ROG May Queen Squeal

[Pakaloabob]

Just finished building Runoffgroove's May Queen on perfboard. I was able to get my transistor voltages very close to the ones listed on the web-page http://runoffgroove.com/mayqueen.html with the schematic. Sounds Great!
However, with my guitar volume maxed I get a high pitched squeal when no strings are played. If i back the guitar volume off a tad - I mean a fraction of a millimeter - the squeal goes away.
Anyone else experience this issue? I was thinking that I might try changing the input cap to a larger value to cut some incoming treble or trying lower gain transistors. i am not sure if that is the way to go. I would appreciate any other suggestions.

[arawn]

If you used the transistors speced I would suggest replacing either r1 - 47k or r2 - 470k with a larger value. You should also see if it does the same thing with different pedals or with no pedals. It could be a circuit problem in the guitar. But we really need more info, see the what to do when it doesn't work thread. Have fun!

[Pakaloabob]

That sounds like a good idea - I'll try it out. Maybe try a couple of pots to dial in the value. Would changing those resistors essentially be lowering the gain of Q1 ?
The reason I suspect the circuit is causing the squeal is that it occurs on both my 15W SS practice amp and my 40W tube amp. No squealing occurs with any other pedals. I do not have any other guitars to try out - I play a G&L Asat Special which has high output pickups. I guess that could be the issue. I will try to get a buddy to bring over his axe and compare. The squeal isn't a terrible issue since it isn't noticeable when playing, only when there is no output from the guitar.
At any rate, the circuit has a VERY high boost which I wouldn't mind toning down a bit.
Thanks for you input Arawn!

[arawn]

you are more than welcome, we are all here to help one another!

[Pakaloabob]

Ok. I guess I shouldn't have assumed this issue would be easy to resolve. Anyway, here is my official debugging info:
ROG May Queen http://runoffgroove.com/mayqueen.html
Built to specifications on perfboard following layout on page with schematic.
Circuit works but there is an audible high-pitched squeal when no note is played. I can't tell if the squeal still is there when notes are played since the circuit is such a high gain.
My transistor pinout voltages are as follows:

Q1: C= 6.48                 Q2: C=1.737       Q3: D=5.29
      B= 0.571                      B=0.649             G=1.740
      E= 25.4 mv                   E=0                    S=1.478

Q2 collector seems to be a bit higher than voltage listed on the webpage.
Arawn suggested adjusting the values of the 47k and 470 k resistors in front of Q1.
I attached pots in place of the resistors and adjuseted each until the squeal disappeared.
When adjusting the 47k resistor, a slightly lower value removed the squeal, but when playing, the sound was gated. I returned the 47k resistor value and adjusted the 470 k. In order to remove the squeal, the resistance had to be set at 15k!!!
The transistor voltages are as follows:

Q1: C= 0.998                 Q2: C=1.780       Q3: D=5.22
      B= 0.736                        B=0.662             G=1.779
      E= 109.0 mv                   E=0                    S=1.508

It seems that Q1 is way off with the lowering of the 470k resistor, without affecting Q2 or Q3 very much. Therefore I hypothesize that Q1 is not the major offender. I am looking at you, Q2.
I am not sure if the higher collecter voltage on Q2 si causing the squeal.
Anyone know how to lower the overall gain of the circuit so I can see if that removes the squeal?
In the meantime I will try different tranis in each of the positions to see what happens.
Any suggestions are GREATLY appreciated. So far I have received excellent help from others.
This forum ROCKS!!!