I didn't make that swap. Changing the op amp results in lower noise, and adding the two resistors gives the final op amp some gain rather than it being a unity gain buffer. On paper not a huge difference, but if you like how it sounds but want less noise then perhaps worth it. To be honest I swapped...

Wow, those resistors are really small! xD I bought the ones suggested here, they are little larger in than the original ones, but they fit. Having a hard time soldering them without them moving around (because of how light weight they are), how do u guys solve this without a third hand? I've done q...

oh and do you have to be careful with placement in relation to the audio circuit board to ensure stray fields from the SMPS are not coupled? I'm guessing the inductor will be the biggest source, perhaps some ferrite shielding will do fine?

thanks for the info about the nixie SMPS and your version Gabriel, that looks great. I'd prefer some level of galvanic isolation, so I don't think I'll just be using the mains voltage directly, although that might be useful for testing purposes. I was just wondering what the specs are on the SMPS - ...

ah yes, I had sort of forgotten about that, thanks!

Hi, I'm planning to build a HV (300V B+) overdrive pedal using 12ax7 tubes. However I'm not sure what the best way to proceed with the HV power supply (12V for the heaters can be easily derived). My options are: 1. Find a suitable transformer (as would be done in an amplifier) that provides galvanic...

Hi Niels, These are the changes that I made: Change R9 to 10k Remove R8 Change R17 to 22k put a 100k resistor between pin 7 of the 12ax7 to the top of R17 change R16 to 100k change R18 to 22k 10k after C12 change R14 to 1M I used 1206 surface mount resistors to make the modifications. Good luck! Aaron

personally I like using small coaxial cable (such as rg174 or rg316) for wiring up the guitar as it ensures you adhere to correct grounding. Sure it's slightly excessive (regular shielded cable will do) but we have loads of the stuff in my lab... That way all your wires are shielded and all you need...

Hi All, I realise it's been a long time since anyone posted, but in case anyone's interested: Today I had a go at Bajaman's mod: I used 1206 SMD resistors, 20k's instead of the 22k's, and I didn't change the opamp. The difference is remarkable, it's actually usable now. It now sounds like something ...

Hi Everyone, Interesting discussion, I love dispelling all the myths that 'experts' have tried to create around the electric guitar. I'm a physicist/RF engineer (I build things for MRI scanners), and it's been really interesting coming back to the guitar with the knowledge I've learnt about RF elect...