MXR Phase 100

Xlrator · December 17, 2003, 05:01:48 PM

I am planning to build this box. I searched this site for any posts about it and found very few. I just wanted to see examples, hi-res pics, even any trouleshooting of the project.

I'm building the one on JDSleep's site. This will be my fourth box. FuzzFace, PT-80, and Gaines Noise Gate in that order. The noise gate doesn't work and have given up on it.

Just wanted to know some background info, skill level, and if it would fit in a Hammond 1590BB enclosure like my PT-80. I want to keep everything in the same case from now on.

Thanks
Ben

petemoore · December 17, 2003, 05:26:13 PM

I know the 90 is///
You will have to match Jfets if this is the case...Look to GEO for Jfet matching info.

BillyJ · December 17, 2003, 07:38:29 PM

It's a big build. I built it but haven't matched the fets yet and probably have some other bugs to work out.
Peter what do you mena the 90 is///?

Joep · December 17, 2003, 07:42:33 PM

The Phase100 uses opto stuff, no fets. I believe the VTL5C3/2's

petemoore · December 17, 2003, 08:05:56 PM

I thought the 100 was like a 90 with more stages...
if theres no Fets then matching isn't necessary.

petemoore · December 17, 2003, 08:07:42 PM

Never again !!! I was half cross eyed for days lol
I don't know what type build you'r planning but even small phazers like MXR 90 are difficult to perf...can be done but whew...

BillyJ · December 17, 2003, 08:10:22 PM

There are five 2N5088's in mine do these not need to be matched?
Shoot if not I should poke around with it some more....
There are 3 VTL5C3/2's as well but I could have sworn I read more than once that the 100 needed to be matched....of course I don't much so :wink:

Xlrator · December 17, 2003, 08:16:34 PM

BillyJ did you follow the plans exactly? Did you etch your own board? I was thinking of buying a board off JDSleeps site to save on headaches.

I went through all my stock and have a list of parts to get from Mouser.

Ben

BillyJ · December 17, 2003, 08:16:49 PM

Only a sick man would perf the phase 100 in my opinion LOL! :shock:
I did the one at GG and I still had a time getting it together.
Now if only I can get it to work someday that would be very nice. :lol:

Xlrator · December 17, 2003, 08:22:19 PM

Does the board fit inside a 1590BB?

BillyJ · December 17, 2003, 10:36:44 PM

I looked in some previus threads I guess it doesn't need to be matched!
I should think it would fit in a BB as that is what they are originaly in.
I did etch my own. I forget what I was able to get out of it but I shelved it becaue I thought I needed to match th efets and thought that was my issue...so I gues i need to look at it again.

Fret Wire · December 18, 2003, 12:48:32 AM

I've got an old block logo 100 with the 1/8" dc jack that I got for nothing because it doesnt phase, just passes the tone straight through. I had these photos laying around. When I get time, I'll do some high resolution pics. BTW, is that a diode on the DC jack?

http://f1.pg.photos.yahoo.com/ph/mw252001/album?.dir=/Phase+100

jsleep · December 18, 2003, 02:46:22 AM

The board will phyically fit in a BB box (sideways barely), but unless you can get that low profile rotary switch and be very creative, you'll have a time getting it in there with all the off-board stuff too.

JD

Mark Hammer · December 18, 2003, 11:02:33 AM

I misunderstood FET-matching in phasers for years, thinking that what was critical was that they all had to have a similar resistance at any point in the sweep cycle. Apparently, the need for matching has more to do with whether they all sweep at the same time by the same proportional amount, not what their current vaue is during the sweep. Phaser circuits can tolerate a fair amount of mismatching with respect to the variable resistive elements and still produce satisfying tone.

Mike Irwin has demonstrated some LDR-based phasers to me that have ridiculously steep notches, and these are using LDR's out of a parts bin with only modest matching attempted. The Uni-Vibe uses only one light source for 4 LDRs, which hardly leads to any sort of precision matching. I guess one of the things about using LDRs is that unless you have them plastered up against a halogen light on full tilt, there is usually a little more sweep left in them so it is rarer that one hits the same sort of wall that occurs with phasers where one can't sweep any more where the others continue.

If I've understood it correctly, the other aspect of FETs vs LDRs in phasers is that the signal ceiling is set by the "weakest" FET in the circuit. In the case of LDRs, there is no such ceiling. The P100 can be expected to be cleaner than the P90 or P45, in that regard.

The long and the short of it is that a set of 3 suitable dual Vactrols is fine for a Phase 100 clone. You could also use 6 single Vactrols but that gets sort of bulky real fast.

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MXR Phase 100