Getting a PGA2310 to be silent

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OK I tried the 120R in series with the output and 10K across the input and it didn't change the noise floor. I don't have any suitable capacitors to use on the input, I only have electrolytic.

Perhaps my layout? Or the relay mounted so close to the PGA?
 
That sucks, wish I could help, noise is always a hard one to figure out and solve.
To review, you have grounded the PGA input and hooked it through a headphone amp and it is quiet. So where is the noise coming from? the $1000?
I have this part breadboarded = wire wrap, on two different assemblies, so that I could write/test my code for it. I have already tried PGA2310 and PGA2311, to verify my code. I have to check I might even have a PGA2320, which is the upgrade to the PGA2310. One proto is running off a +/-5V supply, the -5V is generated from a TC7660 = the worst case supply. I will try and test it out to see how quiet it is, in this worst case situation. The other proto I can use an external PS, LM317/LM337 based. Give me a couple of days and I will report back with my findings. May not help you with your situation but it will be some more information for you to use.

Take care
Rick
 
I didn`t folow tis thread from the start... But did you try another power amp with your speakers??
Try an Analog one for a change???

Unfortunately I don't have another one on hand right now!

That sucks, wish I could help, noise is always a hard one to figure out and solve.
To review, you have grounded the PGA input and hooked it through a headphone amp and it is quiet.

Well the headphones are connected directly to the PGA but yeah that is the gist of it!

Give me a couple of days and I will report back with my findings. May not help you with your situation but it will be some more information for you to use.

I would be grateful :)
 
Hi,
I'm using a PGA2310 but having trouble getting it to be silent. There is always some background noise. Not hum or crackle but just noise. Everyone says these chips are silent when implemented correctly but I'm not sure what I'm doing wrong here :confused:

Here is my setup:
USB DAC ---> Passive 50K Pot ---> Hypex Amp ---> Speakers = Silent
USB DAC ---> PGA ---> Headphones = Silent
USB DAC ---> PGA ---> Hypex Amp ---> Speakers = Noisey

The PGA is not in a case and the Hypex Amp does not have signal ground connected to the chassis.

A grounding issue?
Or a impedance issue?

Any input appreciated :)

The problem is probably caused by having too much gain in your circuitry since the pga2310 is not unity gain while a pot will have no gain of its own. You should consider bypassing any preamplifying stages in the amplifier or reduce their gain.
 
Bypassing Preamplifier Stages.

How do you "bypass preamplifying stages" with this:
USB DAC ---> PGA ---> Hypex Amp ---> Speakers = Noisey
?

This is a very old thread BTW...

First of all you would need to identify the preamplifying stages which could be anything from an op amp or a couple of transistors configured to act as an amplifier. Once you have identified the stages you would need to connect their inputs directly to their outputs and cut the tracks or wires in appropriate places to isolate the circuit which you have just bypassed. You would only need to cut the signal tracks or wires the power connections wouldn't matter. Hope that helps.
 
Just a few other things. Make sure you are driving the pga2310 from a low impedence source which is under 600 ohms. Before you try bypassing you can try adding a 10K pot before the pga2310 to reduce the incoming signal. You would need a unity gain buffer (easy to build with an op amp) after the volume control to provide the pga with a low source impedence.
 
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