[Amps] 3CX1500A7/8877 vs el cheapo GS-35B

Jim Thomson jim.thom at telus.net
Tue Jul 31 07:22:59 PDT 2012


Date: Tue, 31 Jul 2012 06:43:47 -0400
From: "Carl" <km1h at jeremy.mv.com>
Subject: Re: [Amps] 3CX1500A7/8877 vs el cheapo GS-35B

So the gain and efficiency go up but so does the cost of the PS and tank 
components.

Use a good tube to start with, learn how to build fault circuits and enjoy 
life. I wouldnt want to be in the same room with the blower for one or two 
GS-35B's.

Carl
KM1H

##  who cares.  remember the 4-1000 days.  that tube has lousy imd... yet nobody ever bitched
abt imd..on any band... even with a pair of em.  Vac caps  are literally a dime a doz these days.
there are more vac caps  now then there ever was back in  1976.   5-9 kv on a 4-1000 was the norm back then.
2 of em gave u 50 ohms on the input..then drive the mess with a swan 500  or yaesu  FTDX-401  etc.   those were
fun times, simpler..and cheaper.   A  4800 vac  10 kva CCS  120 lb pole pig..removed from oil was $75.00 
Tubes were $40.00 to $60.00 .   I had several brand new ones... and also the 4PR-1000  pulse rated tubes. 
Nobody had more than  $200  to $400 invested. 

##  the GS35B  is just the 4-1000... for the 2012 era.   Its  got a massive copper anode cooler on it..
and easy to cool.   Just put the  damn thing in the shop next door if u want.   u can put em in the closet too...
then slide the doors shut.... and kill any noise.    A few of us got racks  that have .25” 
thick, smoked  plexiglass doors on the front..    close the plexiglass door on the front of the rack...
and now u cn still  see all the metering etc... yet noise is down to zip.   Open the door to tweak it if required.
Phil, K5PC  remoted the blower  on his YC-156  and 3x3 stuff,    then used real long  aluminum dryer hose.
You can get it  from  2 inch up to 6 inch  at home depot.    the blower can be in the shop or another room...
on the other side of a wall.   the air coming out of the tube in the shack is not loud.  the blower can go into
a larger, 6 sided box...line with foam on 6 sides.... just like we do with printers at work.  then u cant hear it
at all. 

##  IF u have  some motor drive  vac tune and load caps..then the entire amp can be 100 feet away if u want.  
the remote head in the  shack can have the plate and grid current  meters  +  on-off switchs,etc.  the remote  head  controls the
tune and load caps.   ever see the henry 8k... same deal.     the gs35b is cheap..and works.   good enough for any hb amp.
I know a few folks  who use  3 of em  for  HF amps.   6 kw out easy.   Bring what ya got... and run what you bring. 
on some pile up on 20m.... nobody cares abt imd anyway.

Jim



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