Rumble on record decks. - UK Vintage Radio Repair and Restoration Discussion Forum

Tony_Sterling · 23rd Jul 2019, 5:18 pm

I have three record decks. A Goldring Lenco GL69, Sony PS-LX2 and a Sony LX56. The first two no matter what I do the rumble on these is quite severe. I am playing them into the amp of a Philips N4450 tape deck.

Does anyone have any suggestions what I might do? Ta

Tandy01 · 23rd Jul 2019, 5:40 pm

Years ago Tandys used to sell a foam mat for the turntable to cut down on this. I see there are quite a few on Amazon nowadays.

Nuvistor · 23rd Jul 2019, 8:20 pm

Hope I have this the correct way around, 50 years since I last visited this subject.

Using a tape deck amplifier to play a record, the equalisation circuit in the amp will cause problems for the record reproduction. The tape amplifier will include a 6db per octave roll off to accommodate the increasing output from the tape head as the frequency increases.

This will accentuate the low frequencies, I.e the rumble. See :-

http://hyperphysics.phy-astr.gsu.edu...dio/tape3.html

The paragraph explains it, unless you to work through the maths, I didn’t.

ben · 23rd Jul 2019, 10:17 pm

The Lenco is idler drive, so any hardening of the rubber idler will result in rumble. The others are direct drive I believe, so any rumble is likely lack of lubrication or wear on the main bearing.

Obviously, try through a 'proper' amp as suggested above!

Beobloke · 24th Jul 2019, 4:49 am

Use the deck that doesn’t rumble?

Restoration73 · 24th Jul 2019, 7:50 am

This tape deck has an inbuilt magnetic RIAA preamp.

Unlike Garrard/BSR the idler on the Goldring is vertical, and more vertical rumble occurs,
which is noticeable in stereo, although it will disappear if you switch to mono. Most
other rumble problems are caused by bearings or insufficient damping between the
turntable and the speakers. An external amp/preamp may have a LF rumble filter fitted.

Craig Sawyers · 24th Jul 2019, 8:31 am

There are circuits around that sum L and R below 70Hz or so only. So for low frequencies, the signal is mono, and above that stereo.

The idea is that the ear is not sensitive to position location for low frequency.

Craig

Tony_Sterling · 24th Jul 2019, 10:14 am

re. rumble on record decks.
thanks for all the threads it gives me plenty to look at .tony

PaulR · 26th Jul 2019, 9:25 am

On some decks the motor is suspended on conical rubber grommets. Although they may look soft and pliable they often reduce in height over the years and the motor is not mounted in the position intended. They are easily obtainable on ebay and I have cured odd noise problems on a couple of decks by replacing them.

If any of your decks have these it may be a good idea to replace them, they are not expensive.

RojDW48 · 26th Jul 2019, 11:22 am

As it happens I have just revived a GL59 (from rustbucket skip fare to really good working order) and it didn't take much effort - just scraped off the rust, oiled and lubricated everything - they shouldn't rumble! I suspect the transit screws which lock the motor chassis to the deck plate for transport have not been released. They are under the platter - usually identifiable by a splash of red paint on them. Remove them (2) to release the motor suspension.

23rd Jul 2019, 5:18 pm	#1
Tony_Sterling Tetrode Join Date: Sep 2004 Location: Plumstead, London, UK. Posts: 76	Rumble on record decks. I have three record decks. A Goldring Lenco GL69, Sony PS-LX2 and a Sony LX56. The first two no matter what I do the rumble on these is quite severe. I am playing them into the amp of a Philips N4450 tape deck. Does anyone have any suggestions what I might do? Ta __________________ taxitony

23rd Jul 2019, 5:40 pm	#2
Tandy01 Retired Dormant Member Join Date: Jul 2019 Location: Reading, Berkshire, UK. Posts: 6	Re: Rumble on record decks. Years ago Tandys used to sell a foam mat for the turntable to cut down on this. I see there are quite a few on Amazon nowadays.

23rd Jul 2019, 8:20 pm	#3
Nuvistor Dekatron Join Date: Aug 2013 Location: Wigan, Greater Manchester, UK. Posts: 9,433	Re: Rumble on record decks. Hope I have this the correct way around, 50 years since I last visited this subject. Using a tape deck amplifier to play a record, the equalisation circuit in the amp will cause problems for the record reproduction. The tape amplifier will include a 6db per octave roll off to accommodate the increasing output from the tape head as the frequency increases. This will accentuate the low frequencies, I.e the rumble. See :- http://hyperphysics.phy-astr.gsu.edu...dio/tape3.html The paragraph explains it, unless you to work through the maths, I didn’t. __________________ Frank

23rd Jul 2019, 10:17 pm	#4
ben Dekatron Join Date: Aug 2006 Location: Madrid, Spain / Wirral, UK Posts: 7,498	Re: Rumble on record decks. The Lenco is idler drive, so any hardening of the rubber idler will result in rumble. The others are direct drive I believe, so any rumble is likely lack of lubrication or wear on the main bearing. Obviously, try through a 'proper' amp as suggested above! __________________ Regards, Ben.

24th Jul 2019, 4:49 am	#5
Beobloke Heptode Join Date: Oct 2007 Location: Southampton, Hampshire, UK. Posts: 824	Re: Rumble on record decks. Use the deck that doesn’t rumble?

24th Jul 2019, 7:50 am	#6
Restoration73 Nonode Join Date: Jun 2013 Location: Surbiton, SW London, UK. Posts: 2,801	Re: Rumble on record decks. This tape deck has an inbuilt magnetic RIAA preamp. Unlike Garrard/BSR the idler on the Goldring is vertical, and more vertical rumble occurs, which is noticeable in stereo, although it will disappear if you switch to mono. Most other rumble problems are caused by bearings or insufficient damping between the turntable and the speakers. An external amp/preamp may have a LF rumble filter fitted.

24th Jul 2019, 8:31 am	#7
Craig Sawyers Dekatron Join Date: Nov 2010 Location: Oxford, UK. Posts: 4,993	Re: Rumble on record decks. There are circuits around that sum L and R below 70Hz or so only. So for low frequencies, the signal is mono, and above that stereo. The idea is that the ear is not sensitive to position location for low frequency. Craig

24th Jul 2019, 10:14 am	#8
Tony_Sterling Tetrode Join Date: Sep 2004 Location: Plumstead, London, UK. Posts: 76	Re: Rumble on record decks. re. rumble on record decks. thanks for all the threads it gives me plenty to look at .tony __________________ taxitony

26th Jul 2019, 9:25 am	#9
PaulR Dekatron Join Date: Oct 2003 Location: Southport Lancashire, UK. Posts: 3,236	Re: Rumble on record decks. On some decks the motor is suspended on conical rubber grommets. Although they may look soft and pliable they often reduce in height over the years and the motor is not mounted in the position intended. They are easily obtainable on ebay and I have cured odd noise problems on a couple of decks by replacing them. If any of your decks have these it may be a good idea to replace them, they are not expensive. __________________ Paul

26th Jul 2019, 11:22 am	#10
RojDW48 Nonode Join Date: Jun 2014 Location: Bristol, UK. Posts: 2,074	Re: Rumble on record decks. As it happens I have just revived a GL59 (from rustbucket skip fare to really good working order) and it didn't take much effort - just scraped off the rust, oiled and lubricated everything - they shouldn't rumble! I suspect the transit screws which lock the motor chassis to the deck plate for transport have not been released. They are under the platter - usually identifiable by a splash of red paint on them. Remove them (2) to release the motor suspension. __________________ '....don't go mistaking Paradise for that home across the road!' (Bob Dylan)