some of my big muffs have that dying battery sound

[timpecter]

I've just made a small run of Big Muff style pedals for myself and some friends.  

I used the standard values for the components and 2N3904 transistors.
I etched my own circuitboards with a hand drawn layout very similar to one of the originals.  
I'm using 1% resistors.
I bought all the components from the same supplier in the same order.
I'm using the same battery to test them all.

The strange thing is that one of them has a much richer, fuller, sound with a lot of gain and 3 of them have a touch of that characteristic 'dying battery' sound and a much less gain.  When I measure the voltages of the transistor pins I get very similar results for all of the pedals.  See below.  Do you have any idea where the difference might be coming from?  Thanks.

Q1 C: 4.68
Q1 B: 1.64
Q1 E: 1.04

Q2 C: 4.20
Q2 B: 0.65
Q2 E: 0.04

Q3 C: 4.95
Q3 B: 0.70
Q3 E: 0.06

Q4 C: 4.86
Q4 B: 0.68
Q4 E: 0.05

[Unlikekurt]

Transistor Hfe?

[PRR]

> Q1 C: 1.04
> Q1 B: 1.64
> Q1 E: 4.68

It appears the C and E are reversed. I don't know if that is true on the board(s) or in the note-taking.

Swap the C and E, low-volt circuits will maybe "work", but with much less consistency.

[timpecter]

Oh, that was a note taking error - I had the C and E reversed in my post.  I've fixed it now.  Thanks for catching that.

[LucifersTrip]

If you have similar voltages and there's really a big difference, i'd compare the audio after each stage with an audio probe.

You'll hear where the signal goes awry in the 3 duds.  

Since you have similar voltages, that leaves the diodes, caps & external wiring. Check for problems (accidental wrong component, solder bridge, weak joint) in those areas.

Did you actually use the same jacks for all?

Edit:
It's also very probable you'll find the same flaw in each of the 3 actual pcb's.

[timpecter]

After trying the audio probe suggestion, I found an almost-microscopic short in exactly the same place on the three faulty pedals. Cutting it with a hobby knife did the trick. Thank you!