique pedals i bought) and love it, but always thought it could use a little more. since i started building i've been looking at other things i can do to it to tweak it, and thanks to a lot of people who have provided guidance in understanding circuit design, and since i've learned how to create layouts (thanks again mark and induction) i took marks pharaoh layout and made some changes.

1: i added a pre-gain pot which will help cut the amount of input going into the circuit so you can use it to make it as clean or fuzzy as you want.

2: instead of having just 3 clipping options (Ge, None, Si), i made a little daughterboard with 6 different clipping options, so you can have more clipping options.
Side Note: I was thinking about having a diode blend instead, but i really haven't used them before so i don't know how it would sound



Then i took it one step further i added a split n' blend to the layout. if you have room, i know 7 knobs is a lot, but i would want to add a blend control, especially since i play bass having a blend will allow for more retention of the tone of your actual instrument. not sure if i did it right, so i would need someone to check it out. I figured it would be nice to have it on the main board rather than have to have another daughterboard inside the pedal.



i think that i would want to mess with transistor type too, maybe try to something like the hoof where Ge transistors are used for Q3 & Q4. but i figured this would be a good start to making what i think would be an ultimate BMP, nit i think it would need either a mids switch or a mid control know, but not sure how/where to add either.

what do you guys think?

[IvIark]

Nice job buddy, looks great

[Heath]

Awesome decision for a first bout pedal.  I LOVE LOVE LOVE the Pharaoh.  I might have to give some of your mods a go.  Thanks!!

[rocket88]

no problem heath. got to say the pharaoh is one of my favorites, but i'm also partial to big muff, and its variants. the first pedals i ever bought was a little big muff and a traditional big muff. there's something about the fuzz you can get out of it, and all the different clones or modified versions just have a special place in my heart.

i've always thought how i can put my stamp on the muff. i love the green russian, and built mine using the right russian parts, but feel the pharaoh has similar characteristics to it as far as low end, but has a control to be able to cut more through the mix. figured how it would be a better starting point and i came up with this. now this is a little extreme, but i was thinking you can even do another rotary switch and replace the diodes on the board giving over 36 different clipping possibilities!!!

[rocket88]

made some corrections to the layouts. they should work now.

[rocket88]

Aaaaaaand, verified.

[traktop]

I´ve got my "normal pharaoh" vero finished in front of me when I found this post... I happen to have a B500k pot, a 2p6t rotary lorlin switch and every diode needed for the daughterboard

Since I´m planning to leave the input switch, I was thinking on using the B500k pot instead of the 470k resistor between tone 3 and ground to get some kind of mid control...
Am I right or wrong...?
Cheers, Gilberto.

[rocket88]

that's way too big for a mids control. IMHO with the Highs control on the pharaoh i don't think a mids pot is needed. if you want to add one, you're going to want to following the wiring for the AMZ presence control, link. btw, the highs pot is a variation of the AMZ presence control, just on to boost/cut the highs instead of mids.

[traktop]

I see. So tone and highs controls are interactive in the sense of highs bringing up some air when rolling back tone control or something...
Anyway, it sounds pretty nice on the demos, so I will build it as it is. I just like to plan some tweaks in advance whenever is possible, just in case I get lazy later... I think this pedal is asking for a second stomp switch for getting creamy low gain settings as I heard on the videos.
Thanks so much.

[traktop]

After cutting the clipping daughter board I found something strange. The sw2 row it is supposed to be "germanium-assimetrical" and just see 2 diodes. Shouldnt be 2 diodes in series and another one in paralell¿

[rocket88]

true. really the diodes on the daughterboard can be anything you want, and any way you want to put them. i just made the daughterboard for the typical symmetrical diode clipping. just do it how you want.

[traktop]

Thanks

[Travis]

This looks like a seven-knobbed buffet of fuzz


I approve

[rocket88]

i'm glad you do. made one that's a little bit different, change some of the values. the thing is a beast. then again i did work to put my stamp on the muff, and muffs should be a beast first and foremost.

[traktop]

Well, it´s finished. I finally used a 500k pot for the "pre" control and made the clipping daughterboard connected to the rotary switch:
pedal


guts

clipping board


It works, but there is definitely something wrong here.
First of all, the unclipped signal sounds much lower than any of the clipping options, (germanium included).
I´m having problems with the mosfet clipping stage, as it behaves exactly like if there is no clipping. I remember using mosfet clipping in my modded proco rat and did it following a layout that had two germanium diodes involved as well. This time I just bridged gate to drain of each mosfet, and used drain and source as a normal diode, but is not working.
Now, when I´ve got any of the clipping options going on, I get a high pitch sound when not playing that changes pitch when twiddling with any of the knobs, (volume/tone guitar pot included), and finally stops when turning down level/pre/fuzz knobs...
I´ve got one doubt about highs pot 1&2 lugs wiring as well. I just throwed a cable from the "highs 1&2" hole from the board to the highs pot lug 1 and then bridged to lug 2. I did the same with the SwA cable that comes from the rotary switch to the highs pot. I´m I doing it right, or do I need to throw a different cable for each lug each time...?
Any idea...?
Cheers, Gilberto

[rocket88]

Hmm. That's really odd, I'm not sure what happened. I can tell you that if you did the layout with the blend, the uncoupled signal will always be lower, because it's not going to get a boost in output. DNA you post your voltages and a clear shot of the top and bottom of both boards? I'll take a look and see if there's something missing or whatnot. When I get home I'll inspect the layout, as I know they've been built successfully before. I'm thinking though there could be a grounding issue with the clipping diodes, so I would check it out.

[traktop]

I built the regular layout, (no blend knob).
Here are the voltages:
Q1

E: 0,29v
B: 0,85v
C: 5,64v

Q2

E: 0,02v
B: 0,60v
C: 3,90v

Q3:

E: 0,02v
B: 0,62v
C: 3,90v


Q4

E: 0,87v
B: 1,46v
C: 4,67v


Thank you for your time

[traktop]

I´ve just realized that I wired the 500k pre gain pot in a different way...
Instead of wiring the signal input to lug 2 and lug 3 to the board I did the opposite, (input to lug 3 and lug 2 to the board. nothing connected to lug 1), but I don´t see this causing trouble, as the pot is doing its job.
I checked rows continuity on both boards, and everything seemed ok, but I made a pass with a cutter between rows just in case.
Mosfet diode clipping still dead, (signal but no clipping), maybe I just messed them or something.
The strangest thing for me, (besides from the pitch tone controlled by pots on any clipping setting...), is the fact that any of the clipping selection sounds far louder than the no-clipped selection, (I mean, I get unity gain with no clipping selected just quite diming the volume pot...).
I forgot to tell that I wired 2x 2m resistors from input and output to ground at the switch.

[traktop]

I uploaded 3 new big clear pictures up there.
I tested the pedal into my pedal board with my hiwatt dr103 this afternoon, and it seemed the high pitch sound has gone. Didn´t test it deeply, but all previous tests were done on a solid state 1w fender amp alone, with no buffers before or after, (my pedalboard has a couple of them before and after), so maybe that´s the problem, (I experienced exactly the same with my rockett animal build, what´s bothering me big time!!!...) Any thoughts?

Anyway, the remaining problem is the one with no clipping selected, that keeps on sounding so low in volume and very dark in tone, (even with both tone controls dimed), so something is wrong there.

PD- Judging the little I heard, I like it, and this is the best big muff I played for sure ;) (and I don´t like big muffs...!! )

[rocket88]

Haven't had any time to look at this, just got in last night and had another concert tonight, but I've got a crazy idea. Disconnect the pre-gain pot and attach the input directly to the board. I wonder if that's the issue. I'll look at this more tomorrow after work man, I promise. Sorry that I've been too busy to really check it out for issues.