Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

donate to eham
   Home   Help Search  
Pages: [1]   Go Down
  Print  
Author Topic: Opinions of the Clipperton L ?  (Read 7709 times)
K9ZF
Member

Posts: 97


WWW

Ignore
« on: May 10, 2014, 07:52:40 PM »

I have a friend looking to sell a Dentron Clipperton L.

Anyone care to share their opinion of this amp?

73
Dan

--
K9ZF
Amateur Radio Emergency Service, Clark County Indiana. EM78el
The once and future K9ZF /R no budget Rover
 ***QRP-l #1269
Check out the Rover Resource Page at:
<http://www.qsl.net/n9rla>
List Administrator for: InHam+grid-loc+ham-books
Ask me how to join the Indiana Ham Mailing list!
Logged

--
K9ZF
Amateur Radio Emergency Service, Clark County Indiana. EM78el
The once and future K9ZF /R no budget Rover
 ***QRP-l #1269
Check out the Rover Resource Page at:
<http://www.qsl.net/n9rla>
List Administrator for: InHam+grid-loc+ham-books
Ask me how to join the Indiana Ham Maili
K7MH
Member

Posts: 455




Ignore
« Reply #1 on: May 10, 2014, 10:12:30 PM »

I had one for several years and it was okay but they are pretty old now days. No tuned input, no grid current metering. It has a rather noisy fan. People tend to want too much for them used. I traded mine back to the original owner for an AL-811 which was more useful for me. I understand that the 572B tubes from China are often not that great in the quality department if you should need new ones.
I have an AL-80B now and I am quite pleased with it.
Logged
W1QJ
Member

Posts: 2966




Ignore
« Reply #2 on: May 11, 2014, 03:18:08 AM »

It's funny, in the more than 25 years that I have been buying, selling and repairing amps I have seen MANY Clipperton amps.  One here right now for repair in fact. MOST of them do not have a tuned input circuit but the one that is here and the last one I had in both had the tuned input boards.  So units with tuned inputs are out there.  That of course would have to be one of the questions you have to ask  in your consideration of buying.  It should not be a blanket statement that the Clipperton amps don't have tuned inputs.  I think they are built very rugged.  Heavy duty chassis that is hard to kill in shipping.  The fans are noisy for sure.  The lack of grid current monitoring is not really a big issue as you can't overdrive the grid with 100 watts of drive.  If you drive it with much more than 100 watts to the point that you would overdrive the grid then the plate current would be  too high as well.  Although it would have been nice to have, I would not consider that a deal breaker.  There is not a lot of bells and whistles to this amp and that makes it very easy to repair.  Using them with newer radios and having a model that does not have a tuned input could be somewhat challenging based on how your solid state radio handles folding back with swr.  Remember, these amps were designed when just about all exciters were tube based.  SUre, the quality of the tubes that are made for this amp is questionable however, I don't think that should reflect on the amp iself.  Ghey work just fine with the Cetron tubes or a good set of Chinese tubes but I do stress the word good.  Figure on paying a bit more for a unit with a tuned input board unless the seller is oblivious to the fact.
Logged
WA2VUY
Member

Posts: 463




Ignore
« Reply #3 on: May 11, 2014, 03:13:27 PM »

Have the mod for 10M operation?
Logged
N6AJR
Member

Posts: 9930




Ignore
« Reply #4 on: May 11, 2014, 03:27:36 PM »

they work ok, I remember ownig several and they are rather "clunky" in operation, and I think 600 or maybe 800 watts  with 4 of the 572's in there.  gud luck
Logged
W8JX
Member

Posts: 13268




Ignore
« Reply #5 on: May 11, 2014, 03:52:23 PM »

I have the successor to the L, it is called the Clipperton QRO. Like stated above lack of grid current meter is not really a issue because you cannot overdrive grids with 100 watts. I have had mine about 20 years now and it is a fairly rugged amp. I have never loaded it on 10m and rarely get it off 40m. I drive mine with about 55w and get about 1000 out. I do run mine off 240v and while previous owner did I never ran it on 120. One mod I did that I highly recommend. I flipped fan on back of unit to suck air out and not blow hot air up into band-switch and power supply. I also removed top cover and rotated it back to front which places intake holes over tank coils and band-switch. I runs very cool that way and front panel is never even warm to touch. While it is no Henry or Alpha I have run it SSB at 1kw out for more than a 8 hrs more than once and it never got hot. You can get a little more out but really not worth the extra wear and tear but with mods above and good tubes it is a pretty solid 1kw amp. If you need more than 55 to 65 watts drive to get a KW your tubes are weak.
Logged

--------------------------------------
Ham since 1969....  Old School 20wpm REAL Extra Class..
W1QJ
Member

Posts: 2966




Ignore
« Reply #6 on: May 11, 2014, 04:37:24 PM »

Have the mod for 10M operation?

Yes, I know what the 10 meter mods are to get it to work on 10 meters.  There were several things that were done to these amps to disable 10 meters and any given amp may have a number of the following.  Each of the following have to be checked in your particular amp to see which apply  to

your unit.  Here is the possibilities. 

1. Band switch does not advance beyond 15 meters...remove stop and reset it
2. No connection from 10 meter contact to tank coil...add wire if needed
3. Remove 27mhz filter.....Remove filter or bypass, not shown on schematic you have to find it if it is there.  It is in series from relay to tube coax.

That should do it
Logged
K9ZF
Member

Posts: 97


WWW

Ignore
« Reply #7 on: May 11, 2014, 04:53:13 PM »

Thanks guys for all of the replies.  You have given me lots to think about.  The amp is in nice shape, and the price is really right, so I might...

73
Dan
 
--
K9ZF
Amateur Radio Emergency Service, Clark County Indiana. EM78el
The once and future K9ZF /R no budget Rover
 ***QRP-l #1269
Check out the Rover Resource Page at:
<http://www.qsl.net/n9rla>
List Administrator for: InHam+grid-loc+ham-books
Ask me how to join the Indiana Ham Mailing list!
Logged

--
K9ZF
Amateur Radio Emergency Service, Clark County Indiana. EM78el
The once and future K9ZF /R no budget Rover
 ***QRP-l #1269
Check out the Rover Resource Page at:
<http://www.qsl.net/n9rla>
List Administrator for: InHam+grid-loc+ham-books
Ask me how to join the Indiana Ham Maili
KO7I
Member

Posts: 134




Ignore
« Reply #8 on: May 13, 2014, 05:52:06 AM »

They are known for having a poorly designed tank circuit that is inadequate for 160M operation. On 80M - 15M they do fine, 10M is a little soft but not as bad as 160M. Expect about 750 to 800 W out on CW. On SSB they put out about 1kW or so. The manual clearly states do not tune the amplifier up in SSB mode. I blew one up doing that. I had a pretty sized fireball come up out the amp because of my over zealousness. Had to install a Harbach power supply rebuild board. Bottom line the amp will do fine as long as you do not push the design envelope to hard. I run a quad matched set of Taylor's that I purchased from RF Parts.
I use mine with an external QSK keying switch and it works out real nice.
They are worth about $500 with a good set of tubes.
To be honest if I were to do it all over again, I would buy the Ameritron 572B amplifier instead.
Good Luck and 73. Don KO7i
Logged
K7MH
Member

Posts: 455




Ignore
« Reply #9 on: May 15, 2014, 12:00:43 PM »

Quote
The amp is in nice shape, and the price is really right, so I might...

That is certainly worth a lot of consideration. No shipping, you get to see it before you buy it, and the price is right for you.

As far as tuned input is concerned, Amp Supply had a tuned input kit for it back then. It was about $79 to $100 as I recall.
I put it in the L that I had and it worked very well. It was a bit of work though. You had to add a wafer to the band switch
or change one to what they supplied. Too long ago to remember although I still have the extra parts. The board was a perfect fit
for inside the amp and it looked like it was factory installed after you were done. Dentron also had an external tuned input unit
and once in a while they surface for sale.
If you do buy it, let us know what you think of it!
Logged
W3HKK
Member

Posts: 5




Ignore
« Reply #10 on: May 15, 2014, 02:00:31 PM »

Bought  the (untuned input) Clipperton L  brand new back around 1978, and drove it hard in all the dx contests for 18 yrs.  Never had a problem  although I changed the 572Bs   three or four times. This was back in my heavy dxing/contesting days.  ( drove it with a FT901dm) Operated 90% ssb and 10% cw back then. Lots of 10m work in those days of high ssns but it got a workout on 160-10. 

Yup. Noisy fan.  No other problems. 

I had a chance to use the MLA2500 amp for a few months and  loved it, but the tubes are very rare these days.  Still, if the amp still delivers full output, and the price is attractive, Id be tempted.  ( also lacks a tuned input.)

Considering their age now, however, Id opt for a newer amp. In fact, I just did.  Just bought a TenTec Centurion 1200w/1000w amp built in 1999 for $1200.  Full output with original finals, but not much more.  Very well built amp.
Logged
W6UV
Member

Posts: 1092




Ignore
« Reply #11 on: May 15, 2014, 02:06:19 PM »

I have never owned a Clipperton L, but used one extensively at a club station (W6BB). I remember having to order new tubes quite frequently (I was the club treasurer) to the point that this ate up 25% of the club budget (the rest went to pizza and beer). But this was a club station, and people tended to beat the amp to death by running RTTY at full power, etc. YMMV.
Logged
KM4AH
Member

Posts: 954




Ignore
« Reply #12 on: May 15, 2014, 04:02:53 PM »

I'm not sure what some of you do to tubes. I have one with the original Cetrons in it and it will still do twice the plate dissipation with less than 100 watts drive. And, an internal antenna tuner in the rig will work in place of a tuned input.
Logged
KA7NIQ
Member

Posts: 334


WWW

Ignore
« Reply #13 on: June 01, 2014, 08:31:04 PM »

I'm not sure what some of you do to tubes. I have one with the original Cetrons in it and it will still do twice the plate dissipation with less than 100 watts drive. And, an internal antenna tuner in the rig will work in place of a tuned input.
Ah, that's the Key!
I rescued one from a local tailgate, but the old codger said it worked just fine, and it was only 375.00 so I said WTF ?
I ran it nearly 5 years, and when I finally opened it up (just for cleaning), it still had the original 4 CETRON 572's in it!
I picked up several newer amps, and sold it off pretty cheap to a Ham Friend who has helped me out a lot, and isn't working right now.
Logged

Pages: [1]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!