Schematic needed ...BOSS PH-1R

[Kent S.]

Does anyone have a schematic for the BOSS PH-1 and/or PH-1R Phaser (4 stage, the R had a resonance ((feedback)) control added), as I have an old PH-1 and would love to convert it to a PH-1R .... anybody? The board is one of the older darker ones and would be very difficult to light boax and trace. Thanks.

[tonda]

Hello, I need BOSS PH-1r schematic, I have one in mint condition, BUT when it´s ON, the volume is increased, I need to modify that pedal. I Have schematic for PH-1, bud this is different, PH-1r uses different opamps (4558).
Please help.  Tonda

[tonda]

again:

the same problem, plese help:

"I am looking for a BOSS PH-1r schematic. I really love that phaser, but there is a volume boost when engaged which makes it unuseable for me. I know some of you say "don't tamper with it, you'll lose its value" well for that I don't care because I am keeping this phaser, I just want to make it more useable. Would it be possible to find what could help to reduce the volume boost ?"

[boyersdad]

Rather than modding the pedal, you could simply modify an old patch cable. Just splice a 100K audio taper pot into the tip lead, use it between your pedal and amp (or pedal and the next effect etc) and voila! Instant volume control.

This method is nice because you can always use it for other things too.

[Zero]

I'd be interested in a schematic as well...
I just bought 2 PH-1R's off ebay ... accidentally! I only wanted one, but it seems no one else was interested

Let me know if you get the schematic.

@tonda: About your volume issue:
You could just follow the signal path from the output jack to the bypass and then back to the effect output (use an audio probe).
There, you could add a resistor in series. I don't know what it looks like inside, but maybe there's already a resistor in the signal path you can exchange or a cap in the signal path from which you can desolder one leg and fit a resistor.

Rather than modding the pedal, you could simply modify an old patch cable. Just splice a 100K audio taper pot into the tip lead, use it between your pedal and amp (or pedal and the next effect etc) and voila! Instant volume control.

The problem with that is that volume will be decreased regardless if the effect is on or off... Tonda just wants to adjust the volume when the effect is on.

[George Giblet]

A PH1r would be ideal but you don't have to trace much.

Take the PH1 schematic.  Trace around the output opamp.  Check that there are two JFETs around the output opamp like the PH1 - i they are there you are on a winner. One JFET switches in the Phase-Shifted signal the other adjusts the gain.   All you need to do is trim the gain resistor (R18 5k6 on the PH1 schematic).  If the output circuit is like the CE2 or BF2 with only one JFET then correcting the gain isn't a simple value change.