Crowther Audio - Prunes & Custard

General documentation, gut shot, schematic links, ongoing circuit tracing, deep thoughts ... all about boutique stompboxes.
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JimiB
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Post by JimiB »

did you do what I suggested?

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MWichni
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Post by MWichni »

Make a photo of solder side of your board.

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Mr. G.
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Post by Mr. G. »

on the top middle of the solder side picture, it looks like one of the 3 larger solder points (the one on the left) might be touching another track.

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jazzercountry
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Post by jazzercountry »

Yes, Jimib I did the scraping in the spots you showed with a magnifier, so I'm sure they aren't shorting. Same thing with the top middle left pad, it's clean. With the earlier problem getting connections to ground, I'm wondering if some of these connections aren't making contact with the trace at all?

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stanimal08
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Post by stanimal08 »

yeah, I also built this last week (for myself, have built two more for friends this week) and had to debug my own mistakes, when i got them all working they sounded (to me) better than the original (i had one years ago), more smooth and musical but still maintaining that odd modulated splat fuzz sound that's just too cool... I noticed an obvious tonal difference in one pedal that I used different components (ran out of 40pf caps so I used another 10pf and 15k resistors because i ran out of 16k and didn't feel like "building" them out of 15 and 1k resistors) which made one significantly less "splatty" and a bit cleaner, sounds pretty good but definitely a wicked step brother.....

thanks to Bajaman again for great PCB's that are fun building....

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Brink
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Post by Brink »

I didn't see a vero, so I made one.
Check the schematic for the offboard wiring.
The 2 switches are not included, effectively hardwired in the positions shown in the schematic. You'll probably want to jumper IC pin 4 to track B, the ground.
I have not built on yet.

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Brink
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Post by Brink »

Also I forgot the input cap.

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Post by Brink »

And the 100u is in the wrong place. I'll post a fixed vero later.

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Brink
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Post by Brink »

Here is my latest vero
(mods, feel free to delete previous posts and this sentence)
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PruCus2.PNG

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bunnycat
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Post by bunnycat »

Anyone successfully built this from the vero layout?
I'm thinking about having a go at it - if I do I will post my results.

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bunnycat
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Post by bunnycat »

Built it and it sounds great... except when it's bypassed with the drive knob turned up past 3 'o' clock. For some reason, it makes a high pitched noise (tone) when bypassed at this (very high) drive level. It only happens when the effect is bypassed, and goes away when the drive knob is turned back down. The only parts I used that are different than the spec were a rectifier diode instead of the zener and a 54n cap instead of the 47n. Any ideas?

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pandadandan
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Post by pandadandan »

bunnycat wrote:Built it and it sounds great... except when it's bypassed with the drive knob turned up past 3 'o' clock. For some reason, it makes a high pitched noise (tone) when bypassed at this (very high) drive level. It only happens when the effect is bypassed, and goes away when the drive knob is turned back down. The only parts I used that are different than the spec were a rectifier diode instead of the zener and a 54n cap instead of the 47n. Any ideas?
How have you wired the switch? Are you grounding the effect even when bypassed? If not, you might benefit from rewiring your 3pdt to have a constantly grounded circuit.

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KindaFuzzy
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Post by KindaFuzzy »

Mine did the same until I grounded the input during bypass, now it's fine.

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bunnycat
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Post by bunnycat »

I'll try that and post my results. Thanks!

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bunnycat
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Post by bunnycat »

Worked perfectly (thanks)! Wow, I really love this thing, especially on my analog synths (SH-1000, SH-2). It gives it some nice organic diode-filter-like qualities when the drive is turned up past 1 o' clock. It's going to be an integral part of my synth sound, I think. It adds grit that makes me think of the Korg MS-20. Now where's that Frostwave Resonator?

And now, on to the Hotcake (soulsonic's LM741CH Mojo version, on vero)...

Thanks again... I learned a better bypass wiring!!

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bunnycat
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Post by bunnycat »

One more question, if y'all are still there: is there any reason to seek out a 10v Zener (to replace the 1n4002 rectifier diode I used in its place)? I was reading about the function of the (8.2v) Zener in the Crowther Hotcake and it seems to limit the circuit voltage to 8.2v. Is the 1n4002 doing anything that is detrimental to the function of the circuit? I assume it's just there to provide reverse polarity protection (which I still don't understand the workings of), but would there be a good reason to use the 10v Zener?

-Samantha

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KindaFuzzy
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Post by KindaFuzzy »

The normal diode should be fine, the hotcake thing with the 8.2v zener makes a difference because the op-amp itself is clipping in that circuit, and limiting the votage feeding it limits the headroom (I guess). The 10v zener in the P&C just dumps any voltage over 10v to ground if you use the wrong power adapter as well as adding polarity protection.

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bunnycat
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Post by bunnycat »

ok, that makes me feel better. thanks!

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Brink
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Post by Brink »

I'm working on a new PCB, one that fits in a 1590B (it's currently 1.9" x 1.9").
I'm working off the latest Krome_Magnon schematic, which I think is the most accurate one traced. (Link:https://img252.imageshack.us/img252/950 ... acegz8.jpg)
The switches in the open position are guitar, LoFreq off. (Closed are Bass, LoFreq on)
Let me know what you think or if you see any errors.
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HamMus.GIF
HamMus.GIF (22.7 KiB) Viewed 3015 times

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cornocopius
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Post by cornocopius »

Awesome Brink! Looking forward to seeing if it can be crammed into a 1590B!

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