Instructables
A lot of hi-fi buffs believe that a volume control made from a resistive ladder gives the ultimate in reproduction. Trouble is they are expensive and hard to build. This project is neither. It can be easily built in a couple of nights, all you need is a drill and a soldering iron. And if you need at kit check out my website which features this and other diy audio designs you might find of interest.

The only compromise made in this design is to use 5db steps rather than the standard 3db. This means that the whole thing can be fitted around high quality 12W rotary switches. 3db steps are, in any case rather small. 5db steps are rather more definite nad when you get used to it more satisfying.
 
Remove these adsRemove these ads by Signing Up

Step 1:

Picture of
The parts you'll need. The resistors specified are 0.1% tolerance types. Although more expensive than the usual1% type the accuracy between channels is a direct function of resistor tolerance. Using the 0.1% types gives a channel balance of 0.01db between channels. About 50 times better than the most expensive audio grade volume pots!

Step 2: STUFF YOU'LL NEED

- What you need,

RESISTORS, 0.1%, 2 OFF EACH VALUE REQUIRED FOR STEREO

R1 = 11k5 R6 = 357R R11 = 47R
R2 = 6k65 R7 = 200R
R3 = 3k65 R8 = 121R
R4 = 2k05 R9 = 68R
R5 = 681R R10 = 33R

SWITCHES

S1A(B) = 1 OFF 4P3W ROTARY SWITCH*
S2A(B) = 2 OFF 1P12W ROTARY SWITCH*

SOCKETS

SK 1-8 High quality phono sockets, gold plated. 4 red, 4 black.

MISCELANEOUS

ABS CASE MEASURING 180mm x 155mm x 40mm
3 OFF 35mm PLASTIC KNOBS

  • Make your life easier by selecting rotary switches with plastic shafts. After all you have to shorten them to fit the knobs.

Hello, First off I have been out of electronics for 20 years after having repaired TV's and Stereos for more than 30 years. I started in the hay day of Tubes. I see your reference to OFC wire and I don't understand why it is desirable, I have seen a reference to it elsewhere but didn't pay much attention. Could you give me an idea on this as I am trying to get back into electronics as a hobby now that I am retired.
jeff-o5 years ago
How does a volume control like this compare to a high quality digital volume control?
jefffolly (author)  jeff-o5 years ago
A digital volume control has a higher number of steps.Whether this is an advantage is debatable. Accuracy and channel balance is about the same. Of course with a passive preamp you dont need and powered electronics.
True... I am just planning out a tube amp that I'd like to eventually build, and would like to keep the signal as clean as possible. Would it be worthwhile to get a rotary switch with a higher number of steps for finer control?
jefffolly (author)  jeff-o5 years ago
Sure a standard stepped vol controls use 24way rotaries. Don't ask me to work out the component values though! Whether you find it worthwhile depends on your temperament I guess. I've come to prefer less steps.
Should be simple enough, right? The question is whether this would be worth doing (cost-wise) compared to a very nice audiophile-quality potentiometer.
jefffolly (author)  jeff-o5 years ago
This is a cosmic decision. Only you can decide!
Indeed. Well, thanks for presenting this great info, it will surely be useful for something I'll build in the future!
Pro

Get More Out of Instructables

Already have an Account?

close

PDF Downloads
As a Pro member, you will gain access to download any Instructable in the PDF format. You also have the ability to customize your PDF download.

Upgrade to Pro today!