Phase Evolution!

[frequencycentral]

Which resistors did you sub with different values? It's important that all the 10K are 10K for example.

[El Heisenberg]

Alrite i got it workin! I think my breadboard is messed up.

Only thing i did dufferent from original phase 45 schen (without mods) was the led. I used two 4k7 resistors.

Now to put together the two extra stages...

[El Heisenberg]

I substituted the 3M9 resistor with a 3M3. Only thhing else i have is 4M7 and 1M. Used two 8k2s for the 4k1 resistor. Besides that, its all according to the schem. Three tlo72s and 4 2n5952s.

I went ahead and breadboarded the extra phase stages. I think that theres less phasing because the fets arent matched. Might be my imagination. It works tho. Im not sure about the blinking LED. Is the resistor supposed to be 24k or 2.4k?? I think it has an effect ob the phasing when i switch them out. Maybe my imagnation again. Guess i gotra go to radioshack and stuff all the fets they have ib my pocket! No way im paying 3 bucks for one j201 or mpf102.

[El Heisenberg]

Also it seems to act weird with voltage. I use rechargable batteries so they run out a little fast. When it was the original phase 45, the phasing stopped at like 6 volts. When i put the extra stages in, it stopped working at like 8.5! Maybw its my batteries. I then tried a duracell and it worked great.

[jacobyjd]

dude, order some from the store--you get a whole crapload of 'em.

[El Heisenberg]

If i could i would. I know about the internet! You need a credit card or a bank account.

[frequencycentral]

I substituted the 3M9 resistor with a 3M3.

That 3M9 is pretty important - have you a 560K or a 680K that you can put in series with the 3M3?

[panterafanatic]

If i could i would. I know about the internet! You need a credit card or a bank account.

that is surely incorrect. i have used SBE many a times. paypal the first. then switched to postal money orders. i do the sam for trading. a little riskier than paypal but i have no B/A so the post office is my friend. its $1.10 per money order. i suggest doing $50+ orders from a business.

[El Heisenberg]

But i got no money either lol!

Why is the 3M9 so important? I already triwd putting a 470k in series with it (its all i got) and it didnt sound like it did much.

[frequencycentral]

The 3M9 sits between the LFO and the FET VCRs. It's value defines how 'high up' the phasing goes. A lower value than 3M9 will mean that all the good stuff is still happening, but at frequencies above your hearing range. You pet bat will adore it however.

[El Heisenberg]

ugh, ok, ill try the 3m3 with 470k and 150k in series.

Could u clear up the led thing for me? Im not sure what the rwsistor is supposed to be. 24k or 2k4? It looks like 24k but the led is really dim. Does this affect the sound much?

[frequencycentral]

I didn't bother with the flashing LED, as I'm wary of flashing LEDs causing audible ticking as they draw current when turning on and off. Besides, who needs to 'see' the speed of the LFO when you can hear it?But the resistor value is certainly more likely to be 2K4. The flashing LED really is optional, and wasn't included in the original MXR P45. It won't affect the sound in any way, apart from if you do hear ticking, the LED turning on and off is likely to be the culprit.

[El Heisenberg]

I used a 4.7 zener diode but i only measure 3.7 on the negative end of the diode. Is it an error in the circuit or wut? I got it from "the shack", package said 4.7!  Ive seen schems that say 4.7 some say 5.1.

[El Heisenberg]

Sorry about all the questions, i appreciate ur help. But can i use MPF102s for the FETS? Irs all they got at radioshack now. Guess they stopped carrying J201s.

[frequencycentral]

I used a 4.7 zener diode but i only measure 3.7 on the negative end of the diode. Is it an error in the circuit or wut? I got it from "the shack", package said 4.7!  Ive seen schems that say 4.7 some say 5.1.

Yes I've seen schematics with 4.7v and 5.1v too. Your measurement of 3.7 volts is fine, as the zener in combination with the 10K resistor right above it form a quite stable voltage divider. Don't expect it to read the same voltage as the zener you use - it won't.

I don't think MPF102s would be a suitable sub for the 2n5458s, as the MPF102s Vgs would appear to -8v, and the circuit is probably looking for -0.8v.

Worthwhile reading: http://www.geofex.com/article_folders/fetmatch/fetmatch.htm

[frequencycentral]

A quick montage of clip, nothing special, just a bit of noodling with a few different settings, the dirt pedal at the start is ny very own Promiscuous Girlfriend:

http://dl.getdropbox.com/u/967492/Phase%20Evolution.mp3

Signal path:

Squier Telecaster Custom (bridge humbucker)   >>>   Promiscuous Girlfriend (just on the dirty bits)   >>>   Phase Evolution   >>>   Shure SM58   >>>   >>>   Event Gina 24 Soundcard   >>>   Wavelab

[Renegadrian]

Gents, need some help here...built the normal version using the layout below. The sound goes thru the circuit (no sound if battery disconnected) but got no phasing. Tried several j201 and 5457. not matched, but some phasing should occour, or luck and several tries could lead me to one almost matched pair.
Anyway, I got unaffected sound even with NO trannies in their sockets.
Got some clues?! I can post voltages if needed. Please help me phase!!! 

[frequencycentral]

Ok, a few things before we get onto voltages. Did you remember to add R23 on the copper side of the board, and are you sure it's in the right location? Does the LFO appear to be working? To test it hook up your DMM to one side or the other of R22, you should measure a moving-up-and down voltage (!). You could even hook up a LED to the LFO as per J.C.'s schematic, to assure yourself that the LFO is working. You could also try wiggling the bias control manually, as this would imitate the action of the LFO. With only 2 FETs in the normal version, the matching would be even more critical, so try matching your FETs using the FET matcher at GEOFEX. With my (4 stage) version I find the deepest phase is with the bias at the mid point and the mix control at 2 o'clock. I find the best way to test phasers is with a nice fat distorted guitar sound - it gives those notches something to eat away at, it'd sound much more subtle with a clean guitar. OR maybe, like me, you're finding 2 stages is just too subtle - I rememeber when I first built the 2 stage version I thought it didn't work when I first hooked it up, but a little knob tweaking just proved to me that it did work but it was very subtle.

[Renegadrian]

Did you remember to add R23 on the copper side of the board, and are you sure it's in the right location?

Not on the copper side, but it is as it should be, one leg at IC1 pin7 and the other at IC2 pin2 with R11

Does the LFO appear to be working? To test it hook up your DMM to one side or the other of R22, you should measure a moving-up-and down voltage (!). You could even hook up a LED to the LFO as per J.C.'s schematic, to assure yourself that the LFO is working.

Put a LED's legs between R19/R20 and ground (it should be correct following the schem) but no, I got it always lit.

thx for replying Rick!

[frequencycentral]

Put a LED's legs between R19/R20 and ground (it should be correct following the schem) but no, I got it always lit.

As this is an unbuffered LFO, a LED without a series resistor may be loading down the LFO enough to stop it oscillating (maybe ?). Try adding a resistor.

Did you try waggling the bias pot? Let your fingers be the LFO, if the LFO isn't working you'll still get phasing by wiggling the bias pot.