Neutron Help Needed

[ThisBrian]

I'm finding it impossible to tame the whine on my Neutron. The build is really clean and wiring is immaculate. The only differences from the pdf project are that i didn't didn't use a battery so I connected the emitter to collector where Q1 would be. I also used a 3PDT switch with an LED. I originally built it with the 7660 but just got in a MAX1044 and it seems to whine just as much or maybe more now. Could the LED ground to the signal ground be the problem? I thought maybe the signal ground shouldn't be connected to the board (6th hole from right on board, also 0V if dual batter or dual power is used) but the pedal doesn't work at all without it, just horrible ground hum. Any suggestions? Thanks.

[R.G.]

How do you switch power to the unit? Battery (-) to a jack?

[R.G.]

oops, forgot. Did you make/buy a PCB or perf board it?

Grounding is a crucial issue in making a Neutron whine free with a MAX1044 or 7660.

[ThisBrian]

oops, forgot. Did you make/buy a PCB or perf board it?

Grounding is a crucial issue in making a Neutron whine free with a MAX1044 or 7660.

Used boards from GGG. I say boards because this is actually the very carefully built rebuild.

[R.G.]

Ok.

So I really need to know - since you hardwired the power switch transistor, how did you do the power switch?

[ThisBrian]

Ok.

So I really need to know - since you hardwired the power switch transistor, how did you do the power switch?

I'm not switching, just the 9v jack (no battery) with the "Bat (+)" connection going to the positive and the "Bat (-)" going to the negative of the jack. Nothing on the "Input Stereo Lug"

[R.G.]

OK.

Is pin 1 connected solidly to pin 8 on the MAX1044? This puts the frequency of oscillation above audio and makes the whine in a frequency where you can't hear it.

If you have an oscilloscope, what is the frequency of the whine?

What DC voltages do you measure on the + and - power pins of the ICs?

Once you know that, flip your meter to *AC* and measure the *AC* voltage on the power pins of the ICs.

Does the whine change nature with any control change?

[ThisBrian]

Is pin 1 connected solidly to pin 8 on the MAX1044? This puts the frequency of oscillation above audio and makes the whine in a frequency where you can't hear it.

I must've missed that when I read about people using the chip. Just did it and it works like a charm. Thanks RG!

[SolderBoy]

R.G. wrote:
Is pin 1 connected solidly to pin 8 on the MAX1044? This puts the frequency of oscillation above audio and makes the whine in a frequency where you can't hear it.

does this work with the 7660 as well?

[R.G.]

On the old 7660, no. On some newer variants, like the 7662??? maybe.

Anybody know the correct numbers?

[SolderBoy]

thanks RG.