late for edit 
anyway-hy I'm asking for that file is because i have one priboj in my shop waiting for fix (first), then major redo (second)..........knowing me-that second will be first probably
so-I'm just chasing "second opinions"......already downloaded schmtc from Jogi's
funny-even if I repaired fair number of Russian gadgets (does "Lorta" usilitel (cyrilic) ring a bell? ) ,once I even own russian CRO,and now just RLC meter......I never get used to russian way of drawing schematics........probably just matter of habit
so-druzja Lisovskiy....I'll be grateful if you translate that russian text...........
anyway-hy I'm asking for that file is because i have one priboj in my shop waiting for fix (first), then major redo (second)..........knowing me-that second will be first probably
so-I'm just chasing "second opinions"......already downloaded schmtc from Jogi's
funny-even if I repaired fair number of Russian gadgets (does "Lorta" usilitel (cyrilic) ring a bell? ) ,once I even own russian CRO,and now just RLC meter......I never get used to russian way of drawing schematics........probably just matter of habit
so-druzja Lisovskiy....I'll be grateful if you translate that russian text...........
gorgon53 said:
I thought you mean Priboj they are speaking about:
An externally hosted image should be here but it was not working when we last tested it.
It uses paralleled 6R3S-1 double ray tetrodes in triode connection developed especially for audio output stages.
Ok, here's the complete article on Priboi mod in Russian. If you Welbourne, could be helpful with some notes we would all be happy. What is important for DIYers is how to fix the transformer to get two separate windings for each of the amps - quasi monoblock.
PRIBOI MOD
I read in AudioXpress about increasing Pout from 6L6 and 807 by having the screen grids at 80V higher than the anode. The tubes were good enough to take it.
PRIBOI MOD
I read in AudioXpress about increasing Pout from 6L6 and 807 by having the screen grids at 80V higher than the anode. The tubes were good enough to take it.
soundbrigade said:
In my mind the article is very weak and I disagree with many statements of the author.
Do you want me to transtale it as is, or may I comment it for you?
Even if it increases output power twice it is not so significantly audible to spend tubes linke matches. I prefer to parallel tubes instead.
Sorry Marrio2005, is it off-topic. Your topic about perfect GU-50 tubes that I love and use turned to question about Russian Priboy amp and it's modifications. People asking me to translate the article about modification of the amp that uses 6R3S-1 tubes that according to my opinion are worse tham GU-50. Do you want me to answer, or should we start a new Priboj topic?
I have both the original article on Priboi and a shortened version in Swedish (my translation), so I don't need a translation.
However Zen-Mod was interested in a translation som Gospodin Welbourne or Gospodin Soundbrigade may give him the necessary points in the article off the list (PM).
Yepp the 6R3S is a tube wellknown for it's poor quality (very unreliable mehanically), so lets stick to the GU50!
I've had my EC52/GU50 singing for some time and I am very happy. Sad the EC52 is such an odd tube, but isn't that half of the fun - to use odd looking tubes.
Next project would possible be a GU50PP., though I have some 6L6 (Russian brands) that would give some power to me. But anyway can anyone a rough idea how such an amp would look like, or could I use an outline for EL34 or 6550/KT88 with slight modifications?
However Zen-Mod was interested in a translation som Gospodin Welbourne or Gospodin Soundbrigade may give him the necessary points in the article off the list (PM).
Yepp the 6R3S is a tube wellknown for it's poor quality (very unreliable mehanically), so lets stick to the GU50!
I've had my EC52/GU50 singing for some time and I am very happy. Sad the EC52 is such an odd tube, but isn't that half of the fun - to use odd looking tubes.
Next project would possible be a GU50PP., though I have some 6L6 (Russian brands) that would give some power to me. But anyway can anyone a rough idea how such an amp would look like, or could I use an outline for EL34 or 6550/KT88 with slight modifications?
Wavebourn said:
Ok, let's call Tubelab on the stage now, to open both tubes and measure/compare internals.
I've compared "externals" for myself, GU-50 sounds much tastier, is more powerful (however, I am comparing now 2 nearly identical amps, with 4x6L6 vs 2xGU-50, though 6L6 and KT88 are a bit different, but they are very similar).
Military ray pentodes won against guitar ray tetrodes.
If you will recall: some time ago I XRay'd both those types.
GU-50 and Chinese 6L6 internal through shots from many
angles. Thread might still exist around here somewhere, if
you care to dig up those photos.
I think GU-50 was a true Pentode, not a ray type. Observed no
alignment of grid and screen. Perhaps this gives GU-50 lower
capacitance for RF? And can abuse G1=G2 drive if everything
holds true according to Telefunken's original LS-50 spec.
Beam tubes (except maybe space charge types) are never
characterized for G1=G2. The G2 screen directly in the focus,
rather than hiding in the shadow of G1. Formula for disaster!
as for the capacitor value you could use a .22uf cap. it cuts off at around 15 hz
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