EH - Big Muff Pi ( Ram Head, Early Version )

Fred_Garvin · Post by **Fred_Garvin** » 23 Oct 2011, 04:35

I know this thread is dead, but, I'm reviving it because of my build.

I bought a reissue muff a while back and never liked the sound much. So, as I was surfing ebay, my eye caught these V2 muff pcb's made by PigeonFX. I thought, gee, wouldn't it be cool to gut this reissue and make it into something better. So, I checked out Kitrae's site and noticed that he had a picture of a V2 muff with the values labelled. To cut to the chase, I bought the PCB from ebay along with a bunch of parts I won in a previous auction and hunkered down to make a magical muff. I found almost every available part I had lying around except a few, the .15uf capacitor so I opted for a .18uf I had kicking around, and the .004uf which I used a .0047uf. I used BC547C for the trannies at 600-799 hfe. The results are truly night and day, this thing sounds amazing, it even beats out my muff with tone wicker, I like it that much. The tone knob sweep is backwards just like a Ram's head. Here are some pics.

This is the picture I used for reference from Kitrae's site. (Thank you, Kit!)

Pictures of the final project.

Kitrae · Post by **Kitrae** » 23 Oct 2011, 05:39

Your are welcome. Nice build. That RH Muff is one of my favorites. Found the original in a pawn shop in the midwest for a few hundred bucks. The thing is noisy, but it sings.

Fred_Garvin · Post by **Fred_Garvin** » 23 Oct 2011, 15:19

Thanks Kit, love your site! If it wasn't for your site I wouldn't have gone forward with the project. As you can see the differences in these things as seen at the beginning of the article, this build has no electrolytic capacitors. Yet, the images I've seen they seem to be all over the map as to regards of parts selection. It's no wonder that they all sound different, there was no consistency, even when it came to keeping to the values in the schematic. I find it very interesting.

You'll notice that one capacitor (big green one) is soldered to the bottom of the pcb because it was to large to fit properly, this being the .18uf (180nf) cap.

Kitrae · Post by **Kitrae** » 03 Nov 2011, 23:14

Fred_Garvin wrote:Thanks Kit, love your site! If it wasn't for your site I wouldn't have gone forward with the project. As you can see the differences in these things as seen at the beginning of the article, this build has no electrolytic capacitors. Yet, the images I've seen they seem to be all over the map as to regards of parts selection. It's no wonder that they all sound different, there was no consistency, even when it came to keeping to the values in the schematic. I find it very interesting.

There was a schematic?

There does seem to have been some intentional logic to it at times, and other times not. I have traced and dated enough of them now to find that they did make long runs of particular versions that were consistent for a period of time. Whether those periods of time were weeks, months, or up to a year is hard to say. I am guessing several times a year they changed to an alternate set of values. If you just look a V2 (Ram Head) BMP's, there are numerous examples that follow the exact same set of values, and often same component types, all with matching graphics changes/color, knobs, and pot dates for this not to be the case. I think I am up to 4 on the triangle and 6 on the Ram's Head that were made in very long runs. I can almost build a sequence of changes over several years from this, though I'm not sure anyone would be interested in it.

It all leads me to believe this was intentional. It may be intention caused by supply, but it was not all just completely random as most of us assumed in the early days of digging through Muff guts. I have not gotten any real explanation from Mr. Matthews about why this was done. The same practice was applied to other EHX pedals too, including the russian made Big Muffs, and even continues with the current EHX line up. Not to the degree that it was done in the past, but since 2000 there have been three minor changes to the large box BMP circuit, and 2 in the LBM.

boog · Post by **boog** » 04 Nov 2011, 02:12

hey kit, just wanted to say that i find your site to be freaking awesome. if, for whatever reason, you decide to post the series of changes, this nerd would eagerly read it. while i haven't gotten into the vintage muffs (could never fathom paying that kind of cash to just pull something apart), i find it amazing to plug in 3 black bmp's (one with the sovtek switch, one it a big box with a 3pdt, one in a small box) and hear 3 different sounds. i've picked some differences out (unmarked russian trannies vs bc547, film caps vs those paper looking things), just bizarrely incredible.

tschrama · Post by **tschrama** » 04 Nov 2011, 07:47

[quote="Kitrae"].....I think I am up to 4 on the triangle and 6 on the Ram's Head that were made in very long runs. I can almost build a sequence of changes over several years from this, though I'm not sure anyone would be interested in it.....quote]

Offcourse people would be interested in a chronological sequence of changes

Big thanks for your great website. and as a real fx-thickerer, and for one would be very interested in a reconstruction of the sequence of changes of the Big Muff circuit. It would greatly help to sort out what makes a BMP sound good (to me) and makes it sound less good.

grtzz,
Thijs

billgraam · Post by **billgraam** » 22 May 2012, 07:30

Hi all!!
Im sorry if I open again this old thread...
I've a problem..
I've built the same ram's head with the same vintage circuit, the same values used by fred_garvin (lot of compliments) indicated by Kitrae .. but with different transistors: 2n5088 and Hfe around 500
My ram's sounds very good, but it sounds like a hi-gain distortion, and not as a muff ..no fuzzing sound...
It could be the HFE too low? Fred has used trannys with hfe around 700...
These are the values measured for the transistors:
q1) C: 4.03V B: 0.63V E: 0.03
q2) C: 4.11V B: 0.60V E: 0.06
q3) C: 4.13V B: 0.62V E: 0.03
q4) C: 4.66V B: 1.66V E: 1.20
I checked the circuit and measured each resistor
I'm going crazy

anyone can help me?
p.s im sorry for my bad english..

billgraam · Post by **billgraam** » 22 May 2012, 08:08

billgraam wrote:Hi all!!
Im sorry if I open again this old thread...
I've a problem..
I've built the same ram's head with the same vintage circuit, the same values used by fred_garvin (lot of compliments) indicated by Kitrae .. but with different transistors: 2n5088 and Hfe around 500
My ram's sounds very good, but it sounds like a hi-gain distortion, and not as a muff ..no fuzzing sound...
It could be the HFE too low? Fred has used trannys with hfe around 700...
These are the values measured for the transistors:
q1) C: 4.03V B: 0.63V E: 0.03
q2) C: 4.11V B: 0.60V E: 0.06
q3) C: 4.13V B: 0.62V E: 0.03
q4) C: 4.66V B: 1.66V E: 1.20
I checked the circuit and measured each resistor
I'm going crazy
anyone can help me?
p.s im sorry for my bad english..

a little demo :
http://www.mediafire.com/?59t0lh0jg64t4f8

billgraam · Post by **billgraam** » 23 May 2012, 20:24

no idea???

blackbunny · Post by **blackbunny** » 24 May 2012, 00:40

billgraam wrote:I've built the same ram's head with the same vintage circuit, the same values used by fred_garvin (lot of compliments) indicated by Kitrae .. but with different transistors: 2n5088 and Hfe around 500
My ram's sounds very good, but it sounds like a hi-gain distortion, and not as a muff ..no fuzzing sound...
It could be the HFE too low? Fred has used trannys with hfe around 700...

Could it be that you put the 2N5088's in the wrong way around? 2N5088 has the opposite pinout of BC547...just a thought.

Kitrae · Post by **Kitrae** » 24 May 2012, 02:51

billgraam wrote:Hi all!!
Im sorry if I open again this old thread...
I've a problem..
I've built the same ram's head with the same vintage circuit, the same values used by fred_garvin (lot of compliments) indicated by Kitrae .. but with different transistors: 2n5088 and Hfe around 500
My ram's sounds very good, but it sounds like a hi-gain distortion, and not as a muff ..no fuzzing sound...
It could be the HFE too low? Fred has used trannys with hfe around 700...

This may be a problem of differing definitions of fuzz or distortion, but the Big Muff is a high gain distortion circuit. "Fuzzing sound" could mean many things, but if you were expecting fuzz tones like a Fuzz Face type circuit, that is quite a bit different from a Big Muff sound. I don't know what type of amp or guitar pickups you used for your sound clip, but that sounded like a Big Muff to me.

billgraam · Post by **billgraam** » 24 May 2012, 07:24

Hi all!! tnx for the answers....

@ blackbunny: transistors are connected in the right way, unfortunately

@ Kit: i love you site...great...
yes, maybe I've used the wrong word, my english is very poor. ... perhaps the proper term is not fuzzin...but saturation...
My muff has great distortion, great sustain and volume...but...
at my ears, lacks of high frequency.....and dont sound like a muff...so im thinking that the problem is the low hfe in my trannys...
I've another big muff and it sounds like a muff must sound..and very different from my ram's...
Tomorrow i'll install new transistors with high hfe... ..and make a litte sample...is easier to understand
My amp is a blues deluxe and my pups are custom shop 69...with this instruments, my other muff sound like a muff...so in think that i've a problem with my ram's...

Ok..tnx for the answers
I hope to still disturbing with another post..tomorrow...
bye...

bato001 · Post by **bato001** » 24 May 2012, 14:14

Replace the the cap between Q2 and Q3 with a .1uF electrolytic, positive side towards Q3. This has become my standard setup for Big Muff Pi circuits as it causes a mediocre sounding build to bloom into thick, fuzzy goodness.

bato001 · Post by **bato001** » 24 May 2012, 14:16

bato001 wrote:Replace the the cap between Q2 and Q3 with a .1uF electrolytic, positive side towards Q3. This has become my standard setup for Big Muff Pi circuits as it causes a mediocre sounding build to bloom into thick, fuzzy goodness.

Positive towards Q2, sorry!!!!!

billgraam · Post by **billgraam** » 24 May 2012, 15:19

yep Bato

tnx for the answer..i will do tomorrow...
i hope this solves

guitarmongot · Post by **guitarmongot** » 24 May 2012, 16:15

Hi Billgraam.
You should also try : Compressor-BigMuff-OD (eg OCD,TS or simular).
I´ve buildt a V2 BigMuff with NOS trannies (300-400 hfe) and if your
going for Smashing Pumpkin tone : you need to push your tube amp with
a lot of volume (LOUD)....
If you devide gain stages into 3 pedals....it´s easier to dial in a smooth fuzzy distortion
with that Big Muff endless sustain...
/cheers M

billgraam · Post by **billgraam** » 24 May 2012, 19:00

Hi guitarmongot...i will try...
I'm trying to get a good base with my muff.. after...I will try many configurations with my pedals...thanks for your answer

billgraam · Post by **billgraam** » 24 May 2012, 19:09

bato001 wrote:Replace the the cap between Q2 and Q3 with a .1uF electrolytic, positive side towards Q3. This has become my standard setup for Big Muff Pi circuits as it causes a mediocre sounding build to bloom into thick, fuzzy goodness.

hem Bato...you means C13 in Kit's schematics..right??
tnx

http://www.kitrae.net/music/Images_Secr ... IC_NPN.jpg

bato001 · Post by **bato001** » 24 May 2012, 19:22

billgraam wrote:
bato001 wrote:Replace the the cap between Q2 and Q3 with a .1uF electrolytic, positive side towards Q3. This has become my standard setup for Big Muff Pi circuits as it causes a mediocre sounding build to bloom into thick, fuzzy goodness.
hem Bato...you means C13 in Kit's schematics..right??
tnx
http://www.kitrae.net/music/Images_Secr ... IC_NPN.jpg

Absolutely.

I don't know why it works, maybe forward leakage of some DC. It is worth a try.

Kitrae · Post by **Kitrae** » 24 May 2012, 20:37

Interesting. I never noticed much difference, if any, in using an electros vs a film caps, but I'll have to give it a try at C13.

Also, just to clarify, the scemo of my '73 that FredGarvin and Billgraam made is this one, lest someone be confused by the "47" Ram's head linked a few posts above.