New acquisition: LXI 564.92591050 Receiver

This really isn't anything special, but I acquired another piece of gear today to feed my fascination with the ugly ducklings: A Sears LXI Series 564.92591050 receiver. I got it cheap, or I wouldn't have got it at all--but it usually isn't difficult to get ugly ducklings cheap. For the price, it's in fantastic condition; the faceplate and case are almost unmarked, all the lights work, there is almost no dust inside the case, and the controls are clean. It's really in fine condition for a piece of early 80's gear.



The instant I got it, I had to crack it open and take a look around. To begin with, as best I can tell it was made by Sanyo. The caps are all by Elna, though, and the aluminum heat sinks are nice--they look to be the same kind used in my Onkyo 506RS. The model number of the output transistors is STK0080II. Basically, it looks like this:




And a closeup of the output stage (the caps rate 8600uF, if anybody's taking notes):



Anyway, after a quick cleaning and reassembly, I hooked it up to a couple of Dayton BR-1 two-way monitors that I built a few years ago. I can't fault the sound--it's clean, the bass is respectable, and the EQ is a convenient feature. The tuner is OK, but seems weaker than other tuners I have. With that said, this hole in the ground that I live in is a challenge for any tuner. I'd prefer an analog dial, but I have to say that the 5 presets are convenient.

This is how it looks when underway in the dark, where it probably looks its best:



So, overall I consider it to be a very decent piece for the price I paid. It should serve me well in the workshop, where the conveniences of the EQ and presets will be handy--although, to be honest, it sounds good enough that I would be satisfied with it in any of my secondary systems. I'd say that the LXI Series gear is worth considering for any such application--and who knows? Perhaps they put out higher quality gear that could give my main system a challenge. I'll keep my eyes open.

I had an LXI Hi-Fi VCR that was clearly a rebadged Hitachi. It was built like a brick and I was very unhappy when after many years, the display went out. :sigh:

Bet it has some punch to it. 80 wpc. Does it still hold the channels in memory? I would think those batteries are from around 1985?

It's a shame that these rebranded units and off brand units are victims of the modern age. These companies have so much more trouble turning out crap than they used to, so everything is too good.

You have a cheap rebranded job that works great and probably is as good as stuff costing much more. Run some curves on it and see how it's doing; I'm sure you will be pleasantly surprised.

Hey those STK0080's will put out 80 Watts each! That is, if the power supply holds up.

Bet it has some punch to it. 80 wpc. Does it still hold the channels in memory? I would think those batteries are from around 1985?

That's the longest model number I've ever seen

So far, it has had power enough to render well everything I've thrown at it. I may have to hook it up to the ribbons as a torture test, just to see how it handles them. And damned if the presets don't hold, even with 25 year old batteries. Of course, we'll see if they're still there when I turn it on next.

By the way: Did I say 6800uF caps? Guess I did, but the damn dyslexia is at it again. The caps actually rate 8600uF, which is obviously rather better.

Bob91343 said:

Run some curves on it and see how it's doing; I'm sure you will be pleasantly surprised.

Click to expand...

Can you direct me to a thread or other writeup on how best to do this? I've done a lot of work on speakers, but I've never done much work on amplifiers. What work I've done has mostly been blind parts replacement (output transistors), which has so far been pretty successful for me. Actual measurement and tuning of amplifiers, however, is all Greek to me.

You put an eight Ohm load on each output, apply a sine wave from a signal generator to the input, and (while watching the output on the oscilloscope) increase the signal until just before clipping. Measure the output power. Repeat at different frequencies from 20 Hz to 20kHz.

Then you run the volume wide open and reduce the signal input until you get about one Watt output. Sweep the signal generator across the frequency range until the output drops 3dB at the frequency extremes and note the frequencies.

If you are affluent enough to own a distortion analyzer you could check it with that as well.

Finally, run the volume control to zero, disconnect the signal generator, short the input, and measure the output noise.

Those tests pretty well characterize an amplifier. There are others of course, transient performance, intermodulation distortion, trying different load impedances, etc. And of course do these tests at various power line voltages and room temperatures and humidity. Then thump the unit while looking for output anomalies. On and on you go until you are worn out or have destroyed the amplifier.

I've had one of their TVs since 1989, and I haven't had a speck of trouble with it. It has speaker jacks on it and it gives great sound from my HPM-100s without an external amp.

Bob91343 said:

Those tests pretty well characterize an amplifier.

Click to expand...

Thanks for the info.

OK...the sum of my electronic test equipment at present consists of a digital multimeter. I guess if I really want to test any of my amplifiers, I'll need an oscilloscope, a signal generator and maybe a distortion analyzer.

kcollins4 said:

That's the longest model number I've ever seen

Click to expand...

Exactly my thought. Imagine the despair of their marketers. How to make that sound sexy?

I have the little brother of the OP’s.