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Model 500A with strange date

Mike244

Mike244

Active Member
In Friday I got Sansui 500A from Japan. From the information available on the web, it follows that they were produced in 1967-1969, but in this one all the Elco-caps have a date of 1975-1976, I am 100% sure that no one has ever touched this receiver with a soldering iron. Unfortunately, there is no serial number, but based on the condition of the chassis and all the parts, I am believe that this receiver was made in 1976.
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I've never seen Fox brand electrolytic capacitors used in a Sansui factory build; Elna, Nichicon, Nippon and even occasionally Matsushita. Not saying it's impossible, but between the odd brand and the odd date codes, I'm not sure what to make of it. Strikes me as highly unlikely the factory would've been assembling these still in the mid 70's. Is there anything else in there with a verifiable date code that puts it closer to the known production date range? I believe the AU-111 was probably the last tube model to be discontinued, as it was purportedly still available for sale into the early 70's. That may have been from existing slow moving stocks sitting, however.

Having said all that, I've seen a couple of other incidents of strangeness in models built after their official production had apparently ended. I picked up an SE-88 equalizer a while back that was built in 1992 (this model debuted in 1985) for the JDM (100V only). Even more strange is it had the pre-1987 logo on it, front and back. That, despite there having been SE-88's made in 1987 and 88 with the "new" logo of the time. The electronics inside were also new production, as revealed by date codes on the chips used on the PC boards. So, they weren't just burning off old parts inventory, or doing refurbs, near as can be determined. I doubt I'll ever have a clear answer on just what brought that about.
 
All the small elco-caps are (also Fox) dated 74-75, NEC HF tubes (which no one ever changes) they also have a date of 75/76, the OPT transformers have a code 76-2, although I'm not sure what that date code is...
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That is very strange, and I have no answer that explains it. This unit certainly appears to have been built much later than the 500A is known to have been in production. I can't imagine they would do a one off, so maybe there was a short run using leftover parts inventory? Even that would be quite odd, since by '75-76, I rather doubt they have all the tubes and related parts (sockets, etc.) still sitting in inventory, so all I can do is speculate.

It's a damn shame the serial number tag is missing, it would give us a definitive answer on the build date, even if it didn't give us clarity on why one of these was apparently assembled so late in the game. These aren't old Japanese date codes done by Emperor Era, either, so we can rule that out. 1975 would have been Showa year 49, if I did my math correctly. The Showa era ended in 1989 at year 64.

And again, these Fox branded caps are an unusual detail. I don't recall seeing those in any other Sansui tube gear I've been under the hood of. Anyone else have a 500A that hasn't been recapped with all these Fox branded caps still in place?
 
I don't think those dates listed for the 500 are correct, it would more likely have been in production from roughly 66-68 alongside the 250 and 1000. Doing a quick and dirty perusal of the serial number database here, I see 500A's with production years from 68 to 71, which runs a bit later than I'd have expected anyway (figuring late 69 or 70 would've been the cutoff), so this current example is still an outlier. This will certainly be the latest production date I've seen so far on a tube model from Sansui (excepting the B-209 and AU-111 reissues, obviously) if it really was made in 75 or 76, as it appears.
 
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@Dswankey, I'm not 100% positive, but I have a feeling that information posted on the classic audio site was taken from the old Orion Audio Bluebook. While it was useful in its heyday (mid to late 1990's), the Internet made it superfluous, and much of the data it listed was of questionable accuracy.

It was intended mostly for pawnshops and resale stores to establish some sort of baseline value on items they had taken in. Keep in mind this was back before the emergence of eBay as the "unofficial reference" for valuations, as well as predating the serial number database here.

Somewhere here I have a copy of it from 1997 or 98, I'll have to see if I can find it. If I do, I'll take a look at it to see if it will confirm my suspicious about where those production date figures came from.
 
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