Author Topic: Morley Sync Attack Box  (Read 428 times)

FUZZZZzzzz

Morley Sync Attack Box
« on: September 20, 2021, 04:15:50 AM »
I saw a second hand ad for one of these devices. Like a swell effect with a metallic pic. It looks really cool, but I could not find any videos online or information on this board. I found the schematic, but it didn't tell me what transistors to use. Looks like a fun build. I asked the seller and he told me that he could only read the transistor near the PIK point. He says its a 5087 transistor. Has anyone ever experimented with this? Also, VT811 doesnt show up on google.

you can find the morley schematics here:
https://www.schematicsunlimited.com/m/morley



« Last Edit: September 20, 2021, 04:19:36 AM by FUZZZZzzzz »
"If I could make noise with anything, I was going to"

duck_arse

Re: Morley Sync Attack Box
« Reply #1 on: September 20, 2021, 10:37:39 AM »
MPSA06, MPSA06, MPSA12. easy subs for those, too.
"I'm your vehicle, baby", but go easy on the clutch.

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pacealot

Re: Morley Sync Attack Box
« Reply #2 on: September 20, 2021, 03:34:44 PM »
This thread about the Pik-A-Wah also discussed a SAB which was observed to have 5087s in it:

https://www.diystompboxes.com/smfforum/index.php?topic=71206.msg1124455#msg1124455

I have an interest in breadboarding one of these myself soon, but I haven't yet, so I can't speak to the merits/demerits of using PNPs vs. NPNs...
"Stupidity has a certain charm; ignorance does not." Frank Zappa

RickL

Re: Morley Sync Attack Box
« Reply #3 on: September 20, 2021, 08:02:58 PM »
This is a great little circuit. If you can deal with having to use a metal pick attached to the box you will find that it tracks better than any other envelope controlled effect you have ever used. Because the envelope of the signal doesn't control the effect. Every time you touch the string with the pick it resets.

I think I just experimented with LED/LDRs I had on hand until I found one that worked. My guess is that just about anything will work with a bit of fiddling.

As mentioned in the linked thread, I think the trigger part of the circuit (or the one for the pik-a-wah - they work in opposite directions) would work great for controlling almost any parameter of an effect that is set by a resistance value. Imagine a distortion that faded in distortion amount on each note at the speed you set or a delay that shortened on each note (raising the pitch each time).

I have got to play around with this circuit more!

pacealot

Re: Morley Sync Attack Box
« Reply #4 on: September 20, 2021, 08:40:32 PM »
Rick, your enthusiasm for the circuit is what piqued my interest in it to begin with! So thank you for that.  :)

Do you recall if you went with NPNs or PNPs in the positions of the two MPSA06s? I'd imagine any ordinary 3904/5088 etc. would probably work for NPNs, but was curious if you ran into any issues there...
"Stupidity has a certain charm; ignorance does not." Frank Zappa

FUZZZZzzzz

Re: Morley Sync Attack Box
« Reply #5 on: September 21, 2021, 05:31:31 AM »
im building one soon. im drawing up a vero as well. just have to gather some parts. what kind of ldr range would be a good start? i would think id start with a 5mm red led. use 2n5087. they're easy to come by. any ideas?
"If I could make noise with anything, I was going to"

pacealot

Re: Morley Sync Attack Box
« Reply #6 on: September 21, 2021, 11:27:31 AM »
I suppose the question I still have (which, if I just cleared off a breadboard and tried it, might be quickly answered) is, if using 5087s or similar PNPs in those positions, do collectors and emitters need to be reversed from the schematic? MPSA06s are NPN, so one would think so...
"Stupidity has a certain charm; ignorance does not." Frank Zappa

PRR

Re: Morley Sync Attack Box
« Reply #7 on: September 21, 2021, 04:57:15 PM »
That drawing top of thread looks wrong. Battery "+" is grounded when g-plug is inserted. So the "Hot" side is -Negative-, and about -8.4V due to the diode. The first two transistors' Collectors go to the "live" wire, which is negative of their Emitters, so PNP would be expected. Seen this way, Q1 defaults ON, forcing Q2 OFF, so the 0.5uFd is pulled to -8.6V through the 500k time-pot. With base of NPN Darlington Q3 near -8.4V, LED is OFF, audio is ON.

When PIK touches grounded string, everything goes the other way, sound stops. When PIK stops touching, it recovers at the 0.5uFd+500k rate.


Why such a brain-pain? I assume because jellybean Darlingtons only come in NPN, and all else followed.

With modern fad for common power supplies, you might re-think that ALL the way through.
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RickL

Re: Morley Sync Attack Box
« Reply #8 on: September 21, 2021, 09:29:01 PM »
I can't find my Sync Attack Box right now, but I used PN2222 and MPSA14 in my Pik-A-Wah, so it looks like NPN works in that one at least.