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Dentron GLA-1000 Series Amplifiers

Bill Smith (KO4NR) on June 16, 2001
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The Dentron GLA-1000 series amplifiers have been resurrected by the importation of affordable Russina Sweep tubes. The Svetlana EL-509/6KG6 tube has been successfully used to convert the Dentron amplifiers from the factory supplied 6LQ6 tubes. Svetlana has an artcile on their Web Site describing the conversion in detail. Check this site:

The Dentron GLA-1000 and 1000A did not have a Tuned Input. A Tuned Input was offered in the GLA-1000B and 160 meters was added in the GLA-1000C. In order to get 10 meters working in the GLA-1000, 1000A and 1000B a modification had to be made. I have all the instructions for all these models.

To date I have sucessfully completed four of the conversions. In addition I have added modifications and betterments to the circuits to protect the tubes and meter from damage. I am no electronic engineer but I can and do read everything I can lay my hands on about amplfiers. I must however give credit where credit is do. Skipp May (WV6F), David Feldman (WB0GAZ) and Rich Measures (AG6K), just to mention a few have provided me with invaluable guidance in my first couple of Dentron GLA-1000 overhauls. I owe my sucess to them and others like them who showed great patience as I peppered them with questions.

I agree that these Dentron amplifiers are not in the same league as the Heathkit, Drake, or Collins amplifiers but they do the job and are very dependable if used properly. In addition their small size and attractive front panel make them a nice addition to any Ham Shack. I can also attest to the fact they can be purchased at a very resonable cost. In fact I have saved two from being thrown in the trash.

I have all the upgrade information on the Dentron GLA-1000 series amplifers in a set of files I can email to anyone that is interested. 73, Bill Smith KO4NR

Member Comments:
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Dentron GLA-1000 Series Amplifiers  
by WB8JKR on June 16, 2001 Mail this to a friend!
Dentron never made anything that was worth a hoot. The
stuff worked, but there were so many engineering short
cuts made it was pathetic. The amps were dirty, and cheaply built. The thing that made Denton was the marketing and the price.
Dentron GLA-1000 Series Amplifiers  
by K4CWQ on June 16, 2001 Mail this to a friend!
I have a Dentron GLA-1000B and really like it. I only wish it had 160 meters on it. I've been considering converting it to the Svetlana tubes. I hear that Far Circuits may be working on a circuit board for the conversion, so that you can just swap circuit boards and plug in the Svetlana EL-509 tubes. They are a much heftier tube than the 6LQ6 sweep tubes.

I find my Dentron to be very rugged, with heavy duty switches and components. I think it compares favorably with other amps in the low power range.
Dentron GLA-1000 Series Amplifiers  
by N6AJR on June 16, 2001 Mail this to a friend!
Not the amp , but I have the Dentron 2000a (3kw) tuner, and I love it. Its big, has huge knobs for my huge hands and works very well..I will find a matching amp soon..I like the looks too.
Dentron GLA-1000 Series Amplifiers  
by KB9ZB on June 16, 2001 Mail this to a friend!
having bought one on e-bay for just a couple of bucks, it was a good investment. it give a big bang vor the buck. the mods i needed to make were abit more than i thought but it made the interest grow. i love it and with the new tubes i am looking forward to a few more years of power. it is a model t type amp but it deleivers the power. the only draw back is it is stripped down a bit much and setting it up takes a bit more time than i like, but for a couple of hundred bucks you can't expect a cadilac!!
Dentron GLA-1000 Series Amplifiers  
by W9JCM on June 17, 2001 Mail this to a friend!
Dentrons are solid I was not a fan of the sweep tube amp at all but the tuners and Clipperton series are build good some people just have it out for certain co. names and will always bad mouth them. I have a clipperton V VHF amp, CLipperton L HF, and a MT-3000A the best high power tuner i have ever used or seen.
Dentron GLA-1000 Series Amplifiers  
by K5OE on June 19, 2001 Mail this to a friend!
Thanks for posting the information. I had an LA-1000-NT (which did have 160 m), but when I looked at the EL-509 conversion, the case was not tall enough without cutting a hole in the top. As I recall, the Svetlana tubes are about 3/8" taller than the 6LQ6/6MJ6 sweep tubes. Did you have to address this issue with the amps you converted?
Jerry, K5OE
Dentron GLA-1000 Series Amplifiers  
by K5AF on June 19, 2001 Mail this to a friend!
Always great to see folks figuring out wasy to extend the life of these and other similar amps. As a buyer and seller of RF components, I can tell you that it is much easier to save a piece of gear than it is to start from scratch. I've often wondered if it would be feasible to convert the Gl-1000 series to 572Bs? I believe it may be a physical challenge due to the tube size, and the voltages aren't quite right, any thoughts out there?
RE: Dentron GLA-1000 Series Amplifiers  
by JAMES_BENEDICT_EX_N8FVJ on June 20, 2001 Mail this to a friend!
If the amp is inexpensive enough, I would buy one- cheap construction and all. If 400 watts goes up the coax, I'm happy.
RE: Dentron GLA-1000 Series Amplifiers  
by KO4NR on June 20, 2001 Mail this to a friend!
The EL-509 tubes just fit in the Dentron GLA-1000 series amps. I did install a piece of HV insulated board between the top of the tubes and the underside of the top cover to make sure I didn't have a short to the chassis.
Bill Smith KO4NR
Dentron GLA-1000 Series Amplifiers  
by AA8X on August 5, 2001 Mail this to a friend!
Dentron made very good products with excellent customer support. I purchased an original MLA-2500 and Dentron Corp upgraded it to the B version, which included a new tapped transformer and other components all at no charge or shipping cost. How many manufactures would do this today? I cant thing of any manufacture that would do so. My MLA-2500 will still puts out maximum power. The MLA-2500 is still a great product for the price.

73, Bob AA8X
Dentron GLA-1000 Series Amplifiers  
Anonymous post on August 6, 2001 Mail this to a friend!

Great job on keeping old equipment alive. We need to do things like this to let the manufacturs know that 5000$ is too much for any amplifier! Maybe if DIY article's like your's show up often enough and the manufactures realize how many sales they don't get, they'll learn how to make amp's cheaper.

Two Russian tubes cost 300$. Peter Dahl xrf another 300, switch tuning caps and hand-wound coil another 300 that's 900. Ain't no way the cheapest full gallon amplifier ought to be over 2000$.
Dentron GLA-1000 Series Amplifiers  
Anonymous post on August 6, 2001 Mail this to a friend!
I can't get past the venom and hyperbole on AG6K's webpage to figure out if he knows anything or not. He certainly doesn't provide any theoretical basis for his claims. I've fixed a lot of amps with so-called "Measures" mods that needed to be un-modded before they'd stabilize and not overheat. To be fair, I would not be able to tell the difference between a "Measures" mod and some truly dumb thing the owner did, so maybe the mods I removed weren't the "Measures" mods. I've only worked on TT, Drake and HK amps, no Dentrons showed up here so far.

You said something really funny there at the end, that the Dentrons aren't in the same league as Heath, Drake, and Collins. Having worked on all those three, I'd say that Heath, Drake and Collins aren't in the same league as each other. And if your statement implies that Dentron's are of lower quality than the Heaths, then I'd just as soon not ever work on one! The Heaths show up with more overheated PC boards, bandswitch contacts melted due to excess circulating current, parasitic suppressor resistors cooked because the cooling fan isn't strong enough to keep them cool and the like, than anything else. And you imply the Dentron is worse? Happy for you on it, but I'm thankful I haven't seen one!
RE: Dentron GLA-1000 Series Amplifiers  
by KB7CIJ on May 26, 2003 Mail this to a friend!
I ma looking for a manual for the Dentron MLA 2500 power amp. Any suggestions?
RE: Dentron GLA-1000 Series Amplifiers  
by KAA8PCJ on November 17, 2003 Mail this to a friend!
i would like to get the upgrades and betterments
via email Iam changing to the el509 Roger
Dentron Clipperton-L Amplifiers  
by N4VHA on January 3, 2004 Mail this to a friend!
I understand that there is a tuned input mod available for the Clipperton-L. It may be the same one that is available for the GLA-1000. I have been told that when the mod is installed in the Clipperton that an extra wiper pad has to be added to the a switch otherwise it is fairly simple to install.

Where can I get the mod?
Edwin Fuqua, N4VHA
800-643-5143 (good untill Jan 10) (good allways)
http:\\ to contact me after FEB 1,04

Thanks in advance for any information.
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