birchoak
Hi-Fi Nut
I've wondered about this model for some time and finally bought one. For those who don't know, the KR-6160 is a 1971, 55 watt, cap-coupled receiver with an engraved face plate and triple tone controls. It's quirky looks endear it to some and repel others. I wasn't sure which camp I was in until I turned it on.
This is the best amp or receiver I've heard bone stock. I'm sure this was a fluke, some temporary gift from the fickle hi-fi gods, but it delivered the goods with 50 year old parts. I often struggle to qualify what I hear when I listen to a given hi-fi system, so I'll just say this: I began digging into my music catalog, playing everything from Abba to Lenny Kravitz. I could not stop listening to this receiver and had to be dragged upstairs to dinner.
The acid test of a receiver's durability is whether or not it can survive a recap by yours truly. Most of the time things work out--a few dramatic moments, some potty mouth, questioning why I was born, etc.--but then the thing works again, with new caps. I was very nervous about recapping this and checked my work after just about every cap, with the DBT and by playing music through speakers.
I did lose FM and AM. I later found a solder bridge on the PRE board. When I removed it I had one channel back in FM, but not the other. I think I shorted one of the driver transistors on that board. A shame as this thing pulled in FM as good as or better than anything I have, with no antenna attached, in my basement.
But everything else still works and the new filter and output caps haven't changed the sound. The amp card was quite easy although needle nose pliers were required to re-attach two spade connectors on the front.
Is it the perfect receiver? No. The amp card socket is made from a clear, hard plastic, and mine was broken at one of the screw hole ears. I fished all the pieces out and attempted to super glue them back together, several times, but found no lasting joy. Finally, I was able to get the pieces to stay together long enough with super glue to squeeze two-part epoxy from a syringe over the fracture. It seems to be holding and I've since pulled the amp card and re-inserted it with no further damage that I can see. This isn't really a deal breaker--as long as the socket will still mate with the card you've got music, and there's so many wires feeding it that even without screws the socket isn't really going any place. It's just not something you want to happen in your receiver and I wonder why Kenwood didn't spec a more robust plastic, like JVC, Fisher, Hitachi, and, um, Kenwood did (in the KA-7002) in similar amps with amp cards that plug in.
Something broke off in the Alps-branded bass pot, allowing the wiper to travel in a continuous orbit, with no stops. I pulled the outer pot shield off, saw that accessing the inner pot might destroy the entire thing, and put the shield back on. I don't typically adjust midrange, so I swapped the bass and midrange pots and bass was back in business.
The volume pot is comically undersized and has absolutely no physical resistance when you turn it--it's like turning the knob on a child's toy radio. But oh, the magic that that knob unleashes...
Aside from one trim pot on the PRE board, I see only two trimmers on the amp card. I imagine these adjust center voltage, and/or bias current. If this is anything like the JVC 5551, you can dial in center voltage, or bias, but not both unless the planets are aligned and it's Tuesday and a magic fish high-fives you. I haven't touched the trimmers and I'm really, really trying hard to not mess with them at all as this seems to release magic smoke or at least a very long trip down the amp adjustment rabbit hole. With output caps my speakers should be safe from DC, and unless I install new TO-3 devices or drivers, I think I can leave those trimmers alone. I'm still smarting from losing one channel of FM
If folks are interested I'll take some pics and post them. BTW, the speakers are newly-restored Polk Audio Monitor 7's and I don't think I've experienced better speaker/amp synergy. I don't have a good handle on the audiophile lingo, so let me just say I was singing along to Journey's Greatest Hits, not something women and children should hear and fortunately a rare occurrence. As soon as I finished dinner I ran right back to the bench to do more listening.
This is the best amp or receiver I've heard bone stock. I'm sure this was a fluke, some temporary gift from the fickle hi-fi gods, but it delivered the goods with 50 year old parts. I often struggle to qualify what I hear when I listen to a given hi-fi system, so I'll just say this: I began digging into my music catalog, playing everything from Abba to Lenny Kravitz. I could not stop listening to this receiver and had to be dragged upstairs to dinner.
The acid test of a receiver's durability is whether or not it can survive a recap by yours truly. Most of the time things work out--a few dramatic moments, some potty mouth, questioning why I was born, etc.--but then the thing works again, with new caps. I was very nervous about recapping this and checked my work after just about every cap, with the DBT and by playing music through speakers.
I did lose FM and AM. I later found a solder bridge on the PRE board. When I removed it I had one channel back in FM, but not the other. I think I shorted one of the driver transistors on that board. A shame as this thing pulled in FM as good as or better than anything I have, with no antenna attached, in my basement.
But everything else still works and the new filter and output caps haven't changed the sound. The amp card was quite easy although needle nose pliers were required to re-attach two spade connectors on the front.
Is it the perfect receiver? No. The amp card socket is made from a clear, hard plastic, and mine was broken at one of the screw hole ears. I fished all the pieces out and attempted to super glue them back together, several times, but found no lasting joy. Finally, I was able to get the pieces to stay together long enough with super glue to squeeze two-part epoxy from a syringe over the fracture. It seems to be holding and I've since pulled the amp card and re-inserted it with no further damage that I can see. This isn't really a deal breaker--as long as the socket will still mate with the card you've got music, and there's so many wires feeding it that even without screws the socket isn't really going any place. It's just not something you want to happen in your receiver and I wonder why Kenwood didn't spec a more robust plastic, like JVC, Fisher, Hitachi, and, um, Kenwood did (in the KA-7002) in similar amps with amp cards that plug in.
Something broke off in the Alps-branded bass pot, allowing the wiper to travel in a continuous orbit, with no stops. I pulled the outer pot shield off, saw that accessing the inner pot might destroy the entire thing, and put the shield back on. I don't typically adjust midrange, so I swapped the bass and midrange pots and bass was back in business.
The volume pot is comically undersized and has absolutely no physical resistance when you turn it--it's like turning the knob on a child's toy radio. But oh, the magic that that knob unleashes...
Aside from one trim pot on the PRE board, I see only two trimmers on the amp card. I imagine these adjust center voltage, and/or bias current. If this is anything like the JVC 5551, you can dial in center voltage, or bias, but not both unless the planets are aligned and it's Tuesday and a magic fish high-fives you. I haven't touched the trimmers and I'm really, really trying hard to not mess with them at all as this seems to release magic smoke or at least a very long trip down the amp adjustment rabbit hole. With output caps my speakers should be safe from DC, and unless I install new TO-3 devices or drivers, I think I can leave those trimmers alone. I'm still smarting from losing one channel of FM
If folks are interested I'll take some pics and post them. BTW, the speakers are newly-restored Polk Audio Monitor 7's and I don't think I've experienced better speaker/amp synergy. I don't have a good handle on the audiophile lingo, so let me just say I was singing along to Journey's Greatest Hits, not something women and children should hear and fortunately a rare occurrence. As soon as I finished dinner I ran right back to the bench to do more listening.
