LOMO up 21 (up 21000) tube preamp info/schematics

[NGH]

Hey all, in search of some info on the LOMO UP 21.000 (maybe it's yp 21000?) preamp. having trouble finding any discussion of this particular module. I have a pair I picked up in a trade currentl;y being used as bookends and would love to try and get them racked up and running. any info or experince would be incredibly helpful! schematics would be a life saver!

thanks so much!

 

[lukas]

...tubey?...how looks inside?

 

[TimG]

Hi - Here is what I think you are looking for. At least I saved it as "Up-21".
If it is solid, I will add it to tech document.

 

[mjrippe]

That is the same schematic I have - although from a different source.

 

[TimG]

Thanks for your files that are out in the wild!

 

[NGH]

here are some more photos in case anybody is interested:

 

[NGH]

Hi - Here is what I think you are looking for. At least I saved it as "Up-21".
If it is solid, I will add it to tech document.

View attachment 118291

giving this a quick look over as compared to the modules I have it does seem correct.

 

[rock soderstrom]

Beautiful vintage device with interesting circuit topology! What is the CF driving in the second stage, is that an EQ? I can't read Cyrillic.

Does the amp work? When was it built? 1969?

 

[ruffrecords]

On the schematic, the first tube seems to have pin 5 two times.

Cheers

Ian

 

[rock soderstrom]

On the schematic, the first tube seems to have pin 5 two times.

Cheers

Ian

Good catch! I think the grid of the triode (~ECF80) is pin9, misprint!

For all those who don't know Russian, here's an info text from a Reverb sales ad.

"Today we offer one fantastic quality LOMO UP-21 tube preamplifier in spectacular condition, made in 1977 Original schematics, exceptional build quality, 3 tubes give up to 75 dB gain, tubes are:

6Ф1П (6BL8,ECF80), 6H3П (2С51,5670,6СС42)
Preamp has 1:15 double-shielded permalloy (mu-metal) input transformer Pulled from a 100% working console.

Specification:
Nominal output level with 600 Ohm load - 1,55V Maximum gain at 1000 Hz - 75 (+-2) dB Frequency range - 30-16000 Hz Total harmonic distortion before 6dB overload - 0,5% Tubes - 6F1P(6Ф1П), 6N3P (6Н3П)- 2 pcs Anode power - 280V +-2% (15mA) Heater - 6,3V (1,2 A)"

 

[gyraf]

output via a 30uF/160V MKT capacitor? That's serious talk..

edit: yup, triode grid is pin9 - https://www.dl7avf.info/Y21/mpi/1970/6F1P.pdf