Amplifier Spoilt?

[Nolasco]

Vintage Sony TA-1630 Amplifier(Made in Japan) Spoilt?

Well I have this Sony Amp TA-1630 which I had not used for about 6 months so connected it yesterday to my speakers and started playing some music from an Ipod using a 3.5mm cable to RCA cable. Worked fine for about 3 hours after which, since the 3.5mm to RCA cable was quite short, I wanted to connect a 3.5mm extension cable.

While the music was playing itself, I removed the 3.5mm plug from the Ipod and connected the 3.5mm extension cable but when I did this, I got this really loud high pitched screeching sound from both the speakers. I tried reducing the volume but the sound continued so finally switched off the Amp. The sound continued for about 20 more seconds and then stopped.

I then switched on the Amp again after removing the 3.5mm extension cable, but now no sound comes at all from the speakers. Tried connecting a dvd player to the amp but still no sound. What could be the issue? I assume connecting the 3.5mm extension cable has done something to the amp. Please advise guys?:huh:

 

[cranky]

Let's see - if you wanted to change a spark plug on your car engine you would

a) do it while the engine was running

b) switch off the engine

Here's the rub - depending on what exactly happened, you could have lost the amplifier, the speakers, or both.

Now the first thing is to disconnect the speakers and turn on the amplifier. Are there any lights or meters to indicate power on? What are they indicating? Are there any fuses on the back panel? Are they blown? Can you check the speakers with another amplifier (can be a small 2.1 system, but please make connections with the power off).

In all probability the ground was missing or wrongly connected on the extension. This basically causes the amp to produce its full output until the ground is restored, or the amp burns down or shuts off due to protection circuitry.

 

[Nolasco]

Well since it was just an extension wire, I thought attaching the same would be fine without switching off the amp.

It seems that Ive lost one of the speakers as well as the amp. Called this electronics guy who repairs Tv's and stuff and he opened up the amp and there were 4 fuses but all of them were intact. He tested the speakers with a battery - connected the wire to either end of the battery and sound came from only one speaker. He said that the two negatives came in contact with each other (I dont know how!)

Anyway he showed me a circuit board on the Amp having 6 chips - looked kind of like the chips on rams. He mentioned that since one speaker is working, only three of them have got spoilt.

He said would cost approx 900rs to get the original Sony ones and will cost 300rs to repair the speakers - They have a 5"driver for the mids and bass I think and a tweeter as well so he said that they would have to be replaced.

He did up the amp and got it today however the sound quality is nowhere what it used to be. Its more like those roadside radios that they play at lamington road!!!
I wasn't at home when he came over with it but he had connected it to the one working speaker and left. The sound is pathetic now!! I think he will be coming over
tomorrow to explain the reason for the same and the workaround to this.

Any suggestions on what can be done in this case? Its a really old amp so not sure if its a case of the new chips that he has put in not blending in.

 

[cranky]

The amplifier would have gone into destructive oscillation when the input was disconnected. Happens in a lot of Sony amps. I've had a similar failure and lost two Beryllium tweeters on my Ushers (thankfully, replaced without cost).

If you are changing the output transistors then it's wise to change out both channels at the same time, and use known genuine parts. Most vintage amplifiers work well with the Toshiba 2SC5200 and 2SA1943 transistors, regardless of what the originals were. These new parts are pretty tough and sound nice - but only if they're genuine. I've done a few swaps and this is as good as it gets. There are a few mechanical issues but it's not something that can't be worked around.The transistors are ~250 a pair, so I don't know where you are getting the 900 figure from. And the third, smaller transistor rarely blows (if ever). It's only for thermal control.

Unfortunately when it comes to the speakers there will be a mismatch between channels and there's not much you can do about it.

 

[Nolasco]

Hi,

Thanks once again for your reply and apologies for my very delayed response! Was quite busy recently.

Anyway, well it turned out that the amp is sounding pretty good now and it seems that only the aux input works properly. The others I assume are

rusted or something of the sort as the radio quality sound as I mentioned in my previous post comes when connected through the other inputs.

Well he did charge me 900 saying he had to change six transistors! Will check this with him - he said they are original sony ones!

As for the speakers, well he did up the one that blew up but yes the sound is quite different as compared to the original. Its louder for one thing and the bass

is more however the high end seems to be missing and vocals are not really as clear as they are on the other speaker. He did mention that if I do not like the

sound he will reopen them and make some amendments. Lets see what can be done now.