Output stage details

[inguz]

Can anyone give a quick sketch of the SB's output stage? I'm thinking of building a dedicated little power amp (with quite low gain - raw SB output is way too loud and the volume steps too big for my normal use), and I'd like to match as well as possible...

[Vinnie R.]

Can anyone give a quick sketch of the SB's output stage? I'm thinking of building a dedicated little power amp (with quite low gain - raw SB output is way too loud and the volume steps too big for my normal use), and I'd like to match as well as possible...

Hi Inguz,

The output stage consists of the analog output from the Burr Brown dac (a voltage output, so I/V conversion is not needed), followed by a JRC opamp, which appears to double the max voltage of the dac.

The SB2 mods that I am now offering completely bypass the opamp output stage, and this reduces the max output voltage to something more "useable" when using the built-in volume control.

Regards,

[Patrick Dixon]

I built some chipamp based amps for Squeezeboxes. I reduced the gain as much as I dared (they need a gain of 10 or more for stability), but you can also use a series resistor to knock it down still further.

Here's a couple of pictures: http://www.at-view.co.uk/pictures.htm