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Category: Music

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Fixing the crackling noise when turning the volume knob of an old amplifier

Last weekend I dragged an old JVC A-G90 amplifier from the attic to my study/work room. I was planning on putting it on sale, but while playing with it I decided to connect my computer to it and see whether it could replace my Logitech Z-680 (see below). A quick inventory of my computer use showed me that I didn’t really need 5.1 sound, so going to stereo wouldn’t be a big loss.

So, I hooked up the amplifier to the PC and a set of Klipsch RB-51 bookshelf speakers for a test. It was great! The only downside were the crackling noises I heard when turning the volume knob. These were one of the reasons why it ended up in the attic anyway. I seem to remember that, several years ago, I used a bit of contact spray to fix this issue. For a while. A bit of internet searching led me to the following hint: “Just turn the amplifier off and turn the knob for 20 to 100 times, this usually makes the crackling noise go away, since it is usually caused by dust in the pot meter”. And it worked!

So now I have a good-working amp and excellent sound (I found another set of Klipsch RB-51′s on sale), even at low volumes. Much better than with the Z-680. I also dug up the JVC KD-WR90 cassette player and the JVC T-E50L tuner, as well as the (not matching because too wide) JVC XL-V231 CD player, so now the old stereo set that I know from my childhood is restored in all its glory :-).

What I should do, of course, is compare this amp to the Marantz NR-1601 and SR-6006 I own as well. Just to see how they compare. Maybe something for a cold winter evening.

P.S. Speaker placement

One note about speaker placement: the speakers are very close to me (i.e. less than 1 meter). At first I placed the right speaker at ear level and the left one 15 cm lower. It seemed that the left speaker had lost most of its high-frequency spectrum. Only after raising it to the same height did I get proper balanced sound. Maybe this specific to the Klipsch speakers with their horn tweeter, maybe not. Anyway, something to keep in mind!

P.P.S. The Z-680 hiss problem

The problem with the Z-680 was that it has a low level of hiss/noise coming from the speakers. The hiss wasn’t noticeable when playing games or listening to music, but when the speakers were idle the noise was very noticeable and distracting. Even when the set was muted it was present. This turns out to be an unfixable problem (there was a partial fix with a firmware update) and several discussion threads about it can be found on the internet.

When I used the set in a home theatre setup I never noticed the hiss, but ever since I used it as my computer speaker set (i.e. sitting closer to the speakers), it annoyed me greatly. Even more so since I started working from home, most of the time sitting behind the computer without music, but still with the speakers on in order to notice e.g. Skype calls coming in.

It happened today…

It happened today
It’s the end of the world as we know it…
I don’t sleep, I dream…
Shiny happy people?

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