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...

My stock YDR has CDSH270 schottky diodes. I'm not aware of BAT41 being used in YDR - but it wouldn't surprise me (and I haven't really spent time trying to validate YDR diodes). A friend once owned a Vintage RAT (1991 reissue) that had BAT41s stock. I believe this was probably a production mistake c...

The green-blue-black-silver-brown markings on R1 and R6 in the pics are unmistakable - 5.6ohm (5.6k in my earlier post was a typo). Are those your own pics of the unit you had? Unless that unit had been modded (which seems unlikely given the values), I'd have to assume those are either a manufacturi...

Also - so D4 is a BATxx schottky not 1N270 germanium. Any idea which BATxx? There are notable differences in Vf within the BAT4x family.

The added resistor R12 is the clr for the led. ;-) Here are the part values from my notes. Part numbering matches your schematic except C5 and C7 are swapped. Ah yes - the CLR! Completely forgot about that. Thanks. Where do these notes come from? A trace? Other source? The 47 ohm R1 and R6 resistor...

The switch makes/breaks the ground connection of the cap. It also adds a 2n2 cap from gate to ground on Q1 (the output buffer). Clipping configuration is: BATxx: anode to ground BS170: drain to ground, gate and source connected. Thanks again - and for the pics you PM'd me. Based on the pics, they h...

And if you could post gut shots that would be fantastic.

Thanks guys. Can anyone confirm the wiring of the FAT switch and cap? Does the switch connect and disconnect the cap at the R6-C7 junction or at ground?

Also - the configuration of the mosfet+diode clipper pairs - there are several ways to do it - can anyone confirm?

I saw this document linked, more than one time: http://www.fulltone.com/PDfFiles/OCD%20complete%20Mods_small.pdf But there's no anymore. May someone link it again, please? :thumbsup That document is old and out of date anyway. It only covers up to "version 3" and all of the information is...