Kenwood L-08M Restoration + L-08PS!!!
- Thread starter Connor G
- Start date
I used them with two Sanyo TSD-N06U step-down transformers. The owner opted for the 100v version over the multi-voltage version because of the external power supply provisions. He has his eyes peeled for a set.
Thank you!Fantastic Work @Connor G
Really inspiring
I am growing really fond of the L-07Mii and L-07Cii combo.
I have a pair of L-07MII's broken down for a full restoration currently. I can't wait to get them built back up. The L-07CII is also on my list. Great preamp!
belay that- I have just discovered that the "thermal switch"- my assumption, is D9- STV-4H- which is an encapsulated diode array- @EchoWars did some great research which I will use (4x uf1004 in series).
My next question- is there a substitute for the speaker relay- Matshusita JC-1A-DC24?
thanks again
My next question- is there a substitute for the speaker relay- Matshusita JC-1A-DC24?
thanks again
Hey everyone, It's been a while since I restored the L-08Ms, and I have something exciting to share with you all...
After a couple years of searching, the owner of these amps and I finally found the missing pieces to the L-08M puzzle: L-08PS!
These arrived to me months back, and I finally got some time to go through them to give them a proper cleaning and service. Needless to say, they've had a hard life.
These came from Europe to get here, and thankfully they made it mostly unscathed. Scratches, dents, and even surface rust are present; something that will be next to impossible to fix without a complete stripping and repainting. I am not currently equipped to do this, so a general cleaning will have to suffice. They don't look too bad afterwards, but perhaps a cosmetic restoration will be in order in the future. I digress...
On the outside, you can see how rough they appear. Not the worst, but not showroom condition either... Also note the electrical tape on the output cable, and the non-original power cables... Under the electrical tape lies missing wire insulation, for whatever reason. It will be repaired properly with heatshrink.
Inside layout is relatively simple: Standby power supply, large power transformer, output contactor relay / related drive circuitry (which is controlled externally by the L-08M), and rectifier circuit. All filtering is done locally within the L-08M - the L-08PS just outputs raw chopped DC straight from the rectifier. Up next is the servicing that was done to these recherché oddities. Also note the wording on the back of each L-08PS: "POWER APPARATUS FOR KENWOOD L-08M"... Too funny!
After a couple years of searching, the owner of these amps and I finally found the missing pieces to the L-08M puzzle: L-08PS!
These arrived to me months back, and I finally got some time to go through them to give them a proper cleaning and service. Needless to say, they've had a hard life.
These came from Europe to get here, and thankfully they made it mostly unscathed. Scratches, dents, and even surface rust are present; something that will be next to impossible to fix without a complete stripping and repainting. I am not currently equipped to do this, so a general cleaning will have to suffice. They don't look too bad afterwards, but perhaps a cosmetic restoration will be in order in the future. I digress...
On the outside, you can see how rough they appear. Not the worst, but not showroom condition either... Also note the electrical tape on the output cable, and the non-original power cables... Under the electrical tape lies missing wire insulation, for whatever reason. It will be repaired properly with heatshrink.
Inside layout is relatively simple: Standby power supply, large power transformer, output contactor relay / related drive circuitry (which is controlled externally by the L-08M), and rectifier circuit. All filtering is done locally within the L-08M - the L-08PS just outputs raw chopped DC straight from the rectifier. Up next is the servicing that was done to these recherché oddities. Also note the wording on the back of each L-08PS: "POWER APPARATUS FOR KENWOOD L-08M"... Too funny!
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Overall, the servicing was quite basic. They needed two electrolytic capacitors replaced per unit, a quick reflow of suspect solder joints, new AC power cords fitted, and their damaged output cables repaired.
As I needed to slide heatshrink tubing over the output cable, removing the plug was necessary. I'm glad I did, as the solder joints holding the wires to the terminals were ugly! After remedying the cable, I made sure to clean up the soldering on the plug.
After a proper cleaning, they look much better than they did when they arrived to me!
I'm very excited to get these gems shipped off to their new owner, and I can't wait to hear what he has to say about them. I will be sure to relay what he thinks back to this thread.
Thanks for reading along!
As I needed to slide heatshrink tubing over the output cable, removing the plug was necessary. I'm glad I did, as the solder joints holding the wires to the terminals were ugly! After remedying the cable, I made sure to clean up the soldering on the plug.
After a proper cleaning, they look much better than they did when they arrived to me!
I'm very excited to get these gems shipped off to their new owner, and I can't wait to hear what he has to say about them. I will be sure to relay what he thinks back to this thread.
Thanks for reading along!
analogwisdom
When in doubt, stuff in a WIMA
Damn, I can't believe how little love this thread got. I'm sure you've heard it a million times, but amazing work. You are a huge inspiration to me, I hope to be able to do work as half as good as you one day! I wish you did a video on these!
Thanks for your kind words!
Yes it should be fairly straightforward to replicate these power supplies. The trigger circuit is fairly rudimentary. From memory, turning the L-08M on sends a small voltage to the power supply that engages the output relay inside. I have the voltages and pinout scribbled down somewhere around here.
I was never updated on the L-08PS as I haven’t been in contact with the owner for a while. If I hear from him I will be sure to update this thread.
AudioAvarice
Super Member
I thought the L-08PS is only compatible with the Japanese version? I have a European version of the L-08M, and the connection slot is blanked.
Correct. The L-08PS was only designed for the Japanese market 100V L-08Ms. There could have been many reasons for this, not the least of which being the fact that the L-08M was not sold in terribly large numbers. They likely wouldn’t have recouped the cost of manufacturing the L-08PS for international models, so the idea probably died early on.
AudioAvarice
Super Member
It's a shame, I've always considered the visual design to be one of the best of the 80's, guess it was a little too 'out there' for the time, I'm guessing the preamp sold even less, with how much rarer it seems to be? Which I can actually understand, some strange design choices there, but a very good sounding pre.
Very much a shame. Many recherché high end pieces from most of the major players were exclusive to the Japanese market - never to see the light of day anywhere else.
The L-08Ms, I believe, are the HiFi equivalent of the Lamborghini Countach. Sharp lines and angles, great performance, and way too ahead of their time. Both also look great as a poster hanging on the wall
sharisselis
New Member
I have six L-08PS units. They can be linked together to provide the L-08M with an immense power capacity. But I have to be honest—if you already have a pair of L-08Ms that have been perfectly restored, connecting them to the L-08PS will actually have a negative effect. The bass becomes overly heavy and sluggish, while the treble turns tense and strained.
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How on earth did you manage to acquire 6 !
What you say is very surprising. I have a Japanese pair that are currently on their way to my friend who is going to restore / upgrade them. They will need a new mains trafos for UK 240v, so I was thinking why not just get higher VA rated ones in lieu of using the external PS units (which I don’t have anyway).
sharisselis
New Member
I think the performance might be limited by the power supply capacitors in the L-08M itself. Although the transformer capacity has been increased, the power filter capacitors remain unchanged. The L-08PS does not increase the capacitor capacity; it still relies on the capacitors in the main unit for filtering.
sharisselis
New Member
It depends on the type of speakers used. The L-08M is particularly well-suited for driving large, bass-reflex speakers. Sigma drive is very effective with these types of speakers, providing a level of damping that most amplifiers struggle to deliver. However, when paired with sealed-box speakers, the results can be somewhat disappointing.