[sdiy] lm308 replacement

[Michael Ruberto]

from tinkering around with my Rat I've found that there are diodes doing the 
clipping. The 308 is just being used as an amp. I have read on some sites 
for distortion pedals that replcaing the 308 with a TL071 is a popular mod 
for making the pedal less hissy. another mod was to use different types and 
configurations of diodes to change the distortion sound.

~M


>From: James Patchell <patchell at cox.net>
>To: "Steve Begin" <trypannon at hotmail.com>,   "synth" 
><synth-diy at dropmix.xs4all.nl>
>Subject: Re: [sdiy] lm308 replacement
>Date: Tue, 22 Jul 2003 16:16:14 -0700
>
>         Man, that is a tough one...the LM308 was just a real dog when it 
>came to speed....something like .1 V/uS slew rate.  Also, it had super-beta 
>input transistors...if the LM308 was used to make the distortion, you 
>probably will be hard pressed to find something that will sound like it.  
>If it was just used as an amplifier, well, probably almost anything would 
>do...I would use a FET opamp to sub for it in that case...although, why 
>anybody would use the LM308 as an audio amp I don't know...I suspect you 
>have a real search on your hands.
>
>         -Jim
>
>At 03:26 PM 7/22/2003 -0400, Steve Begin wrote:
>>I'm looking to build a proco rat distortion since it seems fairly simple 
>>and well liked...although I'm open to suggestion (I'm looking for a hard 
>>clipping overdrive that isn't particularily noisy).
>>
>>Does anybody know what I could use instead of an LM308?
>>
>>thanks,
>>steve
>
>

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