Bizarre mini stereo receiver - Electro-Brand 9700??

lttnorth

New Member
Recently I had been looking for a small-footprint receiver and bookshelf speakers for my garage. A guy at my work has an Optimus STA-20 mini receiver for his desk; only 5 WPC which obviously isn't very impressive, but the physical size was what I was after. And after searching for months I finally came across one that's a similar size -- albeit from a brand I've never heard of or seen in my life.

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I paid $40 for this, which is admittedly too high for what I got. But I was so intrigued by the fact that this was designed to stand vertically. I have never seen or heard of any receiver or amplifier that was designed like this. It also has a clock for some reason? Those "Fast" and "Slow" buttons are for setting the time. For the weirdness factor alone -- plus it checking off all the boxes for what kind of receiver I was searching for -- I thought $40 was worth the price.

But this thing is still a mystery. I have no idea when it was made or who this company is. But doing some digging I found a few other products catalogued on this website: http://www.radiomuseum.org/dsp_hersteller_detail.cfm?company_id=8177
Electro-Brand was (is?) an American company that seems to have outsourced its manufacturing mostly to Hong Kong from what I can tell. However a few products were manufactured in Japan. Looks like mostly bargain bin stuff, as expected. Portable radios, headphones, tape players. But it was odd to see a number of police radios in the list too.

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Like the other products it shares a name with, it looks admittedly cheap. The front is metal but it's not that classy brushed aluminum look, so it winds up looking like plastic. Nevertheless this entire thing is made of metal and it is fairly hefty, just over 5 pounds. It's actually in fantastic shape for its age; it was part of an estate sale so my guess is it got buried somewhere in an attic after some minor use. No dust bunnies or dirt to speak of.

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So yeah this thing is tiny. Aside from that STA-20 I don't think I've ever seen a vintage receiver this small. I hooked it up to some decent Klipsch speakers and was taken aback at how loud I could could get it to go. Again, my expectations were low, so I was pleasantly surprised. The back of the receiver says it has a max of 45 Watts?!? My guess is since there's an input for 2 mains and 2 subs on the back, that "45 watts" is not a per channel rating and they simply added them all together to make it seem more impressive and capable than it really is.

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Because of the vertical nature of this thing I took off the metal cover to see what's inside and how everything was mounted. Nothing spectacular -- it's just not horizontally opposed. The other side of the main component is just the radio tuner; pretty standard-looking pulley system that rotates when you spin the knob. But I was disappointed when looking over this and I discovered that there are absolutely no identifying marks inside whatsoever. No manufacturing date, no component manufacturer's names, nothing. Just a tiny little mystery box.

If any of you guys have information on this little wonder, please share! Or even just your general thoughts. It's kind of incredible actually in my opinion that anyone made something this small so long ago, regardless of its capabilities.
 
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I have had a couple items cross my path over the years, an old amfm 8 track stereo very similar to panasonic models and a boombox I still have in the store - amfm cassette with a world radio tuner AND a strange RDF....info, is adrn near impossible. pre-internet and no one cared to list it
 
I have a onkyo I think that is all heat sink and its bridgeable and the thing is about the size of a big mac box X 3 and the top unit is a tuner and docking port.
100 watts bridged it says. 60w stereo. I will have to get pics of it.
Thanks.
Srinath.
 
Somehow, I think that "45 watts" you mention may be it's power consumption, not it's power output.
 
give us some more nudes of the amp section...is that an AL heatsink over by the transformer? the tuner is a bit low buck with that varcap, I see (I think a SIP and a DIP that handles much of the IF and stereo duties...)
 
Somehow, I think that "45 watts" you mention may be it's power consumption, not it's power output.

^^^ This.

45 watts is the maximum it draws from the wall. Assuming roughly 50% efficiency (very common), that gives you 22.5 watts total = 11 watts output/channel. And that's being generous.

Or, as we used to say, Downhill, with the wind behind it.

Cheers,
Larry B.
 
I love stuff like that. Advent made some small receivers that are high up on my list. Model 350 I think. I have a 400 and used it take with me on business trips. That and a Minimus 7 fit in a suitcase. There should be a ton of those desktop systems around but I guess most were just thrown out. Kinda' sad. Mini components are great for night stands. Much more class than clock radios.
 
give us some more nudes of the amp section...is that an AL heatsink over by the transformer? the tuner is a bit low buck with that varcap, I see (I think a SIP and a DIP that handles much of the IF and stereo duties...)

took some more photos... though I'll be completely honest I dont exactly what to look at; i'm no expert.

Edit: taking a closer look at that integrated circuit, looks like it's Hitachi-made.
 

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$5 and too odd to not share. A ton of 1000uf caps in there.
Deoxit on the crunchy pots and it still had a nasty hum when on or off, loose transformer cover, poke a toothpick in the gap and it's rocking a pair of Minimus 7s.
 
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$5 and too odd to not share. A ton of 1000uf caps in there.
Deoxit on the crunchy pots and it still had a nasty hum when on or off, loose transformer cover, poke a toothpick in the gap and it's rocking a pair of Minimus 7s.
The big PSU capacitors may cause the hum. I have a Kenwood KA-51 which had a hum after power on, one of the two big caps was non-functional.
 
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