Help with stepped attenuator

I've seen the post with a link to an online calculator for determining resistor values. I can't use it on both my home PC and work PC for some reason. I want to make a stepped pot for my gain control on some QE line amps. Here are the app notes to base the max and min values on. http://home.earthlink.net/~nwsoundman/id12.html I plan on using a 12 posistion switch so there will need to be some added values to what is on the data sheet. Any help is very appreciated. I would do it myself but have no patients with computer issues. Hate the damn things. These will be used on some CA-137'S but I think these values will work on the CA-137 too.

NWSM

Java Stepped Attenuator Constructor's Page:

http://www.quadesl.com/attenuator.html

Jakob E.

nwsm-

I have the same relationship with those charts... Get an oscillator with a level control, a meter and clip lead a pot into the circuit, dial in the values on the chart and then figure out your in betweens with the pot. Thats how Ive done all the taper switches on my api amps. Seems like more work, but its pretty quick.

dave

Hi,

I can't work out from your post if you mean that you want a switched-step gain control to connect between pins 9 and 10, or if you need an attenuator pad to connect at the input or output?

I presume you mean an switched gain control. The easiest (i.e. non-scientific method :wink: ) would be to connect a 50k pot as a variable series resistor between pins 9 and 10 and then connect a known low-level signal to the input. Then measure the output level of the amp and adjust the pot. So when you see e.g. a 6dB gain in level, remove the 50k pot and measure the resistance value for that level of gain. Do this for all the different gain positions you need and then you'll have the resistance values directly. You may have to make them up with series and parallel values.

Mark

Ha!

Daves quicker than me!

:grin:

Mark

Gyraf,

That is the site I have been trying to get to work. All I get is a grey square and no calculator.

Soundguy,

I thought about that too. Lets me see exactly where I want finer resolution.

Thanks,
NWSM

Thanks eveyone!!!

NWSM,

Simply enable java in your browser, and you should be flying..

Jakob E.