ampage
Tube Amps / Music Electronics
For current discussions, please visit Music Electronics Forum. New: view Recent Searches.
New: visit Schematic Hell!
The sunn still shines online!

 
Listen to great tunes streaming live right now!

ampage archive

Vintage threads from the first ten years

Search for:  Mode:  
previous: Doug H Tried the LM308 -- 11/5/2000 9:08 PM View Thread

Schematic & Look Ma, No diodes!

11/6/2000 1:10 PM
Doug H
email
Schematic & Look Ma, No diodes!
Here's the schematic for the LM308-based hi gain booster:  
 
http://www2.gdi.net/~mhammond/hiboost308.gif  
 
As you can see, it's basically just the opamp portion of a Rat circuit. Note also that I left off the fixed LPF I had been using. It's just not needed at all with this opamp and circuit. Plenty of highs at low-moderate gain. In high gain it gets thick-just the combination I want.  
 
Just for grins, I threw a couple clipping diodes on the output to see how they affected the sound, first 1n914's and then LEDs. Overall my reaction was, 'Blechh! Why the heck would I wanna do that?' Although the LED's were a little better, they both thinned out the sound too much and obscured the personality of the LM308 when it was pushed into high gain. As expected, they limited the ability for this thing to push the amp as well. Didn't add a thing-took away a lot.  
 
Although I didn't try the Rat FET output stage, this reinforced my feeling that I'm on the right track. Just voice the tone and blast your amp. This is one of those cases where "less is more". Without the diodes the tone is much richer.  
 
Now I'm starting to understand why so many fall in love with their micro-amps and LPB1's...  
 
Doug

 
Replies:
Jake >>Just voice the tone and blast you... -- 11/6/2000 2:44 PM
Kleber Hey Doug,About the diodes, I sa... -- 11/6/2000 3:04 PM
Ed Rembold nice posts Doug,great info, I t... -- 11/6/2000 5:07 PM