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

[Roger]

On 7/31/2012 10:22 AM, Jim Thomson wrote:
> 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.

How about the same room with a 4CX3000 running close to tilt?  <:-))
I do believe that the YC156 or even the 3CX3000 are much quieter.

>
> 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.

Yah, some things were really cheaper back then,  but back in the mid to 
late 70's I could purchase brand new 8877s for $305 including tax, 
delivered to my door.
*UNFORTUNATELY* that is now over $1000 just due to inflation and it 
doesn't count the 30 some % that Geitner has added.  OTOH there is 
another $700 on the price of that tube today that is not due to the 
dollar's loss of purchasing power.

OTOH I would like to build up a couple of RF decks for 160 through about 
20 using a pair of GU-81s.

73

Roger (K8RI)

>
> ##  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.

5" is a good size as it's what most of the shop vacuums and dust 
collectors use out there.  OTOH that's another reason for building that 
extra room.  I could let that big fan blow instead of suck although I'd 
probably need hold downs for conventional tubes.  When that thing is 
running you don't have to be concerned about how much fan noise the amp 
makes.  It just sings, although not very harmonious, just loud.  I think 
the impeller weighs close to 20#


    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.

I wonder if I could sneak an unheated room on the back of the shop. 
I've already reached the limit for buildings external to my house. I 
need to add water, but camoflaged because as that's all it lacks.
Once I get the airplane project out of there I'll have lots of room so, 
I'll add a couch and...


>
> ##  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.

They'll be much happier if you keep the drive up. You may be loud, but 
you won't have a problem with that leading edge spike. <:-))

73

Roger (K8RI)


>
> Jim
>
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