Kenwood KA 9100 rebuild w/pics...and LED questions

[denverben]

Although I got this thing all buttoned up almost 3 months ago, I thought I should properly "break it in" before posting.
I picked this fully functioning unit about a year ago, but the sound was pretty underwhelming--just plain flat really. I didn't do my research before buying, only to find what a royal PITA these can be (for a novice such as myself) to teardown and rebuild. But I thought "well that Marantz 2230 wasn't so bad, how hard could it be?" For anyone considering it, the entire front end has to be disassembled to access the tone/control boards, and those boards are about as dense as a British Columbia pine forest. I found some great threads, and of course invaluable help from some of our residents here ( Echo Wars, Jailtime, pakko, etc... ) and was able to get through it.

front end spaghetti explosion
new speaker terminals/mounting plate

Making some extensions for the new main filter caps from copper tubing, crimped then soldered to the original leads. The new caps were about half the height of the originals. Some rubber tubing was cut down for gaskets around the new smaller diameter caps.


To LED or not to LED ? I love LEDs...I understand the arguments against, but I kinda like messing with the lighting color and brightness of old receivers. And with the longevity, efficiency and low cost of LEDs why not? Also, the new "warm white" versions can just about pass for the color of incandescents.
Anyway, I tried these ( https://www.superbrightleds.com/mor...-4-led-ba9s-retrofit-car-classic-car-bulbs/6/ ) from superbrightleds.com , and it seemed like a good substitute--even bumping up the brightness a little. I love the look of the meters on this amp, but the original bulbs are really very dim in the daylight. The 6V versions of this bulb are rated to operate on 6-9 volts so I figured what the heck. Well they worked great for a couple months, then failed simultaneously a few days ago. I haven't looked into the cause yet. Maybe I should have done a little more homework before just popping them in. Anyway, I'm wondering if anyone else has tried other LED versions that they like, especially if they provide more brightness. I'm all ears!
with Amber LEDs... and warm white...

Despite the lighting issues...I love this amp!!
Vinyl has never sounded better (to me) and paired up with some Dahlquist DQM-9 's I'm in analog heaven. To say the sound improvement with the recap was night-and-day would be a sorry understatement. It really makes these exceptional speakers come alive...anyone looking for a good speaker match up for this amp I would really consider the Dahlquist monitor line--detailed, dynamic, big soundstage and fantastic imaging--the least boxy sounding, big boxy speaker I've heard yet. Beats L-112 's hands down IMO.

PS: I would have posted more pics of the recap but I guess I'm limited to 10 here...

Thanks for stopping by!

Here are some links that helped me along the way...
- http://www.cdkands.com/ka91002/ka91001.html
- http://audiokarma.org/forums/index.php?threads/kenwood-ka-9100-9150-sound-experiments.361443/
- http://audiokarma.org/forums/index.php?threads/kenwood-ka-9100-power-supply-tips.549816/
- http://audiokarma.org/forums/index.php?threads/ka-9100-owners-hep-me.307809/page-2
- http://audiokarma.org/forums/index.php?threads/more-ka-9100-blues.734552/
- http://audiokarma.org/forums/index.php?threads/kenwood-ka-9100-upgraded-and-singing.6922/
- http://audiokarma.org/forums/index.php?threads/kenwood-ka-9100-works-but-how-well.78057/
- http://audiokarma.org/forums/index.php?threads/ka-9100-overhaul.535067/

 

[turboyam]

Nice job!. I like your PSU cap extensions and, those new speaker terminals.

 

[gort69]

Nice work Ben! I just finished the same deal on a 9150 and can attest to the fact that it was a sumbitch. W/O the help of fellow Akers - rjsalvii and hopjohn in particular - I would have been in trouble. I'd imagine we were using the same cuss words on the same day more than once.

I went for the easy and expensive solution to the filter caps - $106 worth of 15,000uf 63V 40mm solder-lug Nichicons from Michael Percy which are drop-in replacements

I recall the supply for the series-wired (if one fails, the other won't work) lamps on these are is 30v AC, and that there is a dropping resistor in the mix - so the lamps need to be pretty close to 150ma 8v to get the final voltage to work out correctly. Something like that. Mine had new incandescent lamps installed by a previous owner so I left them alone.

 

[denverben]

Nice work Ben! I just finished the same deal on a 9150 and can attest to the fact that it was a sumbitch. W/O the help of fellow Akers - rjsalvii and hopjohn in particular - I would have been in trouble. I'd imagine we were using the same cuss words on the same day more than once.

I went for the easy and expensive solution to the filter caps - $106 worth of 15,000uf 63V 40mm solder-lug Nichicons from Michael Percy which are drop-in replacements

I recall the supply for the series-wired (if one fails, the other won't work) lamps on these are is 30v AC, and that there is a dropping resistor in the mix - so the lamps need to be pretty close to 150ma 8v to get the final voltage to work out correctly. Something like that. Mine had new incandescent lamps installed by a previous owner so I left them alone.

Cool! And you betcha there was some cussin!
I'm jealous of the 9150...of course one popped up (for a great price) on ePay right after I got this one. I really like the looks of those dark face panels against the silver controls.
Although your caps were more expensive, the few hours I spent retrofitting mine more than made up for the price savings.

I'll have to get back in there and fine tune the lighting...really liked the amber bulb color but they were pretty dim in the daylight.

How long would you say it took for yours to really "break in" ? It's hard to describe that process, but mine started to gradually sound more refined, smoother and detailed after about 10 days of use ~ 40 hours maybe ?

This is the majority of parts replaced, plus a few more transistors and the relay.

 

[denverben]

Nice job!. I like your PSU cap extensions and, those new speaker terminals.

Merci beaucoup! What are those amazing speakers on your avatar ?

 

[punprankster]

Well, you're a brave guy denverben. I am not very confident of my skills right now, having messed a 9100 up and a couple of other things besides lol.
Enjoy.

From another 9100 fan.

 

[ferninando]

what material did u use for the binding post mount?

 

[denverben]

what material did u use for the binding post mount?

It's black acrylic. Pretty durable material and non-conductive, but a little brittle.

 

[turboyam]

Merci beaucoup! What are those amazing speakers on your avatar ?

Those are Spiralhorns. The driver is a Fostex FE166E. It's basically 4, 7ft long, spiral horns in each enclosures.

 

[Kenny*G]

Denverben, Any chance you have a link to where I can buy some binding post like you used, I have the same issue.