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Kenwood L-09M output transistors: Sanken vs. On-Semi

Must not have replaced very many Japanese transistors. 2SA are always PNP and 2SC NPN.


Any competent tech should be able to suss something like that out even if they did not have a clue of the 2SA & 2SC numbering, access to google or datasheets etc. Basic electronics 101.
 
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Point taken, but in the end, the bad choice falls on me for choosing this tech in the first place. Hmm...but you're right, normally it's that simple: you go fix your car somewhere else.

Thank you OverLoad "2SA are always PNP and 2SC NPN" is what I gathered from wandering around the net for a while.
 
diamo said:
Thank you OverLoad "2SA are always PNP and 2SC NPN" is what I gathered from wandering around the net for a while.
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A glance at the schematic would reveal as much. The identity of the new On-Semi parts can be quickly found online.
 
EW, got it, and I will owe you a cyber flower if this project works. Is there anywhere on Audiokarma I can post the Kenwood L-09M service manual, for anyone else in the quest of resurrecting a Kenny's karma? Heck, I could even scan in the original owner's manual?
 
SoCal Sam said:
Diamo, Seasons Greetings to you as well.

You can harvest original Sanken outputs from a Yamaha P2100 amp, which in the U.S. can be had for around $100. Each P2100 has a total of 4 2SC1116A and 4 2SA747A. Sometimes, P2100 with bad cosmetics can be had for less. I picked up a junker for $20 to support my collection of L-09M's.
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Very interesting idea Sam, obviously you have to get into the schematics to see those similarities. P2100's aren't that hard to find locally in the US, but shipping to France probably makes it a last resort.

diamo said:
EW, got it, and I will owe you a cyber flower if this project works. Is there anywhere on Audiokarma I can post the Kenwood L-09M service manual, for anyone else in the quest of resurrecting a Kenny's karma? Heck, I could even scan in the original owner's manual?
Click to expand...

The AK Database would be the place for any contributions of owners or service manuals, in scan or digital document form.

You can find them here:

http://akdatabase.com/AKview/

And contributions information via this thread:
http://www.audiokarma.org/forums/showthread.php?t=349095
 
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Thanks diamo! I got my copy from a French member of another audio forum. I don't see your copy in the database yet but if mine is of better quality, I will upload it.

BTW, I have the owner's manual around here somewhere but I do not have scan capability.
 
Fellow AK'ers, unless we're drifting 2 miles off-topic, please indulge a few thoughts on whether the L-09M can or should be modified:

  • First off, would mod's of any kind diminish the value of a L-09M in "stock condition", if you will? As l am on my way to having On-Semi's installed instead of the original Sanken's, it took one glass of wine to start pondering phase two...
  • ... because, secondly, I'm hoping that there are (other) reasonable mod's? Reasonable IMHO meaning (bear with me here) a justifiable combination of improved sonic within whatever budget fits the day. If justifiable is the next key word, let's hope for the approval of our better halves. And why am I pouring me a second glass?
  • Please have a glance at the nude photo, included somewhere below this post. For someone like EW, SoCal Sam, yes it may be basics, but graphic nonetheless. Relax gentlemen, we've only stripped her of her top! :smoke:
  • For starters, the cooling fan, I seem to recall a German thread where they were discussing s.c. high end fans, possibly also for more efficient cooling and the likes, but primarily to cut a few dB's. If my memory serves me (it could be the wine) someone then suggested Papst fans from the EBM Company in Germany. Does anyone here have any comments on this?
  • A beefier power cord with Shuko power connectors and whatever else strikes your fancy? Which almost begs a separate power conditioner discussion and that probably enfolds another abyss.
  • What other L-09M modification/s would you think could be potentially interesting? Or to put it in French: :tresbon:

Thank you for your time and please excuse my French. And the wine. :D
 

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The amp is a pretty straightforward design...I see no need of modifications.

I've only worked on about 8 or 10 of these, but most had noisy fans with worn bearings. I found that the 9906 ebm Papst fan makes a great replacement, but to match the unit properly, Rk6 should be changed to 1.2K (12W) and Rk5 to 400 ohm (8W). These resistors get very hot, so I like to use hollow vitreous enamel resistors, which shed heat quickly and help prevent the resistors from desoldering themselves.

While the unit can definitely benefit from new electrolytics, at the very least the caps on the power supply board (same board with the above mentioned resistors) need to be changed out.
 
Opinion on valuation is highly subjective. Original condition can be interpreted as not having been worked on which is sometimes a plus at auction. Installing On-Semi's may have no negative effect on first time buyers. On-Semi's may not change the sound either. If one amp has On-Semi's and the other Sankens, that could be a problem. Are you changing all of them in both amps?
 
Thanks to your kind responses I have just supported AK by paying 25 dollars by Paypal. I believe in positive reinforcement, don’t you?

EW, this is where it either gets embarrassing and/or I’m overstaying my welcome! May I kindly ask for a parts list (again) for your above specified refinements, or would you by any means accept to work on these two Kenny’s yourself? There it is, including my apologies for my bluntness.

SoCal Sam, got On-Semi’s for both units. And you’re right, where’s the line between reparation, restoration and modification anyway? For the sake of argument, let’s put it another way; if your main goal is to keep a unit, aren’t you the musical director? We play, sing and listen to all kinds of music in our house. We’ve got 3 hifi systems, 2 of with which I have audioholic tendencies to experiment with units and mod’s. Yet I’m the proud owner of a Danish-U.S. collaboration JBL Ti5000’s that I bought new in 1996, still in stock condition and I intend to get buried in them.

My L-09M’s were one owner until I acquired them a year ago and the thought of getting them ready for another 30 years feels right. It is subjective. Not unlike discussing a red wine. Thanks again.
 
I can give Digikey's part numbers for the above mentioned parts, but I do not know how much good that will do you in Europe.

ebm Papst 9906 Fan - 381-1078-ND
Resistors-
Vishay Huntington Electric 1.2K 12W Vitreous Enamel Coated - Vishay part number FVTS10-1.2K-5%, Digikey part number FVTS10-1.2K-ND
Vishay Huntington Electric 400Ω 8W Vitreous Enamel Coated - Vishay part number FVTS5-400-5%, Digikey part number FVTS5-400-ND

The lone electrolytic cap on that board is a 1000µf 16V cap. Any good 105°C cap would be OK (should be 10~12mm diameter for a decent fit). I use the Panasonic FM, #P12366-ND at Digikey.

I also like to replace the start-up relay while I'm there. The proper replacement is a Omron LY2-0-DC12, and these can be found from many sources. Digikey's number is Z978-ND.

Yes, I work on other people's gear, But if you are in France, you will go broke shipping these amps back and forth. Stupidly expensive to ship overseas.
 
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diamo said:
Thanks to your kind responses I have just supported AK by paying 25 dollars by Paypal. I believe in positive reinforcement, don’t you?

EW, this is where it either gets embarrassing and/or I’m overstaying my welcome! May I kindly ask for a parts list (again) for your above specified refinements, or would you by any means accept to work on these two Kenny’s yourself? There it is, including my apologies for my bluntness.

SoCal Sam, got On-Semi’s for both units. And you’re right, where’s the line between reparation, restoration and modification anyway? For the sake of argument, let’s put it another way; if your main goal is to keep a unit, aren’t you the musical director? We play, sing and listen to all kinds of music in our house. We’ve got 3 hifi systems, 2 of with which I have audioholic tendencies to experiment with units and mod’s. Yet I’m the proud owner of a Danish-U.S. collaboration JBL Ti5000’s that I bought new in 1996, still in stock condition and I intend to get buried in them.

My L-09M’s were one owner until I acquired them a year ago and the thought of getting them ready for another 30 years feels right. It is subjective. Not unlike discussing a red wine. Thanks again.
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diamo, you are in excellent hands with EW. And, good call with replacing all of your outputs in both of your amps. Make sure your "tech" returns the original Sanken outputs to you. You may be able to re-capture some of your cost by selling them on ebay. Enjoy them for the next 30 years!
 
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