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Conference hips::uk_audioo

Title:	You get surface noise in real life too
Notice:	Let's be conformist
Moderator:	GOVT02::BARKER

Created:	Thu Jul 28 1988
Last Modified:	Mon Jun 02 1997
Last Successful Update:	Fri Jun 06 1997
Number of topics:	550
Total number of notes:	3847

299.0. "Help would be appreciated" by CHEFS::IMMSA (adrift on the sea of heartbreak) Thu Aug 01 1991 09:32

    I am writing this here at the suggestion of noters in UK_Music because
    they assured me I would get some good advice.
    
    Here is a non technical explanation of my problem....
    
    I changed my kit from Sony to Technics but kept the Sony turntable.
    
    The physical layout resulted in the lead from the turntable to the amp
    being too short.
    
    I had an extension lead made up with female phonos at one end (towards
    the turntable) and male at the other (to connect with the amp).
    
    The result was a severe hum, even at low volume and this comes out on
    tapes when I tape records.
    
    To try and isolate the problem, I removed the extension and althogh it
    cannot stay like it all the time, I connected the turntable directly to
    the amp and the hum (I thought), went away.
    
    Assuming it to be a problem with the phono connection in the middle, I
    removed the phonos and connected the extension to the lead from the
    turntable by separating the wires out and taping them up with
    insulating tape. It didn't work.
    
    The simple (?) remedy perhaps would be to put an entirely new lead from
    the turntable, long enough to reach the amp but when I looked at the
    connections at the turntable end, they are far to complex for me or my
    electrician son to touch - not that I would really want to unless and
    electronics whizz was involved.
    
    I am getting awfully fed up with this problem. Here I have a pile of
    pretty reasonable kit and I cannot play my records on it.
    
    Any helpful suggestions would be really appreciated.
    
    andy

T.R	Title	User	Personal Name	Date	Lines
299.1		BURYST::edmunds	strange magic	`Thu Aug 01 1991 10:09`	12
	If you're suddenly getting hum with the extension lead and not without it, clearly the lead is at fault. Check the connections in the phono plugs are secure and well-soldered. What is the problem with using just one lead? You say the connections at the turntable end are "too complex", but it should just be a soldered connection (or is that within your definition of "too complex"?). If it -is- just a soldered connection, anyone handy with a soldering iron should be able to help you out (and there's plenty of them in Digital!). Keith
299.2		FORTY2::SHIPMAN		`Thu Aug 01 1991 12:13`	9
	You did use screened (coaxial) cable, didn't you? Signals from a record deck are very tiny and need shielding. If so, did you check the continuity of the extension cable? That is, that the phono centre pin is actually connected to the phono centre pin, and the phono screen to the phono screen? Hum often means a break in the screen connection. It could also mean screen and centre connections are swapped. Nick
299.3		HAMPS::IVES_J	I've got a bad feeling, Mr Tracey!	`Thu Aug 01 1991 13:34`	8
	I know it's a long time since I used an LP player (:-) ) but I seem to remember that most featured an additional earth wire which you attached to a binding post at the back of the amp. I guess all it was was a straight piece of wire that earthed the turntablle back to a common point. Maybe yours does'nt /have/need one, just thought it might have been overlooked. The effects of not connecting it were awful hum levels.
299.4		CHEFS::IMMSA	adrift on the sea of heartbreak	`Thu Aug 01 1991 13:52`	20
	Thanks for the comments so far. Re connections at turntable end - when i took the bottom board off, what I saw was a piece of material about half an inch square with lots of dobs of solder on it and lots of wires coming off it and my first reaction was that I did not want to mess with it (because I don't know what I am doing) and I did not want my son messing with it either because although he is a qualified electrician, he is not an electronics man... so I said no to dabbling. The screened cable suggestion may well be valid. I don't know if it is or not. I tried the earthing - made no difference. I am coming round to thinking that a single piece of the correct cable with no connections in it is going to be the only way to solve the problem. andy
299.5	Just an aside	TASTY::JEFFERY	Make a new plan Stan	`Thu Aug 01 1991 17:09`	4
	When I changed to a REGA from my old Garrard, I was a little dismayed to find that I did't have a flying earth lead, but it seems to work fine. Mark.
299.6	Sorted - at last	CHEFS::IMMSA	adrift on the sea of heartbreak	`Mon Aug 12 1991 14:24`	23
	Well I've sorted out my problems. I had to reconfigure in the end. That extended lead from the deck was acting like an aerial and was nothing else to do but change it all round. In the process, which for many reasons took me all day, I managed to sort out another problem involving tape to tape copying on two separate deks, Technics and Kenwood which did not seem to want to work properly T--->K but works fine K--->T. There's a lot of spaghetti involved with an amp, graphics equalizer, cd player, turntable, tuner and two tape decks isn't there......more complicated by my lack of basic knowledge about things hi-fi. Anyway.... thanks for the help. Subject closed ( I hope ;-) ) andy