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Kenwood L-05M Vintage Amplifier Review
- Thread starter amirm
- Start date
I haven't said a word about audible performance. Modern amplifiers in that price range are smaller, provide more power and use less energy.
Besides, this amplifier still has issues that could theoretically be heard in specific situations.
Rip out the PSU, fit an SMPS and change the cord too.
You will have a top notch amp.
You will have a top notch amp.
Yes, they are smaller and provide more power per unit weight. On the other hand, they have audible issues like load complex impedance dependent frequency response (cheap toys based on topology with LC filter outside FB), or they may have issues with difficult load like high capacitive load, as I have shown in case of Ncore. I agree with @sergeauckland that we have not moved forward in amplifier's audible performance since about 1980. We have smaller, sometimes less power consuming amplifiers, with new issues, unknown 40 years ago. Better? It is highly questionable.
Yeah, they didn't have modern power cord technology back then.
Vini darko
Major Contributor
Nice work restoring the amplifier. Thanks for the review .
That's just USA vs the rest of the world thingy.Yeah, they didn't have modern power cord technology back then.
I have an 80+ year old British valve radio, it has proper 3-wire grounded cord.
Fabric double insulated of course. Still in good condition.
Schollaudio
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A cap replacement could probably improve the PSU noise and SINAD.
HiFi Engine has the service manual. This is a typical amplifier design for the times with FET input found in many Kenwood amps from late 70s so this unit isn't much different than some integrated amps that sell for a few hundred dollars. Power supply rails are 61.8V 60 watt rated integrated use 50V rails.
It would be interesting to see tests of high end Sony and Luxman amps with more sophisticated designs.
HiFi Engine has the service manual. This is a typical amplifier design for the times with FET input found in many Kenwood amps from late 70s so this unit isn't much different than some integrated amps that sell for a few hundred dollars. Power supply rails are 61.8V 60 watt rated integrated use 50V rails.
It would be interesting to see tests of high end Sony and Luxman amps with more sophisticated designs.
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It seems odd he replaced the smaller caps (which were probably fine) but neglected the big electrolytics.
From those images you can see why there is so much PS noise. Long signal path that crosses the PS twice. I'll bet you could resto-mod this to improve that with some better shielding while staying true to the original circuitry.It appears to be a quality build.
57gold
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Very interesting review/flashback.
I have been enjoying a McCormack DNA-500 driving Aerial 10Ts for @25 years...been through Theta, Wadia, and now Mytek (2) CD/DACs, but the amp speaker combo has stayed constant. Were a couple of reviews back in the day with lots of word, but few measurements, eg:
The DNA-500 replaced a pair of Sonic Frontier Power 3s, huge 8 KT88s per side, which had strong points like great midrange, but fell short on bass control and high frequency extension with the current hungry Aerials. When one caught fire (tube fail and resistor smoke) and had to be sent to Canada for a fix, they had to go. The DNA-500 did everything better.
Would love to see how it measures up in the ASR testing process...though at 25+ years old, it probably needs a re cap.
Been following ASR in part to find a class D amp with high current for when it needs replacement...sometimes, at party volumes, I hear a little roughness...but that may be my old ears complaining!
FWIW, paid $4,500 for amp in @2005 and that equates to @$7K today...all these electronics were significantly pricier on a relative basis 25 years ago. That Wadia 861i, which was great sounding for its day, cost $12K in 2023 $s. A Mytek DSD192 with a dedicated Mac Mini at @ $3K combined killed the Wadia. I used the Wadia for a while with a Wavelength USB to SPIDIF converter to input CD rips using Audirvana to see what all this computer audio was about.
I have been enjoying a McCormack DNA-500 driving Aerial 10Ts for @25 years...been through Theta, Wadia, and now Mytek (2) CD/DACs, but the amp speaker combo has stayed constant. Were a couple of reviews back in the day with lots of word, but few measurements, eg:
The DNA-500 replaced a pair of Sonic Frontier Power 3s, huge 8 KT88s per side, which had strong points like great midrange, but fell short on bass control and high frequency extension with the current hungry Aerials. When one caught fire (tube fail and resistor smoke) and had to be sent to Canada for a fix, they had to go. The DNA-500 did everything better.
Would love to see how it measures up in the ASR testing process...though at 25+ years old, it probably needs a re cap.
Been following ASR in part to find a class D amp with high current for when it needs replacement...sometimes, at party volumes, I hear a little roughness...but that may be my old ears complaining!
FWIW, paid $4,500 for amp in @2005 and that equates to @$7K today...all these electronics were significantly pricier on a relative basis 25 years ago. That Wadia 861i, which was great sounding for its day, cost $12K in 2023 $s. A Mytek DSD192 with a dedicated Mac Mini at @ $3K combined killed the Wadia. I used the Wadia for a while with a Wavelength USB to SPIDIF converter to input CD rips using Audirvana to see what all this computer audio was about.
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Found this link: https://hifi-wiki.com/index.php/Kenwood_L-05_M
“Original price approx.: 60'000 Yen (Japan, 1979), corresponds to about 1'198 DM”
60K Yen = $452 USD in 1979
Using this site to calculate the cost in todays (2022) money value: https://www.aier.org/cost-of-living-calculator/
Result is this unit costing almost $3000 USD. ($2956.06 to be precise). So for a pair you’re talking $6 grand.
“Original price approx.: 60'000 Yen (Japan, 1979), corresponds to about 1'198 DM”
60K Yen = $452 USD in 1979
Using this site to calculate the cost in todays (2022) money value: https://www.aier.org/cost-of-living-calculator/
Result is this unit costing almost $3000 USD. ($2956.06 to be precise). So for a pair you’re talking $6 grand.
Monoblocks are seldom the economy solution
I wasn’t really making any value statements. Just curious how much these would cost in the day and what that equates to in today’s price. They weren’t cheap at close to a Grand out the door in 1979. But obviously, based on the test results 44 years later they were so worth every cent.Monoblocks are seldom the economy solution
Great review @amirm. It’s a useful yardstick to gauge how far we have come in the Audio Equipment industry. And at the same time how little has changed. Amazing that this unit tested so well almost 4 1/2 decades later. Talk about value and quality. Very informative Sir!
A SMPS would most likely reduce LF noise (which is not very audible) but it would also reduce peak power by 60 watts or 35% and alter clipping behavior most likely for the worse. This is not a trade off that makes sense to me.
He did not. Without measurements you cannot be sure. He stated "probably"PMA already answered
Yes but based on measurements of dozens of similarly designed amplifiers and on circuit analysis the guess is quite qualified. Much more than a mere debate or a forum reading arguments. Of course not 100%, but that’s not needed.
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