Lomo Preamp Schematics (yp-25)

[RedBeard]

Hey guys, I recently snagged some Lomo Yp-25 pres off of ebay and was wondering if anyone had the schematic and wiring diagram (for the pins on the back) for it. I've found the yp27 hand sketched in a few plages not not the 25. Any help would be appreciated! Also would love to know if anyone has experimented with modding them and if so, if they landed on anything intriguing.
-RedBeard

 

[ungifted]

Please check it here
http://bookfi.net/book/633191
or Google this file
[CHerkasov_YU.P.]_Spravochnik_kinomehanika(BookFi).djvu
UP25 schematics is on page 288
It's in Pussian, so you can ask if something will be not clear, I will try to find some time and help

 

[ruffrecords]

When I try that URL I get this:

http://www.ukispcourtorders.co.uk/

Big brother lives.

Cheers

Ian

 

[ungifted]

Added to my webpage
http://diyfactory.ru/forum/index.php?act=Downloads&do=download&id=203

 

[RedBeard]

Thanks a ton, I screengrabbed that! Any experience with them?

 

[RedBeard]

Please check it here
http://bookfi.net/book/633191
or Google this file
[CHerkasov_YU.P.]_Spravochnik_kinomehanika(BookFi).djvu
UP25 schematics is on page 288
It's in Pussian, so you can ask if something will be not clear, I will try to find some time and help

If at some point you had a chance to translate the wiring diagram at the bottom, that would be tons of help, but I understand if you don't have time!

 

[mjrippe]

Try this one, with connector pins labelled in english: https://www.dropbox.com/s/85l07v5nvzj5g1g/LOMO%20UP-25%20schematic.jpg?dl=0

 

[emrr]

Looks very similar to what you'd expect a single channel 27 to be, from memory. 

 

[ungifted]

Yes, UP25 and UP27 are similar. UP25 used with Photomultiplier tubes (ФЭУ) in cinema installation. So it depends on how do you want to use them.  This pic seems to be correct, anyway:

legend: circuit - contact
1a - output
1b - ground
2a - B+ (250v)
2b - chassis
3a, 3b - filament 6.3v
4a - ФЭУ (photomultiplier)
5b - feedback
6a,6b - ground
7a - mic input
7b - ФЭУ (photomultiplier)
8a - photo
8b - pickup

Attached diagram of LOMO Zvuk 6-100 (it includes UP25 and UP27 too), as example of usage

img-4398-c936b34167.jpg

 

[RedBeard]

Thanks! You guys rock!

 

[smilan]

Hi,
I'm waiting to receive one yp-25 preamp and I have a few questions:
1. What mic input / output transformers will work well for this preamp?
2. In the BOM the resistors marked with Ом / кОм / МОм
I guess that Ом stands for Ohm, кОм stands for K Ohm, and МОм stands for M Ohm.
If so on the schematic I can't see differences between R26 (3M3) to R16 (220R).
What am I missing here?
3. Where does the Feedback pin (5B) connect to? Does it set the overall gain of the preamp in addition to R5 that acts as a volume pot?
4. Where does the photomultiplier connections (4A and 7B) connects to?
5. I translated the schematic, BOM and the goal voltages with google translate and put them in a single page, If someone who's reading Russian can take a look and see if I'm right it can be great!

 

[TimG]

Hey these guys can hook you up, I’m starting here too.