How to run amp32 ans pre-amp from same power supply?

[legend95]

Actually these converters do look quite promising. A wider input voltage would be more suitable since when the 3 cell lipo is fully drained the voltage can reach 9v before cutout, although I don't usually let it go that far. The efficiency is slightly less, but I guess thats a compromise.

[V-bro]

I have never had any problems with interference so far, I suppose they are pretty well designed to keep EMI in and use a frequency that isn't yet in a too problematic band. Must say I have most experience with the Traco units, which also have a metal case... They also feature a pin to connect the case to earth if necessary.

[djQUAN]

I have made a similar preamp+amp combination using TDA1526 and AMP32. No problems with pops, noise, instability or whatever. It's also powered by 11.1V li-ion battery pack.

Do you have pics and also how you wired your setup? your wiring could be picking up RF noise from the AMP32 switching signals.

[V-bro]

Getting noise isn't guaranteed, if a potential ground loop doesn't pick up any signals it'll not give problems. However my experience is in a 1:1 shootout the isolated fed preamp set-up is still more silent. And when you isolate it the cabling isn't half as important, it'll always work well, whereas with a potential ground loop situation you have to take extremely good care of that.

[djQUAN]

If using a DC-DC converter means that grounding would be less important makes people take less care in grounding which then results to noise if the right (wrong) circumstances come together.

I'm just saying it is possible to make it noise free even without resorting to an expensive dc-dc supply if it can be taken care of proper wiring which costs nothing.

Unless we know exactly how it is wired, the dc-dc converter could just be a bandaid to his problem rather than solving it completely and properly.

[V-bro]

It wouldn't make it less important, just less complicated and more secure to be performing well. If you run them on the same supply it can work well today, but some field inducing influence can still ruin it tomorrow.

Nowadays with loads of small switchmode DC-DC regulators and converters in MP3 players, laptops it is almost impossible to avoid the negative influences of ground loops. How many times I have heard background noises that were related to choosing functions and operating touch screens on a portable player are innumerous. These noises were gone with the isolated regulator.

You can always first try without it, but I fear you'd have to come to these conclusions just the same sooner or later, or you are just a lucky bastard!

[djQUAN]

You can always first try without it, but I fear you'd have to come to these conclusions just the same sooner or later,

I actually concluded that before but later thought that it would still work with better grounding. Although I do agree an isolated supply does make it best case but that doesn't mean it's impossible without it.

or you are just a lucky bastard!

probably. I should try my luck with the sweepstakes.

[V-bro]

I actually concluded that before but later thought that it would still work with better grounding. Although I do agree an isolated supply does make it best case but that doesn't mean it's impossible without it.


probably. I should try my luck with the sweepstakes.

LOL!!

Well, we are still talking sluggish audio frequencies, sure you can make a lay out that shields most of the parts of the loop that can have influence, but as soon as we are talking asymmetric signal going over cabling (ground/shield as signal reference!) what is there to protect?? You'd have to go through great lengths to provide double shielding at least, where the outer shield will be star grounded to the correct end and to the correct ground/earth point. It's far too complex for most and as I say it's best prevented. If there is a strong airborne signal you're still screwed, I've seen it happen. Recently built the company a taxi with five HD cameras and recorders (Sound Devices Pix http://www.aem.nl/sound-devices-pix-240-220?section=.) and six mics, four mixers all running on 12V and then you start to see the importance....

You can give a dog a latex suit, still won't make it sexy....