GSB35 in a Henry 3K?

[WA1HZK]

A friend just dropped a Henry 3K classic. It has (1) 3CX1200A7 in the final. My choices are to find a new stock tube or consider this one for a Rooski transformation. This Amp has the Henry 5K power supply. It was at Cushcraft testing antennas for it's whole life. It's in very fine condition and I have been requested to get it back in operation. This really looks like a job for the GS35B. If I just clamp it onto the chassis and swap the filiment transformer for a 12 volt one it looks like it will work. The question is has anyone ever done this with this amp? If I go this way I'll publish it here for future reference.
Keith
WA1HZK

[WBear2GCR]

Assuming the plate Z is similar and the other operating parameters are met, it ought to be fine... there are some sites on making sockets for some ruskie ceramic tubes, and their care and feeding... there may be some "free experience" to be found there... just talkin' off the top of my head on this one...

                  _-_-bear

[K1JJ]

This really looks like a job for the GS35B.

Keith,

How clean is a GS35B?  Have you ever seen actual IMD tests by USA users? - I'd be curious.


T

[w1vtp]

This really looks like a job for the GS35B.

Keith,

How clean is a GS35B?  Have you ever seen actual IMD tests by USA users? - I'd be curious.


T

This sounds like a natural for Stu, AB2EZ to answer.  He has a HB amp using one of these puppies -- er actually two of them currently

Al

[W1ATR]

Just my .02, but if it was mine, I'd retube it with another eimac tube and call it a day. If it was some garbage Dentron or other worthless hammy hambone amp, it would be a different story. Henry amplifiers were the cats ass of super heavy duty, and that one you have still holds it's own in the $2000-$2500 range. I wouldn't devalue it with a russian toob.

[K6IC]

The only thing about re-tubing this amp is that the 3CX1200A7  went from abt $780, to  $1280 in one step about 9 months ago.  Think that it is now running abt $1200 ea.  That is a tuff tube,  and whould last many thousands of hours of Hammie use,  but it seems a bit expensive to me.

We use two AL-1200's here, and knock,  knock  neither the amps nor the tubes have ever given any problems.  Just have NO spares ... oooops.

73  Have  Fun  Vic

[WBear2GCR]

Well, I think the ruskie toobe is physically smaller... so if you do a nice job the eimac can be retrofit back in (the socket that is). Or do you need a pair?

I think Ken W2DTC also runs a lineeyar with a pair of ruskie toobes... not sure, but he is sure loud up here.

Otoh, one might <gasp> sell the Henri and getcherself another amplifrogger, or build one using some ruskie toobers...

                _-_-bear

[W2VW]

Orange silicone turbocharger hose makes a good chimney for a GS-35B. Don't use the stuff with metal reinforcement.

There would be no point in using a pair if the driver is going to be a 100 watt P.E.P. rig. The GS-35B is lower mu than a 3CX1200. It needs more drive for the same power out and more bias voltage. Additional zener bias can be simply added in series with the existing Henry stuff. 

3.5  kv is a good number. 4kv would be even better.

[WA1HZK]

Thanks for the hints. If it were mine this thing would have a pair installed. It has the 5KW supply. It's not mine so I advised the owner to look at the tubes on E-Bay and try to make a deal on those. When it's someone else's virgin it's hard to make the decision to deflower it. It's still worth a lot of bucks if he keeps it stock.
Keith

[WA1HZK]

The amp owner bought one of the tubes offered on E-Bay so for now this amp will remain stock. With this I agree. If it was mine it would have two rooski toobs using that 5K supply for all it's worth.
Next Time.
Keith

[K6IC]

AND,

Here is an example of just such a combo, 

http://amfone.net/Amforum/index.php?topic=19499.0

In the e-pay/links section of this very site.

Vic

[W1ATR]

Jeez, the seller really gave that amp away. Probably should have set a reserve.

[K1JJ]

http://cgi.ebay.com/Henry-2KD-GS35b-Russian-retro-fit_W0QQitemZ190303320447QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item190303320447&_trksid=p3286.c0.m14&_trkparms=66%3A2%7C65%3A15%7C39%3A1%7C240%3A1318%7C301%3A1%7C293%3A1%7C294%3A50


Yeah, what a deal.  I'd have bought that if I had been aware.

Compare that nice modified amp to the commercial new ham linear junk available for $700. No comparison.

It probably went cheap cuz of the pick-up-only limitation in Ohio.

T