Breadboard a Rat

[fig]

I hadn't planned on it, but the urge struck when Derek mentioned never having played one so I downloaded the schematic from electrosmash and put one together. It's a fairly simple build, with a low component count.

IC1 = LM308N, Q1 = 2N5457, clipping diodes are 1N4148s. I tried stock pots, but found I liked W50K for distortion and B250 for tone.

It sounds pretty groovy as is, but I may try out Derek's proposed mods. It's much easier to adjust a circuit to one's liking by breadboarding it first, whether it's someone else's mod, or your own.

This is bypass for reference...a 150Hz sine @ 500mV

This is engaged, close to unity (6-ish) with the tone rolled back to 3-4

Distortion dimed

Vol maxed...why not?

It's a classic for a reason.

I'm going to tighten up the layout, but I'm pretty happy with placement.

 

[fig]

Just had a thought....if anyone has a groovy mod they'd like me to try, I will try to get a makeshift recording rig together so I can share the results.

 

[Coda]

You’re gonna record examples, how about swapping out some op-amps?…

 

[peccary]

Just had a thought....if anyone has a groovy mod they'd like me to try, I will try to get a makeshift recording rig together so I can share the results.

I bought a few Rat boards and was planning on giving this mod a shot with my bass as it seems pretty simple. If you're looking for something to do!

https://www.google.com/amp/s/marcuseffects.wordpress.com/2016/06/20/proco-rat-bass-mod/amp/

 

[BuddytheReow]

A rat is on my list to breadboard. I built one on vero and it’s pretty dark unless I dime the tone knob. For some reason mine can almost sound gated at times even though it’s opamp based

 

[jimilee]

Instead of silicon or LEDs, how would it sound with a couple of BS170s clipping to ground?

 

[fig]

You’re gonna record examples, how about swapping out some op-amps?…

I'll use my little ZIF socket breakout...

I've got several single opamps, tons of diodes, and a bag of BS170s. I'll try to get them all in before losing interest, LOL.

 

[Dan0h]

You are a mad scientist, a level worthy of aspirig towards. and not the Aspiration that is created in 90% humidity and lether seats in summer, but the other aspiration.

 

[fig]

I bought a few Rat boards and was planning on giving this mod a shot with my bass as it seems pretty simple. If you're looking for something to do!

https://www.google.com/amp/s/marcuseffects.wordpress.com/2016/06/20/proco-rat-bass-mod/amp/

That looks easy enough...

 

[tcpoint]

Try the VFE Red Wolf. That's my favorite Rat variant. I have an extra pcb, if you'd like one.

 

[fig]

The opamp auditioner is online!

 

[fig]

I bought a few Rat boards and was planning on giving this mod a shot with my bass as it seems pretty simple. If you're looking for something to do!

https://www.google.com/amp/s/marcuseffects.wordpress.com/2016/06/20/proco-rat-bass-mod/amp/

The only difference I see is that in the schematic I used for the build, it would go in between R5 (not R7) & C6. I've got the parts out and will graft it into the breadboard. I'll add another switch to swap from BS170s to 1N4148s.

 

[vigilante398]

I tried stock pots, but found I liked W50K for distortion

You already got my favorite there, I went with A50k though. I never turned my Rat's distortion up all the way anyway, and a lower value pot opens up some nice mid-gain areas that are otherwise lost in the taper with a 100k pot.

 

[caiofilipini]

Speaking of Rat opamps, does anybody know if this is accurate?

If it is, it appears the LM308Ns I got from GuitarPCB are not the real thing.

 

[Big Monk]

What are common opamps subs for this? I want to breadboard one this weekend.

 

[benny_profane]

OP07 is in new production Rats. You can try any single op amp provided the pinout is compatible. Hi-fi / fast op amps will be wasted here. Note that the LM308 / OP07 require external compensation, some others will not. This is typically indicated by TRIM, COMP, or offset nulling in data sheets. You can experiment with the compensation cap to shelve high frequencies and limit bandwidth.

 

[fig]

Here's the bass mod Joe..

 

[fig]

provided the pinout is compatible.

The ZIF socket makes it much easier to re-pin by swapping wires at the socket.

 

[fig]

Speaking of Rat opamps, does anybody know if this is accurate?

If it is, it appears the LM308Ns I got from GuitarPCB are not the real thing.

I couldn't say if that conclusiveIy determines legitimacy, but I checked a couple of my LM308Ns and OP07s...nothing betwixt pins 1 & 5 on the DMM.

 

[caiofilipini]

I couldn't say if that conclusiveIy determines legitimacy, but I checked a couple of my LM308Ns and OP07s...nothing betwixt pins 1 & 5 on the DMM.

My 4 LM308Ns from GuitarPCB read around 2.38KΩ between pins 1 and 5.
My LM308AH metal cans read over 8MΩ.