Source for 708N chip to upgrade Rat 2?

[Steve A.]

And I still think they are fakes!!! I just wouldn't want to see my comrade bringing a knife to a gunfight, if you get my meaning.

Complaining to eBay is like calling in a noise complaint- absolutely nothing is ever done about it. However I did learn my lesson about confronting a low-life thieving scoundrel on eBay a dozen years ago. This guy was selling CDs with guitar amp schematics that he had downloaded from various sites- he had some stuff from my site and GEOfex so I sent him a message that all of the material on his CD could be downloaded for free. I should not have identified myself as Steve from Blue Guitar because shortly after that confrontation I got a message from the guy who has been hosting my site for free "Who did you piss off in Phoenix?" My site had been subjected to a very intense DOS attack and Bob S. was using every trick in the book to stop the attack which went on for more than a week.

It didn't occur to me that the guy selling the CDs was a total thug who would stop at nothing to get back at me. I guess I figured it was someone just trying to make ends meet, like a guy I knew who would steal stuff from Goodwill and Salvation Army donation boxes on Saturday night and then try to sell it at the flea market on Sunday morning which was illegal but harmless. At least until he fell into one of the boxes and had to wait for a policeman to pull him out...

Steve

[Chuck H]

like a guy I knew who would steal stuff from Goodwill and Salvation Army donation boxes on Saturday night and then try to sell it at the flea market on Sunday morning which was illegal but harmless. At least until he fell into one of the boxes and had to wait for a policeman to pull him out...

Karma is no lady! I love it.

I think it's just as likely that the guy who tried to bully you was attempting to protect this financial interests in the matter. The quick assault may have been an attempt to make his product more exclusive so that people would buy it. Especially if your arbitration about the material being available for free was publicly visible and attached to his auction. In other words, it might not have been as personal as you think. Sort of an on line mugging.

[Steve A.]

Revised review of chips!

Okay I got my RC-3 Loop Station working and recorded two loops using the NOS NS chip going through the RAT 2 with distortion set to 1:00 filter to 5:00 and volume to 12:00.
Observation: there was not that much difference between the 4 chips I tried (NOS NS, 1984 Motorola, NS OP07 and the new NS from China).

I then plugged in directly to the RAT 2 and noticed the differences I mentioned before. One possibility is that with the low impedance output from the RC-3 there was not that big of a difference between all 4 although there is with the high-impedance signal coming directly from the guitar. So my idea of using a loop to input an identical signal for each of the 4 chips did not work as planned.

Plugged directly into the RAT 2 with the NOS NS or Motorola LM307N I feel very inspired by the sound coming from my amp (a modded Epiphone Galaxie 10) and guitar (my new ESP/LTD EC256FL w/ Seth Lover pickups.) With the OP07 chip the sound is not as inspiring and with the new Chinese LM307N it sounds very raspy.

Steve

P.S. Sound samples to follow, both with RC-3 and without.

EDIT Bottom line I enjoy my RAT 2 a lot more with the real NS and Motorola LM308N chips. My real test for any equipment is how long I want to play before I can put my guitar down.

[Chuck H]

Two things...

1) Maybe put a series resistor on the output of the RC-3. Though I can't say as it would reflect the same impedance anomalies as a pickup at different frequencies and dynamics. That's always been one problem for me when it comes to testing amps on a loop of any kind. All things aren't created equal.

2) IT'S AN LM308N!!! I think your mind has some sort of subliminal block that forbids you to acknowledge that designation. I know that it happens. My brother does this thing where whenever he meets someone he decides he doesn't like, he refuses to remember their name or at least consistently pronounce it incorrectly. He honestly believes his mind isn't doing it intentionally.

Outstanding info and reporting! Of course tone is subjective, but I think anyone who's heard a RAT box (and that means everyone) knows where your coming from.

[Steve A.]

2) IT'S AN LM308N!!! I think your mind has some sort of subliminal block that forbids you to acknowledge that designation. I know that it happens. My brother does this thing where whenever he meets someone he decides he doesn't like, he refuses to remember their name or at least consistently pronounce it incorrectly. He honestly believes his mind isn't doing it intentionally.

No, that was actually a typo (yes, both times!) I was thinking LM308N but my fingers have a mind of their own. Just now I typed "LM308M" although I was aiming for the "N" key...

For me it has been pronunciations that I can't remember- my son has been telling me how to pronounce "noir" (as in film noir) for at least 10 years but I still get it wrong.

Preferences- some people do prefer the in-your-face brashness of the OP07 chip. For such a basic design I think that the RAT captures the vibe of tube amp distortion very well. With the NOS NS and Motorola chips it gets the distorted tube amp sounds that I really like.

Impedances- I think that an audio transformer would work better than a series resistor, but I'm glad that you brought it up! I wasn't thinking along those lines at all...

Steve

[dai h.]

various Rat related links:

History « Rat Distortion

Page 1

ElectroSmash - ProCo Rat Analysis

freestompboxes.org ? View topic - Proco - Rat ( History )

http://www.effectsdatabase.com/model/proco/rat

[Steve A.]

Update on Fulltone Distortion Pro

I replaced the painted over chip with a Motorola LM308N and liked the sound it got. However when you let a note decay you could hear it throbbing. I put the original chip back in and set the trimpots back to the factory setting which pretty much eliminated the throbbing decay (which would be a good name for a band!)

With the original chip back in the pedal was just too bright even with Highs set to the minimum. I could get a pretty cool sound by backing off the tone control on my guitar to 5 or 6. I measured the resistance on the tone pot and it was around 75k at that setting. So I traced the input and adding a 68k resistor in series with a .047uF cap from the incoming signal to ground. Perfectamente! I was getting some really cool sounds that took the basic RAT circuit in new directions (the Distortion Pro is Mike Fuller's boutique version of the RAT with 6 controls on the top panel and two trim pots inside.) I took a picture of the circuit board showing where I added the resistor and cap.

As for my RAT 2 there isn't a lot of tweaking available or needed- just stomp on it and it sounds cool. I usually keep the filter maxed or maybe just backed off a little bit- I wish there was a wider usable range. I was googling for mods and ran across the Ruetz mod which messes with the 560R and 47R resistors on the negative input of the chip (the 560R goes to a 4.7uF cap and the 47R goes to a 2.2uF cap.) Ruetz originally just snipped out the 47R resistor but he later replaced both resistors with trim pots- which just happen to be very accessible when you remove the battery cover. I just picked up two 1k cermet trim pots (28 turn) to do that mod. I guess it would also be a good idea to replace all of the electrolytic caps in the audio signal path with tantalum and use 30pF and 100pF mica capacitors on the chip.

Steve

[David Schwab]

With the LM308N Rats going for $120+ ...

Seriously? I bought one last year on eBay for $40. It's a USA made Rat II with the 308N op amp. Sounds like all the other Rats I've had.

[Steve A.]

With the LM308N Rats going for $120+ ...

Seriously? I bought one last year on eBay for $40. It's a USA made Rat II with the 308N op amp. Sounds like all the other Rats I've had.

Take a gander at some of today's prices...

proco rat in Distortion & Overdrive | eBay

Murphy's Law says that when I really really wanted a Rat the prices were high.

Steve