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Broadwave
Joined: Feb 16, 2007 Posts: 347 Location: Manchester UK
Audio files: 6
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Posted: Fri Apr 19, 2013 2:08 am Post subject:
Help/Info Required - ARP2600 ADSR |
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I've got an ARP2600 in for service, but I would like some info on the ADSR envelope generator...
If anybody has a 2600 handy, could you please let me know what sort of attack time you're getting. I'm getting the following times from the ADSR out (all sliders at max):
Attack time - 1.5 seconds
Decay time - 11/12 seconds
Sustain voltage - 9.8
Release time - 11/12 seconds
As you can see, I'm a little concerned about the maximum attack time... 1.5 seconds! I have replaced the two parallel 1uf 25v timing caps on the 4020 module, but it's made no difference.
I suspect that everything is right, and that the 2600 attack time really is this short, but I would like confirmation if possible.
Many thanks. |
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isak
Joined: Dec 13, 2009 Posts: 847 Location: Israel
Audio files: 18
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Posted: Sat Apr 20, 2013 1:53 am Post subject:
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Hi Andy.
after giving us so much i went for a quest for you searching in youtube what your looking for.
i think the answer to your question is YES, the Attack is very short.
from 4:25 he is talking about the ENV of the arp2600, look at the position of the Attack from the right top of the vid.
i hope it helps you
http://www.youtube.com/watch?v=NqQV5mLVNWs
cheers,
Isak E. _________________ http://www.myspace.com/mgmtrance |
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Broadwave
Joined: Feb 16, 2007 Posts: 347 Location: Manchester UK
Audio files: 6
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Posted: Sat Apr 20, 2013 6:20 am Post subject:
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Thanks Isak,
I think that just about confirms it... very short!
Strangely enough, doubling up the caps to 4.7uf doesn't make much difference to the attack time, although it lengthens the decay/release - Weird!
Andy |
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isak
Joined: Dec 13, 2009 Posts: 847 Location: Israel
Audio files: 18
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Posted: Sat Apr 20, 2013 6:30 am Post subject:
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Happy I was able to help you Andy.
Hope youll "fix" what your trying to fix.
Cheers _________________ http://www.myspace.com/mgmtrance |
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steffensen
Joined: Jul 11, 2012 Posts: 103 Location: Sweden
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Posted: Tue Apr 23, 2013 2:31 am Post subject:
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And here i was hoping for the 2600 ADSR layout!
Isak already confirmed this question, but yes - it is that short. I guess this is one of the reasons many seems to use the 2600 for drums.
What caps did you double? C1 & C2? If so, im not surprised they changed the Decay & Release. They should have changed the Attack too however.. weird.
How about decreasing/increasing R12? |
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Broadwave
Joined: Feb 16, 2007 Posts: 347 Location: Manchester UK
Audio files: 6
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Posted: Tue Apr 23, 2013 9:15 am Post subject:
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steffensen wrote: |
How about decreasing/increasing R12? |
I'll give it a try
Quite handy getting a late 2600 in for servicing... none of the modules are potted |
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isak
Joined: Dec 13, 2009 Posts: 847 Location: Israel
Audio files: 18
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Broadwave
Joined: Feb 16, 2007 Posts: 347 Location: Manchester UK
Audio files: 6
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Posted: Tue Apr 23, 2013 11:40 pm Post subject:
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isak wrote: | Hi Andy,
Are we gonna get the arp2600 env layout? |
Yes, I'll give one a try this weekend
I'm copying the module layouts as fast as I can - the 2600 goes back to it's owner tomorrow
I may not have time to get the 2600 VCF. It's a slightly different design to the 4075 found in my Odyssey (the module adds an op-amp, which look like I/O level adjusters - maybe compensation for the higher VCO outputs?).
Some of the module layouts look like a bizarre mess... but as long as they work, I'm not complaining |
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steffensen
Joined: Jul 11, 2012 Posts: 103 Location: Sweden
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Posted: Wed Apr 24, 2013 12:49 am Post subject:
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AndyR1960 wrote: | isak wrote: | Hi Andy,
Are we gonna get the arp2600 env layout? |
Yes, I'll give one a try this weekend
I'm copying the module layouts as fast as I can - the 2600 goes back to it's owner tomorrow
I may not have time to get the 2600 VCF. It's a slightly different design to the 4075 found in my Odyssey (the module adds an op-amp, which look like I/O level adjusters - maybe compensation for the higher VCO outputs?).
Some of the module layouts look like a bizarre mess... but as long as they work, I'm not complaining |
Sweet! I can trash my try on the 4020 then.
I read there were some (intentional?) errors in the 4020 schematic, so its good to have the original around!
Id love to help if possible in any way. Also, Rob at AM Synths have some good notes on this matter on his site, if needed. |
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Broadwave
Joined: Feb 16, 2007 Posts: 347 Location: Manchester UK
Audio files: 6
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Posted: Wed Apr 24, 2013 1:54 am Post subject:
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I noticed errors straight away! No wonder my attempt a few years ago didn't work
The 2600 service manual addendum for the ADSR is also wrong! |
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steffensen
Joined: Jul 11, 2012 Posts: 103 Location: Sweden
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Posted: Wed Apr 24, 2013 2:02 am Post subject:
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AndyR1960 wrote: | I noticed errors straight away! No wonder my attempt a few years ago didn't work
The 2600 service manual addendum for the ADSR is also wrong! |
Yes, sneaky bastards.
What errors did you find btw? Curious if its the same i have discovered myself.
I hope you do HQ pics of the modules in the 2600 before you return it, those might be handy! |
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Broadwave
Joined: Feb 16, 2007 Posts: 347 Location: Manchester UK
Audio files: 6
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Posted: Wed Apr 24, 2013 2:37 am Post subject:
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steffensen wrote: | Also, Rob at AM Synths have some good notes on this matter on his site, if needed. |
Just found it : )
Yup, same errors - I'm copying the module directly... no point in redrawing everything as it may introduce further mistakes!
I'm not sure what to use as the NPN/PNP's, although I'm pretty sure standard 2N3904/6's will work (I've got no 2N3702's).
I'll see how I get on, it'll probably take a day or two. |
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steffensen
Joined: Jul 11, 2012 Posts: 103 Location: Sweden
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Posted: Wed Apr 24, 2013 2:47 am Post subject:
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AndyR1960 wrote: | steffensen wrote: | Also, Rob at AM Synths have some good notes on this matter on his site, if needed. |
Just found it : )
Yup, same errors - I'm copying the module directly... no point in redrawing everything as it may introduce further mistakes!
I'm not sure what to use as the NPN/PNP's, although I'm pretty sure standard 2N3904/6's will work (I've got no 2N3702's).
I'll see how I get on, it'll probably take a day or two. |
Great! Its even cooler with a direct copy.
Im sure 3904/06's will work fine. If they worked in the Oddy etc..
Really looking forward to this! (im such a ARP junkie) |
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The Real MC
Joined: Jun 20, 2008 Posts: 62 Location: Painted Post NY
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Posted: Wed Apr 24, 2013 7:57 am Post subject:
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Back then, it wasn't uncommon to put intentional errors in schematics to deter copycats. ARP wasn't the only one, Buchla did it too. |
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Broadwave
Joined: Feb 16, 2007 Posts: 347 Location: Manchester UK
Audio files: 6
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steffensen
Joined: Jul 11, 2012 Posts: 103 Location: Sweden
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Posted: Thu Apr 25, 2013 1:36 am Post subject:
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Thats a fun looking build! Should be room for 2 EG's on the same board there perhaps?
About the voltage overshot, i cant say much, but the 2600 do have something going on regarding this. Its definitely noticeable on all the drum patches ive heard/made on it. Makes it very special, and also one of the big reasons i dearly want it!
Good work Andy! |
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alcide
Joined: Apr 20, 2012 Posts: 5 Location: Lille, France
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Posted: Sat Apr 27, 2013 10:18 am Post subject:
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Regarding the length of the complete ADSR cycle of an unmodified 2600, and the unwanted behaviour you're talking about, the section about the 'Contour generators & vca', in this article, may be of some interest (it's an exhaustive comparison between the original synth and its virtual counterpart):
http://www.soundonsound.com/sos/jun05/articles/arturia2600.htm
Hope it helps ! |
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Broadwave
Joined: Feb 16, 2007 Posts: 347 Location: Manchester UK
Audio files: 6
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Posted: Sat Apr 27, 2013 10:32 am Post subject:
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alcide wrote: |
Hope it helps ! |
Yes it did help. Thank you.
So as far as I can tell, the ADSR I've built seems ok although I'm going to tinker with it for a while to see if I can improve anything... or maybe just leave well alone as it has a certain character |
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steffensen
Joined: Jul 11, 2012 Posts: 103 Location: Sweden
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Posted: Sat Apr 27, 2013 10:48 am Post subject:
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AndyR1960 wrote: | alcide wrote: |
Hope it helps ! |
Yes it did help. Thank you.
So as far as I can tell, the ADSR I've built seems ok although I'm going to tinker with it for a while to see if I can improve anything... or maybe just leave well alone as it has a certain character |
I really would like to play with it as is. |
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patroche
Joined: Feb 26, 2012 Posts: 16 Location: montelimar
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