[dip16amp]

Here's a way to have as many steps and as fine a resolution on a step attenuator for less than $10. The rotary switch is a seven position two pole switch that has stops at the minimum and maximum positions. It is wired to a 16 pin DIP socket which has gold contacts and gold pins. A second socket that plugs into it is used to hold eight resistors that are used in series to set the range and resolution of the attenuator.

This plugin resistor pack can be swapped in at any time to change the value (10k, 50k, 100k), range (0-70dB, 30-51dB, 31-37dB), and resolution (10dB, 3dB, 1dB steps) by having other resistor pack sockets with what ever attenuation values set. One socket for each channel is required and they can be matched as close as possible. Different sets of resistors packs can be made for connections to other sources that have higher or lower levels. No need to get stuck with switch positions that are never used and can't be changed easily.

This is also good to set the maximum limit on how loud someone can turn up the volume before a different resistor socket must be plugged in. Once you know what attenuation range is normally used, the steps can be set to use the rotary switch almost all of the time. Swapping sockets can be made real easy by mounting the sockets for the rotary switch on the front panel or behind an access cover to allow the resistor socket to be plugged in or changed at any time.

16 pin DIP socket $.71 each, 10 for $6.40 from mouser 575-113316

rotary switch (make before break) $3.17 each from mouser 10WR027

resistors RN55D-F $.16 each or RN55C-F $.18 each

 

[Edwood]

LOL, is there anything you can't make with DIP16 sockets?

So you have to swap out the resistor "plug in" every time you want to change levels?

So you only have 7 levels to choose from at a time?

Kind of a hassle, but I guess if all of yout music has replay gain at the same level, and you use the same headphones, it's a nice uber cheap solution.

-Ed

 

[drewd]

101 Uses for a DIP Socket!

I never cease to be amazed!

 

[Syzygies]

So one needs one of these per channel...

I love how you play 7 against 8 in the design, that's slick serendipity.

One could generalize the "personality card" concept, use a gold contact tiny computer card to hold the 48 surface mount resistors for a 12 step stereo ladder attenuator. Buy cheap resistors for the first few cards while learning what dB steps one really wants, then spring for the $0.85 good stuff...

 

[Earwax]

Very slick idea!

So, at max attenuation the signal is passing through 7 resistors (if I understand this correctly) Are 7 resistors in series likely to still be better sounding than a panasonic or alps pot? At least the channels will be better matched.

I see mouser also has a 2 pole 12 position switch. DIP24 attenuator anyone?

 

[dip16amp]

The 12 position switch will work but the main drawback is that it doesn't have any mechanical stops at the minimum and maximum positions. External stops would be needed to keep from turning between full quiet to full blast unless the range of attenuator is small enough to not be a problem.
Keeping the number of resistors down is also important so this is better than the 23 position series attenuators. Since most of the steps of a 23 position one is never used, it is best to have only the positions used and have it changable.