Which Rat PCB?

daydreamdelay · November 17, 2006, 09:16:17 PM

hello everyone.. I sold my vintage Rat reissue recently and miss it quite a bit, I just finished rehousing my green Sovtek Big Muff and built an AMZ Mosfet boost in the last week so I've got the diy bug and would like to build my next Rat. A few days back I was looking at PCB's on Tonepad and started looking at parts on the various sites.. I ended up ordering the parts but forgot to go back and order the PCB, something I didn't realize until today. While looking around to see if there's any other Rat projects on AMZ I discovered this site and thought it might be a good idea to ask you guys before putting in my order with Tonepad. I've had pretty much every Rat that's been out and like the original and vintage reissue best as I use it more for low/med gain.. though it has to get nasty like all Rats do. I like that Tonepad and GGG's boards are easy to read as I'm just figuring out schematics and am still somewhat unsure with them. Good news is neither my Big Muff or Mosfet Boost worked at first so I've learned a ton trouble shooting and correcting problems so I think I'm ready for this one.. hopefully there's a 30pf in this radioshack capacitor pack I just bought, I couldn't find that cap anywhere

I'm rambling.. any pcb recommendations for the best example of the classic Rat?

boogietube · November 17, 2006, 10:07:04 PM

Quoteany pcb recommendations for the best example of the classic Rat

I don't know about that, but if you're purchacing a pcb, the GGG was like a board that I could make myself. (unless that's recently changed) The tonepad boards are silk screened, solder masked, and plated through. I find the quality higher at Tonepad. Although I have ordered boards from both and been satisfied. Hope this helps

brett · November 18, 2006, 07:19:14 AM

Hi

Quotehopefully there's a 30pf in this radioshack capacitor pack I just bought, I couldn't find that cap anywhere

Your luck is in. That 30pF cap is only needed if you use an "uncompensated" op-amp, such as the original LM308. Do yourself a favour and use a TL071. It will sound better and you won't need that cap. (A 33pF cap would have been fine, BTW).

A variety of op-amps have been suggested for the Rat. I like a TL071 because:
it has high input impedance (the NE5334 is too low at 30-100k)
it is quiet (the LM741 is too noisey)
it is frequency compensated (the LM308 isn't).

Some people don't like the high-frequency harshness of the Rat. One option that helps just a little is to change the 1M bias resistor (connecting to leg 3 of the op-amp) to 330k or 220k. This change will help with noise, too.

cheers

dano12 · November 18, 2006, 08:48:11 AM

The Tonepad version is excellent. High quality board that is pretty much pure-rat. The last rat board I got from GGG had extra pads for millenium switching instead of true-bypass so it was some extra work to figure it out. BuildYourOwnClone also sells double-sided silkscreened boards for his rat clone. It's a very nice PCB because it has pads for extra diode switching options.

Cardboard Tube Samurai · November 18, 2006, 11:13:32 AM

Having made a few of the GGG Rats, I can highly recommend them for simplicity! You don't need a 3PDT switch for the indicating LED which makes it cheaper too!

markm · November 18, 2006, 11:36:54 AM

Keep in mind that some claim the heart and soul of the RAT is that LM308 and once you change that, it's a completely different animal with less personality. I personally don't know as I have never built one but, with that said, if you do a search on this forum you'll find loads of opinions and threads about this build.
Have at it but, have fun!

daydreamdelay · November 18, 2006, 02:25:31 PM

thanks everyone.. I just ordered the Tonepad board and plan on using the LM308 so I'll have to figure something out as there wasn't a 30pf or 33 in this pack I got yesterday. Anyone know where I might be able to find one???

boogietube · November 18, 2006, 03:09:58 PM

www.smallbearelec.com

daydreamdelay · November 18, 2006, 03:53:05 PM

I didn't see one when I placed my order with them $:-\$

sfr · November 18, 2006, 08:11:36 PM

Look under the Silver Mica capacitors in the stock list. (or search for SKU 1300 ) There's a 33pF in the pulldown list for "value".

darron · November 18, 2006, 09:54:09 PM

i put an ne5534an in a friends. it's an extremely low noise opamp.

Ronsonic · November 19, 2006, 11:51:49 AM

Quote from: dano12 on November 18, 2006, 08:48:11 AM
The Tonepad version is excellent. High quality board that is pretty much pure-rat. The last rat board I got from GGG had extra pads for millenium switching instead of true-bypass so it was some extra work to figure it out. BuildYourOwnClone also sells double-sided silkscreened boards for his rat clone. It's a very nice PCB because it has pads for extra diode switching options.

The "millenium bypass" was pretty much lifted from the Rat. Not that it's a copy, but it is a full bypass as much as any other "true bypass" system, it is very similar to the bypass system that was introduced in the Rat. And, it can be left out altogether if you simply can't grok the idea of having an LED and a bypass on a DPDT.

Ron

dosmun · November 19, 2006, 12:24:32 PM

I guess I'm too late but the BYOC boards are great. They will fit in a 1590B and have places for diode switching mods etc.

and from the BYOC site.

"They all have
plated through holes with solder pads on both the top and bottom of the board. This means
that the possibility of you making a bad solder joint is highly unlikely. All BYOC circuit boards
have a solder mask which prevents any unwanted solder sticking to any of the traces where
it's not supposed to be. And each circuit board has the component layout silk screened on
top so you know exactly where every part goes."

daydreamdelay · November 19, 2006, 04:41:38 PM

the byoc board sounds good.. I'm going to build their tonebender and big muff clones soon so it's good to know they've got quality stuff.

Quote from: sfr on November 18, 2006, 08:11:36 PM
Look under the Silver Mica capacitors in the stock list. (or search for SKU 1300 ) There's a 33pF in the pulldown list for "value".

cool I just ordered it.. thanks a lot!

is there any noticeable difference between this and the 30pf? basically should I bother looking for one and installing it at some point or are they pretty much the same?

$uperpuma · November 19, 2006, 04:44:33 PM

its pretty much the same... and easier to come by..

daydreamdelay · November 19, 2006, 04:49:36 PM

excellent.. now I wait

brett · November 19, 2006, 07:14:02 PM

Hi

Quotei put an ne5534an in a friends. it's an extremely low noise opamp.

Did you notice losing any top end? According to the NE5534 datasheet, the mnimum input impedance is 30k, but the "typical" is 100k. 100k is about the minimum impedance you can use and still get a full amount of top end from pickups. Therefore, the NE5534 is "typically" somewhere near the limit of what is usable without losing some highs.
Thanks to RG for pointing out the low impedance of the 5334 and 5332.

By the way, my Rat is very quiet. It is standard except for a TL071 op-amp (no compensation cap), a 22uF bias cap (instead of 1uF), and a 470k bias resistor (instead of 1M).

cheers

darron · November 19, 2006, 09:16:10 PM

Quote from: brett on November 19, 2006, 07:14:02 PM
Did you notice losing any top end?

it actually sounded more trebly from memory. we both agreed that it was a better kind of distortion, and it did change the tone. but if what you say is true then it's probably be wrong about the maybe it lost some bottom end along the way?

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Which Rat PCB?