• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

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

diamo

diamo

New Member
Hi to all,

one of my Kenwood L-09M blew 6 of it's 8 output transistors due to a badly connected speaker wire (in short: I plead guilty). Granted, nothing that is going to upset the world order, but I figured, among other audio gear criminals, there ought to be a chance for understanding sighs!

Our local tech finally took it apart after 6 weeks, called me up and said, "it should be fixable!!" "However", he adds, "the transistors that I have been able to find cost some 65 euros (80 dollars?) a piece! And, to play it safe", he continues, "I recommend that we should probably change all 8 of them."

I am fumbling for a chair and I'm thinking, don't do the math, you'll be selling your JBL's, it's a no-go. Anyway, my Christmas shopping list is thus extended by:

2 x 2SA747
2 x 2SA747A
2 x 2SC1116
2 x 2SC1116A

After reading the archived Sansui thread about the counterfeit output transistors, I simply don't feel confident about where to purchase my parts.

Hence, my perhaps somewhat desperate & futile questions:

- If I have understood correctly from Echowars input, instead of worrying about Sanken quality or not, apparently On-Semi transistors will work - just as good?!

- Most output transistors I have found with search engines seem to be marked 110V, as I have a 220V European version, do I need 220V versions?

- Could any kind soul indicate where it would be relatively safe (quality wise) to place an order? If I am not mistaking, Digi-key, Mouser, Newark are possible good addresses?

- Finally, if the On-Semi's are a plausible way to "transistify", I humbly ask for part-no's equivalent to the above specified list of Sanken parts, so that I might avoid ordering a shoe horn or a bag of Reese's peanut-butter cups.

Thank you for any answer in advance. Thank you for reading this far...This classic Kenny needs to be saved. I even have my wife's blessings. I know! I had to sit down - again! :0)

Seasons greetings
Diamo from France
 
Register to hide this ad
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.
 
I ordered some 2SA909/2SC1586's from Dalbani years ago. They were not the real deal. Your best bet is to find the amp Sam suggested or use the On Semi replacements. I'd go with the latter as they are great parts.
 
Last edited:
ManyMoonsAudio said:
I ordered some 2SA909/2SC1586's from Dalbani years ago. They were not the real deal. Your best bet is to find the amp Sam suggested or use the On Semi replacements. I'd go with the latter as they are great parts.
Click to expand...

had lots of outputs and other transistors from them ..not a single problem .. if you ask if original or not they will tell you .
 
petehall347 said:
had lots of outputs and other transistors from them ..not a single problem .. if you ask if original or not they will tell you .
Click to expand...

Benefit of the doubt granted. However... The L-09M is a monoblock so getting original outputs to match the other channel would be the call, especially for a fast amp like the L-09M. Plus, harvesting removes any doubt about getting real Sankens.
 
Top of the evening,

and thank you for your kind replies.

Yamaha P2100 is on my hunting list. Thank you SoCal Sam. Have seen your name on this forum many times, in my countless visits for info for gear over the years.

Thank you ManyMoonsAudio, will track down some On-Semi alternatives.

Thank you petehall347, will give dalbani.co.uk a shot, and ask about their origins.

Incidentally, I have saved my JBL's several times by harvesting parts from similar JBL's, good thinking.

It's material, it can be fixed with some patience. A thought goes out to the Connecticut high school massacre of today.
 
Use the On-Semi MJ21193G (PNP) and the MJ21194G (NPN). They may lack the speed of the original Sanken parts (the L-09M is NOT a 'high-speed' amp by any stretch, so speed is a non-issue), but in pretty much every other category that matters they are superior to the original parts. I'd go as far as to say that if the amp had had the On-Semi transistors in it, it might have survived you're little 'accident' (but let's not try it, OK?)
 
Evening Echowars,

I'm quite pleased to get some comments from you, as I have repeatedly read about the countless L-09M's that you have revived! So, I gather that finding something like 4 x MJ21193G (PNP) and 4 x MJ21194G (NPN) On-Semi's will do the trick? And no, no more accidents, I sure feel like a pink elephant taking ballet lessons anyway!

I just stumbled upon a site that claims that output transistors in general have an expected lifespan of some 30 years?
 
EchoWars said:
Use the On-Semi MJ21193G (PNP) and the MJ21194G (NPN). They may lack the speed of the original Sanken parts (the L-09M is NOT a 'high-speed' amp by any stretch, so speed is a non-issue), but in pretty much every other category that matters they are superior to the original parts. I'd go as far as to say that if the amp had had the On-Semi transistors in it, it might have survived you're little 'accident' (but let's not try it, OK?)
Click to expand...

For the sake of self education more than anything else, I looked at the specs for the L-07M and L-09M. The L-07M has a slew rate of 170 V/micro-second. The L-09M slew rate is not published in the service manual but the DF result is better than the L-07M indicating better cone control. For the sake of context, I looked up he slew rate for the Yamaha PC2002M which is 60 V/micro-second. The 'scope results as published on page 6 of the owners manual shows vertical rise for the 20 Hz and 1 kHz trace and slight sloping for the 20 kHz rise. Having heard all three amps, the L-09M sounds the fastest and most objectively accurate. IMO, vintage Sankens are the right call because they are faster than the On-Semi. The On-Semi outputs are no less the right call if you prefer as EW notes the added insurance of being more accident-proof.

To be fair, I have not seen the L-09M square wave results but I have heard amps with near perfect square wave traces and the L-09M sounds every bit as fast.
 
You are focusing on one specification out of dozens, and saying that this is the spec that will make it a superior choice in this amplifier.

I might add that the cascoded drivers and outputs don't lend themselves well to high-speed designs. That, and the choice of (relatively) pokey driver transistors used by Kenwood all seem to point to the design focus of lots of power, not lots of speed.

If trustworthy Sanken's were around, I'd put them in. But given their scarcity and the possibility of a used and damaged part, or a counterfeit part, I'd put in the On-Semi's and not think a thing about it.
 
Gentlemen, thank you.

Echowars, for the record, 8 x On-Semi's have been ordered for a 2012 price of about 53 euros incl. local tax+shipping (within the EU in order to avoid any possible customs). It looks as if Farnell is the mother of Newark, with a subsidiary in France. Another 8 have been ordered alongside in case there is a, shall we call it, "colorization difference", or taking Murphy's law into consideration, another booboo. If this should not be the case, well, then 2 of them will make a cute pair of Christmas earrings for my wife.

SoCal Sam, I did research the P2100, found a "functional" one "at the usual suspects", we're talking some 250 dollars incl. shipping to the EU, without a clue as to whether the french customs are going to feel inclined to collect a Christmas bonus or not. I would still need to verify if the P2100 has a different name in the EU, plus, you're probably pretty much in the hands of the seller in regards to quality, age and function of a second-hand unit like this. Still an excellent plan B though.

BTW IMHO for every thing that you can justify repairing, you could potentially avoid a replacement, which in turn, one or two steps further, could even be considered a form of recycling. Did that make sense?

Voilà, as they would have it on this side of the duck pond, mind you, I am going to come crying again, should we not figure out how to mount the On-Semi's.

For what it's worth, thank you all for your time & please enjoy your upcoming holidays.
 
Just think if you like the sound of the amp with the On-Semis, you will have a large handful of working originals that can go for good money on the bay for someone that has to have the 747s and 1116s.

That might be a late Christmas bonus for you.
 
Blue shadow, although that may be, all I can think about is to get them up and running again. Will try to post a result. Thanks.
 
Are you changing the outputs in both amps or just one? Would seem that it would lend itself to changing all so both amps match.
 
moejr, sure thing, that is why I ordered a double on the rocks, but will cowardly have them fitted one at a time as these babies are almost as vintage as I am...
 
Just received the On-Semi's, very pleased with the Farnell delivery. However, as there are a lot of repairs for Christmas, my local tech kindly asked me to pass on the following question: do the MJ21193G (PNP) go in the place of the 2SA747/A and the MJ21194G (NPN) in the place of the 2SC1116/A? Or vice versa? Thank you in advance.
 
Last edited:
Are you serious? He actually asked that?

Would take about 45 seconds with Google to discover the answer.
 
You must log in or register to reply here.
Back
Top Bottom