I didn't realize the FET path was the bypass path. I thought it was supposed to be another path that offered a different gain type character. The circuit does make sense now. Q6 is bypass only - and only when using "Enhanced Bypass" mode. Q5 is the input buffer for both active and bypass ...

Is it possible that R29 and R35 are not 27k, but maybe 2.7k or 270 ohms? I mean.. Give us GAIN! I've lost track - I'm not sure if you want to know what the circuit (as traced) is actually doing or if you want to modify it for more gain. If you want an always on boost mod, then yes you could drop R2...

micmac wrote: ↑08 Apr 2024, 10:32 So maybe it's C14, on the source of Q6, that was deleted.

Q5 and Q6 are configured the same way, so removing C14 would have an identical drop in volume to removing C15, except that it would be present when in bypass mode only.

With C15 pulled there should be a noticeable volume drop between Enhanced Bypass and True Bypass I recon. Mistake? IIRC, AC gain of Q5 is R27 / (R26||R29) (at 10µ, C15 puts the high pass knee well below audio). With R29 & C15 that's 10k / (1/(1/10k + 1/27k))) = ~1.37. Without R29 we have 10k / ...

thesmokingman wrote: ↑18 Mar 2023, 14:38 so no pcb pictures then?

Better late than never .

Thanks for the update. That previous and per the FR layout that the filter 1 was going in series into the resistor and then cap and not the other way around would make no difference? Also, I see the revision you made: thank you! Having said that, it looks like SW2 for the clipping is to go to groun...

EDIT* It looks like R8 and C9 were reversed on the layout I attached. I swapped them and it sounds better. Let me know if anything else looks off on the layout. That shouldn't make any difference. Maybe in correcting this you fixed a bad solder joint or something? Note: I spotted a drawing error on...

I have a FatRat and the fat cap is not a 6.8uf but a 1uf. Are folks sure the schematic is correct? I built a clone using the layout from tagboardeffects and it doesn't sound anything like my stock Fatrat. It's not uncommon to have a RAT with non-standard values, as it seems they will occasionally u...

It took some digging, but I found your Bass Boost mod. Very clever ! Is it still either 180r + 15µF or 120r + 22µF. Or has your recipe changed over the years ? Those values would be a bit extreme IMO. I don't know whether that's something I suggested for max effect at some point in time or is someo...

Great news ! How do you like the added tones that those two switches bring to the table ? Meh. The MOSFET clipping setting is nothing special. The threshold is slightly lower than the stock setting, so there is a touch more clipping and volume drops a bit. (YMMV depending on what the diode flavor o...

Well, I finally bit the bullet and bought a FatRAT. Traced it and have added the details to my Multi-RAT schematic. The FAT switch mod is kind of interesting. This confirms p.eat's report but note the output JFET is a J109 in my unit. D4 is BAT41. Also worth noting is that the PCB layout is essentia...

Understood. That would be some effort.

bluesky636 wrote: ↑25 Jan 2023, 01:34 Sorry. I'm not interested in taking apart a perfectly good, working pedal.

Understood. That can be a bit intimidating.

I wonder why he wanted to make the pedal darker with the V2. Since apparently there is a trace of a v2 using 1n not 4n7, unless we know which came first, it's possible that 4n7 was an early production run and he switched to 1n to make it brighter - maybe based on initial feedback that v2 wasn't bri...

Not to defend Fulltone, but I don't think it really matters here whether RoHS is to blame or not (it isn't). It's the proliferation of switching type power supplies that are the problem for him whether that's due to RoHS or, more likely, energy efficiency regulations from the EU, or something else. ...

The reference voltage acts as audio (AC) ground, and as far as the diodes are concerned there isn't any substantial difference between true ground and virtual ground. I think the bias filter cap is what allows the DC bias reference point to function as a virtual ground for AC, so as far as AC goes ...

I don't know what ROH has to do with power supply design. RoHS mandates what kind of power supplies can be sold. According to the linked sources, only switching types are allowed which can generate noise that non-switching (e.g. transformer) supplies don't have. Without appropriate power supply fil...

If that's true then restoring the better sound of the pre-1.8 versions can easily be done by using 10µF caps in the PS filter section instead of the new spec 220µF. Fortunately DIYers don't have to abide by RoHS laws.

That project is not entirely accurate. Most notable is R12 which is NEVER omitted in the Turbo RAT and is necessary for the Turbo RAT to sound right. The Turbo RAT also orginally used the LM308 op-amp not the OP07. R14 was necessary for the status LED that was added to the RAT2 and Turbo RAT - known...

Also - so D4 is a BATxx schottky not 1N270 germanium. Any idea which BATxx? There are notable differences in Vf within the BAT4x family. BAT41, very similar Vf to germanium Thanks. Just so that I can be sure, are you getting this from your own FATRAT? Or reporting what you read (or have seen pics o...