Dentron Tuned Input

Requests for information on what Dentron used for their tuned input 
circuit for the GLA-1000 amplifier led me to collect some of the 
information I had and make it available to others.

Located along with this message should be the file called - 
Dentron Tuned Input.Zip

Looking at the files in the downloadable file you should find:
1.  GLA1KB schematic.jpg 
Shows the values they used in their schematic

2.  GLA1000B parts list.jpg
Since the tuned input circuit became a standard inclusion in the
Dentron GLA-1000B, this schematic and parts list should be the
same as used in the board Dentron provided for the older 1000s and
probably also for the circuit boards sold by FAR Circuits.

Also included are some information on the Dentron CM-U and CM-1 external
tuned input for their larger amplifiers.  These units appear, from time
to time, on eBay and seem to sell for up around $130-$150 which seems too
high for me.
3.  Dentron CM-U.jpg
4.  Dentron CM-1.jpg
5.  Dentron CM-U1.pdf
6.  Dentron CM-1 & Addendum.pdf

As an aside, if you have a Dentron amplifier which has no tuned input
circuit, you might consider an auto-tuner made for tuning antennas.  I
have an MLA-2500 amplifier with no tuned input and I had periodically
used the auto-tuner in my IC-756PRO but since there is a possibility of
having too high voltages leading to its destruction, I wanted to get
away from that practice.
I noticed that LDG actually sells the board from their LDG AT-100PRO
tuner (no case, etc.) for building inside an amplifier needing tuned
input.  I almost bought this board but for just a bit more cash outlay
I was able to get the complete AT-1000PRO tuner and have the case, the
indicator LEDs, and a 2 antenna switch option.  Also I couldn't see 
any good location inside the MLA-2500 for the tuner board.

I've been very pleased with the use of the AT-100PRO between my IC-756PRO
and my MLA-2500.  It allows me to get full power into and out of the
amplifier, even on the WARC bands.

Jim - K5LAD
Oct. 15, 2006