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vtl5c3
Joined: Sep 08, 2006 Posts: 425 Location: PDX
Audio files: 13
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Posted: Thu Jun 28, 2007 9:57 am Post subject:
Buchla 218 VC-able Portamento - Works! |
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Last night I finally tested the slew circuit that I cloned from the Buchla 218 keyboard. I'm happy to say that it works. I've posted the schematic and a couple of sound samples below. I may have to do a bit of fine tuning... if nothing else I will try smaller cap values, since it's pretty easy to get way too much portamento going.
Update: I've uploaded the PCB layout, for those who like to roll their own.
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218_slew_01.mp3 |
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218_Slew_02.mp3 |
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Parts layout. Corrected diode part number. |
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buchla_218_Slew_parts.pdf |
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Last edited by vtl5c3 on Tue Dec 30, 2008 11:19 am; edited 5 times in total |
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StephenGiles
Joined: Apr 17, 2006 Posts: 507 Location: England
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Posted: Thu Jun 28, 2007 10:26 am Post subject:
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Interesting - I was waiting for Jeff Beck to crash in! Have you heard him make similar sounds! |
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StephenGiles
Joined: Apr 17, 2006 Posts: 507 Location: England
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bubblechamber
Joined: Nov 04, 2006 Posts: 279 Location: NYC
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Posted: Thu Jun 28, 2007 10:16 pm Post subject:
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thanks for posting |
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krisp14u
Joined: Nov 11, 2006 Posts: 206 Location: uk
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Posted: Fri Jun 29, 2007 8:32 am Post subject:
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Cheers for that vtl5c3 I will have a go at this 1 over the weekend
paul D _________________ Cheers
Paul Darlow
www.krisp1.com |
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StephenGiles
Joined: Apr 17, 2006 Posts: 507 Location: England
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Posted: Sat Jun 30, 2007 5:19 am Post subject:
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I'm not quite sure if I needed to have bothered (subjunctivo!) with the Jeff Beck sample - a lot of synth players would give their right arm to play like that!! |
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Quad
Joined: Dec 30, 2006 Posts: 18 Location: Stockholm, Sweden
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Posted: Sat Jun 30, 2007 8:42 am Post subject:
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Thanks for posting!
What is the difference between Ground and N Ground? and what is L1 & L2?
thanks! |
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vtl5c3
Joined: Sep 08, 2006 Posts: 425 Location: PDX
Audio files: 13
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Posted: Sat Jun 30, 2007 8:53 am Post subject:
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Quad wrote: | Thanks for posting!
What is the difference between Ground and N Ground? and what is L1 & L2?
thanks! |
Noisy ground and regular (quiet?) ground. Buchla often had separate grounds in his modules. As you can see they join together on this PCB. No need to worry about the differences. L1 & L2 are ferrite beads, same as you find on most prefab DIY PCBs these days. You can use low value resistors or jumpers if you don't have ferrite beads.
Romeo |
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Fernando
Joined: Dec 30, 2006 Posts: 286 Location: Barcelona & Emporda, Spain
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Posted: Tue Jul 10, 2007 7:30 am Post subject:
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I missed the thread.
wow, thank you so much!
(actually the "wow" was a "fantastico" before being slewed)
Is the 4.7uF capacitor that you are refering to?
maybe is the control of the LED's vactrol what should be finetuned...?
_ |
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Dave Manley
Joined: Sep 03, 2007 Posts: 7 Location: North Bay, California
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Posted: Sun May 04, 2008 9:25 am Post subject:
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I was looking for the 218 schematics yeseterday and couldn't find them in the usual places. Are they online somewhere?
-Dave
P.S. Is there anything Buchla couldn't (wouldn't?) do with a vactrol? |
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cbm
Joined: Oct 25, 2005 Posts: 381 Location: San Francisco
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Posted: Sun May 04, 2008 1:49 pm Post subject:
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Dave Manley wrote: | Is there anything Buchla couldn't (wouldn't?) do with a vactrol? |
Sort of like Serge and the LM3900.
-C _________________ Chris Muir
http://www.eardrill.com <– My jobby (more than a hobby, less than a job) |
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vtl5c3
Joined: Sep 08, 2006 Posts: 425 Location: PDX
Audio files: 13
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Posted: Fri May 09, 2008 10:59 am Post subject:
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Did you need the entire 218 schematic set? I don't think it's online, but I have them. Could have sworn I got them off the web at some point.
R.
Dave Manley wrote: | I was looking for the 218 schematics yeseterday and couldn't find them in the usual places. Are they online somewhere?
-Dave
P.S. Is there anything Buchla couldn't (wouldn't?) do with a vactrol? |
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cbm
Joined: Oct 25, 2005 Posts: 381 Location: San Francisco
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Dave Manley
Joined: Sep 03, 2007 Posts: 7 Location: North Bay, California
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Posted: Sat May 10, 2008 12:12 am Post subject:
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I was studying the Easel and the 218 is a key part of it. The 216 and 217 are online at Magnus' site, but the 218 is absent. It would be a good addition to his pages if available.
How many pages total are there in the 218? |
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CJ Miller
Joined: Jan 07, 2007 Posts: 368 Location: 127.0.0.1
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Posted: Tue May 27, 2008 1:01 am Post subject:
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Cool... I was just looking over slew/portamento ideas, and I was surprised how few are VC-able.
In the schematic, it calls for a 6V Zener diode. But on your PCB diagram it says 1N5224. Isn't this a 2.8V Zener? What Zener did you use here? I don't know how crucial it is, as I have neither anyway. I'm a vactrol n00b and I don't want to fry them.
Nice efforts studying Buchla's work! Most of his stuff makes my head spin. |
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vtl5c3
Joined: Sep 08, 2006 Posts: 425 Location: PDX
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Posted: Tue May 27, 2008 8:51 am Post subject:
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Good question. I'll have to check my work when I get home. You're correct that the 1N5224 is a 2.8 Zener. It should read 1N5233. Thanks for pointing it out.
R.
CJ Miller wrote: | Cool... I was just looking over slew/portamento ideas, and I was surprised how few are VC-able.
In the schematic, it calls for a 6V Zener diode. But on your PCB diagram it says 1N5224. Isn't this a 2.8V Zener? What Zener did you use here? I don't know how crucial it is, as I have neither anyway. I'm a vactrol n00b and I don't want to fry them.
Nice efforts studying Buchla's work! Most of his stuff makes my head spin. |
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haxster
Joined: Feb 01, 2006 Posts: 246 Location: MONTEREY PARK, CA 91754
G2 patch files: 2
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Posted: Sun Nov 16, 2008 12:21 pm Post subject:
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Is the type of vactrol used critical? Would a VTL5C4 be okay to use. I am new to vactrols. |
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doctorvague
Joined: Mar 14, 2007 Posts: 281 Location: new mexico
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Posted: Sun Nov 16, 2008 1:52 pm Post subject:
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The VTL5C4 would be slower than the usual VTL5C3 that Buchla uses. It's not spec'd here but I'm assuming it is a VTL5C3 in this circuit. The 'slower' would just be response to control changes, not the portamento itself. IOW, if you wanted quick turn-on and turn-off of portamento via control voltages it will have more lag time, especially the turning off or quick turning down of the portamento. Kinda like portamento'd portamento.
Cheers
Phil _________________ doctorvague's youtube channel |
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vtl5c3
Joined: Sep 08, 2006 Posts: 425 Location: PDX
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Posted: Sun Nov 16, 2008 3:25 pm Post subject:
Schematics |
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Forgot that I was gonna post them, but here they are.
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Buchla 218 Board Part Placement |
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probablyjoel
Joined: Aug 31, 2008 Posts: 11 Location: Seattle
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Posted: Sun Dec 07, 2008 9:47 am Post subject:
dumb newbie question... |
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What type of offboard components are you using for the control inputs? Just standard 1/4" jacks? |
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vtl5c3
Joined: Sep 08, 2006 Posts: 425 Location: PDX
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Posted: Sun Dec 07, 2008 10:07 am Post subject:
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I'm using 1/8th inch jacks. Nothing fancy. |
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probablyjoel
Joined: Aug 31, 2008 Posts: 11 Location: Seattle
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Posted: Sun Dec 07, 2008 10:12 am Post subject:
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Thank you! One more question...I'm not so familiar with the buchla... how do the control inputs differ from the input? If i use it for my 4017 step sequencer, would it work through the normal input or through the control input? |
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vtl5c3
Joined: Sep 08, 2006 Posts: 425 Location: PDX
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Posted: Sun Dec 07, 2008 11:39 am Post subject:
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Whatever CVs you'll be processing go into the normal input. The CV input controls how much portamento is applied to the processed voltage.
probablyjoel wrote: | Thank you! One more question...I'm not so familiar with the buchla... how do the control inputs differ from the input? If i use it for my 4017 step sequencer, would it work through the normal input or through the control input? |
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probablyjoel
Joined: Aug 31, 2008 Posts: 11 Location: Seattle
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Posted: Sun Dec 07, 2008 2:54 pm Post subject:
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So i would need another CV control to control the level of portamento? What types work best as controllers? Sorry if this is super obvious... I'm still a newbie:). |
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vtl5c3
Joined: Sep 08, 2006 Posts: 425 Location: PDX
Audio files: 13
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Posted: Sun Dec 07, 2008 2:58 pm Post subject:
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You can use the manual control to set a portamento amount, but the value only changes when you turn the knob. To CV control it, run an LFO into it, have a second analog sequencer control it, or even aftertouch from a keyboard... really any CV source will work.
probablyjoel wrote: | So i would need another CV control to control the level of portamento? What types work best as controllers? Sorry if this is super obvious... I'm still a newbie:). |
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