Rat Circuit Recommendation?
- Thread starter chris.knudson
- Start date
drgonzo1969
Well-known member
Agreed. Stock rat has been my go to forever. But it’s nice to have options
Last edited:
chris.knudson
Well-known member
KR Sound
Well-known member
ElectroSmash - ProCo Rat Analysis
Pro Co Rat Schematic, Power Supply Stage, Clipper Amplifier, Voltage Gain, Low/High Pass Filtering, LM308 Op-Amp Selection, Diode Clipping, Tone Control, Output Stage, Pro Co Rat Frequency Response, Resources
hamerfan
Well-known member
From my notes: Most popular Rat subs
CA3130 - Slew = 10V/µs; MOSFET (In & Out) Ratsub mids push
LF356 - Slew = 12V/µs; FET Ratsub
LM301 - Slew = variable; BJT Ratsub HiFi
LM307 - Slew = 0.4V/µs; FET Ratsub
LM308 - Slew = 0.3V/µs; BJT Rat
LM709 - Slew = 0.25V/µs; BJT Ratsub
LM741 - Slew = 0.5V/µs; BJT Ratsub low drive
LM748 - Slew = 0.5V/µs; BJT Ratsub
NE5534 - Slew = 13V/µs; BJT Ratsub HiFi, low noise
NE5535A - high slew rate
OP07CP - Slew = 0.3V/µs; BJT Rat brighter
TL061 - Slew = 3.5V/µs; FET Rat-sub
TL070 - Slew = 18V/µs; FET
TL071 - Slew = 13V/µs; FET Rat-sub
TL071 / TL081 (BI-FET)
CA3130 - Slew = 10V/µs; MOSFET (In & Out) Ratsub mids push
LF356 - Slew = 12V/µs; FET Ratsub
LM301 - Slew = variable; BJT Ratsub HiFi
LM307 - Slew = 0.4V/µs; FET Ratsub
LM308 - Slew = 0.3V/µs; BJT Rat
LM709 - Slew = 0.25V/µs; BJT Ratsub
LM741 - Slew = 0.5V/µs; BJT Ratsub low drive
LM748 - Slew = 0.5V/µs; BJT Ratsub
NE5534 - Slew = 13V/µs; BJT Ratsub HiFi, low noise
NE5535A - high slew rate
OP07CP - Slew = 0.3V/µs; BJT Rat brighter
TL061 - Slew = 3.5V/µs; FET Rat-sub
TL070 - Slew = 18V/µs; FET
TL071 - Slew = 13V/µs; FET Rat-sub
TL071 / TL081 (BI-FET)
pingpongcomputer
Active member
I recently built a 2 in 1 klone into rat using the Madbean Slow Loris board for the rat side because I wanted easy onboard clipping toggle. I have also built the Muroidea, and the Synthrotek Ratatat. The sound differences between the 3 are negligible, even with NOS 308 in the ppcb and synthro and op07 in the madbean. The only difference in sound I've heard is with the germanium clipping in one build I get a bloomy volume boost(which may be builder error). The ppcb and madbean boards are nice and straight forward, the synthrotek is a pain in the ass.
spi
Well-known member
All the more reason to start with the basic one. For IC, I'd get an OP07 because they are easy to find and sound pretty much identical to the original, but harder to obtain, LM308.
szukalski
Well-known member
I really like @steviejr92 ’s Rat variant. Only thing I don’t like is too many controls on it!
Feral Feline
Well-known member
Like me, IIRC @chris.knudson, you're a bass player...
I built a mostly stock Rat with two switches, one for clipping and another that includes Gord Tranter's mod for better bass response.
I can go totally stock, add bass and add even more bass.
I can go stock clipping (1N914 / 1N4148), Turbo (socketed LEDs so I can pull them for op-amp only clipping), and Phat Rat (Schottky&Mosfet).
I've heard the Reutz mod is good for getting some bass back, but also that it softens the attack or something, basically changing the inherent nature of the Rat Sound (which is fine because you can dial the Reutz back to stock, TTBOMK).
If you build a "stock" Rat board, I recommend adding a minimum-gain resistor, 'cause stock if the gain is all the way down you basically neuter the circuit completely.
Another mod I did was to reverse the TONE wiring, so it gets more trebly as you turn it clockwise (stock Rat cuts treble as you turn FILTER clockwise).
More mods:
Bumped up the input 22n>220n, coupler before transistor 22n>220n and output 1µ>2µ2. Somebody said that does jack-all, to properly tune the rat you need to adjust the filters — where the Reutz Mod resides.
Whatever, I’ve also seen even bigger increases on other peoples’ modded Rat.
The cap after the op-amp, 4µ7, I went Tantalum to save space in the 1590A, wish I'd known about the Wima 4µ7 FILM-caps at the time for higher fidelity…
Tranter has 3 mods, I opted for his Mod #2, and used Tantalums again to save space.
I used a legit LM308, its stock 30p slew cap augmented by a 60p trimmer. Still need to experiment with it more, dial it up to 93p. Some mods suggest as high as 100p.
3N3 bumped to 4n7
I bumped power filtering up as well.
I built a mostly stock Rat with two switches, one for clipping and another that includes Gord Tranter's mod for better bass response.
I can go totally stock, add bass and add even more bass.
I can go stock clipping (1N914 / 1N4148), Turbo (socketed LEDs so I can pull them for op-amp only clipping), and Phat Rat (Schottky&Mosfet).
I've heard the Reutz mod is good for getting some bass back, but also that it softens the attack or something, basically changing the inherent nature of the Rat Sound (which is fine because you can dial the Reutz back to stock, TTBOMK).
If you build a "stock" Rat board, I recommend adding a minimum-gain resistor, 'cause stock if the gain is all the way down you basically neuter the circuit completely.
Another mod I did was to reverse the TONE wiring, so it gets more trebly as you turn it clockwise (stock Rat cuts treble as you turn FILTER clockwise).
More mods:
Bumped up the input 22n>220n, coupler before transistor 22n>220n and output 1µ>2µ2. Somebody said that does jack-all, to properly tune the rat you need to adjust the filters — where the Reutz Mod resides.
Whatever, I’ve also seen even bigger increases on other peoples’ modded Rat.
The cap after the op-amp, 4µ7, I went Tantalum to save space in the 1590A, wish I'd known about the Wima 4µ7 FILM-caps at the time for higher fidelity…
Tranter has 3 mods, I opted for his Mod #2, and used Tantalums again to save space.
I used a legit LM308, its stock 30p slew cap augmented by a 60p trimmer. Still need to experiment with it more, dial it up to 93p. Some mods suggest as high as 100p.
3N3 bumped to 4n7
I bumped power filtering up as well.
Not to derail but I think this question is in the same vein so...
Is there a rodent derivative that has the gutteral drive but completely does away with what I can best describe as nasal honk? That kinda 1.5kHz Is that inherent to the original filter/tone shaping or the nature of the circuit itself? I assume it's the former... I've piled a few rodent spawn boards up but haven't started any for fear of hating the end result. Can't take the Pinocchio tone
Is there a rodent derivative that has the gutteral drive but completely does away with what I can best describe as nasal honk? That kinda 1.5kHz Is that inherent to the original filter/tone shaping or the nature of the circuit itself? I assume it's the former... I've piled a few rodent spawn boards up but haven't started any for fear of hating the end result. Can't take the Pinocchio tone
DGWVI
Well-known member
The Hen's Tooth. It's also got slightly less gain overall
benny_profane
Well-known member
There are two parallel RC networks forming a HPF with the ground connection of the feedback loop. The 47R / 2u2 network creates a 1.5kHz pole. You could modify that (similar the the Ruetz mod on the other pole), but you’ll affect the gain as well. There’s a LPF with the feedback cap and the GAIN pot with a pole at ~16kHz at max gain. Note that the slew rate also affects the LPF because the slow op amp struggles with higher frequencies at high gain.
