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help identify old effect

1/25/2001 2:38 AM
help identify old effect
I built an interflax harmonic perclater thinking it was what I was lookng for. Turned out to be a great fuzz, just not this.  
Looking for a box, originally made in chicago but not sure by who. Called a Harmonic Percolatoror maybe harmoic exciter, came in a big box with sliders, not knobs.  
It sounds a little bit like an octave, but is definitley not an octave effect. I'm fairly certain Steve Albini used one for his guitar on the Shellac records.  
Anyone have any idea what I'm talking about?  
Ever seen the schematic?  
1/25/2001 5:45 AM
Are you *sure* it isn't the Harmonic Percolator?
Although you said the Interfax Harmonic Percolator is not what you are after, it *does* fit the picture and description posted at:  
Go to this URL and check it out. It gives some tips on how to use the Harmonic Percolator for use as more than a simple fuzz, and there are even some soundfiles to download (although I haven't listened to them).  
Note: If you can't get there by going directly to this specific webpage, start at, click on the "Gear" link at the bottom, then scroll down and click on the "Interfax" link to find the Percolator.  
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1/25/2001 6:02 AM
Re: help identify old effect
huh! thats it.  
I built the schematic on arons site and the end product I got most certainly does not make the sound I expcted to hear fromt it. The schematic produced, through my tinkerng, a pretty straight forward fuzz, that is really very cool. But it is a really straight forward fuzz.  
The effect I have heard is more towards the end of something we'd expect from Zvex, its a pretty severe warping of the guitar signal in the same vain as an octave fuzz, but somehow different.  
could I be more vague, bah!  
1/26/2001 1:50 AM
Sean Costello

The Interfax Harmonic Percolator definitely IS the fuzz that Steve Albini uses on Shellac, and for most of his career (Big Black, Rapeman). However, the schematic may not be entirely accurate, as the types of transistors used were not specified. I remember reading somewhere (perhaps an ad for the reissue in an old Vintage Guitar magazine?) that the Percolator used both a germanium transistor and a silicon transistor. Perhaps the PNP transistor in the schematic is yer standard Fuzz Face germanium transistor.  
Also, the Percolator is not the most distinctive part of Albini's sound. Some of his tonal ingredients:  
- Bi-amping. Part of his signal goes into a Fender Bassman head that powers a 4x12 cabinet. The other part goes through some weirdo transistor preamp PA thing, into a full-range cabinet with a 15" speaker and a horn tweeter. Grit probably comes from Bassman, clean bass and treble from transistor PA thing.  
- Lots of presence used on Bassman.  
- Metal pick, metal guitar (Travis Bean).  
- Pick noise, string noise as important as notes.  
The Percolator is only used on a few songs (Rambler Song, the loud part of Wingwalker) - basically where the guitar sounds like a crazy fuzzed feedback thing.  
Sean Costello
1/26/2001 4:02 AM

who's got one of these things??? Gotta figure out what the transistors are!  
Everytime I have seen shellac, he's used that silver boos harmonic exciter on stage.  
As far as his guitar sound goes, I'd say it has more to do with a coles 4038 than anything else in his rig.  
As for the bassman, the one in his head is from a blackface, and he's only using the preamp, the power amp for his amp is solid state, you've got it backwards. Well, this is at least what he was doing in shellac in 1994 or so, I think thats the last time I saw them.  
perhaps his tone comes from the fact that he wears his guitar strapped around his waist... Thats about the oddest thing I have ever seen anyone do...  
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