Attenuator simulation

[andrew]

Hello, I have a resistor based Weber attenuator and I like it on the lowest attenuation setting. It knocks down the highs, smoothes things out making things easier on my worn out ears. Is there a way to hardwire on the amp the same attenuation effect as the Weber? Also there is an OT secondary impedance selector on the unit. Thanks for any help. https://taweber.powweb.com/weber/lpld.htm

[ampdoc1]

I'd think the only problem might be the space that the dual voice coil takes. But with careful layout there is no reason wouldn't work fine.

a'doc1

[d95err]

You can put a fixed L-Pad into the amp. Here's a good L-Pad calculator:
http://www.bcae1.com/lpad.htm

There are also various attenuator schematics floating around the web (I think I have seen one for that resistive Weber attenuator somewhere). Check the Trainwreck Files section for the Airbrake.

[Super_Reverb]

Hello, I have a resistor based Weber attenuator and I like it on the lowest attenuation setting. It knocks down the highs, smoothes things out making things easier on my worn out ears. Is there a way to hardwire on the amp the same attenuation effect as the Weber?

If the unit you are copying is purely resistive, you can use a series and parallel resistor network to attenuate power to speaker.

Let's consider an example:

a) 8 Ohm speaker with 8 Ohm dummy resistor in parallel with speaker b) 4 Ohm dummy resistor in series with parallel speaker/resistor combination above

This arrangement delivers 25% (0.25) of input power to speaker and has an impedance of approximately 8 Ohms. So in dB, this is:

dB(power) = 10*log(Pout/Pin) = 10*log(0.25) = -6dB

So, this means the gain of the attenuator is -6dB or the unit decreases power to speaker by 6dB.

Rule of thumb: A power attenuation of 3dB is a decrease in power by 1/2. Since the above circuit has two 50% attenuation stages, the total attenuation is 6dB.

Make the parallel resistor smaller and series resistor to increase attenuation. Could also add resistor in series with speaker and then parallel the series combination and finally place a resistor in series with above combination for even greater attenuation.

The three factors you're designing to are: effective impedance of circuit, attenuation, and power handling capability of network.

cheers,

rob

[Super_Reverb]

Hello, I have a resistor based Weber attenuator and I like it on the lowest attenuation setting. It knocks down the highs, smoothes things out making things easier on my worn out ears. Is there a way to hardwire on the amp the same attenuation effect as the Weber?

If the unit you are copying is purely resistive, you can use a series and parallel resistor network to attenuate power to speaker.

Let's consider an example:

a) 8 Ohm speaker with 8 Ohm dummy resistor in parallel with speaker b) 4 Ohm dummy resistor in series with parallel speaker/resistor combination above

This arrangement delivers 25% (0.25) of input power to speaker and has an impedance of approximately 8 Ohms. So in dB, this is:

dB(power) = 10*log(Pout/Pin) = 10*log(0.25) = -6dB

So, this means the gain of the attenuator is -6dB or the unit decreases power to speaker by 6dB.

Rule of thumb: A power attenuation of 3dB is a decrease in power by 1/2. Since the above circuit has two 50% attenuation stages, the total attenuation is 6dB.

Make the parallel resistor smaller and series resistor to increase attenuation. Could also add resistor in series with speaker and then parallel the series combination and finally place a resistor in series with above combination for even greater attenuation.

The three factors you're designing to are: effective impedance of circuit, attenuation, and power handling capability of network.

cheers,

rob