Vintage Rat

[Cardboard Tube Samurai]

I've had someone ask me to build them a Vintage Rat clone. He says that he prefers the Vintage Rat over other releases. Just wondering if anyone knows what version of the Rat is shown at GGG?

Link = http://www.generalguitargadgets.com/index.php?option=com_content&task=view&id=92&Itemid=26

[Rocket Roll]

Vintage Rat would be the one with germanium clipping diodes, right?

[petemoore]

  IIRC...
  And those sound sort of mushy and grainy compared to the Si ones.
  I would put a diode selector switch in there...if that's the case...that or select diodes.
  Makes a pretty big difference in the sound, worth trying them out even if it is vintage or not...if ones opinion on tone has any self worth..it should supercede any 'whatever vintage was' guidlines, especially if those guidlines are 'Ge clipping diodes' before trying out Si's.

[alex frias]

Doh... Germanium LM308?

[Mark Hammer]

I may be way off (and please tell me if I am), but my understanding was that they had always used Si diodes.  Differences between issues had more to do with use of a FET input stage or not.

[soulsonic]

I may be way off (and please tell me if I am), but my understanding was that they had always used Si diodes.  Differences between issues had more to do with use of a FET input stage or not.

This awesome Rat History page has lots of gutshots of old Rats.
http://webpages.charter.net/daosmun/Ver%201.htm
They all have Si diodes and NONE of them have FET inputs.
Of the current-model Rats, the "You Dirty Rat" has Ge diodes as standard and the Deucetone has them as a switchable option.

[Cardboard Tube Samurai]

I was planning on putting some clipping options in there for him anyway, since he liked having that option on the one I modded for him (which he is replacing due to someone permanently "borrowing" it). I just want to make sure I'm going to be giving him one that is at least close to what he had because he has a rather specific (and well-known) bass sound

[Mark Hammer]

I may be way off (and please tell me if I am), but my understanding was that they had always used Si diodes.  Differences between issues had more to do with use of a FET input stage or not.

This awesome Rat History page has lots of gutshots of old Rats.
http://webpages.charter.net/daosmun/Ver%201.htm
They all have Si diodes and NONE of them have FET inputs.
Of the current-model Rats, the "You Dirty Rat" has Ge diodes as standard and the Deucetone has them as a switchable option.

Well, I guess Commander Keen would be among the first to suggest that one ought not to blindly trust drawings on the web.  That being said, I am staring right now at a drawing from none other than RG himself, and revised by Jack Orman in October 1998 that shows a BF245A on the input of the ProCo Rat.  It is also worth noting that while the two ground-leg paths are the same values as later issues, this drawing shows a 150k gain pot, in contrast to other drawings that show a 100k pot.  Given the tiny values of the two ground-leg resistors, a mere 50k of extra feedback resistance provides for a VERY substantial increase in maximum gain.

The guts shots on the site linked to only shows a single lonely transistor, which we can safely assume is the output-stage FET.  Either it was initially misdrawn, or there is another earlier issue not shown in the web-site which used a FET input.  Keep in mind that the common trend in effects is to gradually shave off components that don't seem to be essential, in order to save production costs.

[soulsonic]

I may be way off (and please tell me if I am), but my understanding was that they had always used Si diodes.  Differences between issues had more to do with use of a FET input stage or not.

This awesome Rat History page has lots of gutshots of old Rats.
http://webpages.charter.net/daosmun/Ver%201.htm
They all have Si diodes and NONE of them have FET inputs.
Of the current-model Rats, the "You Dirty Rat" has Ge diodes as standard and the Deucetone has them as a switchable option.

Well, I guess Commander Keen would be among the first to suggest that one ought not to blindly trust drawings on the web.  That being said, I am staring right now at a drawing from none other than RG himself, and revised by Jack Orman in October 1998 that shows a BF245A on the input of the ProCo Rat.  It is also worth noting that while the two ground-leg paths are the same values as later issues, this drawing shows a 150k gain pot, in contrast to other drawings that show a 100k pot.  Given the tiny values of the two ground-leg resistors, a mere 50k of extra feedback resistance provides for a VERY substantial increase in maximum gain.

The guts shots on the site linked to only shows a single lonely transistor, which we can safely assume is the output-stage FET.  Either it was initially misdrawn, or there is another earlier issue not shown in the web-site which used a FET input.  Keep in mind that the common trend in effects is to gradually shave off components that don't seem to be essential, in order to save production costs.

Since I'm a big Rat fan, this question has been bugging me for awhile. I've looked all through that site, and the only one that looks like it might maybe have a JFET input is one of the Vintage Re-Issue ones, but it's too hard to tell from the small pic what exactly is going on. The only verrsion that I've never seen the inside of is one of those first "Bud Box" Rats - but what are the chances that was used for the schematic in question?... slim to none.
You know... I'm going to try asking Pro Co directly. If anyone could answer the question, "has any version of the Rat ever used a JFET input buffer?", it would be them. They're friendly folks.

[Mark Hammer]

Alternatively, perhaps RG will chime in and indicate what issue he drew that from and also whether he still stands by the drawing.  I'm sure he'd be quite willing to admit if there was any sort of transcription error that should now be ignored.  I'm also assuming that Jack would be able to corroborate whether his 1998 corrections to it were based on an actual pedal or whether he simply corrected what he believed to be electronically erroneous, based on theory.  There are any number of ways that incorrect drawings can show up and be perpetuated in good faith, just as there are any number of ways that a person can put up a web-site devoted to historical trivia about gear in good faith, and the page creator doesn't have access to information from an earlier era.  It happens.

[Cardboard Tube Samurai]

So nobody can really say what version the GGG "Rodent" is a clone of?

[soulsonic]

So nobody can really say what version the GGG "Rodent" is a clone of?

It's almost identical to the standard Rat 2 I traced last year. It's pretty much the "normal" Rat circuit.

[Rocket Roll]

I've built three GGG Rats so far, and they sound like this (all pots 100K log, all pots at noon, red LED clipping diodes):

"Rough Justice" w/ my Strat - http://www.box.net/shared/wu2x6otc0s
Ibanez 5-string bass - http://www.box.net/shared/ajdcrlckcw
Ibanez GRG250 guitar & Ibanez 5-string bass - http://www.box.net/shared/kkkurzpuss

Now I never had any other Rat, so - does it sound like a Rat should sound?

[petemoore]

  The distortion a healthy Rat poops out varies widely, and depends greatly on where it lives and what you feed it.