Technics SL1210 TT has now got a hum!!

[willie garvin]

Hi,

I picked up a better copy of Dire Straights 'Love Over Gold' on LP this afternoon from a charity shop for the huge sum of £1!!

Got home & eager to play it I put it on the TT & all of a sudden I can hear a hum from my system & too be honest it might have been there a while!!

Today I was up close to the speakers when the LP started playing & I could definitely here a hum.

I can reduce it by setting the gain to zero on the Tag Mclaren preamp, but being relatively new to hifi my question is.........................why is my TT humming & how can I stop it......................perminently, please.

Cheers,

willie G

[Tarzan]

Loose headshell lead?

[jostber]

Have you connected the ground cable to your phono stage or the preamp?

[willie garvin]

Loose headshell lead?

Hi Tarzan,

Thanks for that, there was indeed a wire completely disconnected!!

Have put it back, but there is still a hum!!


Have you connected the ground cable to your phono stage or the preamp?

Hi jostber,

Thanks for your reply & yes my ground cable was connected to the phono stage, I even tried it on the preamp & cd player earth connections & it still hummed!!

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I thought I'd cracked it, I was wondering if I had overtightened the headshell & compressed the small washer between headshell & tonearm, but no the hum is still there.

If I switch the preamp to cd player the hum goes, so it must be the vinyl part of the chain!!

Perhaps a hammer might come in here. :scratch:

Cheers,

willie G

[Spectral Morn]

Has the earth wire from under the arm come lose? the one that goes from under the Technics arm to the spot near the slider. So if you use an original arm check its still connected ok and if you use another arm I would connect a lose cable up for this, just in case you need it. I find with some phonostages/arms etc that the second earth cable is still needed.


Regards D S D L

[willie garvin]

Has the earth wire from under the arm come lose? the one that goes from under the Technics arm to the spot near the slider. So if you use an original arm check its still connected ok and if you use another arm I would connect a lose cable up for this, just in case you need it. I find with some phonostages/arms etc that the second earth cable is still needed.


Regards D S D L

Hi Dalek Supreme,

I'm using the original arm, can I easily access this spot near the slider or is it a major strip down!! :doh:

Cheers,

willie G

[Spectral Morn]

Hi Dalek Supreme,

I'm using the original arm, can I easily access this spot near the slider or is it a major strip down!! :doh:

Cheers,

willie G

Sadly it is a remove the base and have a look.

So remove the headshell and platter and turn the deck upside down and remove all the screws (making sure you know where they came from. I found the first two or so times that laying them out on the floor as you remove them will help you put them back the right way) you then having removed the rubber base have to then remove the inner filler, which is screwed to the underside of the top plate. If you do this you can see the cable at bottom of arm and whether it is still attached ok or is lose. Other possibility is its got crushed and broke by the clamping of inner to top plate at some time.

Its only a suggestion but worth looking into as this being lose broke would cause hum. If its ok then I am not sure I can make another suggestion.

Regards D S D L

[magoorty]

This might be a shot in the dark, but I noticed a worrying buzz in my system recently. After checking cables and fiddling around for ages, I noticed that the nearby t.v was on standby. Turning it off got rid of the noise completely. The noise only came through when the amp was switched to the phono stage so the cartridge must be picking up something.

Just something else to possibly eliminate.

[jostber]

A couple of more things to try:
- Keep the TT away from large power transformers
- Clean the headshell pins thoroughly and reconnect them

[willie garvin]

Hi,

Thank you all for this advice.

1.


Sadly it is a remove the base and have a look.

So remove the headshell and platter and turn the deck upside down and remove all the screws (making sure you know where they came from. I found the first two or so times that laying them out on the floor as you remove them will help you put them back the right way) you then having removed the rubber base have to then remove the inner filler, which is screwed to the underside of the top plate. If you do this you can see the cable at bottom of arm and whether it is still attached ok or is lose. Other possibility is its got crushed and broke by the clamping of inner to top plate at some time.

Its only a suggestion but worth looking into as this being lose broke would cause hum. If its ok then I am not sure I can make another suggestion.

Regards D S D L

2.


This might be a shot in the dark, but I noticed a worrying buzz in my system recently. After checking cables and fiddling around for ages, I noticed that the nearby t.v was on standby. Turning it off got rid of the noise completely. The noise only came through when the amp was switched to the phono stage so the cartridge must be picking up something.

Just something else to possibly eliminate.

3.


A couple of more things to try:
- Keep the TT away from large power transformers
- Clean the headshell pins thoroughly and reconnect them


1.

I will have a go at stripping the TT down & looking for a loose earth wire & while it's stripped down I might replace the phono leads with a better pair!! Advice will be needed here though as I've never done it before!!

2.

There is no TV in my hifi room, but thanks,

3.

Thank you for this advice & I've just ordered a new Sumiko headshell to take care of any loose headshell pins/wires


Cheers,

willie G

[willie garvin]

Hi,

I think I've isolated the hum to the phono stage.

When the preamp is set to cd player there is no hum & as soon as you select the aux setting you get a hum. But I have noticed now that the hum isn't instant, it takes about 30 seconds & then the hum starts.

It's as if something has to warm up first, I'm not into electronics so this is the best I can describe it.

I have tried moving the phono amp away from everything but the hum still persists.

It's getting very close to using a BIG hammer to solve it..............................joking of course. :lol:

Cheers,

willie G

[Macca]

Sounds like transformer hum in your phono stage Mick.

[willie garvin]

Sounds like transformer hum in your phono stage Mick.

Hi Martin,

If it is transformer hum in my phono stage is it cureable or not please or is it a fault in the phono stage circuitry/design!

The trouble with me is that everything has to work as it should & I cannot leave this 'hum' alone so it will have to be fixed one way or another.

Cheers,

willie G

[jostber]

This overview can be useful for troubleshooting:

http://www.padrick.net/Hi-Fi/PhonoHum.htm

and in the last half of this article from KABUSA:

http://www.kabusa.com/setup.htm

[Macca]

Hi Martin,

If it is transformer hum in my phono stage is it cureable or not please or is it a fault in the phono stage circuitry/design!

The trouble with me is that everything has to work as it should & I cannot leave this 'hum' alone so it will have to be fixed one way or another.

Cheers,

willie G

What makes me think it is a transformer issue is the fact that it starts to huim only once it has warmed up. I have had this myself - more than likely you have, in the words of Half Man Half Biscuit 'a dodgy transformer'. It may not be the explaination but it is the most likely. If so you will need to replace it as there is no fix - not that I'm aware of anyway.