[Amps] 30S-1 Questions

[Chuck Curran]

Cecil:

Not having heard the tone of the buzzing, I am taking a shot in the dark.
However, I have had two pieces of older equipment, 35+years old that also
buzzed.

I finally found on the first one after a bit of hunting, that the power
transformer through bolts were loose!  Upon tightening them to a proper
level, the buzz disappeared.  The same proved true with the second
transformer, several years later.

Just one possibility -----

Chuck W9POU



-----Original Message-----
From: amps-bounces at contesting.com [mailto:amps-bounces at contesting.com] On
Behalf Of Cecil Acuff
Sent: Saturday, January 30, 2010 9:45 AM
To: amps at contesting.com
Subject: [Amps] 30S-1 Questions

Hi Folks,

I have had the good fortune to have a near mint 30S-1 given to me.  It is a 
real piece of art for sure.  All original and reported to only have around a

150 hrs. of operation on the clock.  Still sporting the plastic on the front

door of the power supply.

I cleaned it up and gave it a serious visual and found a jumper in the 3 
minute time delay relay socket.  Had a new one so I fixed that.  Amp came 
with a spare tube, a pull stamped as having 1000 hours on it so I assume it 
was a military pull. (4CX-1000A)

I have read for years how quiet the cooling systems are in these things and 
all I have read is true.  But if this amp is typical, all that design was 
wasted because the loudest thing is the HV power supply buzz...not the 
fan/cooling system.

Is this typical for these amps.  With no load it's noisy...under load it 
quiets down a good bit but is still audible.  I really expected that part to

be pretty much silent.

Any history or experience on quieting this thing down would be helpful.

Otherwise I love the amp.

I get around 700w out on CW on 400ma and 1kw on voice peaks on my bird 43 
with 300ma peaks on the Plate meter.  Never a sign of grid current.  Not 
pushing it too hard.

Thanks..

Cecil Acuff
K5DL



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