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Boss PH-1 Phaser-LED?

7/25/2000 3:24 AM
Matt W.
Boss PH-1 Phaser-LED?
Silly question... Is the LED on the Boss PH-1 supposed to go off when the unit is on?  
7/25/2000 12:29 PM
CJ Landry

The LED goes off when you do not want the effect to be activated and the guitar cords plugged into the in and out jacks. It should be on when the phase sound can be heard.  
7/25/2000 4:53 PM
Matt W.

Thanks CJ. I contacted the seller who said that it's normal for that vintage(earlier PH-1 with phenolic board) for the LED only to turn on during switching, but not when pedal in use. On the unit itself, the instructions that say to keep unit unplugged when not in use also mentions that the light will come on when pedal depressed, but it doesn't indicate if it should stay on. Same exact wording on my other Boss pedals(newer), but all of them keep the lights on. I just need to know if I got a lemon. Anyone have a schem for this unit?  
7/25/2000 11:18 PM

I tried an old PH-1, and the LED did the same thing. Only lit up when the pedal was depressed. The seller is correct. No lemon here.  
7/26/2000 12:27 AM
Matt W.

Thanks, Frank and all.  
BTW, anyone know what that little pot does inside the unit? I'm guessing it has to do with effect intensity or such...  
I'm planning on changing out the 'lytics this weekend, and probably playing with that pot after marking where it's at presently.  
7/26/2000 3:04 AM

Matt, I own an original PH-1 and the LED stays on when the pedal is in use of the phase. The LED is off when the pedal is pushed to disingage the phasor effect. Bye the way, I think these boss PH-1s are better than the MXR phase 90. I had the old phase 90 and the boss has more control. Also to me the boss has a sort of leslie effect to it that I dig. I hope this helps.  
7/26/2000 5:50 PM
Mark Hammer

The last thing any pedal manufacturer wants is returns on products because a portion of the range of a given control produces a result that sounds screwy or unusable to the consumer.  
Many commercial phase shifters include a trim pot for setting the ceiling on regeneration/resonance. It is usually set by putting the chassis-mount resonance control to maximum, and adjusting the trimpot so that the pedal is just on the edge of oscillating (too much resonance will result in oscillation).  
Why is it needed? Easy. Use 5% tolerance components, and sooner or later some combination of critical components will be at the upper and lower limits of their tolerances, and the circuit will misbehave. In the case of a 4-stage phaser, there are enough 5% tolerance components in between where the resonance signal is tapped from, and where it is feed back to, that it warrants setting a trimpot, even though that undoubtedly adds to production costs.  
Of course, if you know what you're doing, and what to expect, there is no reason why you couldn't set the max-res trimpot OVER the threshold for oscillation and use that as an effect in itself. I'm sure you wouldn't hold it against BOSS. :)

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