Tube GU50 made in Russia

[duongmt1980]

Hi everybody!
I have 4 tube GU50 made in Russia. I wonder whether it is good or not? if it is good, please let me know the proper circuit so that i can construct it by myself. Thanks.

 

[m6tt]

I've definitely seen those valves being used in audio circuits, so I imagine that they are good. I do not have any schematics for it unfortunately.

 

[oldeurope]

I have a GU50 in my TV set "Rembrandt". It is good.

Kind regards,
Darius

 

[kstagger]

do a search and you'll find a few threads on this tube. I have to pick some up soon.

 

[duongmt1980]

Thanks you so much!

 

[Dj Dog]

hi everybody
my name is Florin and i'm new around here and i love tubes
please excuse my poor english


duongmt1980 see my attachements

single end - very simple

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single end with tone control

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push pull

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i have tested the simple one, it worked great and i am making another one
i can provide the output transformers

best regards,
Florin D.

 

[geshka]

Hello Florin.

What is the output transformer do you use for the SE amplifier with GU50 (shown on first picture)?

Thanks

 

[Dj Dog]

Hello Geshka
The Output Transformer 2500 ohms / 8 ohms, made bay a friend of mine, who has a shop of transformers

An externally hosted image should be here but it was not working when we last tested it.

 

[Dj Dog]

i have allmost finished a new SE amplifier with this tube
the sound is great for a RF pentode like GU50
i still have a little work to do at the case design
for now it's looking like this:

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if somebody it is interested in can provide Output Transformers for this tipe of amplifier for 35E for 1 piece

 

[costis_n]

If the transformers are bifilar wound, have properly calculated airap, and he can porovide covers, i am interested

 

[costis_n]

i mean air gap, sorry

 

[Dj Dog]

hi
i don't understand verry good what du you want to say with " bifilar wound"
teh air gap si properly calculated
i'm sorry but i can not provide covers
the detailes for the opt transf. are:
section: 14 square cm
P1, P2=1400 turns / 0.23mm wire diameter
S1, S2, S3 = 53 turns / 1 mm

S1 - P1 - S2 - P2 - S3

 

[Wavebourn]

the sound is great for a RF pentode like GU50

Do you mean the sound is good for pentode output without negative feedback?
GU-50 are decent tubes, both for RF and AF. Telefunken engineers always knew how to design excellent devices.

 

[Dj Dog]

Do you mean the sound is good for pentode output without negative feedback?

yes

 

[Wavebourn]

yes

Stiff low screen grid bias helps to any pentode to be more linear.

 

[costis_n]

hmmmm, interesting....

i'll think about it...

 

[danzup]

If the transformers are bifilar wound, have properly calculated airap, and he can porovide covers, i am interested

No dude ! Just monofilar wound !
But the guy is a pro at wounding .
I have build my own PP 6P3S with transformers from him .
Works like magic !

 

[Dj Dog]

No dude ! Just monofilar wound !
But the guy is a pro at wounding .
I have build my own PP 6P3S with transformers from him .
Works like magic !

thanks mr. dan
coul you explain on the other forum on privat msg what bifilar wound is?
i'm not verry good with thenical terms in english

a lovely enening to all!!!

 

[costis_n]

dj, i think i am going to need a couple of power transformers. please email me your email, so we can discuss options....

 

[Dj Dog]

hello
you can find me on yahoo messenger
my id is: loc_dog1984