big muff triangle problem

[nokaster]

i'm having a problem with my big muff triangle build.
it sputters and oscilates but doesn't muff...

when i turn down the volume on my guitar it appears to start working...

when i put my boss TU2 tuner in front of it, it works just fine...

so i'm guessing it has something to do with the 3K3 input resistor instead of the 33k on other muffs i've build?
lower guitar volume seems to cure this a little, and the buffer(s) in the tuner fix the problem entirely.

i use play telecasters with custom shop nocaster pickups (lower output).
and i play through a ruby with bassman mods, 9V and a 2.6 ohm load (3 x 10inch at 8 ohm parallel)
maybe my guitar and "amp" have something to do with it as well?
cable is 10ft from guitar to fx, and a patch cable to the ruby.

i'm including my complete setup, because i've had other pedals oscilate in this setup...
when i used them with tubes amps they behaved normally.

i've come far in 10 months of building stuff, but this is weird still...

any help much appreciated!

thx

[theehman]

The 33K sets the input impedance.  With a 3K3, the impedance is too low.  Swap that resistor out and you'll be fine.

[nokaster]

thx!!!

i thought so. and i will swap the 3k3 for a 33k.
i do not understnd why they build it with a 3k3...

but that won't take away the other oscilation problems with my setup...
it will only fix the muff.

anyone any other ideas for a better performing rig?

i don't use the tuner in the chain normally, but the tuner's buffer do seem to fix a lot of problems.

thx

[theehman]

I'd say the 3K3 is an error on the layout you were using.
As for the oscillation, it's hard to say what's causing it.  What's the last effect in the chain?

[scondon]

It sounds like you're working off the same seemingly incorrect triangle schematic I was.  There are two triangle schematics here (scroll down):
http://pisotones.com/BigMuffPi/psst/BMP_versions.htm

the first is correct, the second seems to be way off (omitted resistor, capacitor, wrong input resistor value).

[eurekaiv]

The first isn't the most accurate either...  Skreddy posted one here at one point that was spot on part for part with my vintage Triangle.

[theehman]

The first isn't the most accurate either...  Skreddy posted one here at one point that was spot on part for part with my vintage Triangle.

While the schematic he posted may be spot on with your unit, it's miles away from mine and I've also seen several other variations.  Personally, I don't like the sound of units with that circuit.

[eurekaiv]

Ok well, IIRC he said this was culled from looking at a number of them and represented what he felt was the most common variation he saw.  Whether or not these values actually sound better or worse is a whole different issue and is totally subjective.

[charmboy]

I was having the same problem with a triangle I just finished last night;it only worked when I had a buffer before it.  After doing a frustrated search this morning, I stumbled upon this thread, went out to my shop and swapped in a 39k resistor for the 3k3 I had in R1 and it's not only fixed, but sounds spectacular!  I've never tried a real triangle but this is the best sounding muff I've ever played through.  This build is a gift for a friend but I may need to do another for myself now.
Great forum... Thanks for the help!

[Dan N]

The first isn't the most accurate either... 

That was mine. The only thing I did wrong on my trace was the orientation of the diodes and the .05 caps. Mr. Pistones has them correct on that reproduction schematic so it's an accurate schematic.