Build a (Tayda) RAT.

[italianguy63]

Picked up this Tayda PCB on a flyer... PN#  A-1552

For $8, it is a nice board... well laid out.

To make it totally legit--

Substitute C12 from .47uf electo cap to 1uf electro (unimportant)

And use a LM308N OPAMP instead of the TL071.

I will post pics when I eventually put this together and do an enclosure...  MC

[thermionix]

Did they have the comp cap in there with the TL071?

[italianguy63]

Looked to me they merely swapped the LM308N for the TL071,

The other sub was in the power supply filtering...

MC

[thermionix]

If you soldered in a 30 puff cap, then it's there.  They must have anticipated people using LM308s, because that cap would go nowhere with a TL071, pin 8 is NC.

[italianguy63]

Let me look

[italianguy63]

The 30pf is there.. from Pin1 to Pin8 of the IC.  Same as the "real" schematic I have for the RAT.  (w/LM308N)

MC

[italianguy63]

If you soldered in a 30 puff cap, then it's there.  They must have anticipated people using LM308s, because that cap would go nowhere with a TL071, pin 8 is NC.

They probably subbed the part because Tayda does not sell LM308N's.

[thermionix]

Right on, good to know.  I used one of their 808 boards, no problems.  My only complaint is that they should post a schematic on their build instruction page, with their component numbering scheme.

[italianguy63]

Right on, good to know.  I used one of their 808 boards, no problems.  My only complaint is that they should post a schematic on their build instruction page, with their component numbering scheme.

Yep!  I compared the original to the board.. the component numbering was ALMOST spot on.. made it pretty easy... I did not trace it out totally since it was so close.  But, I think this one is a big winner with the minor tweeks.

MC

[bamslam69]

My next build, a Rat.
Doing lots of googling, found some of BeavisAudio's mods, so I'm going to have some fun with this pedal. Might build one stock, and one with bells & whistles.
Thanks for the previous tips with the 308. (I'll grab some cheap 071's as well).

There's a schematic on the project page now.

[italianguy63]

Wow... 4 year old thread...

I did end up developing a 1590B version of the original PROCO RAT and did a PCB.  I have them if anyone wants to try one.

I also have a mini 1590A version too.

Some pics of the 1590B version:

[iainpunk]

hmmmm, i never actually build a rat.... well, come to think of it, never even build any opamp and hard clipper circuit to full completion,,, dont know if i need one, but i think i should out of respect or something like that

cheers

[bamslam69]

dont know if i need one, but i think i should out of respect or something like that

cheers

Yeah, something like that too. It's just a matter of having something to get my hands dirty with.

[cab42]

My next build, a Rat.
Doing lots of googling, found some of BeavisAudio's mods, so I'm going to have some fun with this pedal. Might build one stock, and one with bells & whistles.
Thanks for the previous tips with the 308. (I'll grab some cheap 071's as well).

There's a schematic on the project page now.

I built mine with a 741 first as it was what I had, then I got hold of a OP07, but now it has the proper 308 inside.

As far as I recall, there wasn't much difference between the 308 and OP07, but I lost my OP07 so did not do much testing. The 741 also sounded cool, but different.

[iainpunk]

i had a rat on a breadboard for quiet a while, even did some blind testing with chip swapping and letting guitarists state their opinion. no one of the people i tried it with heard any significant difference between the 308 and the 07, but most of them guessed one of them to be the 741, and most of them thought the 741 was the 308... i think ill build mine with an LM3900 i read about yesterday

cheers

[Ben N]

I also have a mini 1590A version too.

Truly a Rodent of Unusual Size.

[duck_arse]

the only one I've ever built was with an LM307. that would be a rare beast these days, I'm sure.

an LM3900? what are you going to use the other three opamps for?

[mwelch55]

I built a Tayda Rat a couple of years ago.  I made it with all of the correct values.  I installed a 12 position rotary switch with all of the diode clipping options I could thing of.  The first position is without clipping diodes.  It makes a really good clean boost.  My Rat pedal is one of my favorites.

[iainpunk]

the only one I've ever built was with an LM307. that would be a rare beast these days, I'm sure.

an LM3900? what are you going to use the other three opamps for?

input buffer, output buffer and buffered Vb

cheers

[mdcmdcmdc]

hmmmm, i never actually build a rat.... well, come to think of it, never even build any opamp and hard clipper circuit to full completion,,, dont know if i need one, but i think i should out of respect or something like that

cheers

Everyone needs a rat or three!