Phase90 - A Must Build

[mydementia]

Hi guys.
I know they say that the Phase90 from Tonepad is an 'advanced' build...but I'm here to say it's not too bad!  I threw one together Saturday morning on a PCB I made from here: http://www.tonepad.com/getFileInfo.asp?id=42 and didn't sub ANY parts (well, except that I used a 500k log pot instead of reverse log...).  Lots of parts...but a well thought out layout - very clean.  I built the FET matching circuit a few weeks ago when I knew I was going ot build this thing and found four FETs that were 'close' out of the 10 that I bought (biggest difference between two was 0.09V).  Once I got all the FET's in the right orientation (I seem to get it wrong every time...the FETs/trannies I'm getting from my local surplus store almost always seem to be oriented differently than today's production...eh...) it was phasing right along.  MUCH better than the Phase45 I built!  This one is a definite keeper.

Don't be afraid...the Phase90 is not too 'advanced' for most to build!
Mike

[Bernardduur]

I agree completely! Great build!

I did the mods of the Phase 180 (but not yet the multiple stages; that will be done later!!); great stuff!

[3/4 North]

I'm working on a phase 90, what opamp is used in the JFET tester?

[mydementia]

I used the layout in the upper right corner of this page:
http://aronnelson.com/gallery/Richard-Boop-RLBJR65/test

Looks like a TL071.
Mike

[ildar]

I'm working on a phase 90, what opamp is used in the JFET tester?

Any single opamp should do, I've got a 741 in mine.

[mojotron]

I just threw in some MPS102's and a 2n3906 (I think that was a 2n3906) and poof it worked - no jfet testing or anything  ... And, it sounds great.

[RaceDriver205]

Aye, phase90s good, but Im hoping to build the ARP Quadra phaser at some stage coz its got a huge number of stages.

[RedHouse]

I just threw in some MPS102's and a 2n3906 (I think that was a 2n3906) and poof it worked - no jfet testing or anything  ... And, it sounds great.

I'm pretty sure that's what MXR has done all these years, some how I just can't imagine an assembly line worker matching hundreds of FET's for Phase 90 boards.

[RLBJR65]

I used the layout in the upper right corner of this page:
http://aronnelson.com/gallery/Richard-Boop-RLBJR65/test

Looks like a TL071.
Mike

Cool nice to know some one uses my layouts!
Link to R.G.s article. http://www.geofex.com/Article_Folders/fetmatch/fetmatch.htm
I used a 741 in mine as well. Tried several others didn't seem to make a difference. 741 I had plenty of. Also they are cheap

Richard

[MikeH]

This brings up another question:

The build says to use "matched FETS".  Is this like buying matched tubes?  How do you buy a matched set of FETs?

[Bernardduur]

Build a FET matcher and match them

Some shops also sell matched FETs; I know the Dutch Newtone does

[ildar]

I built a Phase 45 and actually matched the FETs (2n5486, iirc) at first, but it did not phase the signal. Matched a second pair, still nothing. Out of desperation, frustration, and lack of sleep at 1am, I threw in a pair of unmatched J201s, and it worked beautifully.

[mojotron]

I just threw in some MPS102's and a 2n3906 (I think that was a 2n3906) and poof it worked - no jfet testing or anything  ... And, it sounds great.

I'm pretty sure that's what MXR has done all these years, some how I just can't imagine an assembly line worker matching hundreds of FET's for Phase 90 boards.

I agree, I was hoping it would just work and that MPS102's were a bit more consistent than J201s. I'm not sure if that's true, but it worked for me.

[markm]

I built a Phase 45 and actually matched the FETs (2n5486, iirc) at first, but it did not phase the signal. Matched a second pair, still nothing. Out of desperation, frustration, and lack of sleep at 1am, I threw in a pair of unmatched J201s, and it worked beautifully.

I had the same issue with my 45 and I must say the J201's are perfect.
It's my favorite Phaser even though it is overshadowed quite often by the 90.

[mydementia]

I built a phase45 a couple months ago - the one from Torchy's archive on indyguitarist...has the univibe mods.  Even after a friendly forumite sent me a matched pair of FET's (thanks jrem) it still wasn't all that impressive.  I'm going to have to dig that circuit out of my box of 'misfit' circuits and throw in a couple J201's and give it another audition... might even try some J201's in the phase90...but it's so sweet right now...

Mike

[ildar]

I built a phase45 a couple months ago - the one from Torchy's archive on indyguitarist...has the univibe mods.  Even after a friendly forumite sent me a matched pair of FET's (thanks jrem) it still wasn't all that impressive.  I'm going to have to dig that circuit out of my box of 'misfit' circuits and throw in a couple J201's and give it another audition... might even try some J201's in the phase90...but it's so sweet right now...

Mike

Well, as far as versatility goes, the 45 is pretty much a one-note Johnny. But, the one tye of sound it has is very nice imo. I guess the key is hitting that 250k pot just right to get the sweet spot. I use a panel mounted pot so I can occasionally change the setting for a nice mellow buffered tone.

[RaceDriver205]

I built a Phase 45 and actually matched the FETs (2n5486, iirc) at first, but it did not phase the signal.

I had the same problem, you should have flipped the FETs around!

[ildar]

I built a Phase 45 and actually matched the FETs (2n5486, iirc) at first, but it did not phase the signal.

I had the same problem, you should have flipped the FETs around!

Did that, trust me, nothing worked until I semi-blindly put the J201s in.

[mydementia]

What are we doing matching FETs for our phasers anyway? 

I popped a couple J201s into my Phase45 and NOW get a nice deep phasey/wooshy/circular thing going on...did the same in my Phase90 and the effect is more pronounced there as well. 

So...to the electronics wizards...
What are we doing (losing?) to the circuit(s) when we blindly put in J201's?

[ildar]

What are we doing matching FETs for our phasers anyway? 

I popped a couple J201s into my Phase45 and NOW get a nice deep phasey/wooshy/circular thing going on...did the same in my Phase90 and the effect is more pronounced there as well. 

So...to the electronics wizards...
What are we doing (losing?) to the circuit(s) when we blindly put in J201's?

I just read a post from one of the gurus here that stated J201s aren't supposed to work at all in the Phase 45 or Phase 90, but there are a number of people (including the aforementioned guru) who have said they do work, and work well. What gives?