"Got this old Sharp amp, smoked last time it was switched on. Can you take a look?"
Yeah, why not....
It's from the unfairly overlooked range of Sharp Optonica hifi, an SM-5100. Optonica was a sub-division of Sharp, primarily to complete with other manufacturers high-end brands such as Panasonic's Technics.
Nice slender looking thing.... dating from the early 80's.
Removal of the top panel (not as easy as you'd think, it's a very tight fit!) reveals the culprit, the dreaded Rifa X class filter capacitor... in this case it's 0.0047uF 275VAC and X2 rated....
... which is soon evicted and replaced with a nice Vishay one.. again X2 rated. The X2 rating is crucial in this application.
Powering up and there's no smoke. There's also no output from the left hand channel. Pots and switches are all cleaned up to no avail...
After a little bit of head-scratching, and in fear of one of the STK-0050II output modules having failed (replacements are still available, but many are turning out to be faked, and either don't work or fail rapidly) RLY501, the speaker protection relay is found to have failed. A suitable replacement is sourced and fitted.
There's a good range of input and output sockets, two tape loops and a pre-amp to power amp bridge.
Two sets of speakers are catered for.
Look at that nicely shielded toroidial transformer.
The mains lead is replaced, at someone had cut it short at some stage, and fitted one of those daft "Masterplug" things with the tiny round pins.
It performs very well. Outputting a very reasonable 35W in 8 ohms. The phono stage is very quiet.
The amp is soak tested with "Upstairs at Eric's" by Yazoo, an album I never get tired of :)
An excellent amp-ive heard many modern amps {expensive ones}that sound no were near as good as this-
ReplyDeletewhat suitable part I can use instead of RLY501? where to order?
ReplyDeleteOriginal is NLA. Any 10A DPST relay with a 12V coil can be made to work.
DeleteHow may it sound with hooking up with NAD Amp ? How it suits with modern speakers ?
ReplyDeleteNot quite sure I understand the question ... it IS an amp ... Speakers are speakers, modern or not. Whilst speakers have got better over the years, if the amp can drive them, you're home and dry.. A 60 year old amp will still drive modern speakers of the correct impedance.
DeleteHi. I have an Optonica SA 5101 /5105 receiver which has blown its rifa capacitor on the power side. Do you know if the part is the same as yours?
ReplyDeleteChances are reasonable. Checking the service manual is the only way to know. Sadly I can't find a free one online.
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