• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Priboj Reborn

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Please, for direct link use Google translate in a convenient language (english translation is relativelly ok).

After reading this link:
Forumul electronistilor • Vezi subiect - Reconditionare amplificator Priboi
I wanted a russian valve amplifier Priboj.
Finally i find one but damaged (around of 100$).
Another one have a relatively high price (400$ but tunned not to well).

The problems in my Priboj was:
- On power board supply bridge rectifier damaged, some resistors burned and broken capacitors
- On final boards few resistors burned, fuses replaced with wires, tubes consumed, connection wires missed
- one transfo out burned and distroyed by previsious owner
- Wires isolated unpropely
- "Cold soldering"
- Very, very dirty
- A lot of wires missed

The photos are here, with amplifier in initial status and schematics:
Picasa Web Albums - suzuki-san - priboj

Few schemes are here, where Priboj is modding:
Priboj

I buy the amplifier in February 20 then i begin to rebuild.

Now it look like this:
YouTube - Priboi amplifier reborn

In want to relate (in episodes) all steps which I followed up to became this valve amplifier functional, just as out of from factory.

I work alone becouse the prices to rebuid are high in a specialised service.
For my first project Forumul electronistilor • Vezi subiect - Amplificatorul meu cu 6P14P SE - o bijuterie!!! the proposed price was 200 euro, too much for me and i work most time alone.

I will continue ...
 
Priboj new

This amp is a favorite with us for apgreyta.
Best thing you can do this move in triode mode, the sound will get good.No if left in the initial scheme, some changes are very needed.Not bad and the tubes 6p45s (el509) ...
 

Attachments

  • 001.png
    001.png
    47.8 KB · Views: 763
  • gu50sebp.GIF
    gu50sebp.GIF
    7.2 KB · Views: 730
  • 6p36spp.BMP
    41.3 KB · Views: 128
  • gu50se2.GIF
    gu50se2.GIF
    9.2 KB · Views: 725
  • gu50se6e5p.GIF
    gu50se6e5p.GIF
    9.4 KB · Views: 747
This amp is a favorite with us for apgreyta.
Best thing you can do this move in triode mode, the sound will get good.No if left in the initial scheme, some changes are very needed.Not bad and the tubes 6p45s (el509) ...
I now this modifications and in future i want to change in pure class A, but now i describe the rebuild project. The trafo´s are to good and initial conception support a lot of mods.
 
Episode 1:

After buy thea mplifier I go home with this. I check, summary, the problems and first off all I decide to clean all pieces.

So I proceed to dismantle in pieces and to cleaning up.
Picasa Web Albums - suzuki-san - priboj sapunirea

Plastic bottom plate is attached in the 6 screw. I open all screws from frafo for easy access in side.
Picasa Web Albums - suzuki-san - priboj sapunirea
I removed everything:
Picasa Web Albums - suzuki-san - priboj sapunirea
And then with all pieces in go in bathroom:
Picasa Web Albums - suzuki-san - priboj sapunirea
Picasa Web Albums - suzuki-san - priboj sapunirea
After cleaning I wait:
Picasa Web Albums - suzuki-san - priboj sapunirea
Picasa Web Albums - suzuki-san - priboj sapunirea
Picasa Web Albums - suzuki-san - priboj sapunirea
All pices reasambled together:
Picasa Web Albums - suzuki-san - priboj_faze2
 
Administrator
Joined 2004
Paid Member
I took a look, none of the links seem to work but I was able to see them by clicking on your photo link..

I noticed a lot of electrician's (black) tape holding wiring together which IMO is not a good thing - tie wraps are really indicated here or if you are feeling ambitious you can lace the wiring as was done in priboj originally.

The duct tape on the power transformer has to go, this is a FIRE hazard. :hot:

Glad it is working otherwise, amazing how different in some ways Soviet gear was from ours. The OPTs look pretty interesting..

I assume you reconfigured the OPTS for SE operation by regapping them and made the changes shown in the schematics or are you still using PP operation? The 100 ohm screen stoppers shown in the original design should probably be retained to prevent VHF oscillation.
 
Last edited:
I do not see any sense to restore the initial circuit - she it is obsolete also lamps unreliable, and the sound is not so good. Better in my opinion being based on the given target transformers-2500/8 to apply other lamps More reliable - ГУ19, ГУ-18, ГУ-42 and ГУ-29...
 

Attachments

  • 29pp1.gif
    29pp1.gif
    49 KB · Views: 610
  • 29pp.jpg
    29pp.jpg
    78.6 KB · Views: 342
I do not see any sense to restore the initial circuit - she it is obsolete also lamps unreliable, and the sound is not so good. Better in my opinion being based on the given target transformers-2500/8 to apply other lamps More reliable - ГУ19, ГУ-18, ГУ-42 and ГУ-29...

You have right. Now i work to a GU-19 project, based on Priboi ideea.
Anyway, almost based:p
I this case only i tried to "put on the road" a dead Priboi.
 
Thank you for your positive feedback.
Due to the geographical location I have the opportunity to repair or modify a lot of interesting tube amplifiers. They are often produced in a small number of copies and are almost unknown. For example, this interesting design: Bridge tube amplifier ARG 6S33S.
As for the Priboj amplifier, I know some of its owners, and all praise its sonic performance :).
 
Hi Grzegorz,
realy nice amp, congrats. How does it sound?
I´m looking for that nice russian transformers and those marsian style greeeen chokes. Have you a adress for me where i can buy them?
Thanks,
Hilmar

You mean the ARG amplifier? If so, it sounds very good. I'm not an audiophile, so I can only compare it's sound to other tube amplifiers. It is comparable to some popular mid-priced tube amplifiers. A completely separate issue is the hopeless assembly (one circuit board I had to make from scratch and replace the original one - see the photos - more detailed description is only in polish version of the article).
As you mentioned these green chokes are russian chokes - strictly speaking russian hermetic military ones. You can find them from time to time on eBay (mainly from Ukrainian sellers). Unfortunately, that's all I know about it.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.