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Re: [Amps] Interested in re-purposing a Dentron Clipperton-V - question

Subject: Re: [Amps] Interested in re-purposing a Dentron Clipperton-V - question about possible power power transformer ICAS KVA
From: wb0gaz via Amps <>
Date: Thu, 7 Mar 2024 23:06:16 +0000 (UTC)
List-post: <>
 Had a few helpful off-list replies - in a nutshell, the KVA of the transformer 
remains unknown.

The HV secondary of the "V"'s transformer is probably about 800V (so through a 
doubler gets you to the 2200-2250V plate voltage. 

I had initially thought of a GI7B russian tube (have some, and sockets) on 6M, 
however, the 2200-2250V plate supply would starve the tube (2500V seems like a 
better fit) and augmenting the HV transformer (either by boosting the 220V 
primary up by 10% or so, or adding 100V or so to the secondary winding) might 
(or might not) work based on whatever is in my walk-in junkbox.

So, I much appreciate the off-list replies, however, the HV supply voltage 
would be a problem and the current capability of the transformer in the 
envisioned application is unknown.

73 Dave WB0GAZ

     On Thursday, March 7, 2024 at 02:45:05 PM MST, <> wrote:  
  Follow-up to my original post (trying to assess the utility of the Clipperton 
V's power transformer) ---

I found an internal photo of a Dentron Clipperton L amplifier in a youtube 
video (URL below.)

While the transformer appears to be the same overall size (at least comparing 
picture of transformer vs. cabinet with with my amplifier's transformer vs. 
cabinet width), the schematic of the Clipperton L shows a low- and high-voltage 
tap on it's power transformer (and the rectifier/doubler board has eight 
electrolytics populated; this amplifier's rectifier/filter board appears to be 
the same PCB but only six electrolytics populated.) Also, the "L" has filament 
and control voltage windings, but lacks the bias and screen supply windings of 
the Clipperton V's transformer.
     On Thursday, March 7, 2024 at 01:35:11 PM MST, <> wrote:  
  I've got a Dentron Clipperton V (2M 500W single 4CX250) amplifier, purchased 
used some years back (when shipping was cheaper!).

It looks like it's in clean but not pristine condition.

I've never used it, and my fixed-station circumstances somewhat discourage tube 

>From everything I've read (and just looking inside at the "RF Deck" design), 
>I'm inclined to agree with commentary that it's not a very effective RF design 
>for 2M (lumped output tank elements, open frame T/R relay, etc., as if it was 
>designed by someone that hadn't looked at VHF amplifier designs of the same 

So, I'm interested in whether the amplifier (cabinet, metering, power supply, 
cooling path, etc.) could be re-purposed, by cleaning up the power supply 
(replace components in the HV rectifier/voltage doubler circuit) and replacing 
the "RF Deck" (but with what, not decided.)

About the power transformer - what is done with this in terms of a project is 
dependent on the power transformer (assuming it's not dead, which I'd verify) 
capability as much as anything else.

In the spirit of "look before leap", I'm eyeballing the power transformer 
(which in the manual is just "power transformer" with no other spec.) It has 
two primary windings (so 115/230V primary), a HV secondary winding that uses a 
voltage doubler to generate the (claimed) 2250V plate voltage, and several 
auxiliary windings (filament, 12V control, negative V for grid bias, positive V 
for screen voltage.)

The transformer's core dimensions (excluding the windings) are 3-1/2" x 5-1/4" 
x 4-1/4".

By comparison, my Dentron GLA-1000B's power transformer (same, excluding the 
windings) are 3" x 3-1/4" x 4". 

Comparing the cubic inch volume of the two transformer cores yields that the 
Clipperton-V is about 1.8 times that of the GLA-1000B's power transformer 
(whose only duty other than HV appears to be four sweep tube 6.3V filaments, so 
it has a bit more work to do there.)

Given that a GLA-1000B can deliver 500-600 watts (including whatever drive 
power passes through, maybe 75-100 watts), would comparing core volume (above) 
be a reasonable way to estimate the power transformer power thru capability?

Thanks for any comments, observations, or (if you're in Colorado) a plea to 
rescue the amplifier!

73 Dave WB0GAZ
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