Attenuator advice

[Nounours18200]

I want to build an Attenuator (based on a DACT stepped attenuator 2 ways) to be used as a volume control between a DCX2496 that I plan to use as a 2 way active filter.

The DCX2496 will be inserted between a CD-DRIVE and 2 power amplifiers (one as the main amp, the other one dedicated for the subwoofer).

The main Amp is a Threshold SA-3.9E class A, so i would like to know what is the DACT impedance I should choose as the DACT are available with 10k, 20k, 50k, 100k, 250k and 500kOhm impedance (just have a look at www.dact.com) ?

I am also looking for schematics explaining how to build this attenuator (the DACT are already cabled with resistors), so I should just have to buy some RCA cinch, solder, internal cabling and a box.

I would like to discuss with somebody having already built such attenuator because it is my first try in the DIY world, and somebody with enough patience to help me by mail...

Thanks very much (and I apologize for my English: I am French !)
N

[metalman]

For some info on attenuators, the Goldpoint website is pretty good at explaining the workings and different approaches.

I posted a tutorial of sorts a while back on building a simple series attenuator which you can find here.

Have a read and if you need more help, send me an e-mail through the forum.

Cheers,

Terry

[DIAR]

DACT recommends using 10 kohm attenuator. I use 10 k DACT CT2 and I'm very happy with it but a passive preamp doesn't fit to all setups so a listening test before purchase is recommended. Here's how I build the thing:
http://kotiweb.kotiportti.fi/audiovideo/DIY/preamp1/

[Nounours18200]

I have studied how you have built your preamp : congratulations ! that's beautiful...

My atteuator will be used between a DCX2496 outputs and 2 power amplifiers.

The DCX2496 output impedance is about 160ohmss and the main power amplifier impedance input is about 50.000ohms.

So I suppose that the 10kohm attenuator impedance value recommanded by DACT is the best compromise. We use to say that this impedance should be 10 times bigger than the output impedance and 10 times lower than the input impedance, but the is no solution to this equation...

I have a question about how you attached the DACT onto the aluminium plate ? did you use special screws, or are the screws provided with the DACT ??

The second question is about the cable: I have visited the internet store you mention, but I cannot identify the cable reference you have used.

Thanks very much for your reply,

M.