Old amplifier connection issue, very low sound
totorlalligatore
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baladur13 Posted messages 47328 Registration date Status Moderator Last intervention -
baladur13 Posted messages 47328 Registration date Status Moderator Last intervention -
Hello,
I have an old Harman Kardon amp (TA 602 maybe, the label is half worn off)
Both speakers work perfectly (I swapped the connections to make sure it’s not the speakers).
The problem is that the left side (left of the amp) is producing a very low volume sound, making the music play in mono.
This has happened before but sporadically; I thought it was due to a bad wire connection because when I fiddled with the cables, it would resolve quickly.
Today, during a big cleaning, I reconnected everything properly.
With my brief tests, it seems to be neither the cables nor the speakers.
Also, the same problem occurs if I connect the cables to the "system 2" of the speakers.
Is there anything that can be done?
I love my sound system, it’s the best purchase I’ve ever made in my life, bought second-hand from a retired electrician.
Thank you!
I have an old Harman Kardon amp (TA 602 maybe, the label is half worn off)
Both speakers work perfectly (I swapped the connections to make sure it’s not the speakers).
The problem is that the left side (left of the amp) is producing a very low volume sound, making the music play in mono.
This has happened before but sporadically; I thought it was due to a bad wire connection because when I fiddled with the cables, it would resolve quickly.
Today, during a big cleaning, I reconnected everything properly.
With my brief tests, it seems to be neither the cables nor the speakers.
Also, the same problem occurs if I connect the cables to the "system 2" of the speakers.
Is there anything that can be done?
I love my sound system, it’s the best purchase I’ve ever made in my life, bought second-hand from a retired electrician.
Thank you!
4 answers
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Hello,
Is this the model?
If so, where are your speakers connected? System 1 or System 2
It's very difficult to catch a black cat in a dark room.
Especially when it's not there... -
Hello,
My idea is that the left power transistor is quite worn out
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I call a spade a spade *
*in French in the text -
Hello.
<<< because when I fiddled with the cables, it got solved quickly. >>>
It’s strange that this channel works from time to time. The volume or balance pot may be dirty.
A spray of Weicon (or WD-40) into all the pots, while turning back and forth with each spray, let it dry for a couple of hours and try again.
But if there's no improvement, I would agree with Andy's opinion. Defective output transistors. Apparently, they are TO-126, so not too expensive (4 pieces). After that, it’s clear that a good overhaul wouldn’t hurt, but of course, you need to know what you’re doing.
(For humor) Unless you want to treat yourself... if you have the means ==>
https://hifivintage.eu/fr/amplificateurs/1747-harman-kardon-ta-600.html
See you later...
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"Patience leads to good, haste leads to nothing."-
Thank you for the advice,
<<< because when I was tweaking the cables, it was resolved quickly. >>> :
yes indeed, I attributed it to poor connections on the wires, but upon retesting, it's hard to misconnect them. But in this case, could a bad connection have damaged the infamous transistor?
I must have one or two screwdrivers; let's just say I don't feel up to doing the electronics; I imagine there are meticulous soldering jobs to do.
I'm going to spray some cleaner in the pots, you never know...
"Good lifting" I bought it 4 years ago from a retiree electrician musician who has done this before, other than that everything works perfectly.
I'm flattered to see that the machine sells for 9000€, thanks for this info! I was even more flattered when I saw it appear in a scene from Wrong Cops by Quentin Dupieux.
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The polarities have been properly respected (+ of the amp connected to + of the speakers)
What happens if you adjust the balance?
You have two headphone outputs, if you connect a headphone, does the same issue occur on the left side?
A spray of "contact cleaner" on the "Balance" and "Volume" potentiometers as well as the switches that activate system1 or system2 and a bit of all the contacts might be a solution.
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Very difficult to catch a black cat in a dark room.
Especially when it's not there...-
Yes, the polarities are respected, I have every other wire marked with a red stripe.
Good catch on the headsets, but I don't have any, no adapter, no jack, nothing, I'll try to borrow some.
Go for the contact cleaner, but I don't really believe in it.
While playing with the balance I have the described problem; no sound on the left unless I turn the volume all the way up, the speaker works, I connected it to the 'right' input, and no issue.- If I understood correctly, it does the same thing on the left side of System 2, and that's why I think the issue could come from one of the volume or balance potentiometers, or from the switches that direct to System 1 or System 2.
In fact, we should be able to test the circuit with professional equipment...
For your information, I am attaching a link to a site where you can find the electronic schematic for this amplifier.
see https://elektrotanya.com/harman-kardon_ta600_sm.pdf/download.html#dl
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