Yeo from DIY Paradise recently added Rudolf Broertjes' SS I/V gain stage to his Monica2. I looked over the original DIY Audio thread and saw it works for the TDA1543 chip as well. Having also recently purchased a DAC-AH, I decided to give this I/V converter a shot.

Here's the original schematic:



Here are the pictures of my modified DAC-AH. Power for the gain stage is provided by a TREAD. The transformer for the DAC-AH conveniently outputs 18V, perfect for the gain stage. The only differences from the schematic are Ri/V is changed to 475ohms rather than 1.5kohms and the output caps are 12uF Sprague vitamin qs instead of a 100uF electroytic. Click on the pictures for the larger high res version.









Since this mod is nothing short of extensive, I also took the opportunity and changed the voltage regulators to 8V isntead of the 6V. I also replaced the power supply electrolytics and exchanged some generic MKT caps to WIMA MKP.

The end result? Some more gain, so I don't have to turn up my amp's volume as much. The bass is very tight now, instead of being boomy and muddy. The midrange is very smooth and highs sparkle just right. The sound is also very dynamic. Overall, this was a great mod.

Nice mod. Obviously an old post but first time I've seen it. Do you still have it?