mudbunny volume drop?

[add4]

i just breadboarded a mudbunny ram's head.. it sounds marvelous! i thought i didn't liked muffs, but i was mistaken, BIGTIME!

only problem is: theres a volume drop on it, even with volume cranked to the max.
Do you experience the same thing with yours? or did i made a mistake somewhere?

i plugged my guitar into the breadboard after every stage and i found that the first stage output is VERY low.. maybe it has something to do with it? or a gain problem on the last stage? not enough volume recovered after the tone control?

i'll double check the values while you guys answer :p

[mgwhit]

Low output is certainly not normal for a Big Muff circuit.  Triple check your resistor values and confirm the orientation of your transistors.

[madbean]

Following the Mudbunny schematic, the problem likely resides with R3, R4, R5 and R6. A wrong value with any of those four could cause the problem you are experiencing (low output with the Sustain maxed).

[add4]

Thanks to you guys i'll look into that !

It indeed didn't seemed normal to me ... :p i turned it on now knowing where the pots were and i was ready to turn it off again in case my ears exploded and i hear a volume drop i'm like .. cool, lets turn it up .. and i see that volume is maxed, and sustain too ... hmmmm what's wrong?!?

[add4]

Bean ... i tried plugging my guitar into the circuit after building each stage. after the first stage i had VERY little output.. so you're probably right and comes from the first transistor stage..
that also means that i'll have MUCH more sustain when i correct that ? it's already singing, but i love it with sustain maxed out . i'd love to have another turn on that sustain pot right now!

[bigmufffuzzwizz]

This circuit definitely should not have a low output..One way to decrease volume is increase the R1 (39K) to something like (390K), try checking that part too.
If you want more gain jumper the emitter resistors from each gain stage..I generally do the first three (I believe they are R6,R11 and R16). This will add a good amount more gain to the circuit. You can also do this with the last emitter resistor (2.7K) but I haven't played with that one at all. Increasing the Limiting resistors (8.2K) to something in the (10-18K) will make this pedal more gainy, but change its characteristics IMO. When increasing those two it gave it a more high gain sound, but more like a chunk chunk to me. I didn't really want my muff to sound like that. If you got it on a breadboard, experiment!!

[add4]

experimenting is the point !! thanks for the good leads on modifications of this circuit..

[add4]

ok guys ... i rechecked every part value.. i had one mistake .. it sounds better now, but i still loose volume ..
subs i did:
R12 and R17 are 12k instead of 15K (that should add gain doesn't it?)
R23 is 2.2k instead of 2.7K
C10 is 4.7n instead of 4n.

I still have a noticeable volume drop when i engage the effect (only half the volume is there) gain and volume cranked to the max.

i also checked the cap values.. all are ok

i'm short of ideas. i'll take any of yours if you have some :p

[mgwhit]

R12 and R17 are collector resistors, and lowering their values should lower the gain for their transistors.  R23 is an emitter resistor, and lowering its value should increase the gain of its transistor.

I used a 4n7 for C10 in my VRH Mudbunny, and, while I'm sure it changes the gain at a certain frequency, it certainly didn't make mine quiet.

Have you tried swapping the transistors?  Maybe one is a dud.

If you can post good (big, clear) pictures of your breadboard, I'd be happy to look at it.

[add4]

i certainly broke 11 of the 10 golden rules of breadboarding.. but here are pics

if you need something else, just ask .. i tried to take close ups of each transistor stage ... figured it would already be very hard for your to figure out anything in this mess

and ... thanks for helping!

[add4]

stage 2

[add4]

stage 3

[add4]

stage 4

[add4]

and a general view in case you get lost

[bigmufffuzzwizz]

Good idea MGwhit! Try swapping the first stage transistor out with another and see if that helps. It's hard for me to tell but I'm thinking maybe you shorted a component by installing wrong on breadboard(I've done that before).
This is a mod and not something you should have to do to get unity volume but lifting the first pair of diodes on gain stage 2 is supposed to give a volume boost. I believe that's the main difference between a tonebender and muff schem..

Just so you know the values I'm giving you are corresponding to Ram's Head specs.
The emitter resistors are the ones I'd omit to really increase gain. Like I said before I've only experimented with omitting the first three stages (from 100r to a jumper wire). For R23 I'd think you'd need to lower it more (than 2.2K) to really hear a difference. Try something like 1K or even omitting it.