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DIY Stompboxes => Building your own stompbox => Topic started by: Noplasticrobots on February 10, 2006, 06:58:26 PM

Title: Need help finding a schematic...
Post by: Noplasticrobots on February 10, 2006, 06:58:26 PM
Hi all, about a week ago I was trying to find out how to combine a guitar signal and a 555 signal output timer and I came across a simple circuit and a hand drawn schematic calling for a 555 and a TL702 op amp. Inititally I didn't think it'd be of much use to me; but now I need it. Anyone know or seen what I'm talking about? I believe the description said it would give some synth like sounds. I've been Googling like crazy but to no avail! Any help would be appreciated.
Title: Re: Need help finding a schematic...
Post by: H S on February 10, 2006, 07:04:47 PM
Try looking for Crash Sync.
Title: Re: Need help finding a schematic...
Post by: hank reynolds 3rd on February 10, 2006, 07:08:46 PM
I think ,going off what you described,it's the crash sync ....
Try the search,I think there's a couple of layouts already done...
Title: Re: Need help finding a schematic...
Post by: nelson on February 10, 2006, 07:31:01 PM
http://www.hollis.co.uk/john/


;)
Title: Re: Need help finding a schematic...
Post by: Noplasticrobots on February 10, 2006, 10:59:44 PM
That was it! Thanks a ton!
Title: Re: Need help finding a schematic...
Post by: Noplasticrobots on February 11, 2006, 12:11:53 AM
One little thing...the schematic calls for two ICs, but the component layout only has one. Which one is correct?


Component layout: http://www.hollis.co.uk/john/crashsynclyt.jpg (http://www.hollis.co.uk/john/crashsynclyt.jpg)

Schematic: http://www.hollis.co.uk/john/crashsync.jpg (http://www.hollis.co.uk/john/crashsync.jpg)
Title: Re: Need help finding a schematic...
Post by: nelson on February 11, 2006, 12:23:58 AM
The schematic calls for only two IC's. The 555 and a DUAL opamp.

They are both correct.
Title: Re: Need help finding a schematic...
Post by: Noplasticrobots on February 11, 2006, 11:30:34 AM
d'oh! Will a Rat Shack TL082 suffice? http://www.radioshack.com/product/index.jsp?productId=2062594&cp=&kw=dual+op+amp&parentPage=search (http://www.radioshack.com/product/index.jsp?productId=2062594&cp=&kw=dual+op+amp&parentPage=search)

One more question: is the 100k pot connected to pins 6 and 7 of the 555 bridged?

ok....I've actually got one more question: what's the deal with LP555, NE555, LM555. I know they're all timers, but will using a different prefix cause major differences?
Title: Re: Need help finding a schematic...
Post by: nelson on February 11, 2006, 11:38:57 AM
Any standard dual opamp will do and any 555 will do, I think that some are just less current hungry than others.
Title: Re: Need help finding a schematic...
Post by: tiges_ tendres on February 11, 2006, 01:32:58 PM
Quote from: nelson on February 11, 2006, 11:38:57 AM
Any standard dual opamp will do and any 555 will do, I think that some are just less current hungry than others.

a cmos 555 will be what you would want in reagrds to needing less current
Title: Re: Need help finding a schematic...
Post by: Noplasticrobots on February 11, 2006, 10:06:12 PM
Anyone have a cleaner schematic for the Crash Sync which indicates what pin numbers to connect components to? The component layout doesn't have pinouts on it either, so I'd kindly appreciate anyone's help in deciphering the schematic!

http://www.hollis.co.uk/john/crashsync.jpg (http://www.hollis.co.uk/john/crashsync.jpg)

Also, the two grounds aren't connected. Is this just how the schematic is drawn or do they need to be kept seperate?
Title: Re: Need help finding a schematic...
Post by: Noplasticrobots on February 12, 2006, 12:30:57 PM
I was hoping to work on this when I get home from work, so please excuse the bump. I compared the schematic to the TL082 datasheet and I think I found the correct pin numbers. The numbers are small, but they're on the graphic. Can anyone verify the validity of this?

(http://i13.photobucket.com/albums/a278/Noplasticrobots/crashsyncnumbered.png)



Title: Re: Need help finding a schematic...
Post by: Connoisseur of Distortion on February 12, 2006, 12:51:05 PM
i'm pretty sure that people were having trouble with that schematic. One of the Hollis schematics, anyways...

I have the Torchy Vero layout, if you want it. Just PM me, and i'll email...
Title: Re: Need help finding a schematic...
Post by: Noplasticrobots on February 12, 2006, 11:08:48 PM
I knew some people were having trouble with one of Hollis' layouts also, but I didn't think it was the Crash Sync. This sucks, I have all the parts but no idea where anything goes on the TL082. All dressed up and nowhere to go!