Hello everyone,
First time post in the Solid-state amp forum, I'm usually a tube guy ala Hammond and guitar amps.
My friend brought me a Harman Kardon 330a which had some issues - no tuner back lighting, no phono input and overall "old electronics" issues. I popped in some 6.3v pilot lamps and restored the backlight issues. The phono in was a broken ground wire, all good now. Some cleaner into the pots and this thing is starting to respond properly!
I'm noticing that the main ripple capacitor and some other large caps are swelling. In my repair realm (usually old tube gear) my M.O. tends to be search and replace all electrolytic caps. Is this warranted here? The out-of-shape caps shouldn't be a problem, but I'm looking at the 24 or so small electrolytics on the amplifier board and thinking to myself that maybe these should go too? Maybe the caps on the phono preamp as well? This stereo will mainly be used for phono applications, possibly the AUX in as well. What's the consensus here as to component replacement?
Cheers!
First time post in the Solid-state amp forum, I'm usually a tube guy ala Hammond and guitar amps.
My friend brought me a Harman Kardon 330a which had some issues - no tuner back lighting, no phono input and overall "old electronics" issues. I popped in some 6.3v pilot lamps and restored the backlight issues. The phono in was a broken ground wire, all good now. Some cleaner into the pots and this thing is starting to respond properly!
I'm noticing that the main ripple capacitor and some other large caps are swelling. In my repair realm (usually old tube gear) my M.O. tends to be search and replace all electrolytic caps. Is this warranted here? The out-of-shape caps shouldn't be a problem, but I'm looking at the 24 or so small electrolytics on the amplifier board and thinking to myself that maybe these should go too? Maybe the caps on the phono preamp as well? This stereo will mainly be used for phono applications, possibly the AUX in as well. What's the consensus here as to component replacement?
Cheers!
I'd replace the visibly swelling ones first, and then burn it in. At that time you can decide
whether to go further. Doing too much at one time can backfire if a new problem crops up.
Thank you, that seems like a very sensible course of action.
Would anyone happen to know the model year and estimated value? Is it desirable?
Would anyone happen to know the model year and estimated value? Is it desirable?
"Is it desirable?"
Not really.
The newer 330/430/730 are pretty good though.
A 230 should be tossed in a dumpster.
Not really.
The newer 330/430/730 are pretty good though.
A 230 should be tossed in a dumpster.
> Should I replace the AC cable with either a polarized type or earth grounded?
Stage-amp thinking.
On one hand, YES, 3-pin anything you see.
OTOH, home hi-fi is NOT stage audio. On stage you have several musician amps, a PA system, maybe lighting gear, and a cheap bar-owner who won't replace the bad wiring from 1953. And beer. And the musicians Hold Ground all the time they are playing.
Home hi-fi, everything is (poorly) "bonded" together by RCA cables. Floors are usually dry wood or carpet. Wine is not spilled. Folks are not rowdy. Nobody holds onto the hi-fi, just touch it to flip records. Yes, I have got shocks on home hi-fi, but it's not the problem it is for musicians.
And a remarkable number of good-old hi-fi were non-polarized. This was a problem when I upgraded systems with new tables and decks on older but still good main amplifiers. The sources usually plugged to AC outlets on the amp. If this was non-polar, the new plugs could not fit. I hate to admit it today, but I used to carry butchering tools (nipper and file) to "adjust" new plugs to fit old holes. ($2 3-way polarized extension cords were a better plan when the system allowed.)
In stage-amps, the customer HAS to have it Friday or he loses money. Hi-fi folks go into withdrawal but don't actually suffer lost-income problem. (OTOH my work was in music-school classroom systems, and lost class time IS a disaster to profs. Even the wordiest feel a need to play examples.)
So in Hi-fi....
If the cord is ratty, shock-risk to touch, replace it.
If vintage Collectible, ask Collectors what they feel is appropriate.
If vintage shelf-fodder (good but not godly) replace like with like, if possible, or polarized since it is hard to find any other cord-set today.
Note that if the plug is cracked but the zip-cord is good, "most" replacement plugs are non-polar (we are not trusted to get it right). Of course most replacement plugs are ugly. But IMHO plug-jobs are "period correct": we managed to bust a lot of plugs even without getting rowdy. (Wall outlets lower than furniture is stupid.)
It is usually "OK" to run hi-fi not bonded to building ground. You'd think code would require metal chassis bond, but apparently not. You'd think the hi-fi would hum less if bonded to local electric field, but un-grounded hifis usually play fine, it is enough if all is bonded together and floating to average electric potential. And multiple 3-pin plugs in hifi begs for ground-loops. IMHO the phono may be grounded and all else follow it. In practice the power amp may be 3-pin and the other stuff tags along as 2-pin plus RCA links.
Stage-amp thinking.
On one hand, YES, 3-pin anything you see.
OTOH, home hi-fi is NOT stage audio. On stage you have several musician amps, a PA system, maybe lighting gear, and a cheap bar-owner who won't replace the bad wiring from 1953. And beer. And the musicians Hold Ground all the time they are playing.
Home hi-fi, everything is (poorly) "bonded" together by RCA cables. Floors are usually dry wood or carpet. Wine is not spilled. Folks are not rowdy. Nobody holds onto the hi-fi, just touch it to flip records. Yes, I have got shocks on home hi-fi, but it's not the problem it is for musicians.
And a remarkable number of good-old hi-fi were non-polarized. This was a problem when I upgraded systems with new tables and decks on older but still good main amplifiers. The sources usually plugged to AC outlets on the amp. If this was non-polar, the new plugs could not fit. I hate to admit it today, but I used to carry butchering tools (nipper and file) to "adjust" new plugs to fit old holes. ($2 3-way polarized extension cords were a better plan when the system allowed.)
In stage-amps, the customer HAS to have it Friday or he loses money. Hi-fi folks go into withdrawal but don't actually suffer lost-income problem. (OTOH my work was in music-school classroom systems, and lost class time IS a disaster to profs. Even the wordiest feel a need to play examples.)
So in Hi-fi....
If the cord is ratty, shock-risk to touch, replace it.
If vintage Collectible, ask Collectors what they feel is appropriate.
If vintage shelf-fodder (good but not godly) replace like with like, if possible, or polarized since it is hard to find any other cord-set today.
Note that if the plug is cracked but the zip-cord is good, "most" replacement plugs are non-polar (we are not trusted to get it right). Of course most replacement plugs are ugly. But IMHO plug-jobs are "period correct": we managed to bust a lot of plugs even without getting rowdy. (Wall outlets lower than furniture is stupid.)
It is usually "OK" to run hi-fi not bonded to building ground. You'd think code would require metal chassis bond, but apparently not. You'd think the hi-fi would hum less if bonded to local electric field, but un-grounded hifis usually play fine, it is enough if all is bonded together and floating to average electric potential. And multiple 3-pin plugs in hifi begs for ground-loops. IMHO the phono may be grounded and all else follow it. In practice the power amp may be 3-pin and the other stuff tags along as 2-pin plus RCA links.
- Status
- Not open for further replies.