Welcome to my DIY audio forum.

Per-Anders Sjöström

Main Menu

QSXM2 - The Swiss Cheese

Started by DFM, February 16, 2007, 10:59:44 AM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.


Hi all,

We have just finalized Stage1 of a dual mono QSXM2. 1st stage includes "simple" SM mounted transistors while stage 2 will use 2 pairs of ultra lownoise types. Doesn't have all the parts for that yet, so that will be done when we got all the parts collected.

The first listening (2.nd day of listening) experiences or impressions is that it has a lot of dynamics and power, however it also has a very agressive upper mid. Have been trying various attempts of changing the load from the default 100ohm (E3/R3), and by lowering the load some of the agression disappears. A little confusion here: the drawings page 1 and 3 says E1/R1 are resistors for MC, but it has to be E3/E3?

I'm using an AudioTechnica AT-OC10 MC, and according to to the manufacturer, the "load resistance is 20/100 ohms while the coil impedance is 12 ohms". I've currently ended up with a load of 33 ohms, but i will continue to try other values.

The rest of the setup is:
Thorens TD 320mkII turntable w/original Thorens arm
Thule PR200 Preamp
Midgard Oberon 6.1 Power amp
Usher CP6311 speakers
Sony QS XB930 CD player
Various Kimber Hero interlinks
Synergistic Alpha Quad speaker cables
The Thule and Oberons connections are balanced, the others are not.

Oh, and the name - the bottom alu plate has been used for DIY projects previously and has quite a number of holes in it...


Congratulations to one of the most nice looking QSXM2 projects! Well done!
/Per-Anders Sjöström, owner of this forum

Homepage with my DIY hifi stuff