issue with Sansui au alpha 777dg (au x911dg)

[newbie4ever]

hi! need a little help...

I have the Alpha 777DG (AU X911DG) and i only recently "discovered" the magic of "digital direct". Absolutely love it! i. I'm having a bit of an issue though. I noticed that when on digital direct, i get a bit of imbalance between left and right channels. No drop outs, but the right channel is noticeably quieter than the left. Any idea on what may be causing this? No issues when the knob is set to "source" or "off", although it sounds inferior to "digital direct" (even with the slight imbalance).

thanks in advance!

 

[Hyperion]

I haven't studied the schematic but as I understand it engaging Digital Direct removes some of the circuitry in the signal path, thus simplifying the signal path, which is supposed to make the output cleaner and clearer.

I would think the first place to check would be the digital direct switch, for oxidised contacts, maybe loose connectors, and any signs that someone has been 'in there' perhaps changing components or making 'modifications'. Oxidised contacts should be cleaned with a proper switch cleaner like DeoxIT.

Just been looking at the AU-X911dg schematic.
Does it show the imbalance on any input? and which input are you using?

It could be some issue with the volume control itself - VR2a,b - again oxidised contacts a possible cause.

 

[Robisme]

My AU-X711 does that, but if I wiggle the source direct knob it clears up. Needs a cleaning. Try wiggling the knob and see if it changes.

Rob

 

[newbie4ever]

I haven't studied the schematic but as I understand it engaging Digital Direct removes some of the circuitry in the signal path, thus simplifying the signal path, which is supposed to make the output cleaner and clearer.

I would think the first place to check would be the digital direct switch, for oxidised contacts, maybe loose connectors, and any signs that someone has been 'in there' perhaps changing components or making 'modifications'. Oxidised contacts should be cleaned with a proper switch cleaner like DeoxIT.

Just been looking at the AU-X911dg schematic.
Does it show the imbalance on any input? and which input are you using?

It could be some issue with the volume control itself - VR2a,b - again oxidised contacts a possible cause.

Thanks for the prompt reply!

The imbalance is present when I use Digital Input 1 (Digital Coaxial). No issues when I use Phono. Haven't tried other inputs yet aside from the two. Yeah, I'll probably have to attempt to give the switch a good cleaning. Kind of dreading it though, since I'm not very technically inclined.

My AU-X711 does that, but if I wiggle the source direct knob it clears up. Needs a cleaning. Try wiggling the knob and see if it changes.

Rob

Good to know I'm not the only one. I'll try doing that as well... Any pointers you can share as to how to go about actually cleaning the knob? Would removing the front (bottom) panel be enough or would I have to disassemble/remove the switch entirely?

 

[JOMARK911]

Apart from the source direct switch, you'll have to clean the two rotating bezels on the back where the dams switch is to get clear contact on that pcb where the bezels rotate and select each input.

 

[newbie4ever]

Apart from the source direct switch, you'll have to clean the two rotating bezels on the back where the dams switch is to get clear contact on that pcb where the bezels rotate and select each input.

Ok got it! by the way, read in another thread that one guy had to use a syringe + DeOxit (liquid form, i suppose) to get in there and effectively clean the switches. Would I need to do the same? As I don't normally do these things, I would have to purchase/prepare the things I would need beforehand.

 

[Hyperion]

You'll have to check how accessible the controls and switches are, and weigh up whether an 'aerosol with a straw' or a 'dropper bottle', or 'syringe' will get it where you want it.

Make sure you follow up any DeoxIT D5 or D100 treatment of pots with F100 or Faderlube, you don't need to do this part for the switches.

Use DeoxIT sparingly, after applying try to leave it overnight, then gently work the controls a few times.

 

[LBPete]

Please post the serial number for the database. Click on the link in my signature block.

- Pete

 

[bikingbuddha]

hi! need a little help...

I have the Alpha 777DG (AU X911DG) and i only recently "discovered" the magic of "digital direct". Absolutely love it! i. I'm having a bit of an issue though. I noticed that when on digital direct, i get a bit of imbalance between left and right channels. No drop outs, but the right channel is noticeably quieter than the left. Any idea on what may be causing this? No issues when the knob is set to "source" or "off", although it sounds inferior to "digital direct" (even with the slight imbalance).

thanks in advance!

What really happens in digital direct is still a kind of mystery to me.

 

[Hyperion]

What really happens in digital direct is still a kind of mystery to me.

Read post #2 para 1

(I have now studied the schematic and what I said in post #2 is what happens. You have the added complexity of the internal D/A converter involved in the switching, but in other respects it is the same as an amplifier without one).