Hello,
I'll clear up the confusion. For the daughter board, the schematic is correct. The - and + pins on one op amp are swapped, basically. I use a CGS simple mixer PCB, which needs to have those physically swapped, as the ground trace is a bit too big there to simply cut. You then run jumpers to the points those pins need to go to. Those jumpers are wired directly to the pins of the TL072. If doing it on your own, you could use protoboard or a Tellun MUUB-2 if my solution seems inelegant :) It works well with my bracket, though, and is not hard to do.
By the by, a great place to get the tap from the oscillator core is very close to the "Sync" pad, on the closest "extra cap hole" if you use a .2" cap. I'll try to get a pic up if anyone wants to see that.
As an aside, kudos again to Ken for providing extra holes for different size components!
I think Jim means that the power _header_ is backwards, compared to MOTM modules -- that is, +V and -V are opposite of what you may be used to. However, if you put the header in according to the silkscreen, everything is fine. I supply friction lock headers, so as long as the headers follows the proper silkscreen, you can't put it in backwards. The silkscreen may be hard to cipher, though, since it's made for MOTM and .Com power headers; I triple check my own each time I make an assembled module :)
I did indeed sacrifice the Linear FM for the oscillator outputs, and a 2U module instead of 3U.
If there is ever interest, I could add a 1U expansion. This would include Linear FM, PWM square output, and VC Bandpass. It still needs to be tested, the PCB made, etc...
I must say that this filter is very deep. Sound destruction and such are easy to do, as well as some very subtle effects. Small changes in bandpass and frequency can lead to very different sounds. I made some sound samples -- they should be on my site next week, after my web guy catches up w/ all the new stuff...
I'll clear up the confusion. For the daughter board, the schematic is correct. The - and + pins on one op amp are swapped, basically. I use a CGS simple mixer PCB, which needs to have those physically swapped, as the ground trace is a bit too big there to simply cut. You then run jumpers to the points those pins need to go to. Those jumpers are wired directly to the pins of the TL072. If doing it on your own, you could use protoboard or a Tellun MUUB-2 if my solution seems inelegant :) It works well with my bracket, though, and is not hard to do.
By the by, a great place to get the tap from the oscillator core is very close to the "Sync" pad, on the closest "extra cap hole" if you use a .2" cap. I'll try to get a pic up if anyone wants to see that.
As an aside, kudos again to Ken for providing extra holes for different size components!
I think Jim means that the power _header_ is backwards, compared to MOTM modules -- that is, +V and -V are opposite of what you may be used to. However, if you put the header in according to the silkscreen, everything is fine. I supply friction lock headers, so as long as the headers follows the proper silkscreen, you can't put it in backwards. The silkscreen may be hard to cipher, though, since it's made for MOTM and .Com power headers; I triple check my own each time I make an assembled module :)
I did indeed sacrifice the Linear FM for the oscillator outputs, and a 2U module instead of 3U.
If there is ever interest, I could add a 1U expansion. This would include Linear FM, PWM square output, and VC Bandpass. It still needs to be tested, the PCB made, etc...
I must say that this filter is very deep. Sound destruction and such are easy to do, as well as some very subtle effects. Small changes in bandpass and frequency can lead to very different sounds. I made some sound samples -- they should be on my site next week, after my web guy catches up w/ all the new stuff...
----- Original Message -----
From: Mark
To: cgs_synth@yahoogroups.com
Sent: Friday, April 13, 2007 12:17 AM
Subject: Re: [cgs_synth] Re: Success! (Was: bi-n-tic filter...help!)
On 4/12/07, James Elliott put forth:
>I ordered the MOTM Bridechamber version from Scott. I had some
>difficulties initially with the construction, however once I got
>everything figured out it worked fine
After looking at the docs, the daughter board for the VCO outputs
seems a possible source of confusion. It says "You need to bend two
pins so that they do NOT go into the socket," but the schematic shows
all eight pins -- as one would expect -- of the dual op-amp being
used.
>(BEWARE THE 'REVERSE' POWER SUPPLY PIN-OUTS! - I'm supprised I
>didn't fry everything on the board).
The power supply pins don't follow MOTM format?? I could see how
that could cause a problem. Do you need to make a special cable??
>The panel looks good & it was pretty easy to build. As for the
>module itself - I consider it more of a VCO than a filter. It's as
>much of a filter as a flanger is..... Meaning it does not really
>resemble a filter :) To me its seems more of a frequency shifter,
>with some added crazyness. HOWEVER I personally think that it is a
>pretty cool module once you realize what it is vs what it isn't
While I have no idea how it could sound like a frequency shifter, I
do like the demos that I have heard -- very impressive. That it can
be used either as a regular VCO or an unusual filter makes it seem
much more practical.
Also, while I'm typing, the schematic on the CGS website shows a both
1V/Oct and linear FM inputs, but the Bridechamber panel looks like it
has a an "EXP FM" input. Is the linear FM input unused??
http://www.bridechamber.com/bi_n_tic_big.html
http://www.cgs.synth.net/modules/pic/schem_cgs57_bintic.gif
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