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Mu-tron Bi-phase questions


 
8/2/1998 7:05 PM
eric p
email
Mu-tron Bi-phase questions
Hi everybody,  
 
Some time ago I was granted custody of a thoroughly non-functional Bi-Phase. I felt the responsible thing to do was bring it back to life, especially after people kept seeing it in the corner and saying "those are really wild, etc.". After poking around for big, obvious troubles I turned it over to a local tech.  
 
Four IC's, several weeks (but only two hours of actual labor), and $160 later it works, but I'm wondering what all the commotion is about.  
I also had to spend $35 for the original dual footswitch, which was probably a lucky find, actually  
 
What I've got is a very flexible 70's phaser, two I guess, but I'm not getting a deep swirling thick underwatery thing I was thinking it might do. The sound is more ringy than 'vowely'. The B channel is much stronger than the A channel. The A channel robs me of a lot of tone when engaged. The B channel is less tone destructive. The A channel also drops in level a bit when engaged.  
 
Are the two phasors supposed to sound of different quality?  
 
Are there internal trimpots for output level or something? It was a while ago when I opened it, and I don't recall. I do remember that it was rather tricky with that ribbon cable inside.  
 
What sort of sounds could I get if I could find (or build?) the sweep pedal controller?  
 
I've never used another unit, so I don't really know if I'm missing something or if it's just not my bag. I'm very good at getting good tones from the right things, otherwise.  
 
So many questions, please have at it!  
with thanks,  
eric
 
8/3/1998 6:45 AM
CJ Landry
email

Ok, a few things about the Bi-phase,  
 
1. It was made famous by Bootsy(can't remember his last name) and Funkadelic in the 70's.  
 
2. The real cool feature of the Bi-phase is the fact that you can run channel A into Channel B so you have 2 phasors running at the same time and you get some really wierd / synthesizer type sounds out of the Bi-phase. IT is a cool pedal, but it has its place in certain songs. It is not like a distortion pedall where you can play it in almost all songs.  
 
3. I have not seen BiPhase yet that did not work without the footpedal. I made one for a guy in Florida and he was pleased. I also included a sweep pot in this foot pedal so the phase rate could be adjusted with your foot.  
 
.....Are the two phasors supposed to sound of different quality........  
 
Yes, they are different. The B channel is much stronger and more definitive.  
 
.../.Are there internal trimpots for output level or something? It was a while ago when I opened it, and I don't recall. I do remember that it was rather tricky with that ribbon cable inside......./  
 
Yes there are a few, but I do not recommend adjusting them unless you are confident in what you are doing.  
 
/What sort of sounds could I get if I could find (or build?) the sweep pedal controller? /  
 
As mentioned earlier, I built a foot controller with 2 stomp switches to turn Channels A & B in and out and also a slide switch that you could sweep with your foot to control the rate. I think it sounded real cool and my customer in Florida said he loved it!  
 
Hope this answered some questions,  
CJ Landry
 
 
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8/3/1998 11:08 PM
Hi
email

Bootsy Collins.
 
8/4/1998 10:34 AM
Mark Hammer
Another good place to listen to Bi-Phase sounds is in some of the early Steely Dan albums. E.g., the song Green Earings off the Kid Charlemagne album is a wonderful piece of bubbly phase magic.  
 
As for Bootsy Collins (and his fabulous star-shaped sunglasses and bass), I was always under the impression that he was a Mutron III kinda guy, although I may be seeing him in too limited a light.
 
8/4/1998 3:43 PM
eric p
email

Thanks CJ for some clarifications, particularly the difference of intensity between A and B "phasors" (they spell it with an 'o' and it cracks me up - somehow it's more sci-fi than "phaser").Since posting I have come up with a few fascinating sounds, but I'm not sure I'll actually use it that much. I got a big cash offer for it from a noise band dude, but since my girlfriend heard it yesterday she has forbidden me to sell it. She wants to use it on her vocals, that's the kind of gal she is - thank God.  
 
CJ, can I simply attatch an expression or volume pedal to the correct pins on that funky five pin jack, or is there more of a circuit involved? I've found that modulating the phase rate with the knobs produces some lively effects. Does the pedal control more than one rate (A, B, A/B)? Can you assign the pedal to A, B, etc?  
 
As far as Bootsy goes, one of his more trademark tones was with the MuTron III envelope filter, but I've had several players bring up his name when they see the Bi-phase.  
 
I've got that Steely Dan LP, I believe it's "The Royal Scam" I really dug their music and it will be fun to pick out the effect. Back then the tones would just seduce me and I didn't think about how they were produced.  
 
-eric
 
8/5/1998 7:39 AM
CJ Landry
email

Of the 5 pins on the foot pedal jack, they consist of in no particular order,  
+15vdc  
Channel A enable  
Channel B Enable  
one side of the reostat  
other side of reostat (I think I spelt that right)  
 
Shorting the +15 to Channel A or B turns each channel on induvidualy or simultaneously and I just connecting a pot across the remaining two pins will adjust the rate.  
 
However, in different settings of the selector switches, the foot controller rate pot will either adjust the rate of the sweep or generate one sweep with the rate at which you sweep the foot control. Much like a wah wah. The volume pedal thing should be OK. You can get some really cool sounds using the foot control rate pot as a wah wah type thing, especially when both channels are running together.  
 
Yes, this is a collector pedal. Having a Bi-Phase is like having a Mint condition TS-808 or original Mutron III.  
 
I would not sell it  
 
CJ Landry
 
8/5/1998 8:14 PM
eric p
email
Anybody seen the sweep pedal?
Fascinating. I can see how working one long sweep with the pedal could sound pretty wild.  
 
I'm wondering how the original sweep treadle interfaces with the unit when the footswitch is using the entire jack (physically, if not electrically) Does the treadle replace the dual footswitch, possibly having two buttons of its own or do you use both devices somehow?  
 
I'm thinking I'll make a harness that shares the plug and has the volume pedal in/out 1/4" jacks at the end of the short harness, then use basic 1/4" patch cables to get to the vol. pedal.  
 
BTW, I believe it's "rheostat". And I don't think "spelt" is a word, but I like it.  
 
< other side of reostat (I think I spelt that <  
 
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