MBP Runt (Proco Rat)

[MichaelW]

Build Rating

5.00 star(s)

Taking a wee break from my "Juhl-Fest"...mainly because I'm waiting for components

I built this for a buddy of mine. (Same guy that's getting the ADHD Ge and Mojito Deluxe)

I've been sitting on this board for a while. When I ordered it, I didn't realize it was for a 1590A. I'm not interested in 1590a form factor so I never built it but built the Muroidea instead.

Anyway, took a little jiggering to make it work in a 1590B. You'd THINK there'd be a lot more room but there really isn't because of my insistence on top mounted jacks....

The build itself went quick. It's a Rat, not many components. I used an MMBFj201 for the output buffer and an OP07 for the opamp. It sounds great, like a stock Rat should sound.

Glad to have used this board and a much needed distraction this afternoon.

 

[jimilee]

That looks really great!

 

[HamishR]

That shadow over the board is a little unfortunate - I didn't realise it said Runt at first! Great build as always.

You can use a CA3130 in this circuit of course - that's what Bjorn uses - but you'll need to change the 30pF cap on pin one to eight to 100pF.

 

[MichaelW]

That's EXACTLY what my buddy said! He said "what? you built me a K*nt?"

 

[MichaelW]

I'm out of 3130's it's not something I normally stock, I just ordered a bunch from Mouser since I've been on my Bjorn kick, but they only had the CPMF SMD version. But I have some adapter boards from @Robert for my next builds.

 

[ADAOCE]

Hahah what unfortunate shadowing!

 

[Feral Feline]

I'm out of 3130's it's not something I normally stock, I just ordered a bunch from Mouser since I've been on my Bjorn kick, but they only had the CPMF SMD version. But I have some adapter boards from @Robert for my next builds.

Thet's whut them thar writers whatchamcallit...

foreshadowing...

 

[HamishR]

So did this pedal actually work? There is something missing...

 

[MichaelW]

So did this pedal actually work? There is something missing...

Um...yes....it works....whats missing?

 

[HamishR]

A transistor!

D'oh - I missed the SMD!

 

[MichaelW]

A transistor!

It's an either or, see the wee little SMD soldered above Q1? That's an MMBF5457.

 

[HamishR]

Another reason to dislike SMD. They make me look like an idiot.

In my defence I have just cooked a load of schnitzels in the traditional way, which I am assured involves drinking lots of German and Austrian beer. I have discovered through much scientific method that Weihenstephan Pils goes especially well with chicken schnitzel. I have done the experiment with many different beers and found Weihenstephan Pils to work the best. Trumer Pils is also excellent. I suspect that Saaz hops make the difference. They add a dry spiciness which seems to play off the sage and thyme so well. It's a tough experiment and it tends to blunt my observational skills. I may have to have a lie down and a passout.

 

[MichaelW]

Also in your defense, I think it's a little goofy to call the SMD alternative "Q2". (They should both be Q1, imo) You have to get 47 pages into the build doc before you see where it says "SOLDER ONLY ONE TRANSISTOR" haha

 

[HamishR]

I recently bought a bunch of old school tin-can LM308Ns from Tiny Bear because they look cool. I was curious to see if I could hear a difference in a Rat circuit. And I might be able too but I don't really know for sure! I'm not really a huge Rat fan. I bought a Rat when they first came out in around 1890 and they didn't do it for me then so I sent it back. But this year I built a Rat with a bass control (thanks to Chuck) and don't mind it. Then I built one with a bass control and tried a BJF trick of putting clipping diodes on the first gain stage as well and that made it slightly more interesting. It's a decent dirt pedal but not exactly a complex, amp-like sound. Still, it's more versatile than I originally gave it credit for.

 

[MichaelW]

I built this one for a friend. The one I built for myself kinda sits forgotten. It's cool but not for me.

I prefer the Expandora for a bit more tonal and gain-al (is that a word?) flexibility. I used my tin hat LM308's in that build.

I just ordered another board during this current PPCB sale, now I can't remember what it's called hahahah but it's allegedly "a Rat for people that hate Rats."

 

[MichaelW]

Oh and btw @HamishR I'm building YOUR tweaked and Chucky-fied TSV808 today. Matt was kind enough to send me one of his TimbreMan boards. Since I know you and I share the same tastes in low gain drives, I'm super eager to get this one built!

 

[JamieJ]

@HamishR - is the bass control you added the ruetz mod or something different? LEDs on the first gain stage sounds interesting to have on a toggle or dip switch in addition to hard clipping. The rat I built had hard/soft/no clipping but I bet that combined hard/soft would sound interesting. Definitely need to try that on the breadboard.

 

[BuddytheReow]

You might want to try the MadBean Slow Loris. It’s a rat with a few mods on it (diode selector and Ruetz). Very tweakable for low and high gain (sometimes fuzz) applications. It’s been on my board for months…

 

[mybud]

I recently bought a bunch of old school tin-can LM308Ns from Tiny Bear because they look cool. I was curious to see if I could hear a difference in a Rat circuit. And I might be able too but I don't really know for sure! I'm not really a huge Rat fan. I bought a Rat when they first came out in around 1890 and they didn't do it for me then so I sent it back. But this year I built a Rat with a bass control (thanks to Chuck) and don't mind it. Then I built one with a bass control and tried a BJF trick of putting clipping diodes on the first gain stage as well and that made it slightly more interesting. It's a decent dirt pedal but not exactly a complex, amp-like sound. Still, it's more versatile than I originally gave it credit for.

Not Darwin's prototype (Rattus Norvegicus) from 1877?

A true rarity, definitely unobtanium...

 

[HamishR]

I am very old! I did try some waxed paper LM308s too, but they had perished.

The bass pot mod wasn't the fabled Reutz mod as far as I know. It was Chuck's mod, detailed somewhere here...