My madness continues...

[digi2t]

First off, a big fat THANKS to all that helped me out with my sample/hold questions. You know who you are.

Mike at Prophesysound gave me some valuable insight a while back on sample/hold, and stereo output, on the Infinitphase. Since I can already split the signal in my rig, the stereo  option was less interesting. The s/h option really intrigued me though. Following Mikes advice, I made a little daughterboard for my Infinitphase, and mounted it to the vero.

Finding the right transistor was a PITA, that's why the sockets. I must have gone through a few dozen transistors before this Motorola 2N5087 made the cut. Tuning the output was another struggle, but in the end... success!









I'm still tweaking it a bit, but overall, I'm pretty happy with it. The random phasing is really cool. I asked Mike where the output taps into the phase, but he wasn't going to reveal all his secrets. He only told me where it wasn't, so, process of elimination.
In the end, I have it tapped in to where the smooth pot can be used to cut down on the popping if so desired. Mike said that the original isn't this way, but I like it. If you dial up the smooth just enough, it's more of a slurring of the phasing, rather than random stepping. Too much smooth kills it, but all in all, total coolness.

Get a video out soon. Just totally swamped of late.

[midwayfair]

Oh ... my ...

[glops]

WOW 

[digi2t]

Here's a demo of the sample/hold in action. I had to change the 1nF cap to a polystyrene cap in the end. It just makes the LF398 perform better. Why, I don't know. As Brother Jimi would say, "That's above my pay grade".

Just too cool.

[thehallofshields]

I'm going through a sample/hold phase and have lots of questions.

Could you link the thread?

[digi2t]

I'm going through a sample/hold phase and have lots of questions.

Could you link the thread?

Go easy on the question chief, I'm quite the noob at this.

What thread do you want me to link?

I'll post all the final details on the build, and integration into the vero, as soon as I can.

[Mark Hammer]

1) Pretty much every schematic for a S&H that I've ever seen notes polystyrene caps being preferred.  I gather this pertais to their low leakage.  Keep in mind that the cap is acting as a sort of memory cell for the sampled voltage, and you want it to be able to hang on to the sampled voltage  for as long as needed.

2) Phasers can often provide 2 flavours, those that use the phase-shifted signal in an additive way, and those that use it in a subtractive way.  This will often show up in the form of dual output jacks and some lame mention of "stereo" on the chassis.  I have a DOD FX-20 phaser with these complementary outputs.  One is decidedly peakier-sounding than the other, and the resonance control has a noticeable (and desirable) effect.  The other output sounds fine on its own, and is more suited to rhythm playing than Alex Lifeson solos.  And on that output, the resonance/feedback control is utterly useless.

Insomuch as use of a S&H form of modulation is really intended to use the phaser almost like a multi-bandpass filter, refocussing attention on these peaks here, and then those peaks there, I can see where it would sound decent for the one kind of phasing (the peaky type), but not for the other kind (non-peaky).

That's not a criticism, just a recognition of the match/mismatch between some types of modulation and the sound/process they are modulating.

[italianguy63]

I missed this!  Seriously Dino?  Building vero condiminiums now... what's next?   

Future thread topic:  How many "floors" can you fit in a 1590A?  (note:  alarm lightbulb just lit in Pickdropper's head)

MC

[amptramp]

Whatever you do, don't tell pickdropper about cordwood construction:

[digi2t]

Whatever you do, don't tell pickdropper about cordwood construction:

Now THAT... is rad! 

I missed this!  Seriously Dino?  Building vero condiminiums now... what's next?   

Future thread topic:  How many "floors" can you fit in a 1590A?  (note:  alarm lightbulb just lit in Pickdropper's head)

MC

The whole piggyback idea was spawned by my dissection of the Spaceman Gemini III Dual Fuzz. The nice thing is that I could use the lower stand-offs to transfer the power, cutting down on the wiring.  

[amptramp]

Cordwood was the advanced construction standard of "jet age" avionics in the 1950's.  You may still be able to find surplus pieces.  I used to work with a draftsman who had to design cordwood (and there were no CAD packages in that era).  It paid his mortgage but it ate his soul.

[digi2t]

It paid his mortgage but it ate his soul.

Alas.... my soul is gone, but the mortgage remains. 

[Freppo]

Here's a demo of the sample/hold in action. I had to change the 1nF cap to a polystyrene cap in the end. It just makes the LF398 perform better. Why, I don't know. As Brother Jimi would say, "That's above my pay grade".

Just too cool.

VERY cool! Thanks for sharing
Sound great. Very synthy
How many phasing stages are there?

I have dabbeled with s&h myself recently with this circuit:
http://www.diystompboxes.com/smfforum/index.php?topic=110314.0
It's pretty crude and it took alot of components for the s&h.. a dedicated chip would probably been prefered.
Sometimes I think pic-chips would do the job so much easier.. but it require programming and i'm totally lost there.. 

cheers / Fredrik