Special Designes Proucts SDP 1000L Linear

[kc2dhu]

I was wondering if anybody here might have a Schematic, or Manual for this amp.
Had been sitting for a while and I finally got it up on the bench to give it once over.  It does make power, so the HV and all works.
Searching Google only turn one blog from the Bunkerofdoom.  Seems like and oddball but looks like it could do 100W carrier with no sweat on AM.
If anyone had the joy or misery of dealing with one of please let me know.

2.2 Mhz to 28 Mhz 2 3B28's for rectifiers 1 OA2 and 2 OB2's and a pair of 4CX250B'S

Thanks in advance and well during these trying times.  Jim KC2DHU

[KA7WOC]

I have one of these amps with some paper as well though the copy of I have is not very good.  I’ll have to dig it out and see what I can do as far as copying
Bob ka7woc

[KA7WOC]

I spotted it at swap 10-15 years back and convinced a fellow ham to buy it.  $80 as I recall.  We swamped a Ranger into it.  Best sounding rig he ever ran.  I got it from him maybe ten years back but have only used once or twice on ssb.  I have recently thought about firing it up    I will copy what I can but expect low quality
Woc

[kc2dhu]

Thanks Bob. Got a usurers manual coming from the manual man. From what I have seen which is not much, mine seems like a a is an odd-ball. It is not rack mount, does not say military mars, and the 2.2 to 3.0 tap goes no where. Also the forward air variable on the tuning control does not exist. From the few inside pictures I've seen of this beast. I would appreciate any documentation you could send. I have it running in testing mode on 80 meters it will do 600 Watts with about 25W Drive. 10 Watt drive carrier on AM with good modulation will put it right at the 600 watt peak. Iron stays cool too. I would have to do some mods to make it key (switching in and out). Kinda got that figured out in my head but waiting for the Manual before I give it the hack, just to be sure I am not missing something.

Wondering if my SPL1000 may have been a prototype for a desktop unit for 80 to 10 meters?
Only time and clues will tell. Love the oddballs.

                    Jim KC2DHU

[Opcom]

If I saw one of these for $80 and it had good iron etc I would buy it immediately.

I posted late not seeing the last post but for what it;s worth;


The one on BunkerofDOOM is mine and graces a rack in that hallowed hall.
For over 10 years there have been no troubles.
The 4x250Bs are cheaply had, but nothing has ever happend during use to ruin them.
You can run 866's, 3B28s, or solid state sticks with no changes.

The terminal strip on the back has 1KVDC, 400VDC, 110VAC, and -150V on it, so be careful. Most of it is for an external mod scope, SDP No. 1S. Opening and closing a contact on terminals 5-7 controls cutoff bias/normal bias. This is a non isolated 110VAC circuit.

There is no built-in T/R relay, but there is a manual amplifier in/out switch. So you will need a Dow Key or whatever to automate it.

I know more than one guy who flips 3 or 4 switches going from RX to TX.

BTW this is designed for 110V, so a good idea to buck the line a bit or at least adjust it so the heater voltage on the tubes is correct. It should have a 15A outlet or equivalent.

On AM, I got 100W carrier, 400W PEP easily from mine. Trying for 500-600W on AM is likely to trip the plate current overload.
However, when operated within its ratings, it is a wonderful general coverage amp.

The power supply is rated 1KW DC, CCS duty; 2KV@500mA. The amp is also rated for continuous duty on SSB at that average level, which ought equate to 2000W PEP input (no compression obviously).

I found the blower a little weak IN MY OPINION but then I like overkill air. Nothing actually overheats and it's pretty quiet. If one wishes, a larger blower can be attached via a hose and a home made adapter to the simple screened intake hole on the back. Just make sure the blower is actually running because it is quiet.

No input tuning is required.

Drives very easily, says 100W PEP, but I found it to work OK with less.

Grounded Grid circuit, AB1, using the normal AB1 element voltages on the tubes (as Eimac says to do)

I have indeed seen the screen current go negative when properly loaded at full power. The screen current meter is a fine aid to loading it and helps avoid overloading the screens.

Here are the Ratings from the Plate Power Ratings chart in the book, since you have the unit and should be careful with it til you know it. Because it's a little unusual, The manual's procedure is really needed for tuning it properly.

CW
key down conditions (continuous):
drive 30-40W
input 1000W
output 575W

====================

SSB:
average meter reading on voice peaks
drive 40-50W
input 1000W
output 625W

PEP 2-tone test
drive 65-80W
input 1600W
output 1000W

PEP voice
drive 80-100W
input 2000W
output 1250W

====================

AM carrier with DSB
drive 15-25W
input 700W
output 300W