Dentron GLA-1000

[KE5EKO]

I'm in the market for an amplifier and, of course, I want the most bang for the buck. I saw one of these amps for sale a while back and when I checked it out on Rig-Pix, they said it uses " 4x D-50A ".
I give up. Are these tubes or what? I haven't been able to find out any info on these D-50A things and being a curious fellow, it's killing me.
Thanks in adavance....Mike

[K0BG]

Here is my best advice: DON'T buy it! If memory serves, it uses 4, 6KD6s (or a very similar sweep tube), the the supply of them is all but dried up.

If you want a decent, low price amp, look for a used ALS-811 or ALS-811H.

Alan, KØBG
www.k0bg.com

[KE5EKO]

That's what I have decided to do...But I still don't have any idea what a " D-50A " is....Mike

[KA5N]

D-50A is just the stock number Dentron gave for whatever selected sweep tubes would work.  
Those of us who were around in the days of yore remember when color tv sets hit the market big time and some ham discovered that he could run the then cheap horizontal output tubes (sweep tubes) with a 1000 volts or so on the plate and get a lot of power out of 2, 4, 6 up to maybe 16 of these dudes in parallel.  A number of transceivers used a couple in  the finals and a number of amps were so equiped.  Today these tubes cost a small fortune (if you can find them) so avoid like the plague.  Some of these  amps have been modified to use other tubes such as some of the Russian triodes (not for the timid of heart).
Steer Clear!
Allen

[KE5EKO]

That makes sense...
Was just curious what the " D-50A "..notation was all about..
When I started looking about an amp, the availability/cost of replacement tubes/parts of an amp was a major concern. think I'll stick with the 811 or 811H...Thanks for the info and advice...73...Mike

[KD7HVL]

D-50 is the Japan version of a 6LQ6 horizontal sweep tube made for TV.  Other tubes that you can ues are 6JE6 adn the 6KD6 with modification to the socket wirring.  there is a Russian tube that requires different sockets that can be used and last there are some that have been convaerted to a GI7B single tube triode with extensive modification.  If you are looking for a good plug and play amp like everyone else is saying "STAY AWAY FROM ANY AND ALL SWEEP TUBE AMPS".  Last but not least the GL1000 does not have pull up bias and as such even when your in standby the tubes are cooking due to foward biasing,  this amp has no cut off bias.

[W9GB]

Mike -

You have received good advice.  
NEWCOMERS should AVOID Sweep Tube amps (dead end for plug-n-play operation).  
IF you want GLASS RF tubes go for a nice SB-200, Collins 30L-1 or Ameritron that use 811A or 572B tubes.

The Russian EL-509/EL-519 conversion for a GLA-1000 is a short term solution -- that does not address the design shortcomings of the amplifier.
http://www.geocities.com/ko4nrbs/
http://www.xs4all.nl/~pa0fri/Lineairs/GLA1000/gla1000eng.htm

The Dentron GLA-1000 amplifiers are very good for Russian GI-7b builders for raw parts (a better starting point than CB sweep tube designs that lack HF multi-band switching hardware).  
http://www2.wcoil.com/~tlee/
http://w4emf.gs35b.com/GLA-1000-retro-GI7/
http://www.xs4all.nl/~pa0fri/Lineairs/GLA1000/gla1000eng.htm

Tony King, W4ZT and Ron Wilson, K4POZ have Builder's Notes for experienced builders using the GLA-1000 or other HF amplifier as a base for a GI-7b conversion.
http://gi7b.com/
They have also built a very nice socket, based upon Lawson Summerrow, W4EMF earlier work.
http://gi7b.com/inspiration/index.html