Other Chips For a RAT Circuit?

snap · April 29, 2009, 01:57:01 PM

what`s all that slewrate stuff about?

aron · April 29, 2009, 02:04:10 PM

Slew rate.... I typed it into the find command above:

http://www.diystompboxes.com/smfforum/index.php?topic=70767.0

Mark Hammer · April 29, 2009, 04:28:16 PM

Quote from: WGTP on April 29, 2009, 10:40:43 AM
I'm no expert, but it looks like the LM308, NE5534 and TL070 all have the same pin out with the compensation cap at pins 1 and 8.

As does the LM/ua748. Keep in mind that part of the soul of the Rat is that the gain bandwidth product of the LM308 is very restrictive, such that when you ask it to provide gains of >1000 and compensate it just right, the chip craps out on you. That's what keeps the tone more musical and less buzzy. Both the NE5534 and TL070 can be expected to handle gain-bandwidth products well in excess of what the 308 or 748 can do. So, while I have no doubts that the 5534 or TL070 would do something interesting in a Rat circuit, the stock compensation wouldn't necessarily nail you what the stock, Rat provides. You might have to explore other compensation-cap values and even that might not get you what you want. Of course, if such a change in chip means the compensation is simply irrelevant, then all doors are flung wide open for chips choices. You could simply decline to compensate at all, and use half a 4558, or a TL071, or an uncompensated 5534, or a 741, whatever the heck you felt like. It'd work, and it might even sound nice. It just wouldn't be a Rat.

grolschie · April 29, 2009, 05:43:48 PM

I was told that perhaps one could use a dual opamp by wiring it up as a single. This should open up some more possibilities, right?

aron · April 29, 2009, 06:16:09 PM

Well we need to figure out why this thing is not playing nice with other pedals. Just to be clear, you get this problem with your guitar plugged straight into the Rat right? It's a not a DIY rat, but a production model....

sevenisthenumber · April 29, 2009, 10:50:45 PM

Quote from: aron on April 29, 2009, 06:16:09 PM
Well we need to figure out why this thing is not playing nice with other pedals. Just to be clear, you get this problem with your guitar plugged straight into the Rat right? It's a not a DIY rat, but a production model....

Who is having a problem?

DougH · April 29, 2009, 11:19:42 PM

Quote from: StephenGiles on April 28, 2009, 03:56:08 PM
Quote from: DougH on April 28, 2009, 08:43:01 AM
TL070, different pinout than LM308

No, it's the same pin out.

Good. My LM308 is in the circular package.

grolschie · April 30, 2009, 04:14:39 AM

Quote from: sevenisthenumber on April 29, 2009, 10:50:45 PM
Quote from: aron on April 29, 2009, 06:16:09 PM
Well we need to figure out why this thing is not playing nice with other pedals. Just to be clear, you get this problem with your guitar plugged straight into the Rat right? It's a not a DIY rat, but a production model....

Who is having a problem?

Me? I am having problems with my production rat, but that is in another thread. In this thread, I was offering more IC options.

sevenisthenumber · April 30, 2009, 10:09:09 AM

Quote from: grolschie on April 30, 2009, 04:14:39 AM
Quote from: sevenisthenumber on April 29, 2009, 10:50:45 PM
Quote from: aron on April 29, 2009, 06:16:09 PM
Well we need to figure out why this thing is not playing nice with other pedals. Just to be clear, you get this problem with your guitar plugged straight into the Rat right? It's a not a DIY rat, but a production model....

Who is having a problem?

Me? I am having problems with my production rat, but that is in another thread. In this thread, I was offering more IC options.

ohhh!!! I didnt see that. Hope you get it rolling!

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Other Chips For a RAT Circuit?