Author Topic: Holy Roller - Verified  (Read 1114 times)

zoof

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Holy Roller - Verified
« on: December 11, 2017, 04:48:02 PM »
Works like a charm! Got best result with 1m dark ldr and 5mm red diffused.

madbean

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Re: Holy Roller - Verified
« Reply #1 on: December 11, 2017, 05:51:31 PM »
Great news! What's it like?
I own madbeanpedals (duh). I am part owner of Function F(X).

zoof

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Re: Holy Roller - Verified
« Reply #2 on: December 12, 2017, 10:52:52 AM »
I love it. Built it on vero a couple of weeks ago, this is a little more fun to put in a box though!
Don't know how to describe it, it's there, but not harsh. It does the job it says it will do, it's a limiter :)
Really recommend this.

jubal81

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Re: Holy Roller - Verified
« Reply #3 on: December 12, 2017, 11:04:59 AM »
Seeing a couple points on this schematic that could possibly cause noise issues. Find it any noisier than other compressors?
"If you put all the knobs on your amplifier on 10 you can get a much higher reaction-to-effort ratio with an electric guitar than you can with an acoustic."
- David Fair

zoof

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Re: Holy Roller - Verified
« Reply #4 on: December 12, 2017, 11:31:34 AM »
Quite the opposite, didn't notice any noise at all. Haven't played it loud yet though.

chordball

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Re: Holy Roller - Verified
« Reply #5 on: December 12, 2017, 01:09:39 PM »
Seeing a couple points on this schematic that could possibly cause noise issues. Find it any noisier than other compressors?

Can you elaborate? Any ideas for improvements? I haven't built it but it was on my radar.

jubal81

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Re: Holy Roller - Verified
« Reply #6 on: December 12, 2017, 01:37:22 PM »
Seeing a couple points on this schematic that could possibly cause noise issues. Find it any noisier than other compressors?

Can you elaborate? Any ideas for improvements? I haven't built it but it was on my radar.

Mainly thinking about the LDR on the noninverting opamp input going to a reference voltage. Noninverting inputs have ridiculously high impedance, so that net is extremely sensitive to picking up noise. It's a good idea on layout to keep any traces connecting to a noninverting input absolutely as short as possible.

I've noticed that phasers that use a negative voltage for a split supply rail are much quieter than those with a single rail and reference voltage. If you look at the Mutron Phaser schematic, you see the noninverting inputs and corresponding LDRs are referenced to ground in the phase stages.

"If you put all the knobs on your amplifier on 10 you can get a much higher reaction-to-effort ratio with an electric guitar than you can with an acoustic."
- David Fair

chordball

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Re: Holy Roller - Verified
« Reply #7 on: December 15, 2017, 02:08:32 PM »
Seeing a couple points on this schematic that could possibly cause noise issues. Find it any noisier than other compressors?

Can you elaborate? Any ideas for improvements? I haven't built it but it was on my radar.

Mainly thinking about the LDR on the noninverting opamp input going to a reference voltage. Noninverting inputs have ridiculously high impedance, so that net is extremely sensitive to picking up noise. It's a good idea on layout to keep any traces connecting to a noninverting input absolutely as short as possible.

I've noticed that phasers that use a negative voltage for a split supply rail are much quieter than those with a single rail and reference voltage. If you look at the Mutron Phaser schematic, you see the noninverting inputs and corresponding LDRs are referenced to ground in the phase stages.

Thanks for the explanation. Definitely not something I even considered before so I learned something new. If/when I build this circuit I will play around with the supply scheme.

gordo

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Re: Holy Roller - Verified
« Reply #8 on: December 15, 2017, 08:32:54 PM »
This one has been on the radar for a long time so might have to bust out the FeCl if I can find the pcb's (house is packed up and ready to sell).