Quadraphonic issue

[Peter34]

I own a Bang & Olufsen 6000 quadraphonic turntable with MMC 6000 cartridge, both of these items were designed to work with CD4 records.

I have two quadraphonic receivers, one Marantz 4220 and a Sansui QR1500.

When I play records on both these via the B&O using either SQ or QS records everything is fine.

Recently I purchased a CD4 decoder, a JVC 4DD-5 which was brand new old stock, this came with all the low capaticance leads needed for connection.

I have to connect the 4 channel output of the decoder to the 4 channel aux input of the receiver. when playing a CD4 record however, I get severe distortion despite adjusting the settings of the decoder.

It appears that the cartridge is overloading the input on the receiver, does anyone have am possible solution to my problem.

[Rare Bird]

Have you tried the 4DD-5's 30Khz level adjuster?

[PaulStewart]

Hi Peter,

This takes me back to the late seventies when I was technical customer liaison officer at JVC UK.... First make sure the cartridge is tracking correctly as a poorly set up arm/cart may sound Ok on 2 Channel or SQ/QS but it has to be perfect for CD-4 and both angle and weight are critical. If all that is OK look on the back of the 4DD-5 and you will find left and right CD-4 trim pots. Adjust these to the minimum position, then slowly increase the level 'till you have balanced quad sound without distortion. If you have an audible signal that is distorted with the pots at minimum are you sure the cartridge is tracking the 30KHz signal correctly? I do still have a JVC CD-4 test disc but as these are now as scarce as hen's teeth I wouldn't like to lend it out, if you ever come down to London i'll happily take a look at it for you.

[Rare Bird]

Paul
You don't have a 4VR 1006 Quad Reciever hanging about do you? :eyebrows: