[Amps] LK 550-ZC

[Dick Green WC1M]

As far as I know, there was no individual manual for the ZC. I think the
"400/500 Series" manual was intended to cover all the variations in both
series. I don't recall exactly what set the ZC apart from other models in
the 550 series, but I think it was QSK. The BAMA manual has the schematic
and some instructions for the QSK Board. Is there some part of the manual
you specifically need?

I happen to have a working LK-500ZC sitting unused in the basement. It has
QSK, but I'm pretty sure it lacks the No-Tune option (it's been a long time
since I used that amp.) I don't recall if it has the "new" step-start
circuit discussed in the BAMA manual, but I think so. It carries the Amp
International label, which I believe indicates that it was one of the last
amps made by Denny before the enterprise went under. The manual that I got
from the previous owner is almost identical to the BAMA version, but appears
to be an earlier edition. Perhaps that means I have it backwards, and that
the original company was Amp International and the last-gasp company was Amp
Supply, and that my amp is an earlier model instead of late one. My manual
does have the pages missing from the BAMA manual (3, 15, 21-24), but those
pages don't contain any critical information. The BAMA manual has more
complete schematics and bills of material.

I did a lot of repair work on the amp when I got it. The previous owner's
wife had thrown something at him during a fight (a chair, I think), and the
amp got knocked off the desk. All three tube seals were compromised, and
when the previous owner turned it on, the resulting arc fried the plate
choke and a number of other components. I also replaced a 40m output cap
that was actually broken by the blow to the amp. The meter bezels were
damaged, too. I fixed all that stuff, added a glitch resistor to protect the
plate choke from future mishaps, replaced all of the meter calibration
resistors (which had either deteriorated or were replaced by a previous
owner with the wrong values in order to fool the ALO circuit, throwing off
the meter readings), slightly increased the fan speed at the low setting to
prevent it cycling into high speed mode so often, and lowered the fan speed
in high speed mode so it wouldn't sound like a freight train.

73, Dick WC1M



> -----Original Message-----
> From: Paul Kraemer [mailto:elespe at lisco.com]
> Sent: Thursday, March 15, 2012 2:29 PM
> To: AMPS
> Subject: [Amps] LK 550-ZC
> 
> Can someone help me find a copy of manual for Amp Supply LK-550 ZC.
> 
> I have the download from BAMA which covers the 550 but not the ZC
> 
> Thanks
> 
> Paul K0UYA