Sample/Hold and my Neutron

[A.J.]

I build the single chip sample hold from here:

http://www.musicfromouterspace.com/analogsynth/singlechipsampleandhold/singlechipsampleandhold.html

because I was thinking I might build a synth - never finished that - but over the weekend I was going through the PCB graveyard found the Neutron I don't use anymore (built a Meatball) - thought for a minute, built a quick noise source from that same site, stuck it all together with the S/H driving the Neutron LDR, and damned if it didn't work surprisingly well (had to tweak the S/H to get ok voltages, only took a minute) - bleeping and burbling away - a bit of a very quiet tick in the background, but I think I can fix that with some better wiring - leads all over the place right now. 

So now I'm thinking that I can do a lot better with this - the Neutron makes a nice base - my plan is to to get a more adjustable S/H - something with portamento - and then maybe use a quad op-amp as a mixer for the lowpass, bandbass, highpass channels on the Neutron (will that work?).  Might also bring the LDR resistor out to allow for some adjustment there too.   

Has anyone tried this before?

Also, since I sort of destoryed the envelope section of the Neutron I can't go back to measure what the voltages were at the LDR at the low end and the high end - any idea of a reasonable range to get the most out of the sweep?

Thanks!

A.J.

[caress]

i just perfed up the same s&h a few days ago for a control source project...haven't tried it yet, but i'm pretty sure you can add a "glide" control to the s&h to make it a bit more versatile - search around on the MFOS site.it would probably be less work than building another s&h, especially if yours works well already...

[Bassmanfox]

I've been messing with the mu-tron for a while now.  I've made a few different varieties based on both the mu-tron, the meatball and some of my own design.  Initially I made it do a self induced sample and hold.  I've drawn up a quick schematic showing this, Please excuse the messiness as I prefer to draw them by hand.



Please note that the LM1458 is the BEST CHOICE BY FAR for U2, Also I used VTL5c3 Vactrols for the Opto's, Honestly I've never had any other kind work as well or as consistently.

First you must include the sensitivity control(basically after the cap of IC1) with either design and leave out the 4k7 resistor after it.  The Mutron just has a 22k resistor there and the meatball has a sensitivity control with a 4k7 after it.  Then add a switch that can select or remove D1( in the neutron), D3 in the meatball.  The setting that removes D1(D3) gives is the one for sample and hold.  Once the sweep is in the down position you will get some sample and hold sounds when the sensitivity control is at its lowest setting, i.e. the resistance across the potentiometer is basically 0.  To control the sounds and the down sweep colour, add a potentiometer or trimmer in place of r18/r19 on the mu-tron.    There are a million different mods to the mu-tron you can do, its really unbelievable.  Also you see that values can vary as I put some values ranges that you can use. Really the Meatball is just a modified to the max mu-tron.  You can add attack and decay controls that will mess with the sample and hold.  Using my schematic, R4 is attack, R9 is decay, just change them into potentiometers. 

As with the TRUE sample and hold on music from outer space, HELL YEAH.  Its ironic because today, 10 minutes before I read this post, I connected my sequencer found here http://www.musicfromouterspace.com/analogsynth/SEQ16_2006/SEQ16_2006.php
to the mu-tron the same way you connected the S&H to it.  I was measuring the the envelope section and I found that 0-6V was about the range of its output, but I could be somewhat off as its only 1 guitar I tried and my scope can be somewhat of a liar.  Still the sequencer outputs a CV just around there and that seems to work perfect.   I'm in my lab today and tonight I'll head to the practice space tonight see the real results.

Also if anyone is interested in the sequencer contact me.  I made a "compact" Layout for it.  Hopefully I'll post some pics of all this soon.

[Mark Hammer]

I like the fact that you've included the "down colour" control.  I keep harping on this, but the fact is that upward sweep works nicely starting out from the lowest possible filter frequency, but downward does NOT sound all that pleasing starting out from the complete opposite end.  It needs to start its sweep from part of the way along.  Happily, Mike Beigel realized this and the Mu-Tron's up/down switch adjusts the starting point appropriately for the downward sweep.  Still, change the sensitivity/width of sweep and the range of the filter, and suddenly what was a reasonable place to start out is not such a reasonable place.  The colour control you have provides some room for tweak-to-taste without going so far to one extreme or the other that downward sweep starts misbehaving.

Nice feature.  I tip my hat to you.

[Bassmanfox]

Thanks Mark, I really love the mu-tron and have spent a lot of time with it.  I'm really excited to try the sample and hold idea too, getting more from your pedal is what I love about this forum.  I just added a  CV input to the tremulus lune and ran the sequencer thru it, so far so good.  I I think I may have to add a pot to dial down the CV voltage as the Lune doesn't seem to need more than 2.5v to get a full trem.  Next I am gonna build that S&H and add it to the mu-tron and maybe try it on the Lune for more fun.  I'll make sure to post the results.