OK, I'll jump in Roger.
The L needs some serious help IMO to be a serios daily driver these
days. USA made 572B's have been gone since the early 90's and Ebay has
driven the prices way up.
The L was never fully neutralized so it smokes the parasitic suppressors
on 15 and above, besides the carbon resistors have gone way up in value
anyway. The problem becomes much worse with Chinese tubes.
Ive designed new suppressors that use 5W MOX resistors with some C to
compensate for the XL. A PC board will be available soon.
For 12M you have to remove 3-4 turns from the top of the plate choke.
160M needs several changes to get full efficiency at 100W drive. New
filament choke, plate choke bypass, incresed loading C at the minimum.
Plus a real glitch resistor.
There is not much that can be done about the steel cover almost touching
the tank coil unless you fabricate an aluminum one. That cover really
screws things up.
Change the PS filters to much bigger values will help the regulation. I
use 330 uF CD 381LX series at a minimum.
Properly set up you can expect 1200-1300W on all bands with 100W drive.
I dont know what the xfmr overhead is if you crank up the drive to 150+
W.
As a 6M monobander they do fine with 2 tubes at 700-800W.
Later models had a tuned input network and an added switch section. An
outboard unit is the only option today and two or so universal models
are available.
IMO the L is a $400-500 amp with perfect tubes but it seems that all the
new nocoders have driven the prices up to new levels. As with most older
desktop amps.
A Dentron sleeper is often the DTR-2000L, especially with a missing or
bad 8877. Add grid protection, and a few other mods plus a 3CPX1500A7
medical pull and you have a reliable 1500W. Ive done many for 6M, add a
big outboard xfmr plus added filters and its a serious EME player.
Carl
KM1H
----- Original Message -----
From: "Roger" <sub1@rogerhalstead.com>
Cc: <amps@contesting.com>
Sent: Monday, January 19, 2009 1:40 AM
Subject: Re: [Amps] Amp Comparison Advice Please
>
>
> Kevin Nathan wrote:
>> Hi All,
>>
>> Several of you sent me manuals for the Kenwood TL-922 last night and
>> today
>> for which I am grateful. I have the opportunity to pick one of these
>> up for
>> a good price in excellent condition.
>>
>> I also have the opportunity, if I wish, to pick up a Dentron
>> Clipperton L
>> for less money. In looking at ratings on these on Eham, they are
>> rated at
>> the same point on the scale of 5.
>>
>>
> I'm going to have to disagree with Mike on a couple of points.
> First, I've had and used about everything Dentron sold. The Cliperton
> is
> a nice little amp, but I don't consider it to be half the amp the 922
> is.
>
> If a rig is for sale at less money than another rig, there are only
> about three good reasons for that. The guy needs the money bad, there
> is a problem with it, or they go for less money because they are worth
> less.
>
> Having said that, I wouldn't hesitate to use the Cliperton L and I
> never
> noticed drive or low output being a problem and I used mine on
> everything from 160 through 10 with no mods and drove them with about
> everything out there. I found the voltage regulation to be a bit weak
> so when tuning I always used the CW/Tune position and then switched to
> SSB for full power. I ran the things near full rated output for many
> hours and had no problems and I squeezed every watt out I could get.
> Back then the rigs were cheap, the tubes were cheap, and I beat the
> snot
> out of them. I did repair a few Clipertons for other hams that had
> the
> dielectric in the coax to the TR relay melt with the result the coax
> shorted. I never ran into that problem on my setup. The only ones
> that
> ever got really hot was the little sweep tube amp, the GLA1000.
> That's
> not to say the compact Cliperton with 4 glass tubes didn't put out a
> lot
> of heat as it did and you might not want to lay your bare arm on the
> cabinet over the tubes after operating for a while<:-))
>
> I loaned these things out on a regular basis, so many of their hours
> were put on by many hams who only had a basic introduction to tunning
> them. I did demonstrate tuning them and then have them show me they
> could really do it before letting the amps out the door. Some times
> I'd make up a wiring harness to their rigs for FD and some times they
> had something that would work. It was after all a simple hook up. Few
> used ALC. All were run on 220 except for the GLA1000. No, I didn't
> loan
> my Collins amp or the Hallicrafters HT-33B<:-))
>
> They were popular due to being compact, light weight, and relatively
> inexpensive.
>
> If he catches this thread, Carl can give you a good evaluation of the
> Cliperton as he converts them for 6 IIRC and I think he is also
> familiar
> with the 922.
>> Would those of you who know these two amps please give me your
>> thoughts
>> regarding pros and cons and which you might choose. One obvious
>> selling
>> point for me is that the local ham offering the Clipperton L promises
>> me
>> assistance if I need it if anything does go wrong and since I am
>> blind, this
>>
> The Cliperton is light weight, simple, and uses relatively inexpensive
> tubes even today.
>
> My own choice "If I had the money" would be the 922, more than likely
> there are others who would choose the Cliperton.
>
> 73 and good luck,
>
> Roger (K8RI)
>> appeals. but, I don't want to buy a dog just because I can get it
>> serviced
>> easily.
>>
>> I would appreciate any and all thoughts on these two amps but please,
>> no
>> wars. <GRIN>
>>
>> Take care all and very 73.
>>
>> Kevin :)
>> Amateur Radio: K7RX
>>
>>
>>
>> _______________________________________________
>> Amps mailing list
>> Amps@contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>>
>>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|