PT-80 Echo - Noisy

[antojado]

Hi Ya'll,
I just finished building a pt80 and it seems to me that it's a little noisy. The noise it's making is a shhhhhhh sound. Not real loud, less than a fuzz pedal, but noticable. It's pretty constant, but does vary with changes in the level. Also, when a chord or note is hit it seems to diminish, but comes back up as the input decays. I built the millenium version, but jumpered the 12v reg. and I'm powering it with a voodoo lab pp1. I didn't use sheilded wire for the input / output wires. For the 1mF caps I used miniture box style caps that small bear sells (they don't really fit the pcb too well). I'm wondering if this noise is consistent with this pedal or not. If not, aside from bad solder joints and unsheilded wire, are there any specific parts I should check out?

[zjokka]

I built the millenium version, but jumpered the 12v reg. and I'm powering it with a voodoo lab pp1. I didn't use sheilded wire for the input / output wires.

-the box caps can't possibly be the problem, but why did you jumper the regulator?
-if you have shielded wire at all, I would use it on in and output before anything else. you didn't use BARE wire?
-what voltage are you actually feeding it?
-is the guitar you're using shielded and stargrounded?

Will go back to mine and check, but hard to tell how much hiss?
thought mine was pretty clean though.

zj

[antojado]

Thanks for the reply, zjokka. Yeah, I don't think the box caps would be the problem; I just thought I mention everything that was sort of different.

I jumperd the regulator because I'm running it on 9v. At least that's what the build notes in the project file said to do if not using an 18v adapter. I don't know if the noise level is different when using 9v instead of 18v.

Of course I didn't use bare wire! I'm probably going to pick up some shielded wire and try it out. I might try moving some of the wiring inside around to in case the routing is part of the problem. My guitar isn't shielded and it can be pretty noisy at times, but it's not causing this. This hiss is there whether the guitar volume is up or not.

[markm]

I jumperd the regulator because I'm running it on 9v. At least that's what the build notes in the project file said to do if not using an 18v adapter. I don't know if the noise level is different when using 9v instead of 18v.

Interesting.
I didn't know this....perhaps I should go and read the build notes!!

[bdevlin]

I have a noise issue with mine when I put it in front of anything with any amount of gain or distortion.  It only cleans up when I put it in front of a clean amp setting.  Off topic, but mine also draws over 100mA (yikes).  I built a version with the millenium and a charge pump for the 18 volts.

[blanik]

i did the Rebote 2.5 instead of the PT-80... been using it regularly for the last 4 months without changing the battery...    (draws less than 10 mA)  !

R.

[geertjacobs]

My PT-80 is not noisy at all. It uses an unregulated (!) power supply without any issue. I did install the 7812 voltage regulator.

Things you can try:
- did you use new metal film resistors or something you had lying around? Resistors are a noise source so maybe that can be worth looking at.
- have you tried switching the opamp for another one?
- you could try using a 9V battery instead to see if it makes a difference.
- you could try to put in the 7812 and use a +15V supply and see if it makes a difference.