Phase 90 Build - getting it to sound better

[ItsGiusto]

Hello all. I just completed a phase 90 build. I followed this veroboard layout:
http://tagboardeffects.blogspot.com/2014/05/mxr-phase-90-with-script-switch.html


I used a matched 4 transistor set (2N5952) I bought from general guitar gadgets for the phase transistors.The following are the mods I added:

1) A rotary switch to change the phase cap values
2) A switch to change from phasing to vibrato
3) An on-off-on switch for the "script" switch instead of the standard on-on. On the additional lug, I used a 10k resistor instead of 22k so that I could have an option for an even deeper resonance
4) A status LED

I tweaked the trimpot for a while to get it to is deepest "swish". All in all, the phaser sounds bland.. It just doesn't really get all too much of a phasing sound. It pretty much sounds like a univibe with the intensity turned way down. It's got more low end throb than high end and mid, and it's just kind of isn't all that obvious of an effect. I would like to get it sounding like a phase 90 should.

What are possible culprits for why it doesn't sound lush? Could it be due to some actual mistake I made, like a short somewhere, or is it more likely that it's just hard to dial in a good tone with the trimpot, or that some transistor isn't matched right or something?

[Focalized]

Could be any of the things you mentioned.  Maybe check the depth mod area first. I never heard of a phase cap switch.

I'd back it down to stock and get it working from there.

I built the unmodded phase 90 from the site layout and only added the bias pot outside. It gives a very good range from wishy to wowy.

I just get pretty loud ticking as with many modulation builds I've done.

[Mark Hammer]

I never heard of a phase cap switch.

I think what was meant was cap-value switching to produce a UNi-Vibe effect.

The 3M3 (or 3M9, depending upon issue) resistor off the LFO sets the width of the sweep, and the 1M resistor coming off the trimpot, sets the range of the sweep.  Often, the "lushness" can seem to vary by where in the spectrum the notches are being produced, and how far the sweep goes.  3M9 gives narrower sweep than 3M3.

I replaced the 1M fixed resistor on mine with a 1M pot in series with a 330k resistor, so that sweep  range can be set higher and lower than stock.  A lot more variety in sound that wat.

Whether all of this corresponds to what you consider "lush" is a whole other thing, though.  Maybe what you want is to get rid of the resonance/feedback altogether.

[ItsGiusto]

Thanks guys. I think it's got to be some problem somewhere, not just a "taste" thing. The effect just isn't evident at all, the way Phase 90s usually are. It must be either a bad transistor or a short somewhere.

I'm trying to debug it, so I measured voltages. I've never done this before, however. I assume that I'm supposed to measure the voltages from ground? Also, what am I supposed to actually do with this information now that I've measured the voltages? Is there some standard to which I'm supposed to compare against?


Here are the values:

Power supply voltage:   9.39v

Q1 through Q4 :
      D  4.95v
      S  5.01v
      G  1.50v

Q5: C  3.17v
      B  4.40v
      E  5.01v

IC1: Pin 1  5.00v
       Pin 2  5.00v
       Pin 3  4.95v
       Pin 4  0v
       Pin 5  4.95v
       Pin 6  5.00v
       Pin 7  5.00v
       Pin 8  9.39v

IC2: Pin 1  5.00v
       Pin 2  5.00v
       Pin 3  4.95v
       Pin 4  0v
       Pin 5  4.95v
       Pin 6  5.00v
       Pin 7  5.00v
       Pin 8  9.39v

IC3: Pin 1  5.00v
       Pin 2  5.00v
       Pin 3  3.40v
       Pin 4  0v
       Pin 5  Fluctuating from 3.70v to 5.30v
       Pin 6  Fluctuating from 4.40v to 5.75v
       Pin 7  Fluctuating from 1.40v to 8.60v
       Pin 8  9.39v


Polerized Cap 1 (10uf)  Negative Side: 0v
                                  Positive Side: 5.00v


Polerized Cap 2 (15uf)  Negative Side: 0v
                                  Positive Side: Fluctuating from 4.40v to 5.35v



Please let me know if this looks normal, or let me know how I should proceed to debug the pedal from here. Are there any other voltages I should measure?

[POTL]

Hi
that tell about the J113 transistors
In my country to find 2N5457 or 2N5485 or 2N5952, at best, can be found this doctrine smd and uncomfortable for the selection and installation =)