Anyone have schematics for an elop

[pucho812]

This is a weird case.  Can work it without one but would be nice to confirm things with one 

 

[pucho812]

really? NO PM on my end.

 

[pucho812]

well I could ask the mothership as I have a legit serial but who wants to do that when I can just ask here

 

[gyraf]

I don't think we ever saw one in the wild (yet)..  :'(

Jakob E.

 

[scott2000]

Here's some pics of an old VTL ELOP ....

https://www.proaudioeurope.com/info/wp-content/uploads/2011/07/p1020821.jpg

https://www.proaudioeurope.com/info/wp-content/uploads/2011/07/p1020823.jpg

https://www.proaudioeurope.com/info/boffin-island-blog/vtl-manley-electro-optical-leveling-amplifier

 

[fazer]

Cool link Scott.  Wow that elope with those output caps and no transformers and looks like opamp driven opto’s  And 6k pricing ?  Reminds me of Demiter gear.  Would be nice breadboarding  one of those together.   

 

[fazer]

So I read at the end the this was an early design and different from newer versions.

 

[pucho812]

yes. the one I have on the bench has the vactrols mounted one way for channel one and upside-down for channel two. Hard to say if that is normal or what. . ???

 

[scott2000]

upside-down for channel two. Hard to say if that is normal or what. . ???

Well, I really like the Diana Ross version so maybe it's perfect that way

 

[pucho812]

Well, I really like the Diana Ross version so maybe it's perfect that way

I would say not. 4  x stepped attenuators of the same value. ch1 is normal, ch 2 with same settings is not.  it's fixable.  Working blind  just eats more time.

 

[scott2000]

One normal channel is a good start..... Better than none and can give you some reference?

You'll get it....

Maybe some info out there that can give some clues too??

Here's a thread referencing that topology in some ways I guess......???

https://groupdiy.com/index.php?topic=29986.0

 

[fazer]

Another great link Scott.  So much great info on this forum. Stuff I’ve missed from the past.  I have some vactrols to play with .  Need to get them out.  The Manley tube make up amp with large output coupling caps instead of transformers.  Very elegant like PRR says.

 

[pucho812]

I know i'lol get it in time.  Just need time.

 

[pucho812]

I set this aside as I had to deal with life and work.

I took any possible voltage measurement between channels and they match pretty well or they are off by few mv.  I swapped any tube and part between channels and there was no change. About the only thing different is one the good channel the photocells are label up and on the faulty channel they are label down but facing the same way.  a quick trace of the PCB and that is correct.  daft but correct.
so I am not sure what else all pots are the correct values and everything. being stepped I can watch the difference in gain and so far the working channel has minimal change between position, the non working channel has big changes between steps. I would suspect the resistors were the wrong value but they were pre-made and the numbers all match up....

 

[scott2000]

is this the one you have???

I've been looking around at info on these but I guess there are different versions???? Which one are you working with???

Lot of trimmers in there..... I've had issues with those things in the past but they were more random bursts of funky.......

 

[pucho812]

Yes.  The trimmer info is in the manual which you can get online in a PDF. I did calibrate then per  the manual.

 

[pucho812]

sorted finally.  each lesson is a learning, a win or both.