Photocells in clones of Univbe (Neovibe) & Mutron (Neutr

[Johnny Guitar]

Hello,

I'm getting some part orders together for Mouser and Small Bear to finish all the half built projects I have laying around.

I've never done the LDR matching that is needed for the Univibe/Neovibe. I think I understand how to do it. What I'm wondering is how many I should buy in order to match the four needed for the project. I think they're around $1.50 each so I don't want to buy too many more than I will need.

I also noticed that Small Bear offers a replacement part for the Mutron/Neutron:

Hamamatsu P873-13 Dual Photocoupler Clone/Repair a Mutron or Neutron!  for $7.25

I'm wondering if anyone has any experience with this part or with another way of dealing with the dual photocoupler.

Thanks!
John

[Tychobrahe1979]

When it comes to matching LDR's for the neovibe I've read from RG's Geofex website that it really makes very little difference. I however have not tried this but I just thought I would pass along what I have read from a very reliable source.

[sir_modulus]

Yea, matching makes a big sonic differance. If I were you, go to the buy/sell sect. and ask for old Mutron/etc... optoisolators(photocouplers), As i'm sure many people have tried to match these and have ones left over.

[STOMPmole]

FWIW, I just built a Neutron with the Hamamatsu Photocoupler from Smallbear and it worked great!  

I'm sure you could go with one of the other options and get fine results...if you want an easy trouble free build though, I'd recommend spending the extra $$ to buy the Hamamatsu.

[Johnny Guitar]

Thanks STOMPmole, that's just the kind of advice I was looking for. I think I'll take your advice!

(I'm still hoping for similar advice before I order my LDRs for my Neovibe)

J

[STOMPmole]

Glad to help!  One thing I forgot to mention was that I put a 100K pot in place of Rx for 'tweaking' purposes after reading on the forums that the suggested 10K pot was too small for some Photocouplers (Hamamatsu?).

Anyway, I haven't pulled the 100K pot to measure the resistance value yet...(I plan on replacing it with the closest standard value metal film resistor) so I can't say for sure if it's value is >10K or not.

Another thing to note is the extra jumper you have to install when using the Hamamatsu (it's easy to overlook it on the diagram).

Lastly, I followed the diagram and used Alpha pots...during testing I found that they were both hooked up backwards...I swapped the wire to the opposite terminal (keeping the wiper wire the same) and it worked great.

Just thought I'd point that stuff out to help you avoid any troubleshooting headaches after completing your build.  Good luck with the project!!

[smallbearelec]

According to Mouser, the 338-54C679 is no longer being manufactured. I called this morning and bought the last of their stock. I have about 2,000 pieces now, and I will continue to sell them, retail only, at $2.50 each.

I will also send a couple of samples to Silonex and ask if they offer anything similar.

My stock of the Hamamatsu P873-13 and the Clairex CL9P4 is good for some years yet, and I will keep my bearish ears open for announcements from Vactec.

SD