Friday, October 29, 2010

New power supply for the Quad 405 1 and 2

A new double power supply for the Quad 405 1 or 2 and DIY projects.
We developed a new supply with an integrated DC protection for your speakers. It is based on the circuit in the Quad 306, 606, 707, 909 and 520f range. It uses the so called virtual earth technique.

Some advantages:

Integrated DC protection for your loudspeakers.
Only one fuse in the AC circuit, integrated in the power supply.
You can remove the clamp circuit from the 405 modules or the chassis.
Also you can remove and short circuit those non linear fuses in the DC circuits of the 405 modules. These two measures are strongly advised!
Symetrical clipping due to PSU voltage offset, like in the 606 range.
No transformer needed with a central tap, simple cable layout.

Price information will follow soon. The production unit may differ in detailing, also there will be a choice in capacitors, but the minium will be 10.000uF.

Joost Plugge

Update 18 december: The Dual Mono power supply with 4x15000µF BHC Aerovox and Loudspeaker-protection is available in the Webshop now. Click here.

Monday, October 25, 2010

One step further: Piotr's 405-project

Piotr, from Poland, revised his 405 with the Dada-kit ... and some other components:

He wrote:


-Dada Electronics basic revision kit on OPA604,
-mains voltage selector removed,
-double power supply with common zero (chasis),
-8x10000uf/63V BHC power supply capacitors,
-WBT speaker terminals,
-Cardas Rhodium RCA sockets,
-Furutech pure copper ICE socket,
-3N silver, gold plated wire for most power supply connections (plait),
-new rear panel, moved backwards to fit in with lots of capacitors,
-Cardas 3%Ag solder used,
-all PCB pins shortened and resoldered,
-Ultralink Challenger 2 signal cable (6N OFC),
-C1 caps removed (short),
-abandoned PCB fuses .
-1,2V input sensitivity

General philosophies:

-Minimum connections - zero connections except primary fuse, PS capacities, and ground to case screws.

-Power supply wiring made of silver wire is constant, uncut, unsoldered, no connectors, handmade plait - from "source" to "target" (rectifiers to PCBs passing capacitors, case to speaker's zeros, all zeros passing one crossing)

I didn't meet any serious problems. Almost didn't test the unit before run. Started from the first time. Results are stunning. Believe me. No partial distortions. Perfect, stereophonic, focused sound. Pleasant and reach at the same time. Pure black background with natural, creamy recording's noise. Much more agressive, faster, precise but still natural, rich, transparent sound to live with. Bass not foggy. Similar bass shape and depth like before but this is not coffee with milk anymore. This is more like.. dark brown, thick espresso that you can feel, but you cannot touch.