Search found 5474 matches
- Fri Jul 16, 2010 10:09 am
- Forum: Pro Audio Design
- Topic: A VCA-Based Phaser
- Replies: 25
- Views: 57803
Re: A VCA-Based Phaser
yes gain cell is non inverting, looks like voltage input, not current input. I think it's current in. http://www.analog.com/static/imported-files/data_sheets/SSM2164.pdf The 30K is the input V-I converter. The 30K wrapped around from the output back to the 2164 input alters the gain control slope (...
- Fri Jul 16, 2010 6:25 am
- Forum: Pro Audio Design
- Topic: An Idea
- Replies: 23
- Views: 37949
Re: An Idea
That's a good question. I think I would include in that design the use of digi-pots for some things (e.g. makeup gain, threshold etc in the dynamics) where you're potentiometrically controlling DC. For the preamps and line inputs a 1570/5171 combo might be included since VCAs wouldn't lend themselve...
- Fri Jul 16, 2010 6:02 am
- Forum: Pro Audio Design
- Topic: A VCA-Based Phaser
- Replies: 25
- Views: 57803
Re: A VCA-Based Phaser
John: I found another cite for an SSM2164-based phaser and it looks like the Cfb around the I-V converter were made bigger so that it acts more like a voltage variable integrator: http://userdisk.webry.biglobe.ne.jp/000/024/65/1/Vcph0505.GIF From looking at the all-pass network, doesn't it look like...
- Thu Jul 15, 2010 12:41 pm
- Forum: Pro Audio Design
- Topic: A VCA-Based Phaser
- Replies: 25
- Views: 57803
Re: A VCA-Based Phaser
Here's a demo of the 8 pole with the last tap summed with direct. This one is mono output. http://www.proaudiodesignforum.com/content/VCA_Based_8_Pole_Phaser_Demo_8th_Tap_Only.mp3 (~1.5 MB) This following sample is with both the 4th and 8th sections summed with the direct. It's a little thinner but ...
- Thu Jul 15, 2010 9:21 am
- Forum: Pro Audio Design
- Topic: A VCA-Based Phaser
- Replies: 25
- Views: 57803
Re: A VCA-Based Phaser
No complication for the 12 pole - just running out of VCAs and protoboard room. I think this thing could be cascaded in three blocks of four to do a 12 pole. I'm not sure if the SSM2164 inverts or not. It looks like a voltage variable integrator with local feedback taken into the input summing node....
- Thu Jul 15, 2010 5:06 am
- Forum: Pro Audio Design
- Topic: A VCA-Based Phaser
- Replies: 25
- Views: 57803
Re: A VCA-Based Phaser
I think for now I'll align them using equal C values. That's how I usually see them. The Ec will be bused and they ought to track well. I may experiment with having an inverted CV to four of the (eight) poles so that as one goes up the other sweeps down. I also need to revisit Thomas Henry's Barber ...
- Tue Jul 13, 2010 11:24 am
- Forum: Pro Audio Design
- Topic: A VCA-Based Phaser
- Replies: 25
- Views: 57803
Re: A VCA-Based Phaser
Should I continue with this?
- Tue Jul 13, 2010 7:02 am
- Forum: Pro Audio Design
- Topic: A VCA-Based Phaser
- Replies: 25
- Views: 57803
Re: A VCA-Based Phaser
Ever since I built an 8 pole "DynaPhaser" prototype back in the early 80's using a pair of SSM2040s I've wanted to rebuild that prototype using modern VCAs. I recalled that listening to it was such a mindf**k (pardon my English) it was worth revisiting. One of the things the SSM2040 had go...
- Mon Jul 12, 2010 1:12 pm
- Forum: Pro Audio Design
- Topic: A VCA-Based Phaser
- Replies: 25
- Views: 57803
A VCA-Based Phaser
I decided to make a THAT2180 VCA (actually three) into an all-pass filter. This is a three pole demo. I'm not going to stop building until I get to eight. A stereo output is derived from polarity inversion and a sum/difference network. Here's a quick and dirty demo. https://www.proaudiodesignforum.c...
- Tue Jun 29, 2010 1:01 pm
- Forum: Pro Audio Design
- Topic: B+ and filament PSU problem
- Replies: 13
- Views: 21863
Re: B+ and filament PSU problem
There should be a trim for the crowbar threshold. If it's an older power supply the carbon comp resistors that may have been used could have drifted significantly. The crowbar might also have an electrolytic for noise filtering that's failed.