Kenwood L-07M

Kenwood L-07MII

1977

1978

1980

TRIO in Japan, Kenwood elsewhere - the big-little monoblock.

Price-wise at the lower limit of high-end separates in Japan : a Yamaha B-2 cost 200,000¥, a Sony TAN-8550 285,000¥, a Luxman M-4000 350,000¥ ; a pair of L-07M cost 200,000¥...
Sound-wise, however, the L-07M was near the upper limit of most power amps !

Updated in 1978 as L-07MII, with a skyrocketing 600Khz frequency response and a smaller sibling (L-05M) and an x-rare bigger, much bigger brother (L-09M).
All high-speed, all very very tight, controlled and linear.

The L-06M variant is a late 1980 unit, fairly different in looks and design as it sported the Sigma-Drive circuit - even tighter :)

Replaced by the futuristic-looking L-08M in 1980/1981.

Kenwood L-07M specifications
Title	Value
L-07M (L-07MII in off-white)	L-07M (L-07MII in off-white)
Power :	1x 150W (20Hz...20Khz, 8 Ohm, 0,008% THD) 0,007%THD
Continuous power :	1x 150W (8Ohm, 1Khz)
Dynamic power :	1x 200W (4Ohm, 1Khz)
Dynamic power :	1x 300W (4Ohm, 1Khz) 1x 250W
THD :	0.008% (rated power, 8 Ohms, 20Hz...20 kHz) 0,007%THD
	0.008% (15W, 8 Ohms, 20Hz...20 kHz)
	0.002% (rated power, 8 Ohm, 1 kHz) 0,007%THD
	0.003% (15W, 8 Ohm, 1 kHz)
	0.003% (rated power, 4 Ohm, 1 kHz)
	0.003% (20W, 4 Ohm, 1 kHz)
IMD :	0.002% (rated power, 8 Ohm)
	0.002% (15W, 8 Ohm)
	0.003% (rated power, 4 Ohm)
	0.003% (20 watts, 4 Ohm)
Rise time :	? 0,55µs (-1V > +1V)
	? 0,55µs (-20V > +20V)
	? 0,55µs (-40V > +40V)
Slew rate :	? ±170V / µs
Frequency Response :	DC...200Khz (+0 / -0,5dB) DC...600Khz (+0 / -3dB)
Frequency Response :	DC...150Khz (+0 / -1,5dB)
Signal to Noise Ratio :	120dB (IHF-A)
Damping Factor :	100 (8 Ohm) 120 (8 Ohm, DC...20Khz)
Damping Factor :	120 (8 Ohm w/out speaker cable)
Input Sensitivity/Impedance :	1V / 50kOhm
Speaker Impedance :	4...16 Ohm
Speaker Cable Loss :	0,01 Ohm
PC :	630W max.
PC :	45W idle
Dimensions :	20 x 15,5 x 39cm
Weight :	13kg.

Kenwood L-07M : 1 topic
(last updated topic shows up first)

Kenwood L-07M and L-09M (10)last updated by Socal Sam - 16/11/2012, 17H21 Open this topic in TVK Talk
- #1
  
  Socal Sam
  
  17/10/10
  05H50
  
  Hello all! Check out my Kenwood L-09M's and L-07M's. The L-09M is a technical tour de force. It has dual transformers for a single channel! One drives the positive rail and the other the negative rail. Both use the same Sanken output transistors. The L-09M is my favorite solid state amp.
- #2
  
  Axel
  
  18/10/10
  11H54
  
  Hello Sam !
  
  Is that a sextet of NS-1000Ms I see behind your tower of 09Ms and 07Ms ?!
  
  You wouldn't have found a dedicated catalog for the 09Ms, would you ?
  I've been scouting Japan high and low for the past four years and wound up with nothing :(
  I have beautiful 07C/M /CII /MII catalogs waiting to be shipped but the 09M remains abosulte Invisibilia...
  
  From what I have gathered, it seems it may have been the last high-end project launched while the LX series prototypes were getting ready but only to be somewhat rapidly shelved alongwith the unproduced LXs.
  There are mentions of them here and there as sidekicks to 07MII ads or catalogs, but nothing dedicated, let alone detailed !
  
  Is the service manual all I can hope for ?
- #3
  
  thedevilin
  
  18/10/10
  13H17
  
  the kenwoods
  wow, just wow.
  
  wow.
  
  http://www.VintageAudioArchive.com
  ^^ i assume you check here axel, this guy does have a good collection of rare original adverts/reviews for sale (including Kenwoods L-07MII), got a advert on celestion's rare UL range from him and was impressed by service and will probably go back for a review of the pioneer SX 1980, he trades on ebay as 'effjgm' and he does do deals.
  
  amusingly his wife as obviously got her claws into him as he uses Bose lifestyle speakers (rofl). imagine having all those beautiful bits of kit staring up at you from the reviews/adverts and having to listen to those rubbish efforts. sometimes i feel sorry for my fellow man.
- #4
  
  Socal Sam
  
  20/10/10
  04H57
  
  Hello Axel: Nice to be here! I've always been an admirer of TVK and have used your site as a resource many times.
  
  Sadly, I do not have any literature on the L-09M. I don't even have the service manual although I think I can get it from my tech if I ask nicely enough. Interestingly, the owner's manual (which I have along with an original sales slip for $600 and change) isn't a glossy item like Yamaha's and in fact, it is a little amateurish. Perhaps this reflects low production numbers for the L-09M.
- #5
  
  Axel
  
  23/10/10
  10H25
  
  Thank you Sam !
  
  For the 09M... your owner's manual fits the general scheme I could see for others "semi-released" or "released after shelving" components of other brands.
  I think it was mainly an export-only item, too, which would mean it was up to the local distributors to get rid of the (little) stocks. (?)
  
  Are the 09Ms based on the 07MIIs with high-bandwidth/slew-rate/rise-time/hi-fTs or are they completely apart ?
- #6
  
  Socal Sam
  
  24/10/10
  18H50
  
  Here in So Cal, the L-09M was sold in the second tier stores and they were heavily discounted. The receipt I have shows a sales price around $650, which for new 300 wpc monoblocks was good value. It is possible these amps didn't fit the market and were not an easy sell.
  
  The L-07M and L-09M share some parts like the Sanken output transistors. Both are fast and share the same family sound. However, the similarity ends there. The L-09M is unusual for having a pair of transformers per single channel. One transformer controls the positive rail and the other the negative rail. I suppose this is for superior control of signal swings but whatever the reason, this is overkill. The L-07M is more conventional with a single transformer. Interestingly, the L-09M has 106 Volt rails which EXCEEDS Japanese line voltage. The main filters are rated 125V, which is the highest I have seen for solid state amps.
- #7
  
  Axel
  
  24/10/10
  18H55
  
  sold in the second tier stores and they were heavily discounted
  That sounds like Kenwood US didn't know what to do with them...
  
  the L-09M has 106 Volt rails which EXCEEDS Japanese line voltage
  ... so export-only indeed.
- #8
  
  NEMOaudio
  
  20/07/12
  09H12
  
  If you are still interested, I have the Service Manual (.pdf) for the KENWOOD L-09M.
- #9
  
  Socal Sam
  
  16/11/12
  00H04
  
  One more pair for the stacks! I bought these amps locally. They were advertised as non-working so the price was peanuts. The seller had the other L-09M which was not advertised so I bought that one too. Nice to have them in pairs. Anyways, ignore the "Broken" sticky. The output fuses were blown. After a quick DC offset adjustment, the amp works fine. The power switch is busted but no worries, I installed an exact ALPS replacement from a parts L-07C.
  
  I'm a little late catching NEMOaudio's kind offer for the service manual. I need to adjust the Bias current on all my L-09M's. Hopefully!!!
  
  BTW, the Philips 5781 was part of the deal. It comes out of protection but it needs a restoration. One channel is out.
- #10
  
  Socal Sam
  
  16/11/12
  17H21
  
  NEMOaudio wrote:If you are still interested, I have the Service Manual (.pdf) for the KENWOOD L-09M.
  
  My thanks to NEMOaudio for the L-09M service manual! The scan is excellent.

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