Today I gave the Purifi Eval1 a go. Terribly shocked how loud is was.
I have a question about Eval1 J3. I connected Eval1 J3 5,6,7 to respectively SMPS1200 J5 3,5,7. What is the function of this connection?
Others have shown how to additionally connect Eval1 J3 1,3 to SMPS1200 J4 6,10. What is the function of the extra connections?
I dont understand that you would be shocked, I don't find mine particularly loud?
But its allways a good idea to start at a low volume setting when using a new amp for the first time.
The connections can all be found in the documentation.
Here are my understandings of the connections.
The first 3 you mention are VAUX+, GND, and VAUX-
Basically power for the frontend's opamp circiutry.
Make sure you have the SMPS jumpers J6 and J7 set for unregulated VAUX, as the SMPS will otherwise supply to low a voltage. From the picture it seems to be right.
The last two are "Amp enable" and "DC error".
The first turns the amps on when the SMPS's voltages have stabilized, and the last reports back to the SMPS if the power amps are generating DC on the speaker terminals (or are otherwise malfunctioning), after which the SMPS will turn off to protect both the amps and your speakers.
These last two connections are not absolutely necessary, the amp will work without them.