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  #1  
Old 06-21-2004, 11:23 AM
somedude somedude is offline
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How can I get power sag without using a tube rectifier?

Thanks.
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  #2  
Old 06-21-2004, 11:32 AM
saros141
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Series resistor.

Hey - is Canada Heaven, or is Canada South of Heaven?
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  #3  
Old 06-21-2004, 11:42 AM
somedude somedude is offline
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South of heaven.

So, something like an attenuator, but meant for household current?

Is that what a variac is?
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  #4  
Old 06-21-2004, 12:35 PM
saros141
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Not really... I'm talking about inside the amp, after the wall voltage has been stepped up by the transformer and turned into direct current by the rectifier. A mod that really should be done by a tech, and would of course affect the originality of the amp.

Heh heh, I get it, in that case this whole world is South of Heaven. I guess you got dibs on that as a band/album/song name.

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  #5  
Old 06-21-2004, 02:01 PM
somedude somedude is offline
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If I get it done, I'll get a tech to do it. I'm just getting my knowledge up so I can communicate my idea better.

So, after the tranny you'd install a series resistor?

If that's true, would it be possible to some kind of variable rate resistor in there? And, if I can do that, would it continue to effect the sound of the amp even when bypassed (by how much if any)?


The amp I'm looking to do this to is a Mesa 2:100 power amp. It's supposed to have the same circuit as the Dual Rectifier, except that it lacks the tube rectifier, so I can't get the sag sound I could get out of a Recto.

Here's a pic if it helps any
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  #6  
Old 06-21-2004, 02:02 PM
somedude somedude is offline
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Oh, and the band Slayer made an album called South of Heaven back in '88 or something. It's where I got that from.
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  #7  
Old 06-21-2004, 11:10 PM
rjmmusic rjmmusic is offline
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The mod I've seen puts a 100 ohm, high wattage resistor in between the rectifier output and the first filter cap. To bypass it, install a switch so that when the switch is closed it shorts out the resistor. It wouldn't affect the sound of the amp at all when bypassed.
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  #8  
Old 06-22-2004, 09:39 AM
Jeff Flowerday Jeff Flowerday is offline
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WeberVST also has a copper cap module rectifier that needs to be installed inside your amp. You can purchase them to emulate a multitude of rectifiers.

http://www.webervst.com/ccap.html
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  #9  
Old 06-22-2004, 10:33 AM
somedude somedude is offline
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Quote:
Originally posted by Jeff Flowerday
WeberVST also has a copper cap module rectifier that needs to be installed inside your amp. You can purchase them to emulate a multitude of rectifiers.

http://www.webervst.com/ccap.html
I thought those were only for amps that already had a tube rectifier that you wanted to convert to solid state?

I already have a solid state rectifier, and there's no tube socket for me to plug one of those in.
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  #10  
Old 06-22-2004, 11:38 AM
Jeff Flowerday Jeff Flowerday is offline
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Quote:
Originally posted by screamingdaisy
I thought those were only for amps that already had a tube rectifier that you wanted to convert to solid state?

I already have a solid state rectifier, and there's no tube socket for me to plug one of those in.
I'll repeat myself, there are module versions of his rectifier that need to be installed inside the amp. They replace the solid state internal rectifier, no tube socket required.
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  #11  
Old 06-22-2004, 11:50 AM
somedude somedude is offline
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Quote:
Originally posted by Jeff Flowerday
I'll repeat myself, there are module versions of his rectifier that need to be installed inside the amp. They replace the solid state internal rectifier, no tube socket required.
Thanks for the clarification, I'll send them an email and see what info they can give me on it.
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  #12  
Old 06-22-2004, 04:28 PM
vladorg vladorg is offline
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Quote:
Originally posted by Jeff Flowerday
I'll repeat myself, there are module versions of his rectifier that need to be installed inside the amp. They replace the solid state internal rectifier, no tube socket required.
Hmm,
that's quite interesting. Pretty much I can swap my Mesa's soid state rectifier with one of these bad boys and have it sag like a tube rectifier. Is this mod possible to be done by everyone or just a tech? Thanks for the tip Jeff,

Vlad
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  #13  
Old 06-23-2004, 08:42 AM
somedude somedude is offline
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FYI

Quote:
Originally posted by Ted Weber
I was told you guys make a version of the Copper Cap Rectifier that's
designed to work with a solid state rectifier. Is this true?


Yes, it will take the place of the solid state rectifier and give the amp more feel of an amp with a tube rectifier.

The amp in question is a Mesa 2:100 power amp, and I'd like to simulate the
characteristics of the 5U4 rectifier tubes normally used in a Dual
Rectifier.


That would be our WU4GB.


http://home.cogeco.ca/~screamingdais.../power_amp.jpg

Yikes.. that's quite a layout. You would need to determine if it is full wave or fullwave bridge, and then find the proper wires to disconnect to patch in the copper cap.
.
.
Thanks very much,

Ted

I sent another email asking if it was possible to wire both rectifiers in the amp, with a swich to choose between the two. Just waiting on an answer.
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Last edited by somedude; 06-23-2004 at 08:47 AM.
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  #14  
Old 06-23-2004, 09:39 AM
Jeff Flowerday Jeff Flowerday is offline
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The mod should be done by a tech. If you made a mistake you could easily take out your power transformer.


Jeff
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  #15  
Old 06-23-2004, 09:41 AM
Jeff Flowerday Jeff Flowerday is offline
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Quote:
Originally posted by screamingdaisy
FYI



I sent another email asking if it was possible to wire both rectifiers in the amp, with a swich to choose between the two. Just waiting on an answer.

Yes it could be done. How easily depends on how the inside of your amp is layed out.
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