Carlin Phaser: LDR values?

[Puguglybonehead]

I was looking for a simple phaser schematic that could be breadboarded easily and would allow some experimentation with adding extra stages. I came across the Carlin Phaser:

http://www.experimentalistsanonymous.com/diy/Schematics/Phasers/Carlin%20phaser.gif

It also has a manual control option, which is something else I would really like. (ie: expression pedal controlled sweep) The schematic however, does not suggest any value for the LDRs. Anybody out there with some Univibe experience or anything who would have an idea as to which LDRs to try? This thing would probably be living on a breadboard for quite some time, until I actually get it working. I'm wondering just how many stages could be added before noise levels get too much? 12? 18? 24?
Also wondering how hard it is to find a lamp that matches the one in the schematic?

[daverdave]

No idea about this particular design, but I designed a phaser that used optocouplers for my first year uni project. I just used yellow LEDs heatshrinked to LDRs, the LDRs weren't matched as far as I'm aware, but the phaser worked. I made it with 8 stages and it sounded pretty sweet. Not sure how many stages you'd get away with, maybe just do 4 at a time or something and see how it sounds as you go, I think I remember Mark Hammer posting something about having more than 8 stages if you search the forum.
Dave

[maarten]

Have a look here for your LDR question:

http://www.diystompboxes.com/smfforum/index.php?topic=85823.msg717904#msg717904

Maarten

[petemoore]

  The LDR Limbo...how low can you go ?
  High R dark resistance went way up enough to make serious signal impedance with all the LDR's I tested.
  Low R light resistance...varied enough from unit to unit..hand picked when it mattered with some of the builds.
  Speed matters too if you need it, such as with a compressor, perhaps if you like uber-fast wobble-phasing sweep [different...
  The 'relaxing' effect of LDR's that don't sweep ''so far...so fast'' is likely preferable so that as phase speed increases past 'fast', the sweep range diminishes, creating less of ''wibble-wobble-went too wild" ramping of phase sweeps...which makes ''space ship with dodgy flux capacitor'' sound instead of 'leslie-like'.
 

[daverdave]

I found that my home made optoisolators weren't that fast, when the speed was up to wibble wooble territory they didn't have enough time to get to the lower end of the sweep.

I've looked at the silonex NSL32-2 (I think that's the part number anyhow) datasheet and it claims a pretty fast decay response, quick enough for a phaser anyhow.

[Puguglybonehead]

Thanks for all the responses! Some very helpful information from all. 
Seeing as wide range is something I would be going for at slow LFO speeds, (or manual sweep) I guess I will go with one of the two LDRs that Small Bear recommends for Univibe builds.
The decreased range at higher speeds makes sense as well. If I can get this to work in 6-stage form, then it should, hopefully work with more.

[bms19]

I'm very late here but there are some informations
Carlin phaser kit instructions