this is a kenwood KA-701 , there a lot of talk in setting the bias, here's my findings... pls comment. #bias, #biasissues,#biasissues, #bias26mVisnotpossible,
Really nice to see this amp in such great shape; a little tune up goes a long way. Pristine examples from the receiver/watt wars are getting hard to find out in the wild. They are performing in homes and listening rooms keeping the music alive. Thank you for your time!
I think you're wrong about the bias bit. 54mV across .66 ohms yields about 80+ mA idle current. 26 mV across the pair of resistors equates to about 40 mA idle current. This is much more in the range to be expected for this class amp. Further, the higher bias on both channels would explain your higher current draw at the mains. I think the inability to adjust is caused by a problem elsewhere. I would ask if the amp seems to idle rather on the overly warm side at the heat sinks.
Another fine session at your bench. Your right to use common sense when reading schematics and service manuals, as they often can be wrong. From what I have read, many companies make errors on their manuals. Apparently Marantz is famous for marking polarity wrong on the boards etc.... Anyway, I look forward to having my receiver next up on you bench. It should prove an interesting session for your viewers to see.
Nice work Joe!👍 I wouldn't mind finding one of these clean & serviced to own! I already have the Kenwood matching companion tuner to complement this amp!⚡
I just came across your channel after watching audio repair videos for years, and subscribed. A fellow Maritimer? I pick up a PEI accent, I think. I could be way off.
Thanks Joe, very interesting and great idea with the plastic straw over the screwdriver! Could you tell me what you were reading on the meter when testing the filter capacitors. I could see the probes but not the meter. Thanks again!
ouffff! I'm not sure the customers would absorbed the high cost of these fuses...maybe you can elaborate on these fuses, I'm interested to hear your views on them.
@@VintageAudioFever OMG! I cannot express how impressive these fuses are. I have a modest system, comprising of a Cambridge Azur 851 N Preamp DAC, a pair of Focal Solo 6; I started by upgrading to ceramic fuses, then went to the synergistic orange fuses and then to the synergistic purple fuses. The increase in sound quality was unbelievable ! Pricey, I know, but the improvement in sound quality was well worth it. Of all the dollars that I’ve spent on this stuff, including IsoAcoustics, audience cabling-used of course), this was the most significant.
sir gud am, i have def. kenwood integ. amp, can i perform dc biasing for my ka990d without connecting output transistor, thnk you so much for your reply...
Really nice to see this amp in such great shape; a little tune up goes a long way. Pristine examples from the receiver/watt wars are getting hard to find out in the wild. They are performing in homes and listening rooms keeping the music alive. Thank you for your time!
I think you're wrong about the bias bit. 54mV across .66 ohms yields about 80+ mA idle current. 26 mV across the pair of resistors equates to about 40 mA idle current. This is much more in the range to be expected for this class amp. Further, the higher bias on both channels would explain your higher current draw at the mains. I think the inability to adjust is caused by a problem elsewhere. I would ask if the amp seems to idle rather on the overly warm side at the heat sinks.
Another fine session at your bench. Your right to use common sense when reading schematics and service manuals, as they often can be wrong. From what I have read, many companies make errors on their manuals. Apparently Marantz is famous for marking polarity wrong on the boards etc.... Anyway, I look forward to having my receiver next up on you bench. It should prove an interesting session for your viewers to see.
I'm really enjoying the ceramic screwdrivers for adjusting pots in a powered amplifier.
something to thing about....good point!
Nice work Joe!👍 I wouldn't mind finding one of these clean & serviced to own! I already have the Kenwood matching companion tuner to complement this amp!⚡
Yea.they are nice amp!!! If you keep your eyes open...one will pop up for you....
Rare but there are some floating around.
Good video and cool explanation
I just came across your channel after watching audio repair videos for years, and subscribed.
A fellow Maritimer? I pick up a PEI accent, I think. I could be way off.
welcome onboard, I am from the east coast yes...but not the island haha!
Thanks Joe, very interesting and great idea with the plastic straw over the screwdriver! Could you tell me what you were reading on the meter when testing the filter capacitors. I could see the probes but not the meter. Thanks again!
I see it now...the Capacitor Wizard.
Highly recommend, a fuse upgrade to the synergistic purple!
ouffff! I'm not sure the customers would absorbed the high cost of these fuses...maybe you can elaborate on these fuses, I'm interested to hear your views on them.
@@VintageAudioFever OMG! I cannot express how impressive these fuses are. I have a modest system, comprising of a Cambridge Azur 851 N Preamp DAC, a pair of Focal Solo 6; I started by upgrading to ceramic fuses, then went to the synergistic orange fuses and then to the synergistic purple fuses. The increase in sound quality was unbelievable ! Pricey, I know, but the improvement in sound quality was well worth it. Of all the dollars that I’ve spent on this stuff, including IsoAcoustics, audience cabling-used of course), this was the most significant.
Ok....well it's good to know....and thanks for sharing
Haw close are the specifications at rated output
sir gud am, i have def. kenwood integ. amp, can i perform dc biasing for my ka990d without connecting output transistor, thnk you so much for your reply...