Quicksand That Sinking Feeling

[Paul Birkeland]

Ah, yes, I could imagine that the turn on thump would be a bit more troubling if the driver wasn't mounted into any kind of enclosure.

[aleman]

Have completed all I wanted to do to the the quicksand now the volt meter has arrived fitted today fairly straight forward but no template .Works  as it should  will rebuild quickie preamp next year to incorporate these meters as an indicator of batteries running out.Now back to the music.

[Paul Birkeland]

That's pretty cool!  You'll end up having the most analog looking digital amp out there.

[aleman]

Must admit had not given any thought to that aspect of things.The amplifier continues to improve I cannot believe the sound quality for the money superb ,from what I have read the parts to burn in last will be the Russian Teflon bypass caps I have used so the sound may change again slightly over time  must have about  80 hrs on the amplifier so I will see.

[aragorn723]

Hi,

Someone might have asked this already, but what kind of wire did you use?  Also, where did the voltage meter come from?

Dave

[aleman]

Wire used is 0.5mm pure silver as had some spare on a reel from about 10 years  wire with Teflon insulation Teflon used as does not melt so readily when in contact with soldering iron,there is some debate as to which insulation to use but I find this works for me a now middle aged and hands not as steady as once were . The meter was from this seller on ebay sellerbible price was around £3.21p cheap and works well given coming from china delivery was quicker than expected.Hope this helps also  there other sellers on ebay selling these analogue meters if hey should run out of stock.

[badman]

Does the chip mute when shorted on the output?  I saw nothing in the application notes to indicate this as a recommended mute function, in fact, there's a 0-2v mute logic pin included for that purpose, and it's generally poor practice to short output terminals, though being chip based it may simply enter protect mode- I just want to confirm before I drill in my switch hole for the build.

Thanks.

[Paul Birkeland]

No, the shorted output is just to soak up the turn-on transient.  If you left the outputs shorted (and played music through the amp for a long time), the chip may enter protect mode.  With no signal going into the amp, it will not see the short at the output.

[Grainger49]

"You never close your eyes any more when I kiss your lips.... You've got that sinking feeling.... That Quicksand sinking feeling."

Couldn't help it.

[badman]

No, the shorted output is just to soak up the turn-on transient.  If you left the outputs shorted (and played music through the amp for a long time), the chip may enter protect mode.  With no signal going into the amp, it will not see the short at the output.

OK, I guess proof in the pudding, I was just wondering, as switching residual or other fun goodies could be an issue in some class D designs with a shorted output.  I'll throw an extra switch back there in any case.

[Paul Birkeland]

You could also "short" the amp with a pair of 1 Ohm 1W resistors.  The turn on thump will be absorbed well by them, but playing a lot of music into them would open them up.