Clicking tapping noise possibly coming from valves after turning off. - UK Vintage Radio Repair and Restoration Discussion Forum

Vakito227 · 28th Mar 2017, 10:12 pm

I'm not sure if it's normal or not but I have recently realised after switching off my valve amplified record player after the valves have fully heated up (>20mins) there is an irregular clicking/tapping noise coming from the amplifier somewhere, most likely the valves and persists for about a minute after turning off.

My best guess is that it's the sound of the metal and glass contracting as the valve cools although you don't hear those noises when you turn a hot incandescent light bulb off. Should be noted that the amplifier still works absolutely fine.

Is it an early sign that the valves will need replacing soon? any help is appreciated.

The amplifier consists of 2 UF89 valves and 2 UL84 valves. 1 of each on 2 separate circuits.

Thanks
Peter

Boater Sam · 28th Mar 2017, 10:32 pm

Turn it off and go and do something else away from it. Stop worrying, its normal when things cool down.
0.1A heater valves are cheap and easy to find anyway.
Its likely to be a metal part cooling anyway, valves are quiet beasties.

kalee20 · 28th Mar 2017, 10:54 pm

Definitely! I've heard the same. Nothing to worry about.

Unusual valve line-up, is it a stereo record player or a fairly powerful mono one with push-pull output? The UF89 is a variable-mu pentode so would introduce a bit of distortion.

Refugee · 28th Mar 2017, 10:57 pm

They mount the chassis on rubber feet of one kind or another on posh sets to stop the heat expansion noises being heard. They are normal on things with metal frames in wooden cabinets.

Diabolical Artificer · 29th Mar 2017, 5:35 am

The amp I'm working on at the minute sound's like it's ripping itself apart when it cool's down, the normal pop's and clicks are amplified by the chassis. It can sound like something is wrong but is just normal contraction as you say.

Still our senses are there for a reason, maybe you've picked up on something. If your UL84's are running hot due to leaky coupling cap's or a similar fault, it will sound louder. Are they blackened? Check the cathode current to be on the safe side.

Andy.

Edward Huggins · 29th Mar 2017, 9:29 am

Quote:

Originally Posted by Vakito227

The amplifier consists of 2 UF89 valves and 2 UL84 valves. 1 of each on 2 separate circuits.

This sounds like an early HMV/CAPITOL/EMI stereo record player from 1958/59.
Yes, it used an IF valve for the AF function.

Vakito227 · 29th Mar 2017, 10:50 pm

Quote:

Originally Posted by kalee20

Unusual valve line-up, is it a stereo record player or a fairly powerful mono one with push-pull output? The UF89 is a variable-mu pentode so would introduce a bit of distortion.

It's a stereo record player made by EMI/Capitol but badged as HMV in 1958/9 as Edward said. I was told that the amplifier uses U series valves simply because they were cheaper for the manufacturer to buy.

Refugee · 30th Mar 2017, 12:15 am

I would be prepared to say that the U series valves were used for their low heaters at 100ma in series so that they could get away without using a transformer.
The valves cost the same as any others.

RojDW48 · 30th Mar 2017, 12:21 am

Probably not the problem but I did get a couple of 'ticking' 6V6G Russian equivalents from a nice guy in Ukraine a few years ago. He eventually found a couple of good ones for me but he had a whole batch that ticked! Mind you - that was when the amp was running.

28th Mar 2017, 10:12 pm	#1
Vakito227 Hexode Join Date: Apr 2016 Location: Yeadon, West Yorkshire, UK. Posts: 251	Clicking tapping noise possibly coming from valves after turning off. I'm not sure if it's normal or not but I have recently realised after switching off my valve amplified record player after the valves have fully heated up (>20mins) there is an irregular clicking/tapping noise coming from the amplifier somewhere, most likely the valves and persists for about a minute after turning off. My best guess is that it's the sound of the metal and glass contracting as the valve cools although you don't hear those noises when you turn a hot incandescent light bulb off. Should be noted that the amplifier still works absolutely fine. Is it an early sign that the valves will need replacing soon? any help is appreciated. The amplifier consists of 2 UF89 valves and 2 UL84 valves. 1 of each on 2 separate circuits. Thanks Peter

28th Mar 2017, 10:32 pm	#2
Boater Sam Banned Join Date: Dec 2013 Location: Middlewich, Cheshire, UK. & Winter in the Philippines. Posts: 3,897	Re: Clicking tapping noise possibly coming from valves after turning off. Turn it off and go and do something else away from it. Stop worrying, its normal when things cool down. 0.1A heater valves are cheap and easy to find anyway. Its likely to be a metal part cooling anyway, valves are quiet beasties.

28th Mar 2017, 10:54 pm	#3
kalee20 Dekatron Join Date: Feb 2007 Location: Lynton, N. Devon, UK. Posts: 7,081	Re: Clicking tapping noise possibly coming from valves after turning off. Definitely! I've heard the same. Nothing to worry about. Unusual valve line-up, is it a stereo record player or a fairly powerful mono one with push-pull output? The UF89 is a variable-mu pentode so would introduce a bit of distortion.

28th Mar 2017, 10:57 pm	#4
Refugee Dekatron Join Date: Apr 2012 Location: Worksop, Nottinghamshire, UK. Posts: 5,553	Re: Clicking tapping noise possibly coming from valves after turning off. They mount the chassis on rubber feet of one kind or another on posh sets to stop the heat expansion noises being heard. They are normal on things with metal frames in wooden cabinets.

29th Mar 2017, 5:35 am	#5
Diabolical Artificer Dekatron Join Date: Jul 2009 Location: Sleaford, Lincs. UK. Posts: 7,658	Re: Clicking tapping noise possibly coming from valves after turning off. The amp I'm working on at the minute sound's like it's ripping itself apart when it cool's down, the normal pop's and clicks are amplified by the chassis. It can sound like something is wrong but is just normal contraction as you say. Still our senses are there for a reason, maybe you've picked up on something. If your UL84's are running hot due to leaky coupling cap's or a similar fault, it will sound louder. Are they blackened? Check the cathode current to be on the safe side. Andy. __________________ Curiosity hasn't killed this cat...so far.

30th Mar 2017, 12:15 am	#8
Refugee Dekatron Join Date: Apr 2012 Location: Worksop, Nottinghamshire, UK. Posts: 5,553	Re: Clicking tapping noise possibly coming from valves after turning off. I would be prepared to say that the U series valves were used for their low heaters at 100ma in series so that they could get away without using a transformer. The valves cost the same as any others.

30th Mar 2017, 12:21 am	#9
RojDW48 Nonode Join Date: Jun 2014 Location: Bristol, UK. Posts: 2,074	Re: Clicking tapping noise possibly coming from valves after turning off. Probably not the problem but I did get a couple of 'ticking' 6V6G Russian equivalents from a nice guy in Ukraine a few years ago. He eventually found a couple of good ones for me but he had a whole batch that ticked! Mind you - that was when the amp was running. __________________ '....don't go mistaking Paradise for that home across the road!' (Bob Dylan)