DentronMLA 2500A

[WA7BUY]

I recently aquired two Dentron amplifiers. One states on the front it is a MLA 2500 and came with an Operating Manual for a MLA 2500. SR# is 2494. Tag on back states it is MLA 2500, 220 volts 7 amps, 10 amp fuse. Covers 160 thru 10 meters. Five front switchs are STANDBY,CW TUNE,PLATE VOLTAGE,PLATE AND GRID CURRENT. Uses slotted screws to hold top and bottom covers on. The second amp states on the front it is a MLA 2500 but came in the box with an Operating Manual for a MLA 2500B. SR# is 3743. However the tag on the back states it is a MLA 2500A, 234 volts, 12.5 amp, 15 amp fuse. It has counter sunk screws holding the top and bottom covers on and requires an allen wrench to remove them. Covers 160 thru 10 meters and has the same five front switchs as the first one. I would like to know what the difference is between a MLA 2500 and 2500A.  Is the second Amp a 2500 or 2500A and which Operating manual do I use for the second amp as there are differences in the two manuals I have.  Hope this all made sense and thanks for any help.
Jerry WA7BUY

[W9GB]

Jerry -

Dentron/Amp Supply changed over the years - but I was not aware of the changes that you noted.
The eHam.net reviews talk about some differences between the 2500 and 2500B
http://www.eham.net/reviews/detail/1440

BAMA has the schematics for both
http://bama.edebris.com/manuals/dentron/mla2500/

The MLA-2500 is a heavily modified amplfier due to its usage fo the now discontinued Eimac 8875 tube.

B.N. "Bob" Alper - Svetlana Application Note on conversion to Russian 4CX400A tube (tetrode)
http://www.svetlana.com/docs/TechBulletins/technoteNo14.html

Tom Rauch, W8JI has some comments (proper use of tetrodes) regarding Mr. Alper's article
http://www.dxer.org/w8ji.html

W4EMF mod to Russian GI-7BT
http://www.nd2x.net/w4emf-MLA.html

WB8WJU conversion to the Russian GS-35b
http://www.nd2x.net/WB8WJU.html

w9gb

BTW, after a large number of legal cases - as of 2003,
New Sensor/Electro Harmonix/Sovtek is the new owner of the Svetlana trademark.
The former owner of the Svetlana is now called SED (Winged C logo).