Has anyone ever done a "filter bank"

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[quote author="jameshspencer3"]I want to build a filter unit (kind of like a Sherman filterbank) i was wondering if anyone had built one or had drawings i could reference before i dive in.[/quote]

I built one from the Oakley minimal kit http://www.oakleysound.com/projects.htm

oopsie wrong link it's
http://www.oakleysound.com/rack.htm

I built the original one - VCF-1. It is very cool. I have it in a case with a bucket brigade delay I made from the SAD4096 chip and they can sync to each other or sync to a LFO. Quite cool.

If you want to build from a board that comes with the harder to source parts I can recommend Oakley. The boards are very nice quality too.

Kiira
 
I can second this - the Oakley stuff is good & well documented. Ordered the VCF-1 as well and also a few smaller boards and delivery & support is excellent. Starts to sound like an ad...

Bye,

Peter
 
I just continue on the oakley praising. I think I have built every oakley design there is, including all synth modules. The documentation and quality of both PCB's and the designs are outstanding. You can't get anything better according to me.

The filtrex is probably what you want, a great filter with pre-amp, envelope follower, envelope, and LFO.

http://www.oakleysound.co.uk/filtrex.htm

Robert
 
Hello - I'm new here to group DIY. I also can vouch for Tony's Oakley designs, the PCB's are excellent - I've built 2 VCO's and a State Variable Filter for a modular system and they sound great, stand up well with my vintage synths easily. Great guy to deal with too.

- Michael nil-x
- Pressure : Penetration
 
Tony Allgood is the man! A friend has walls of his modules and MOTM, I'm deeply jealous. Tony is also a very decent guy, he takes support seriously.

I have a Sherman bank mk2 - they're not to everyone's taste I assure. Users complain that they distort everything which is true, but you can get "clean" sounds if you have the patience, and I mean patience. They've come down in price new now, you could probably get one s/hand for little more than the parts to build one.

Justin
 
justin-

what prices have you seen and where? I keep seeing $700-800 on them new, which is too much for me to pay when you can get the frostwave korg filter for $300 and be about what, %68 of the way to a filter bank, which is good enough for me based on the price. those things sound great too! Ive always wanted a filterbank for parallel busses but never could justify the cost.

dave
 
Also I recommend for a lower cost filterbank the AKAI MFC-42 - it's not as smooth as a synth filter but it can sound really good - my favorite application for it so far is using it to filter a stereo digital delay. I can post up some examples later if ya'd like. I picked it up for like 200$ if I recall correctly. It has a not so great but useful analog phaser and distortion too.

- Michael nil-x
- Pressure : Penetration
 
i'm a big fan of the sherman too. i got mine directly from herman gillis during a trip thru belgium. very nice man. and brilliant filterbank for sure. the sub-octave pitch tracking is sick.

i wouldn't mind having a mutronics mutator to go with it though, true stereo and some of the richest sounding LPF's i've ever heard. unfortunately, a mutator costs even more than a sherman.

-scott
 
The thing that always kept me from getting the Oakly is it is a Moog style transistor ladder VCF. For a filter bank type use I would want to go with a state varriable filter or a pair of filters, a high and a lowpass. The Moog filter is great in a synth or as part of a modular, but not much for a standalone filter box. The nice thing about the oakley is that it is Q compensated, none of that volume goes down and resonance goes up crap.

I would look at the oberhiam SEM filter for a filter bank. It is simple to make and cheap. The EDP wasp VCF would also be a good canidate. Its all pretty simple as far as construction goes, and pretty cheap. Unless you want midi control, if you want midi you might want to just buy a sherman filter bank.

adam
 
The Mutator is great, but expensive. It is also just a 24 db transistor ladder lowpass. I think the Oalkley might beat it in a side by side test, but thats jsut because the Oakley has the Q compensation. Although some of you out there might like the sound of your VCF getting quieter and quieter and you increase the resonance, then you should go with the Mutator. The only Filter Bank that ever seemed worth the money to me is the Sherman, but thats just because it had Midi, and that was when I cared about midi. A filter bank is a very simple thing to make, especily if you build it modular. And now for the Links that I forgot in the last post, just a few off the top of my head for now.

EDP Wasp Filter Clone with Envlope and LFO, A simple little VCF with HP, LP, BP, Notch and a distortion thrown in for an extra $0.50
http://www.oldcrows.net/~jhaible/tonline_stuff/hj_wasp.html

MS20 VCF and other along with a bunch of other fun stuff. The MS20 VCF can be made HP quite simply or even switchable between HP and LP, so a pair of these in a box can give you a wide range of filter responses
http://www.uni-bonn.de/~uzs159/

Then there are also all the Kit options if you prefer.
Oakley http://www.oakleysound.co.uk/
paia http://www.paia.com/
Blacet http://www.blacet.com/
MOTM http://www.synthtech.com/

and there are many others. searching about for synth diy site will give you many more filter choices. Or you can try the Synth-DIY mailing list, you should get a whole lot of responses over there. They really like to talk about VCFs.

adam
 
...there is a little more to it than that. It's based around an SSM2045, but yes it is 24dB LPF. It does have MIDI implementation though.
Cutoff, Resonance, VCA, LFO re-trigger all controllable via MIDI. Cutoff controllable directly via CV too.. :grin:

chef
 
Did they switch it over to the SSM clone at some point? I could have sworn it was a Transistor Ladder. I was not even aware it was still around, the last time I had heard of it was shortly after it came out, midi was an extra lump of cash back then. Either way I sure had alot of fun with it the one time I got to play with one, but it was to much money for a standalone filter box that was just LowPass. Built incredably well though, its build quality is about 100 times better then Sherman. Playing with a sherman after the Mutator left the Sherman feeling like a toy. Just gave the Mutronics Site abit of a look over, they really do not give any information on it anymore. Seems to me they went quite abit indepth on what it was and features back when it came out. Seem like it is abit cheaper now to, but that could just be the exchange rate to US funds.

adam
 
Well, that answers that, do you happen to know of any synths or anything that used the 2045. This is a new one to me, I gave the data sheet for the 2045 a look but it gave no clues, just made me wonder why Mutronics did add another switch in there and take advantage of the 12db out on the chip, you think they could eat the extra cost of a toggle switch with prices like that.

The mutators manual does not give much info either, I remember the web site originaly going into quite abit of technical specs and such, but then again I also remember it being a Transistor Ladder. Off to try and find out about this damn SSS2045, I am getting curious about it now. It seems like a chip that never got used in anything. Which might explain why Mutronics has been able to make the Mutator for almost 10 years now without running out.

adam
 
[quote author="adamasd"]Off to try and find out about this damn SSS2045, I am getting curious about it now. [/quote]

http://retards.org/library/technology/electronics/audio_circuits/synths/components/ssm/ssm2045.pdf
 
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