For a little while I have wanted to experiment with laser cut plywood boxes. There are software tools available to design the box joints at the corners and I wanted to try these. A 1/8” thick plywood “shipping crate” for the v3.0 attenuator provided the perfect excuse. The pictures below show the completed crate.
v3.0 Attenuator “Shipping Crate” closed.
v3.0 “Shipping Crate” open.
The shipping crate measures 22 cm x 8.5 cm x 9 cm (L x W x H) and sports a black plastic draw latch to keep it closed. I’m very happy with the results.
DÆ phono preamp v2.1 Update
I have also continued testing various design iterations of the v2.1 Phono Preamp and have achieved the following excellent results:
RIAA accuracy of +/- 0.05 dB from 20 Hz to 20 kHz;
Noise less than 35 uV with a gain of 40 dB at 1 kHz and 100 Ω source resistance;
Distortion of 0.0025% at 1 kHz and -45 dBV input. The distortion was almost equally as low from 100 Hz (and below) to over 5 kHz where it started to rise. The distortion at 1 kHz was less than 0.009% and 1.7 Vrms output.
I am in the process of designing a new printed circuit board based on the latest tests and will have this ready for listening tests by mid February.
New Complete Preamp
Also in the near future I will redesign the complete preamp enclosure to house the v3.0 attenuators and v2.1 phono preamp. More to come on this…