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
(https://s25.postimg.org/rtlzuvfiz/RAT.jpg) (https://postimg.org/image/rtlzuvfiz/)
Did they have the comp cap in there with the TL071?
Looked to me they merely swapped the LM308N for the TL071,
The other sub was in the power supply filtering...
MC
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.
Let me look
The 30pf is there.. from Pin1 to Pin8 of the IC. Same as the "real" schematic I have for the RAT. (w/LM308N)
MC
Quote from: thermionix on September 30, 2017, 06:15:03 PM
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.
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.
Quote from: thermionix on September 30, 2017, 06:34:14 PM
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
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.
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:
(https://i.postimg.cc/FYdxDVkN/Nutria.png) (https://postimg.cc/FYdxDVkN)
(https://i.postimg.cc/1gDrZRKd/Nutria-PCB.jpg) (https://postimg.cc/1gDrZRKd)
(https://i.postimg.cc/R6R1NPyQ/Nutria-PCB.jpg) (https://postimg.cc/R6R1NPyQ)
(https://i.postimg.cc/Wt56VHMs/Nutria-Top.jpg) (https://postimg.cc/Wt56VHMs)
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
Quote from: iainpunk on November 10, 2021, 06:13:46 PM
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.
Quote from: bamslam69 on November 10, 2021, 05:53:59 PM
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.
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
Quote from: italianguy63 on November 10, 2021, 06:02:44 PM
I also have a mini 1590A version too.
Truly a Rodent of Unusual Size.
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?
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.
Quote from: duck_arse on November 11, 2021, 09:25:35 AM
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
Quote from: iainpunk on November 10, 2021, 06:13:46 PM
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!
Quote from: Ben N on November 11, 2021, 09:07:18 AM
Quote from: italianguy63 on November 10, 2021, 06:02:44 PM
I also have a mini 1590A version too.
Truly a Rodent of Unusual Size.
The little one!
(https://i.postimg.cc/nsG81r0G/Nutria-Mini.png) (https://postimg.cc/nsG81r0G)
(https://i.postimg.cc/7CDdbDwG/Mini-Nutria1590-A.jpg) (https://postimg.cc/7CDdbDwG)
(https://i.postimg.cc/FYXnnmfW/Mini-Nut-Gut.jpg) (https://postimg.cc/FYXnnmfW)
(https://i.postimg.cc/Bj3MBgyR/MiniNut.jpg) (https://postimg.cc/Bj3MBgyR)
Quote from: italianguy63 on November 14, 2021, 06:14:42 AM
The little one!
And all thru-hole! That is insane! Kudos, and I won't be trying that.
Quote from: mwelch55 on November 11, 2021, 10:40:31 AM
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.
Actually going to do something similar, but thinking about using a DIP switch arrangement, so you can add in whatever clipping arrangements. Dumb move?
i think that dip switches can be really cool for inside a pedal, but another thing that impacts clipping a lot more that people realise is the 1k resistor before the signal hits the diodes. on my breadboard, i used a 5k trimmer and a 330 ohm resistor in series, to change the curve/knee and the treble amount in the distortion, going from bright and hard to softer and darker.
cheers
Finally built my RAT, but just from the layout on the tagboard effects site. I added the 8 switch DIP board for diode clipping, and currently have it set at some random red LED's.
The thing sounds wicked! Can't wait to give it a run at band rehearsal.
has anyone done a cmos rat yet? i think an opamp driving a cmos gainstage into distortion would be cool.
to match the amount of distortion created by diode clippers, and to keep the opamp in control of the frequency spectrum, the gain of the CMOS inverter stage should be low, like really low. i think between A= 5 and 10, quick and ditry calculations say 7.
cheers
Quote from: iainpunk on January 26, 2022, 05:52:35 PM
has anyone done a cmos rat yet? i think an opamp driving a cmos gainstage into distortion would be cool.
to match the amount of distortion created by diode clippers, and to keep the opamp in control of the frequency spectrum, the gain of the CMOS inverter stage should be low, like really low. i think between A= 5 and 10, quick and ditry calculations say 7.
cheers
That sounds cool, but what is Rat-like about it?
I'm pretty sure peeps have built Rats with a CA3140, so that's one way to get CMOS goodness in a RAT.
Quote from: Ben N on January 27, 2022, 09:35:35 AM
Quote from: iainpunk on January 26, 2022, 05:52:35 PM
has anyone done a cmos rat yet? i think an opamp driving a cmos gainstage into distortion would be cool.
to match the amount of distortion created by diode clippers, and to keep the opamp in control of the frequency spectrum, the gain of the CMOS inverter stage should be low, like really low. i think between A= 5 and 10, quick and ditry calculations say 7.
cheers
That sounds cool, but what is Rat-like about it?
I'm pretty sure peeps have built Rats with a CA3140, so that's one way to get CMOS goodness in a RAT.
what makes a rat a rat is the frequency response of the opamp and its negative feedback loop. using cmos in the way described doesnt change this, as it has the same ''relative gain'' as diodes would have.
CA3140 isn't cmos, its bipolar for the most part, but uses 2 input mosfets, AKA Bi-MOS. you want the 3130 or 3160 for that.
just substituting the 308 for a cmos or bi-mos opamp, where it has its cmos gain stage inside a strong feedback loop and still utilising diode clipping, is wildly different than replacing the diode clipping with cmos clipping.
cheers
Quote from: iainpunk on January 27, 2022, 06:25:51 PM...CA3140 isn't cmos, its bipolar for the most part, but uses 2 input mosfets, ...
Correct. An odd old duck.
(https://i.postimg.cc/H8gn2yVS/CA3140-42.gif) (https://postimg.cc/H8gn2yVS)