AUDIOCLINIC (Q and A) (Feb. 1977)

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Patch Panel

Q. My stereo system sits inside a cabinet for protection against dust and other disturbances. However, when making connection changes in the rear of the components, it is difficult to remove the units and hold them while making those connections. I once read about a control board or control panel, that can be easily constructed, enabling one to make the various connections and hook-ups quickly. I cannot find the article, but, perhaps, you can shed some light on this subject.

-John R. Garne, West Franklin, N.H.

A. You can make up a "patch panel" which will enable you to make all the necessary connections to your equipment without having to remove it from the cabinet. There are commercial devices which do at least some of this, and if your needs aren't too complex, they might solve your problems with a minimum of effort.

The unit is a metal panel mounted to the front of an equipment cabinet.

It contains rows of quarter-inch phono jacks, which are more durable than the little phono jacks used on the rear of some high fidelity equipment.

Their use permits you to connect and disconnect equipment without worrying about the connectors becoming intermittent and loose.

The exact number of jacks will depend on your present and future needs, and each input and output is connected to its own jack. Interconnections between the pieces of equipment are made through cables with phono plugs at each end. These cables should be made of shielded wire with the shield wired to the ground, and the "hot" or center conductor wired to the "tip" side of the plug. The shields from the various cables are connected at the end which faces the input only, which means that the shield is used as a means to prevent hum from stray fields, rather than as a means of signal return.

Because all the jacks are mounted on a common metal panel, it is sometimes possible to have ground loops which could give rise to hum, although this usually doesn't happen.

However, if it does, it is often cured by having one ground brought from the offending equipment to the panel. Be sure to label each jack on the panel with a label suitable for quick identification. Any logical system will suffice.

Wake Up to Records

Q. Is there harm in leaving either a belt-driven or a direct-drive turntable in the play position, with stylus on the record but no power applied, for several hours at a time? This is an attempt to wake up to the sound of a record rather than FM. 1 realize that this practice would flatten idler pucks on models with such a drive system, but I haven't encountered any warnings with the other drive types.

-Gary Sunada, Honolulu, Hawaii.

A. I see no problem in terms of damaging either your turntable or stylus by using the setup you just described. The only reservation I have in mind is in terms of the dust which will collect on the surface of the record, so be sure to close the dust cover of your turntable once the stylus has been placed on the record and the timer set. The discs should also be cleaned before they are put away which may be inconvenient when you are preparing to go to work.

Back Cueing Wear

Q. For precise cueing on record cuts when I am taping them, I have been backtracking my phono cartridge by rotating the turntable backwards. Can this cause damage to the stylus?

-Larry M. Bauer, Dayton, O.

A. I do not believe that back cueing your turntable will cause any damage to the stylus, but it may cause excessive record wear if any cut is cued very often in this way.

Turntables of the belt-driven or direct-drive variety can be back cued very nicely. However, turntables which employ an intermediate idler assembly will be difficult to cue when the idler is engaged. Furthermore, this could ultimately damage these idler pucks.

If you have a problem or question on audio, write to Mr. Joseph Giovanelli, at AUDIO, 401 North Broad Street, Philadelphia, Pa. 19108. All letters are answered. Please enclose a stamped, self-addressed envelope.

(Source: Audio magazine, Feb. 1977, JOSEPH GIOVANELLI)

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