How does the variable output work on a CD player? (1 Viewer)

[RobWil]

I have a CD player with variable output. When I had it connected directly to a power amp I did not know at the time that you're not supposed to use the fixed output for this.
So how does it work when I connect directly to the amp with the variable output? Exactly what am I adjusting with the variable control? The signal strength? How would I connect the CD player if I'm using two bridged amps?

 

[Wayne A. Pflughaupt]

The variable output jacks have a volume attenuator that reduces the voltage of the output signal. There should be either a volume knob on the face of the CD player, or provisions to adjust it from the remote. If you’re using two bridged amps, you connect one output (L or R) to each amp. The amp's manual will tell you how to connect when in bridged mode.

Regards,
Wayne A. Pflughaupt

 

[RobWil]

One of my CD players has a problem with the fixed outputs.
Are there any issues to consider when using the variable output connected to a pre-amp (receiver)??? Where do I set the attenuator on the cd player. I have noticed when I set it to the lowest setting and use strictly the attenuator on the receiver I seem to get no or little sound from the right channel. I have to set it at least half way. I know there is probably an optimum signal level to the pre-amp but does this vary between pre-amps and how do I know what the signal level is at various attenuator postions?
I have found a few articles where the authors seem to discourage the use of the variable output, but this is usually associated with bypassing the pre-amp and connecting directly to an amp. Something about cheaper parts in the variable output circuitry. But what about using the variable output through a preamp?? Any comments?

 

[RobWil]

OK....I subsequently found an article which stated that the fixed output is a fixed 2V output whereas the variable is 0-2V. So I'm assuming I would set the attenuator to maximum, but I guess I'm still introducing some additional circuitry which would not be present using the fixed output?

 

[Reginald Trent]

In layman's terms a variable output is a volume control that allows you to adjust the output. This can be very useful when running straight to a amp without volume controls.

 

[BruceD]

Rob,

I would be very careful here.

Many CD players control the volume (varaible output jacks) by using digital controls to reduce the bit-precision of the digital-to-analog conversion. i.e. they reduce the quality from the 16 bit source signal down towards 12-bit or less. This tends to mask fine detail in the source recording.

The way to control output to two amps is to use a preamp (active or passive with remote control if desired) or use some passive volume attenuators on each cable from the fixed CD player outputs to minimize equipment in the signal path.

 

[RobWil]

This tends to mask fine detail in the source recording.

Doh!!!

I think I damaged the fixed output jacks on the cd player because I've been switching a lot of cables in and out lately. All that pulling and twisting. I get a loud hum now when I connect cables to them which seems to disappear if I give a slight tug sideways on the cables. I'm assuming I've screwed up the grounding on these jacks. Any suggestions?? Do I open it up and look for something obvious?

BTW, my cd player is a Sherwood Newcastle CD-980, dual 20 bit DAC/digital servo. Anybody familiar with how the variable output might work on this particular unit?
Thanks for the replies!

 

[RobWil]

Anybody ever replace their output jacks? I've heard of people upgrading them and such.

 

[BruceD]

Rob,

I'm not saying you should, so please if you do be careful.

This is not a recommendation for you to open the player up, but . . . .

The RCA input jacks can either be directly soldered to a PCB board (with all the other electronics), soldered to a small PCB board for the output connections, or indivudally mounted jacks soldered to the back panel with wires running to the PCB.

You could, unplug the unit from the wall, open the cover and try to investigate if a soldered connection on the jack has been broken (use a plastic probe of some kind) by gently trying to move the jack (or wires to the jack) inside the case with the probe. Movement usually indicates a broken solder joint, as you inidicated below;

I get a loud hum now when I connect cables to them which seems to disappear if I give a slight tug sideways on the cables. I'm assuming I've screwed up the grounding on these jacks.

If it requires resoldering and you're up to the task, maybe it will work. Or take it to be repaired by a local shop.

 

[RobWil]

Thanks Bruce....I've done some electronics repair (seat of my pants) in the past and can use a soldering iron. I'll give it a look. Thanks again.

 

[RobWil]

Found it! Bigger than s@#t....looks like a questionable soldering job to begin with. Sucker came completely loose. Thanks!