Phase90 - A Must Build

[sta63bmx]

I dunno, but I'm going to try them.  I built a Phase 45 as the last effect from the very first batch of boards I etched, and I honestly thought it kind of blew. lol  Then again, I had just finished an Electric Mistress build, and the lack of tweakability combined with the fact that it wasn't an EM, maybe I just wasn't ready for it, I dunno.  I'll get it out soon and give it another whirl.

I haven't touched a soldering iron since mid-August when I was desperately finishing up a bunch of equipment at the last minute.  I've got a blackface Princeton on my bench, though, and after that maybe it's time to go ahead and start up another project.  If the Phase 45 doesn't work out, I may try a Phase 90.

[mdh]

Hey Mike, thanks for the heads up. I had been wanting to build something like a phaser, and had been considering ROG's Phozer (which I might still build). Because of this thread, I built a Phase 90 today, and I'm very happy with it. I used J201s and haven't yet bothered to match them, but it's definitely phasing. I'll probably breadboard R.G.'s FET matcher next weekend so I can evaluate whether matching the FETs results in a "tighter" sound, whatever that means.

Francisco's layout is excellent. It's very tight, but not exactly cramped. I'm not sure if I'll be able to fit the whole thing into a 1590B, but I'm definitely going to try. Great stuff!

[Fuzzy-Train]

I'm giving the phase 90 (tonepad layout) a shot.

Is this true that J201's will work with this, and that there's no need to match 2N5952's to get phasing?

Thanks for your time and help.

[mars_bringer_of_war]

Well, it's been proven that the circuit can work without matching the jfets, but for optimal performance you should match them, so long as they're within correct operating range.

[vanessa]

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.

Ditto! For some reason those J201's make this one really come alive. 

[raulgrell]

How does the 45 compare with the 90 sound-wise?

I've been debating on which one to make for quite a while... input?

[oldrocker]

I may have to try some J201's in my Phase 45 also.  Although I think it sounds darn good now.  I like its smooth phase sound that's not overdone. 
I also recently changed my EasyVibe from a Univibe phaser to a Phase 90 type phaser by replacing the Univibed configured caps to all .01uf caps. (No Jfets to match.)  Although I haven't compared it to the Phase 90 yet and haven't been able to get a feedback circuit working in it yet.  The Easyvibe sounds good as a stand alone phase shifter IMHO.

[vanessa]

How does the 45 compare with the 90 sound-wise?

I've been debating on which one to make for quite a while... input?

I've built a P90 that I can switch out 2 stages for a P45 like phaser. I really have come to appreciate the P45 mode more than the P90. I like having the P90 stages (just in case), but I'm finding that I use them less and less. I might even build a true P45 and forget all about the P90  down the road. Then I would mod the heck out of the P45! 

Van

[vanessa]

Has anyone ever tried a Maestro Phase Shifter PS-1?

[R O Tiree]

In the Phase90 I have been mending, the FETs I pulled out had a Vgs figure of 1.15V. Mind you, I think they got fried by the owner when he tried to do the Script mod with a pair of scissors... I suspect he reversed the polarity when he put the battery connector back on. (Yes, I know it's supposed to be idiot-proof, but you can still do it if you put it on off-centre.) The bunch (130) I bought from the States recently were mostly in the range 1.30 to 1.80V. There was only one at 1.16 and the next was 1.24.

Why is this important? Well, the Zener diode that sets Vref is a 3.3V one as stock. Next is the voltage divider with the trim pot, so you can adjust the centre-point of the voltage coming out of the LFO to the FETs. If you stick FETs with too high a Vgs in there, there's just not enough range in the trim pot to get them to work.

Fixes are as follows:

Adjust the values of the 2 resistors either side of the trim pot, so you can get it in range.

Swap the Zener out for a higher value, which raises Vref, which puts the pot range back in range of the FETs.

So, stuffing a few un-matched J201s in there is why the circuit is suddenly working. It's not working as well as it could, perhaps, but it's definitely phasing.

Now, if someone with more knowledge than I about opamp oscillators could have a look at my question in "Schematics & Layouts -> Phasers/Flangers/Chorus" I'd be most grateful.

[rasco22862]

I´m agree, an awesome project. I have a little volume drop when FX is on, what can i do?

Thanks

[Fuzzy-Train]

That's great news people.

Did anyone else have problems finding a 15uf elctro cap? I couldn't seem to find one on SB or futurlec... maybe a nice forum member could send me one if possible??? PM or E-mail me if you can spare one.

rasco22862: Check the tonepad site.... I think they have something on inceasing decreasing the level/gain.

[rasco22862]

Ok, thanks but if i want to remove the volume drop, i should put a 180k resistor instead 1 or 2?


Thanks

[Fuzzy-Train]

I think it's #2, the site says the resistor that connects between the collector and base of the PNP transistor. 120k to DEcrease 180k to INcrease... so you'll want 180k.

http://www.tonepad.com/project.asp?id=7

[oldrocker]

Sorry for the highjack and change of the subject.  I tried some J201's in my Phase 45 not matched.  Since they weren't matched this might not be conclusive.  It phased OK but there seemed to less adjustment on the pots.  I also couldn't get the slight vibrato selection that I could achieve with matched 5952 Jfets.  The 201's gave a more choppy sounding phase which was probably do to them not being matched.  The 201'a sounded more like a Univibe in some ways though.  I also tried some MPF102's also with interesting results.  Again without matching them.  These were what I had in my P45 originally.  They worked and sounded good.  I still had trouble dialing in the slight vibrato but the phase portion sounded decent.  I went back to using the matched 5952's since it gave me more versatility when adjusting the pots but other Jfets can be used with nice phasing depending on what sounds good to you.

[Fuzzy-Train]

^ that cool. It's good to know that the 201's sound more like a univibe because I wanted a more cost and enclosure efficient phaser and didn't want to spend a crap load on all the parts needed for the univibe.

Has anyone done the intensity mod everyone was talking about in the build reports for the tonepad phase 90? They say to wire a 500k pot in series with the 1m resistor... I'm just not sure how to wire it... I did a little diagram in paint, can anyone verify or correct it for me.



I think it's wrong, but I'm just not sure.

[Fuzzy-Train]

^ Anyone???

Thanks in advance for the help.

[mdh]

Well, that certainly is a 500k pot (wired as a variable resistor, which is the only reasonable thing to do in this case) in series with the 1M resistor, so it fits the description fine.  I've never tried that mod, but I've noticed that R.G.'s "Phase 180 Plus" has a 1M pot labeled "width" in place of the 1M resistor.  Personally, I would just experiment with combinations of pots and fixed resistors that add up to something close to 1M when the pot is at its highest resistance.

[Fuzzy-Train]

Cool... thanks for the help. I'll get a few pots and see what I like best.

Thanks again for the help.