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Conference napalm::guitar

Title:GUITARnotes - Where Every Note has Emotion
Notice:Discussion of the finer stringed instruments
Moderator:KDX200::COOPER
Created:Thu Aug 14 1986
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:3280
Total number of notes:61432

1561.0. "Disable PV DDT compression?" by FSTVAX::GALLO (That's 400 watts... *per* channel!) Mon Nov 27 1989 10:45

    
    
    	
    	Does anyone know whether it is possible to disable the built in
    DDT compressor on PV amps? By disable, I mean permanently, by a mod
    to the amp itself. If that's not possible, can a repairman adjust the
    threshold that the controls when the compression kicks in? 
    
    	PV doesn't give any user control over compression and on all
    the amps I've tried, it kicks in way too soon, squashing some of the
    dynamics of the bass. 
    
    	BTW, would this type of mod pose any danger to the amp or 
    speakers? I have plenty of speaker headroom (2x400W EV-15L), so
    I don't think speakers will be the problem. I don't want to
    blow up my bass head, though.
    
    -Tom
    
    
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1561.1I wouldn't advise it...WEFXEM::COTEOK, who wants a Tangwich???Mon Nov 27 1989 13:4711
    Any time you disable compression you run the risk of hurting something,
    probably your speakers, if you push the amp to clipping. Having mondo-
    watt rated speakers isn't the solution, as if the AMP runs out of
    headroom, the speakers will get sent a garbage wave.
    
    Better to have more headroom on the amp. Or compress.
    
    I've got a schematic of the PV DDT circuitry from my XR-1200 board.
    I imagine it's similar to whatever you have. You're welcome to a copy.
    
    Edd
1561.2FSTVAX::GALLOSolid!Mon Nov 27 1989 14:5712
    
    
    	I have a PV MAX bass which has 2 400W CS800 Power amps. I think
    this qualifies as enough headroom. I guess I'm not real sure why 
    PV would put compression on amps with this kind of power. I'm also
    at a loss to explain why the compression LED lights up so quickly.
    
    	I know my band plays loud, but there is no way I'm doing 400W,
    even on the peaks. 
    
    -Tom
    
1561.3I got what you want!WEFXEM::COTEOK, who wants a Tangwich???Mon Nov 27 1989 15:067
    Tom - I just remembered that my board has 2 toggle switches precisely
    for the purpose of disabling the DDT circuit. (I always leave them
    enabled...)
    
    Perhaps you can adapt the circuit to your needs....
    
    Edd
1561.4USCTR1::EDEGAGNEI awoke on impactMon Nov 27 1989 15:259
    
    
    Tom - I goota agree with you, I've had two Peavy Bass Amps before
    	  going to all rack gear, and the DDT comes on way too early.
    	  I liked everything else about them though.  Like the rack
    	  stuff a bit better though.
    
    	  
    Mr. Ed...
1561.5Cones On The FloorOTOO01::ELLACOTTFreddie's RevengeMon Nov 27 1989 15:283
    		W A R N I N G ! ! ! ! !
    Make sure your cabs can handle the peeks, especially if pop & slap,
    otherwise......^  8^(
1561.6USCTR1::EDEGAGNEI awoke on impactMon Nov 27 1989 15:338
    
    Disable it and use a footpedal compression box.  I was using the
    DOD model bass compressor and it works fine and is adjustable.
    
    Mr. Ed... 
    
    
    
1561.7DDT - arghhhFSTTOO::GALLOSolid!Mon Nov 27 1989 17:5713
    re: .5
    
    
    	I have a pair of EV-15L speakers that are rated at 400W continuous
    and 1600W peak. No problem in the pop department.
    
    re: .6 
    
    	If I can have it disabled, I going to. The DDT really zaps the
    dynamics in my playing.
    
    -Tom
    
1561.8No problem...WEFXEM::COTEOK, who wants a Tangwich???Mon Nov 27 1989 18:445
    Tom - I can't connect to FSTTOO:: (network partner excited)...
    
    I'll get the prints right out to ya...
    
    Edd
1561.9Wasn't DDT banned?CSC32::G_HOUSEI just can't slow downTue Nov 28 1989 15:435
    > The DDT really zaps the dynamics in my playing.
    
    Yeah, it's really tough on bugs and small animals too!
    
    ;^)