Tuesday, July 22, 2008

The KLH 51 Receiver

KLH was a quality '60s company that has devolved in the last few decades to low end consumer schlock. Started by the renowned Henry Kloss, Malcolm Low, and Anton Hoffman (each contributing an initial to the name) KLH produced sonic quality with cosmetic style.

I confess I had never seen a KLH receiver in the flesh before the relatively basic 51 arrived.
This unit was clean and in working condition with a modest case of slightly damaged switches. The years tend to be unkind to exposed switches on electronics. These were repaired after this photo was taken. All the bulbs worked and the 51 is quite attractive when lit, blue on silver. Note the KLH logo on the left. Mike likens it to a sonic pressure wave. Whatever, it looks cool.

Here are the innards:
The 51 is a simple 3 board receiver with a two gang tuner section at the right. The amp/preamp board in the center (half of which is visible) had the the two large caps replaced with Sanyos after this photo was taken as a last minute precaution. They tested fine, but it seemed prudent. Not visible is the preamp section underneath the shield just in front of the output stage. The power supply board is at the left. The inputs along the back, just behind the heatsinks, are shielded. It should be noted the vinyl covered exterior case was shielded on the inside, a rare touch in this price class. KLH obviously cared about shielding.

A total of 41 capacitors were changed, mostly with Panasonic FCs.

Back in the '70s a relatively modest receiver was a sonic bargain. Despite relatively modest wattage they could drive a reasonable set of speakers to unreasonable sound levels with grace. The KLH 51 is no exception. The FM tuner sounds good. Even the AM tuner sounds good. And it looks good.

12 comments:

vintagesound said...

These units had very moderate ratings for output. Great sounding too! thanks

Nedda said...

I have this very model and it still works except that the radio dial in unable to move across the band to different stations. Does anyone know where/how I can get this fixed? I love this receiver and I don't want to buy a digital one.

Nedda
email: neddaw@sbcglobal.net

aherrero said...

Hey! My KLH "MODEL FIFTY-ONE" Is puttering out here and there. What is it that you think should be replaced? Is it worth it? I don't know much about these things, but I thought perhaps it just needed some new fuses? When I toggle the power button it also works a bit better. Let me know your thoughts! Much appreciated! - A

TonyVito said...

I have a KLH a-501, I don't know where I got it from, perhaps ebay? a local flea market? I don't know, but what I DO know is that this amp is the backbone of my DJ service! I've been using it since 2003 for all my DJ gigs.... several times, I've had this amp cranking for 9 hours STRAIGHT!!! Powering 2 MTX-p215 speaker towers (both with dual 15" woofers and 1 midrange driver). People can can the music 4 blocks over with no problem. Just last week at a gig, the amp started to sputter and then wouldn't power on. I just had it repaired at a local electronic shop for $100. It is the most awesome integrated amp; If anyone knows where I can find another one please advise.... Thanks; www.djtonyvito.com

Anonymous said...

Can I use this to run sound from my TV to my speakers?

jim karl said...

I know this is a way old post - but I'm looking for info on the stereo indicator bulb for a Model 52 - hoping your 51 has the same bulb. Do you have the schematic/parts list and can tell me the Voltage/Current rating on that stereo indicator bulb?

Karl Goellner said...

jim karl, if you read this, let me know if you still need the indicator bulbs or any others! I have them and also upgraded LED's that I bought for mine.

I recently purchased one in great condition from ebay. I went through it with Deoxit and the control knobs now turn smoothly and scratch free. I LOVE it. I have several vintage receivers that I swap out from time to time and find myself going back to this one most often. It's just a really cool and classic unit.

Great write up, Nat!

Anonymous said...

Hi Karl, I too have this receiver. The only issue with mine is that when in stereo mode (mono sounds normal) via the tuner, the left channel is weak with static. Both channels sound fine in stereo engaged in phone mode. I've thoroughly deoxed all pots and switches from the front and back with no improvement. No electrical parts have been replaced, as of yet. Any advice on where to start to fix this issue? Thanks, Eric S

Karl Goellner said...

Eric, YES!! Mine did the exact same thing, as a matter of fact, it would only play the left speaker in MONO and in stereo temporarily when I'd reset the A/C breaker switch on the back. The problem with mine was the selector switch. I used Deoxit really well and worked it really well from FM to AUX back and forth and the left channel came back in STEREO immediately with no static and has been fine ever since. See if that helps. Unless it's a bad channel this should work. Good luck! Karl

Karl Goellner said...

Eric, the Source switch, not selector, sorry, wasn't in front of the amp, and also work it from phono to AM with plenty of Deoxit. Use Deoxit in the red can, not the green can.

Anonymous said...

Thanks so much for this Karl. I did use the red Deoxit on all switches/pots, and did figure that there was likely one that was the culprit. I will thoroughly clean the source selector dial again and let you know how it goes. Can't see how it would be a bad channel, as in phono both channels work perfect in stereo. I figured it was most likely dirty switches and/or then maybe a failing electrical component on the tuner board. Anyway, thank again! Eric

Karl Goellner said...

Eric, perfect! I missed that part about you saying phono works in both channels. Yes, I'm feeling pretty hopeful that a little more cleaning of that Source switch will fix your issue. If I remember correctly the Source switch assembly cover/cap has a lot of open areas where dirt and dust can accumulate. I think this is why we've seen this problem. Also, while you're in there, if you need bulbs/lamps for the display lighting, I found some from a guy named Joe Mirabella who is on the FB Vintage HiFi group. Great guy to work with and recommended by the guys from the FB group. I replaced my burned out incandescent lamps with warm white LED's and they look fantastic! It takes 6 and he sells them in sets of 8 so you'll have a couple of extra if you need them. I think it runs about $12 plus shipping IIRC. Let me know if you're interested, I don't make anything off of it this is just to help another KLH Model Fifty One'r out! :)