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I bought a cheap second-hand system for a friend who needs something to connect her turntable to.
Speakers are more than decent (JBL ES30) but the receiver is THE WORST I'VE EVER HEARD in 20 years in this hobby.
All plastic class H Technics SA-EX120.
I really thought, having owned a few Technics in the past, that this one would have a flimsy build but decent sound -NOT. It is nasty as hell. Slow and undynamic, with a muffled and dead sound and a decidedly nasal character. Damn :/
I could obviously tell her to upgrade soon but in the meantime there might be something to do to help SQ a bit.
I've noticed electrolytics are generic and quite small values, even main caps. I'm thinking maybe I could replace those with something like Panasonic FC and dérate a little? There's two times 4700uF and two times 3300uF.
While I'm at it, anything else I could try? I don't feel like recapping the whole thing except if I hear it will bring stupendous results. I did it on my equipment but it is not lousy low-end crap.
Any suggestion welcome :)
Edits: 03/22/17Follow Ups:
You could put a BUNCH of money into it and still end up with a pile. I once bought a Marantz receiver for my father when I was in the service, unfortunately Marantz had been bought out by a Japanese concern, it wasn't much. I tried to upgrade it a bit years later, it's still junk. You have been given good advise already, buy a better receiver.
"If at first you don't succeed, keep on sucking till you do suck seed" - Curly Howard 1936
Forget the receiver, she most likely won't listen to radio anyway and get one of these. It's a Kenwood KA-4006, sweet little amp that can be found on eBay for a song. Nice aluminum faceplate and knobs, wood side panels, and did I mention it's oh so schveet sound?
Well thanks all for the (good) suggestions, and I'm fully aware there are better amps available, even for cheap (we don't have goodwill in Brussels tho).
However, the receiver is bought and shés getting it tomorrow.
As I enjoy tweaking electronics, I'm merely looking to improve this one in the meantime.
What's more, the receiver is 2x 80w / 8ohms which can be helpful with the 88dB JBL for those accusional party moments, so if I can make it a bit better for a few euros, I would try.
Next time try posting what your real objective is. Some of us were trying to save you from yourself; that is your trying to make a silk purse out of a sows ear. However, if that is what you want to do say so if you want advice on how to do it.
Well I thought it was all written in my first post, but maybe I wasn't clear enough, my apologies.
My feeling about hi-fi is that passive components are responsible to 50% of an amplifier (lack of) good sound.
I mean if you look at the difference between a 150$ amplifier and a 600$ amplifier (high-end being a different story of course), what differs most is the quality of the parts.
I'm not trying to make a bad amplifier turn into a good amplifier. I'm just trying to make this one a little bit better until she has the $ to upgrade.
Considering what I see inside the amp, improving on what's there should be too hard.
I've ordered some Nichicon FW main caps. Cheap enough, will replace 20 years old cheap generic caps.
If there's no change for the better, i will stop there and put the amp back on sale. If it makes a change, I might consider recapping all small lytics as well.
Spray all pots and switches with Caig D-100. Use silver grease on the fuse or Caig. Put a big, fat 10AWG powercord on it with a better plug like the popular, inexpensive P&S. If appropriate I would suggest the Elna Silmic ll capacitors where appropriate. Dampen the chassis and at least the large caps with Mortite rope caulk. Set it on a tripod of brass cap nuts. Change input resistors to something good. It seemed pretty clear what you were asking to me. Your new caps along with a power cord will make a big difference. T456
"The Borg is the ultimate user. They're unlike any threat your Federation has ever faced."
- Q, 2365
and substituted a single 5532 opamp (I think). It was a big improvement and no tone controls. I think the piece should have some redeeming qualities or else just go fishing again.
...half of my post got deleted?
Anyways, so if I replace the main filter caps with fresh Panasonic FC, possibly slightly derating, I might get an improvement? Maybe the original no-name caps have dried up... it's a 90's receiver...
I would definitely replace all of the electrolytic capacitors. The receiver was manufactured between 1998 and 2000, so the capacitors are at least 17 years old. Hopefully non of the chips are bad.
which probably means 0.09$ capacitors!
Too much is never enough
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