>From my experiance with gs-35b, I can agree with the need to condition the
Russian tubes...I have several here and all the ones I conditioned before
use worked very well....I tried a tube without burn-in and experianced flash
over, also tried to condition after failure and found it impossible to save
the tube (Unlike some American tubes)
Have recieved reports similar from other builders concerning the need for
burn-in.
Have a great day, 73, Jim
----- Original Message -----
From: "SM0EJR 'Joe'" <crabspider@telia.com>
To: <amps@contesting.com>
Sent: Monday, October 13, 2003 10:22 AM
Subject: Re: [Amps] Conditioning Spare Tubes After Storage
> Hello Jeff, Rich, Skipp Et. al
>
> I have had some experience in this....
>
> After buying a few different russian tubes....(GU-43B, GS-35B, GU-84B,
> GI-6B/7B).
> I've made some tests:
>
> I have about 10 of each type, except for the GI-7B, for which I have about
> 20 or so.
>
> Here's the story:
>
> A GS-35B which could handle max 1100 volts before it started to
> 'leak'/spark...
> After 24 hours of heaters on, the tube can withstand 7800 volts on
> Anode-Cathode potential.
> It now works in HF-PA without problem...I don't think it would if I didn't
> do this heating-up!
>
> Another GS-35B had 3kv as upper limit, but after cooking it, a 8 kv limit
was
> reached before a leakage 50 microamps occured!
>
> One of the GU-43's had a 2200 volt limit, but after letting it cook for a
> while,
> it can 'take' 6 kv before leaking.
>
> A copule of GI7Bs had about 1500 v, but after ritual, I think at end, I
had
> approx 3900 volts on both...
>
>
> The gadget for these measurements was a K8CU High voltage breakdown
tester.
>
> http://www.realhamradio.com/High_Voltage_Breakdown_Tester.htm
>
> I even tried it on 5CX1500A's ( I have four of them on hand )...all were
> about slightly below 6 kv before...
> Not much happened after heating them up...They were already quite
healthy!!
>
> So to finalize the whole story:
>
> 1) Western tubes with external anode MIGHT be more stable..
> But I only tried one type of tube..
> I have a 4CX5000A, but no transformer for it's filiament, so I don't know
> that much about that one!
>
>
> 2) Russian tubes with external anode gains, at least if storage/shelf time
> is long.
> Some tubes were quite good, but wouldn't bet too much on that!!
> The methods for gettering might be different from western tubes?.
> Or just that the sealing for russian tubes is just more leaky, so that you
> have to use
> the mechanism of gettering to solve it ;o)
>
> So, I WOULD NOT PASS this 'cooking ritual' before kick-starting a new PA
> with russian tubes!!
>
>
> I don't know anything about the glass-tubes of the GU-81M-type...
>
>
> Regards
> /Joe
>
>
>
> At 19:55 12/10/2003 +0100, you wrote:
> >>
> >>I have a pair of 4CX800A tubes that have been on
> >>the shelf here for a few years (and for an unknown
> >>period before I got them). I'm about to swap them
> >>into one of my Alpha 91b amps.
> >>
> >>Is there a recommendation to let these tubes run
> >>without HV for a period before pressing them into
> >>full service?
> >>
> >>I did a search of the archives, and it seems that
> >>there is no consensus on the need for this procedure
> >>for any but the largest "tubes with handles".
> >>
> >? Even for a gassy tetrode with handles, I have never found one that
> >would magikly get mo' betta by operating the filament. The bottom-line
> >seems to be: if there's gas, you'd better pass. However, if there's a
> >leaky ceramic-metal seal, Econco can resolder it during the rebuilding
> >process. It is my opinion that Ham radio is not free from old wives'
> >tales.
> >
> >cheers,
> >
> >> Jeff Maass K8ND
> >
> >
> >Jeff, Rich, et. al
> >
> >If I recall we discussed this on the list back in September 2001 and
> >the conclusion was that that for small tubes there is no requirement to
> >"condition" them.
> >
> >We talked about getters and ion pumps in some of the larger tubes
> >and the conditioning process(es) that might apply to them.
> >
> >I recall reading somewhere recommendations for 8877's to be run
> >on fils and blower only for 24 hours before use of a new ("green")
> >tube and did with mine before taking it in to service, but suspect it
> >was totally un-necessary.
> >
> >So, in short there are no Eimac recommendations for smaller tubes
> >but you can if you want and think it might make a difference - it doesn't
> >appear to do any harm.
> >
> >
> >Mike G8TIC/M0VHF/M0BAA
> >
> >
> >
> >
> >
> >
> >
> >_______________________________________________
> >Amps mailing list
> >Amps@contesting.com
> >http://lists.contesting.com/mailman/listinfo/amps
> >
> Life is too short for QRP -- Speak softly, and run a BIG amp!
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