Has anyone tried to build the E-H MiniQ-Tron?

[ModulusMK]

Hi, has anyone built a copy? I'm specifically interested for the HTV P873-13 photocoupler part, I can't find it to buy it... is there a replacement OR what photocells to use to make one?
Anyone familiar with this or any suggestions?

These are the specs of the photocells in HTV P873-13:

Part Number = P873-13
Photocell Type = LDR
P(D) - Max. Power Dissipation = 30mW
V(BR)Out - Min. Breakdown Volt = 100V
I(IN) - Min. Control In. Curr. = 20mA
V(IN) - Min. Control In. Volt. = 2.1V
r(on) - Max. On-state Res. = 10kOhm
r(off) - Min. Off-state Res = 10MOhm
t(off) - Max. Turn-off Time = 20mSec
t(r) - Max. Rise Time = 20mSec
Viso - Max. Isolation Voltage = 5.0kV

I've looked at the P722-7R photocell from smallbear but I'm not sure if it will work properly, has not the same specs with it and I don't know what tolerances are allowed here.

Thanks! 

[Processaurus]

Not sure about that specific part, but the Mini Q-tron is based on the famous Mu-Tron III.  There is a well documented clone project at geofex.com called the Neutron, if you haven't seen that yet.

[ModulusMK]

Thanks man, I know that Neutron exists as copy of Mutron 3, but didn't thought of that it might have any substitutions noted in the project for the optocoupler part.
I read the article, it is from great help although not the same as Q-Tron but the "roots" are there.
One reply was enough 

[jdub]

I built one about six months ago.  I tried finding the P873-13 to no avail, so I used two VTL5C3s instead and it works (and sounds) pretty good.  Not as rich sounding or as predictable as a big Q-tron, but a lot easier on pedalboard real estate.  I have a perfboard layout for it that I've been meaning to post in my layout gallery but haven't gotten to yet; fits (snugly) in a 125B.  If you're interested, I can post it today or tomorrow.

[reveil]

Hello everybody, I built the effect basing myself in the following diagram electronic pdf, but I have identified that the zener appointed as D4 - 1N5529B actually is a zener of 9.1v, and the scheme is written 4.3V (in my particular I I used a 1N4731 zener 4.3V). I was confused and the effect does not seem to be working well.

I built on a perfboard replacing two TLC2262CP by a LM324N in order to save space, and am doing a debug correcting links I had forgotten. If anyone has a credible blueprint, or could check with the effect the voltage at the point of D4 and its name, I appreciate that!!!

file: http://www.sendspace.com/file/sj8xui