late 80's kenwood true amps

quaddriver

120 What?'s per channel
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like the KM series, that use the KC series preamp-controllers.

I picked up 3 sets last weekend at auction for a song, and just a wee song at that.

All 3 clicked out of protection so I figure, gotta be a good risk.

The amps are well built, well laid out class A/B with massive sankens. the LITTLE amps are 125 watts. I got 2 of them and a 150 watter.

starting on one and using tape out from my DD to CD in on the KC208 it sounded great but...how do you say?

so I did the patented echowars DCO test and aha, 25mv left, 50mv right.

These amps have a 2 stage differential before we delve into class A, constant current, class B silicon...and they use older 2sc1845E's and 2SC945s for stage 1/2 respectively.

pulling out my supplies I match up 4 KSC1845Fs, glue em in, pow, DCO at .8 and 1.0 (its not settable) I didnt touch the C945 section. long story short these are well built and the idle is straight to set. The manuals are on hifiE and these packed a crap load of power with tiny distortion.

Now the pre-amps...they are loaded with features but I fear little attention is paid here when if could be for a few bucks. Its ALL chipset. every amp is an op-amp making you at the mercy of the op amp in question. Im not saying there is anything wrong with the KC 208(s) (I have 3 of them now) but if you have a stellar pre, try these amps.

on and the LED dual range 'power meters'? a simple scalar and a bunch of lights. Kenwood REALLY could have put a couple needles in here for panache.
 
Rewind 30 years you could say the same for silver face. Will the black plastic era have it's time in the sun in the same way?, doubtful. Bargains o plenty if sound is the only game you're playing. Demand is a fickle mistress.
 
ha! I forgot to mention, the control amp (since I had it apart) actually has a black aluminum faceplate! when they built them to survive a drop!
 
Now the pre-amps...they are loaded with features but I fear little attention is paid here when if could be for a few bucks. Its ALL chipset. every amp is an op-amp making you at the mercy of the op amp in question. Im not saying there is anything wrong with the KC 208(s) (I have 3 of them now) but if you have a stellar pre, try these amps.

Can you tell me how the trigger port works?

power on the KC and does the trigger supply 12v or does it close a relay?

I'm adding a trigger function to an existing pre for my mono blocks. These need a simple on/off switch.

i think a simple Wallwart ->relay will work but haven't built it.

I notice the KC-208 has a trigger port. How does it work?
 
ok are you refering to the switched 680watt power jacks on the back?

The amp is 480 watts and the amp has plugs for an additional 200w - 200+480 = 680 in most states so without consulting the manual it appears the intent was to plug the amp into the preamp/control os you can use 1 switch or the remote.

from being inside it, the switched power is fired by a relay and if you needed to go higher I would do 2 things: upgrade the KC to a heavier power cord, it is actually THINNER than the KM!!!! and upgrade the relay (or at least check that its contacts can go higher, most allow 10-15amp and if not I am sure someone has a mouser part number)

but yes, control power turns on a relay that enables a few ports with a LIMITED draw capability.

now dont confuse that with the green 1/8th jacks...that is for connecting like components that can be controlled remotely, without a remote.
 
Sorry, I had questions about the green 1/8th jacks...that is for connecting like components that can be controlled remotely, without a remote.

Does this provide power (like 12vdc) or a simple on/off switch. my l-07Ms want only a switch and not any power.

remote.JPG

Since these are different style jacks: 1/8" jack on the KC-208 and a 5.5mm power jack on the L-07m, I think they might have different characteristics. I just don't know.
 
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ok, those i believe are to connect other similar year kenwood components. and btw - I need to wear my reading glasses more, I have a KC-209!! not 8 jesus. lol
 
quaddriver, what would help is if you could plug in a 1/8" plug cable into the system control jack and measure the tip and sleeve on the other end of the cable. turn on the pre and measure again. are both measurements 0v? I looked at the KC-209 schematic and looks like both tip, ring and sleeve are used. Tip for 'busy', ring for 'data' and sleeve for ground.

my guess is some kind of power is used since base of Q7 is connected to the same busy and data signals.

no hurry. I'll probably just use a relay (I have many).
 
quaddriver, never mind. I built a wallwart/relay to trigger the remote. Seems to work. I had all the parts too!
 
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It was purchasing a KM-209 in early 2003 which brought me here looking for Echowars' expertise in all things Kenwood. After lurking for 8 months I joined. AK stoked the fire. That led to purchasing the C-2/M1 Basic preamp/amp. The M2. The M2A. The KA 9900. The 700C. Another 700C but this time with EW modifications. 2x L-1000M. 2 L-08Ms. 6 L-06Ms. The L-A1.

Beware of the slippery slope. AK makes it even more slippery.
 
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Beware of the slippery slope. AK makes it even more slippery.
This is so true. i thought my mcintosh/hafler setup was fine until you start reading about all the hi end kenwood stuff and get curious. I spent 6+ months fixing and flipping gear (not all Kenwood) to have the funds for my latest mono blocks.
 
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