Big Cheese Transistor Gain

[danfrank]

Hi, I'm about to build a Big Cheese clone (DEFX board) and had some questions about the transistors used. I've read that the original pedal used BC549C (hfe ~400) and the DEFX version (plus all others I've seen) asks for 2N3904 (hfe~200) transistors.
Has anyone played around with this? Does it matter in this circuit?
Thanks,
Daniel

[LaceSensor]

Hi

I think the BC549C sound better, but honestly, you probably wont tell the difference.
Ive built both (multiple times), and own the original Big cheese and Cheese Source so consider myself somewhat in the know about Lovetone stuff.

Watch out for the pinout in any case, BC549C is 180 degrees that of the 2n3904

YMMV, if in doubt socket

FWIW, the various clones out there, including ones Ive made, are generally based on the OLC chunky cheese variant
They sound almost identical to my ears. The main difference is the output opamp stage is boosted for more output, whereas the original ciricuit is arranged as a unity gain buffer. There is also some subtlety with Vref voltage divider for 1/2 supply voltage for the second opamp stage in the Lovetone that seems irrelevant and was therefore changed for the OLC.

I never found the Big Cheese quiet, but some people want the extra volume. In any case its easy, just jumper either the resistor or capacitor across pin 6 and 7 and remove the two other parts (cap and resistor to ground). In the DEFX schematic that would mean omitting R19  C15 and C14 and wiring a jumper over R18.

Enjoy

[alanp]

I'm picking that other projects use the 2N3904 because it's more likely to be lying around in parts stashes than the BC549C. (I'll second what Lace said -- he's the expert on all things Lovetone )

[danfrank]

Thanks for the replies and all the useful information! Luckily, I have 3 BC549C left so now I know what they'll be used for.
I'll look at the schematic and see if i can add a switch to change the 2nd op amp gain characteristics, thanks for the info on that. I was already planning on doing that for the clipping diode.
Thanks again!

BTW, I have no idea why I posted this in the "Build Reports". It was either a brain fart or my fat fingers pressed the wrong header on my phone screen... My apologies.

[LaceSensor]

Thanks for the replies and all the useful information! Luckily, I have 3 BC549C left so now I know what they'll be used for.
I'll look at the schematic and see if i can add a switch to change the 2nd op amp gain characteristics, thanks for the info on that. I was already planning on doing that for the clipping diode.
Thanks again!

BTW, I have no idea why I posted this in the "Build Reports". It was either a brain fart or my fat fingers pressed the wrong header on my phone screen... My apologies.

Be aware that one of the BC549c will be used as a diode

I wouldn't bother personally with the output opamp stage switching
Either decide if you want more overall volume on tap or comparatively less abs build appropriately

What I have built up is a version which allows you to footswitch into the cheese wedge gated mode with selection of any of the tone settings, which arguably has more FUNctionality

That being said I've never messed with the clipping diodes myself

Good luck look forward to seeing what you come up with