Mosky Super rat Guts shots and mods

[Killthepopular]

Top right pot: Gain.
Top Left: Volume
Bottom: tone
Top switch: Diodes

Looks like the resistors are all MF 1/8 watt or 1/6 or whatever.
IC chip has 308 written on it in extremely faded writing.
All pots are A100k 9mm PCB mount. The tone control is wired the "right way round", meaning turning it clockwise makes the tone brighter but they used the original A100k pots instead of switching to c100k for that pot, so all the useable range of the control is bunched up in one quadrant of the sweep. Apparently Mosky made the same mistake on the gain control of the D250x. Microamp style circuits need a C taper and the gain is all bunched up in one little region on that pedal according to the reviews so using the wrong taper seems to be a common quirk of mosky pedals.
The LED is blindingly bright (another common quirk of mosky pedals) so I'll try and find that resistor and replace it with one of double value.
The diode clipping options are 1+1 Si, 1+1 LED and 2+1 Si. The 2+1 sounds weird to me so I might try and solder in an extra Si and make it a 2+2.

I've ordered a c100k 9mm pot so I'll try replacing that mis-tapered filter control. The gain pot seems to jump suddenly from clean to moderately high gain, like there's a defect in the taper. The rest of the sweep seems ok, it's just this one little bit like the pot is defective rather than simply the wrong taper. I might take out the gain pot and replace it with the A100k pot that I'll be removing from the filter position in the hopes that that's a less dodgy pot.

I've never had a rat before. It seemed like an insanely dull, flubby tone whereas I always thought of a rat as being more nasally and thin. I examined the tone shaping bits, convinced that mosky had tried to "upgrade" the original design by making it way more bassy.
I compared the resistor and cap values (goddamn mother-effing tiny resistors) to the electro smash schematic:

https://www.electrosmash.com/images/tech/pro-co-rat/pro-co-rat-schematic-parts.jpg

The RC filters to the bottom left of the opamp are 47r->2.2u and 560r->4.7u. The caps either side of the opamp appear to be 30pf and 100pf. The tone control appears to be A100k into 3.3nf. I can't remember what r7 was but I suspect it's 1.5k.

From the parts I've examined it looks like a classic rat with no significant changes to the schematic.
When I breadboarded the rat I used an LM741. Perhaps the 308 gives a much duller tone. I was thinking of ordering some OP07s and trying those. The IC is already socketed. Could i just stick an OP07 in without needing to do other mods to make it work correctly? I know from youtube demos that the difference between the 308 and op07 is very subtle. Would it even be worth bothering with?

My super rat sounds just like the ones that are demoed on youtube. Seems like a normal one besides the slight defect in the gain pot.
Just seems duller than I expected it to be somehow. I always thought rats were really thin and nasally. My DS1 and my Dist+/250 pedals sound a lot clearer to me. The super rat sounds really dull and boomy although there is a definite bass cut.

Wiring is true bypass. Build quality seems fine besides the issue with the gain pot. Otherwise it's just a couple questionable design choices that I would fault: Wrong filter taper, overly bright LED, 2+1 clipping option probably sounds worse than 2+2 si or 1+1 ge.

Cost me £28.56 in total shipped from china. Here's the ebay listing:

https://www.ebay.co.uk/itm/222733151654

Includes a gut shot which looks pretty similar to mine.
All in all I'd say it seems like very good value. The impression I get with these chinese companies is that the lowest of the low like mosky will give you a good quality pedal with a few design errors whereas the slightly higher priced guys (Dolamo/Caline, Joyo/Harley Benton, Mooer) give you really good pedals with no errors.

[Rob Strand]

From the parts I've examined it looks like a classic rat with no significant changes to the schematic.

The JFET seems to be wired like that, single gate resistor to ground.

[snk]

I have a vintage Rat, and, out of curiosity, I bought a cheap chinese clone a couple years ago : the latter is very good, on par with the original.

I always thought of a rat as being more nasally and thin.

I wouldn't call a RAT nasal and thin at all
I'm using it on bass synths and drum machines, and it is one of the beefiest pedals for that duty (well, I mean as a non-DIY, tweaked pedal) 

[Killthepopular]

From the parts I've examined it looks like a classic rat with no significant changes to the schematic.

The JFET seems to be wired like that, single gate resistor to ground.

Do you mean that they have modified the design in some major way? I just looked at the main tone shaping bits of the circuit.

I've spent a bit more time playing around with it and it does sound more like I expect it to sound. I think I wasn't considering how a rat is like two different pedals depending on the gain range. Thin and tube-screamery at low gain, huge and beefy at high gain.

I'd say I'm quite happy with it besides the issues with the 2 pots. I can see it being a pedal I use a lot.

[Rob Strand]

Do you mean that they have modified the design in some major way?

I was just agreeing with you.  The JFET connection looks like a classic Rat.   
I only scanned over a few parts of circuit.