Help needed: DAC output switch between power amp and headamp

[harruharru]

Hi

I am in the process of building a DAC/AMP/HA unit. I am planning to use a TPA Opus dac, TPA Volumite, Amanero USB to I2S, Ventus EZ HA, IVY III (Balanced to SE I/V stage) and Audio Sector LM4870 AMP.

I need to make a switch to be able to quickly change the output between the power AMP and headphone amp. The output of the DAC is balanced. Would a simple DPDT (Double pole, double throw) switch work or do I need a more sofisticated circuit to avoid switching spikes/noise?

 

[sharpi31]

Use a DPDT per channel or QPDT so that you're switching ground connections as well as signal. Then just make sure that your amplifiers are switched off or at least muted for each switch.

You may be able to fix all ground connections and hot switch signal only with amps unmuted, but this would require some trial and error and would make the grounding imperfect when either amp is in use.

I'd switch signal and ground and mute/kill both amps at each transition.

 

[harruharru]

OK,

Maybe the best solution is to use a relay to switch off the amps and then use a delay 3PDT (or QPDT) relay to switch signal and ground between the DAC and the HA.

That is probably the safest way to do it.

 

[harruharru]

Then with some more delay switch on the headphone amp or power amp. I do not know of any simple cuircut to do this. It is however very easy to do with arduino.