mike stehr Posted September 27, 2016 Share Posted September 27, 2016 Anyone ever used vintage Kenwood receivers with Klipsch? I picked up a KR 3400 receiver for ten bucks at a local yard sale. Cleaned the dirt out of it, blew out and lubed the pots, tore down the face plate and cleaned everything out of there. The receiver sounds quite nice with my Cornwalls, a lot better than I thought it would. A little research indicates it's 18-22 watts per side, with 10Hz-30kHz response. They were made from (74-78?) I think I have an older unit possibly. Some of the newer versions of KR 3400s use the STK power packs. (power operational amplifier circuit?) My version has four metal cap type output transistors. No relay, cap coupled to the speakers. The tuner works really well for a receiver of this age. This isn't mine, but here's a image... Quote Link to comment Share on other sites More sharing options...
willland Posted September 27, 2016 Share Posted September 27, 2016 My buddy used an older Kenwood integrated amp with Chorus and it sounded very well together. Congrats on your find. Bill Quote Link to comment Share on other sites More sharing options...
Schu Posted September 27, 2016 Share Posted September 27, 2016 makes you think there really has been very little advancement in sound reproduction on the amplification side that does anything but move sideways. Quote Link to comment Share on other sites More sharing options...
mike stehr Posted September 28, 2016 Author Share Posted September 28, 2016 9 hours ago, Schu said: makes you think there really has been very little advancement in sound reproduction on the amplification side that does anything but move sideways. Yup. But I'd still like to hear the latest offerings of hi-end class D amplification. Hi-Fi engine has the service manual for KR 3400...that helps... Of course for a vintage receiver, the panel lights are fried. No easy swap in and out like the fuse panel lamps Marantz uses. These are 8 volt 300 milliamp flashlight looking bulbs, with wire directly soldered to the bulb, and then the bulb slides into a rubber boot. Fortunately, eBay has LED replacements in the same size and voltage, with a little less current...250 mA. No panel lamps means you can't see what FM station it's on, but the tuning meter lamp and stereo beacon lamp work. And with no power button indicator and the panel lights burned out, switching over to auxillary makes the unit turn completely black like it's unpowered. Nice... Quote Link to comment Share on other sites More sharing options...
Woofers and Tweeters Posted September 28, 2016 Share Posted September 28, 2016 Like I had a KR9600 Quote Link to comment Share on other sites More sharing options...
Rxonmymind Posted October 6, 2016 Share Posted October 6, 2016 Congrats on your pickup. Nice looking unit. While I don't have any experience to add never having owned a Kenwood, I will say it's amazing how little power one needs to run Klipsch speakers. Quote Link to comment Share on other sites More sharing options...
paul79 Posted October 6, 2016 Share Posted October 6, 2016 All the Kenwood gear is very good. The older integrateds like the KA-6000 and KA-7002 are VERY good sounding. Quote Link to comment Share on other sites More sharing options...
Woofers and Tweeters Posted October 9, 2016 Share Posted October 9, 2016 Have read several times that Kenwood has a great tuner section. The only thing that I notices about the couple of Kenwoods that I have had is the trying to run 2 pair of speakers, it's like the power is divided (drops off) when a second pair is added (A+B). Quote Link to comment Share on other sites More sharing options...
HDBRbuilder Posted October 9, 2016 Share Posted October 9, 2016 21 minutes ago, Weber said: Have read several times that Kenwood has a great tuner section. The only thing that I notices about the couple of Kenwoods that I have had is the trying to run 2 pair of speakers, it's like the power is divided (drops off) when a second pair is added (A+B). Did those Kenwoods have SEPARATE power supplies for each channel driven, like the old H/K "X30" twin-powered receivers had? Either way, when hooking up a second pair of speakers, all being driven from the same amplifier section, the output ohms drop for all four speakers, which is what you experienced. Amplifier ratings are NORMALLY based upon two channels being driven, with a single speaker on each channel. I actually have a nice Kenwood integrated amp from back in the 1970's and it sounds pretty good, but I haven't used it in a long time, since I tend to run a 430 most of the time...simply because it has a decent tuner. Too many H/K receiver items in my "collection", but I may be thinning them out soon. I went overboard a few years back and starting grabbing up old H/K quad receivers, and need to unload some of them. I will keep the forum folks posted on what will go and when, in case any are interested. Quote Link to comment Share on other sites More sharing options...
Woofers and Tweeters Posted October 9, 2016 Share Posted October 9, 2016 4 hours ago, HDBRbuilder said: Did those Kenwoods have SEPARATE power supplies for each channel driven, Yes. Had the KR9600. I couldn't use it to AB speakers because of its loss. I have to say that if I wasn't trying to AB speakers and just left it on A, B, C or A+B, then all was well. Quote Link to comment Share on other sites More sharing options...
paul79 Posted October 10, 2016 Share Posted October 10, 2016 There are a few vintage 2 channel receivers from Kenwood and Sansui, that actually series wire the pair of speakers per channel when running 2 sets. That turns your 8 ohm speakers into 16 ohm. They did this for safety reasons so you couldn't hurt the amp by overloading it with more speakers. So yes, this will divide the power using A+B with these particular receivers. Reason being is, if you hook up a set of 4 ohm speakers, then want to add another set of 4 ohm speakers, if A+B mode parallels the pairs, your receiver would see 2 ohms, which is a no no for most any receiver, and will most likely burn up the amp. They did this so the unknowing consumer could hook up any combination of speakers and not hurt the amp. Quote Link to comment Share on other sites More sharing options...
mike stehr Posted October 13, 2016 Author Share Posted October 13, 2016 I figured about 25 bucks to re-cap the receiver. I'm pondering over it... The receiver sounds good for a ten dollar 42 year old unit. But after some listening I can hear the weedy, gritty, sour sound of old electrolytic capacitors. It's mostly emphasized in the treble. Quote Link to comment Share on other sites More sharing options...
Woofers and Tweeters Posted October 13, 2016 Share Posted October 13, 2016 On 10/10/2016 at 2:44 AM, paul79 said: There are a few vintage 2 channel receivers from Kenwood and Sansui, that actually series wire the pair of speakers per channel when running 2 sets. That turns your 8 ohm speakers into 16 ohm. They did this for safety reasons so you couldn't hurt the amp by overloading it with more speakers. So yes, this will divide the power using A+B with these particular receivers. Reason being is, if you hook up a set of 4 ohm speakers, then want to add another set of 4 ohm speakers, if A+B mode parallels the pairs, your receiver would see 2 ohms, which is a no no for most any receiver, and will most likely burn up the amp. They did this so the unknowing consumer could hook up any combination of speakers and not hurt the amp. Makes sense. I have experienced it a few times, but not on any of the Sansui that I've had. Quote Link to comment Share on other sites More sharing options...
Woofers and Tweeters Posted October 13, 2016 Share Posted October 13, 2016 3 hours ago, mike stehr said: I figured about 25 bucks to re-cap the receiver. I'm pondering over it... The receiver sounds good for a ten dollar 42 year old unit. But after some listening I can hear the weedy, gritty, sour sound of old electrolytic capacitors. It's mostly emphasized in the treble. 10 + 25 = If you re-cap it, you will enjoy it and know what it was supposed to sound like when it was new. Quote Link to comment Share on other sites More sharing options...
paul79 Posted October 13, 2016 Share Posted October 13, 2016 5 hours ago, mike stehr said: I figured about 25 bucks to re-cap the receiver. I'm pondering over it... The receiver sounds good for a ten dollar 42 year old unit. But after some listening I can hear the weedy, gritty, sour sound of old electrolytic capacitors. It's mostly emphasized in the treble. These early Kenwood receivers are loaded with noisy by reputation, transistors as well. Look out for 2SC458's mainly. They should all be replaced with low noise modern equivalents. Quote Link to comment Share on other sites More sharing options...
mike stehr Posted October 14, 2016 Author Share Posted October 14, 2016 21 hours ago, paul79 said: These early Kenwood receivers are loaded with noisy by reputation, transistors as well. Look out for 2SC458's mainly. They should all be replaced with low noise modern equivalents. Going over the schematic and parts list from the service manual and I didn't see any 2SC458. There is 2SC945, which I think is similar or equal. I can't really be certain unless I look over the PCBs on the unit. Quote Link to comment Share on other sites More sharing options...
paul79 Posted October 14, 2016 Share Posted October 14, 2016 2SC945 is a good part, so no worries there, and these may not have 2SC458's in them. I can't remember everything, but if you don't see them, you should be good with just a recap. Quote Link to comment Share on other sites More sharing options...
mike stehr Posted October 15, 2016 Author Share Posted October 15, 2016 On 10/14/2016 at 7:38 AM, paul79 said: 2SC945 is a good part, so no worries there, and these may not have 2SC458's in them. I can't remember everything, but if you don't see them, you should be good with just a recap. Okay, I'll proceed. What's your opinion on Tantalum capacitors? There is six of them in the receiver. Four are 3.3uF, (10 volt from what the schematic claims) which are configured around the bass potentiometer in the control/pre-amp board. The other two are .47uF 35 volt. They appear to be coupling caps for the main amplifier, right at the input transistor. (2SA620WL) It seems some have the opinion that tantalums should not be used in a audio signal path, but okay for PS de-coupling, etc...I'm the sort of if it ain't broke don't fix it camp, but was just curious. Quote Link to comment Share on other sites More sharing options...
paul79 Posted October 16, 2016 Share Posted October 16, 2016 Yes, get rid of Tantalums if you can, and you absolutely can here. Replace them with electrolytic caps. Quote Link to comment Share on other sites More sharing options...
mike stehr Posted October 24, 2016 Author Share Posted October 24, 2016 Got the parts, and so far have the power supply board re-capped, along with the main amplifier board. Control amplifier board and tuner are next. I can't find the digi-camera batteries right at the moment to show current progress, but here's a gutted image... However, I still need to order the 3.3uF and .47uF electrolytic capacitors to replace the tantalum types. I figure I could pick them up from eBay when I find panel lamps. Quote Link to comment Share on other sites More sharing options...
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