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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: Mon Jan 19, 2009 4:19 pm Post subject:
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I have mastered Polivoks VCF building and will soon post a full proper schematic. If you don't feel like getting into etching your own pcb I will be selling one on ebay this week. It is kinda pricey but that is because i do short runs. It has an onboard LFO, and Gain stage. Look at this blog to see the details if you would like to build this.
http://bluelanternclones.blogspot.com/
i will post the pcb on ebay right now. |
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handsfelloff
Joined: Sep 01, 2008 Posts: 24 Location: uk
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Posted: Tue Jan 20, 2009 3:36 am Post subject:
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Hey nice one mate
The pcb is pro! is it double sided? I would love to etch my own stuff, but prehaps for the first build this could be more sensible. I have some software that helps you design layouts, but one step at a time! I live in the uk I hope that wont be a problem for shipping.... I checked out ebay for the pcb but could not find it would you kindly send a link
cheers again!
Wilson |
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haxster
Joined: Feb 01, 2006 Posts: 246 Location: MONTEREY PARK, CA 91754
G2 patch files: 2
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handsfelloff
Joined: Sep 01, 2008 Posts: 24 Location: uk
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Posted: Wed Jan 21, 2009 3:36 am Post subject:
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Thanks for the link!
Someone has tagged that already, but unforunately with the shipping its already getting out of my reach for me now.... UPS to UK at $46 is steep for a flat light weight letter size package. Damn couriers are a rip off and since its letterish it may be cheaper to send parcel post. Apologies for being a cheap stickler... your pcb is amazing and I'd love to build it if I can afford!
Alternatively or in the mean time.... still since I have my etching gear I would like to have a go myself on the cheap....whats the worst that can happen? I etch a hole in the bottom of my boat and sink to the bottom of the canal (5f max)
Do you reckon I could do a single sided hack or your design? Would be a great learning experience. I have some software that helps to create layouts and if it okay with you I could base off your latest schematic.
If you happen to have any prototype singlesided layout jpg's that I could start with that would save some time...Ah but that would be cheating
Im excited to get etch solder hacking!
many thanks
Wilson |
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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: Wed Jan 21, 2009 1:06 pm Post subject:
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I will post a proper schematic then. I will start on it this evening pacific time so you could start planning your own pcb.
If you could find out how much shipping is for something under a lb. in weight USPS priority I could also ship it that way. That takes longer though.
The size of the pcb is roughly half a sheet of paper. |
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handsfelloff
Joined: Sep 01, 2008 Posts: 24 Location: uk
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Posted: Wed Jan 21, 2009 2:49 pm Post subject:
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Thanks haxster,
What a legend
Very much appreciated you have really help to bring this amazing little filter to the diy world with some nice extra twists...
I did some research into sending the pcb....Any courier seems prohibitively expensive $42 being a reasonably conservative figure. however this is because the package is calculated by rounding up to the nearest kg so...half a sheet of paper you say...should fit nicely into a large padded letter envelope it bound to be cheaper and customs don;t get nosy...We have a national post office royal mail cheap for delivering letters airmail. Not sure, but i guess there must be some equivalent over your way if the package fits into an envelope airmail sizes...
If there is no easy immediate cheap way I will have some fun making my own layout etches from your schematic trail and error way. In fact I definately will anyway for the experience...Ive got to use this tub of acid for something then prehaps if you have some stock/increased demand i can give you a shout in a couple of months when I have some surplus £'s (like I ever have surplus)
thanks again for busting out the schematic.
Wilson |
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haxster
Joined: Feb 01, 2006 Posts: 246 Location: MONTEREY PARK, CA 91754
G2 patch files: 2
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handsfelloff
Joined: Sep 01, 2008 Posts: 24 Location: uk
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Posted: Thu Jan 22, 2009 4:02 am Post subject:
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Thanks mate this is great!
I have just ordered the parts I will start working this out in cad today.
Wilson |
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loss1234
Joined: Jul 24, 2007 Posts: 1536 Location: nyc
Audio files: 41
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handsfelloff
Joined: Sep 01, 2008 Posts: 24 Location: uk
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Posted: Fri Jan 23, 2009 1:55 pm Post subject:
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Damn right!
Order haxters board or even buy a complete build!
Parts are standard and cheap.
Wilson |
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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: Fri Jan 23, 2009 6:41 pm Post subject:
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Yeah you build this with LM4250 Programmable Op amps (2 of them), here in the states those are not hard to find or obsolete. You can use the original IC also but you would have to change the 1.2M resistors to something lower. I don't think it is worth getting a hold of the original IC's. I will have the actual schematic soon, by Monday. The fix i used for this seems to be working for alot of filters were the cutoff range is poor. The trick is to put a 100k trimmer with +/- on pin 1 and 3 and have pin 2 with 100k go to the Control voltage portion of the circuit. Usually it has the Cutoff, and CV inputs tied together. Yusynth does this to alot of filter designs. I learned that from his stuff.
The polivoks alternative project was started from here:
http://m.bareille.free.fr/modular1/vcf_polivoks/vcf_polivoks.htm
You had to tweak it yourself to get it working.
No updated pcb was ever made or maybe there was no demand, it had kinda died.
I simply fine tuned and finished the job proper to a final reliable pcb.
This fixed worked with a Synthacon Steiner VCF too. |
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handsfelloff
Joined: Sep 01, 2008 Posts: 24 Location: uk
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Posted: Mon Jan 26, 2009 3:11 am Post subject:
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I've put haxters/raywilsons gain stage into cad and come up with a starting point for single layer pcb (with 3 jumpers) Its my first attempt at board design so I'll work on it more till I present it
When I have done as best I can i'll post for comment and advice.
Im getting the parts this delived this week so i can start breadboarding!
its adictive |
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handsfelloff
Joined: Sep 01, 2008 Posts: 24 Location: uk
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Posted: Tue Jan 27, 2009 11:53 am Post subject:
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Hey,
So I have come up with a single sided layout of the schematic Haxter posted.
Its the very first board I have ever attempted to design and has taken the best part of a day even with this simple little schematic its quite a challenge to work out single sided fun though...I think ...so I was wondering if you kind people (haxster if you have a moment) could check it out and advise me. I have done some learning about pcb layout so hopefully I have got some way and avoided the major pitfalls...
Anyway this is stage 1 the simple part...next comes the actual vcf that going to be fun!
Cheers,
Wilson Last edited by handsfelloff on Wed Jan 28, 2009 3:30 am; edited 2 times in total |
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handsfelloff
Joined: Sep 01, 2008 Posts: 24 Location: uk
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Posted: Tue Jan 27, 2009 11:57 am Post subject:
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single side pcb layout first attempt! Let me know if I made any obvious rookie errors
cheers,
wilson
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jumunius
Joined: Apr 19, 2010 Posts: 346 Location: San Francisco, CA
Audio files: 13
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Posted: Fri Mar 04, 2011 8:41 pm Post subject:
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haxster wrote: | You get different Rez notches, it is a Rez Notch Hack. |
I tested this Rez notch hack with my nearly-complete Papareil build last night. I don't know if it works the same since your build is slightly different. Anyways, the LPF mod is quite excellent, and will make it into my panel. The BPF made a difference but wasn't as immediately overwhelming... actually rendered the Polivoks uncharacteristically subtle! I don't know if it was just the sound sources I was processing or maybe it works better with the values/components in your build.
For anyone out there who is building the Papareil version and is curious, the mod is a pair of SPST switches which connect the center wiper of the Res pot to the negative pins of U5. (Do I have that right?) The one that works best for me connects to the junction of U5 pin 6, R21 and R22.
Thanks for the cool mod and other tips. Very handy. |
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davebr
Joined: Jun 09, 2007 Posts: 198 Location: portland, or
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Posted: Mon Feb 04, 2013 8:40 pm Post subject:
Polifoks VCF filter |
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I just built the Polivoks VCF on a breadboard using NTE888M parts. They seem to work quite well. I was less than enthusiastic about the self-oscillation so made a simple modification to make it more to a 10V pk-pk sine output. I've documented my modifications and have scope images of various waveforms over on my Polivoks filter page at http://modularsynthesis.com/kuzmin/polivoks/polivoks_vcf.htm.
[EDIT - I just got some УД1208 Russian parts and did frequency plot comparisons between the NTE888M and УД1208 parts. There is a slight frequency and output amplitude difference but they look very similar. Scope images have been added to my website for comparsion.]
Dave
Last edited by davebr on Sat Feb 16, 2013 11:01 am; edited 3 times in total |
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jumunius
Joined: Apr 19, 2010 Posts: 346 Location: San Francisco, CA
Audio files: 13
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Posted: Mon Feb 04, 2013 9:52 pm Post subject:
Re: Polifoks VCF filter |
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davebr wrote: | I just built the Polivoks VCF on a breadboard using NTE888M parts. They seem to work quite well. I was less than enthusiastic about the self-oscillation so made a simple modification to make it more to a 10V pk-pk sine output. |
Cool Dave. I have a second board. Someday I'll build your variation -- your mods seem useful and well considered as usual. _________________ -Jim |
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davebr
Joined: Jun 09, 2007 Posts: 198 Location: portland, or
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Posted: Sun Mar 10, 2013 8:55 pm Post subject:
Re: Polifoks VCF filter |
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davebr wrote: | I just built the Polivoks VCF on a breadboard using NTE888M parts. They seem to work quite well. I was less than enthusiastic about the self-oscillation so made a simple modification to make it more to a 10V pk-pk sine output. I've documented my modifications and have scope images of various waveforms over on my Polivoks filter page at http://modularsynthesis.com/kuzmin/polivoks/polivoks_vcf.htm.
[EDIT - I just got some УД1208 Russian parts and did frequency plot comparisons between the NTE888M and УД1208 parts. There is a slight frequency and output amplitude difference but they look very similar. Scope images have been added to my website for comparsion.]
Dave |
I got some uA776 parts and added a comparison of those as well as a couple of videos and sound samples to my Polivoks filter page. - Dave |
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gasboss775
Joined: Jan 02, 2016 Posts: 217 Location: Scotland
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Posted: Sat Feb 03, 2018 6:19 am Post subject:
HOW DOES CURRENT SOURCE WORK? |
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Can anyone explain how the voltage to current circuit works on this, I can't get my head round it? |
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