Substitution and Decade boxes

The parts in the old sub boxes were typically either 10% or 20%, depending who made the box, and the era.
Typically 1/2 watt resistors unless stated on the box too.
 I have some that used 1/2, 1, & 2W resistors.
The capacitors were often ceramic inside them, and some tubulars, and the 'lytics could be about anything they chose to put in them. Voltage wise, typically 400V and up, and +-100% on the cap values too.
 Just depended on what the mfg. decided to use.
 Some used rotary switches, and some used slide switches. The really cheap ones just used pin jacks.

Decade boxes are another term that is used instead of substitution box.
However Decade boxes are usually Lab quality, and sometimes used with bridge measurements.

Of course you have to realize that the problem with thumb-wheel switches and surface mounted cap, resistors and inductors is limited voltage, Accidently apply 15 volts or any high voltage, well by now you know, POOF

Still ..... not a bad idea when you already have the parts on hand. This kind of project is one of the justifications I use for not throwing anything out.

For a simple, inexpensive resistor-capacitor substitution box, see Marcus & Levy, Elements of Radio Servicing (1947 ed.), pages 455-57. The paragraph beginning "Any number of. . ." is especially relevant. My guess is that this little home brew item performs just as effectively as the complicated Kripton ones linked above, which are probably intended for laboratory research use, not hobby antique radio repair.

Interesting post to be sure. I just picked of an old combination Micronta CR substitution box, I will have to replace most of the resistors and caps, as tolerances are out.

His approach is interesting, never thought of surface mounted parts. The only thing I can think of that may be a problem would be if the switches would add error since they may not be gold plated.

A bit different take on sub boxes for the home-brew crowd. I've not tried these myself but plan to once I have some spare time. [You must be registered and logged in to see this link.]

They do have one resistor box that uses slide switches, and its 1% 1 watt resistors sold on Amazon.com
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The others with rotary switches are 5% 1/2 watt I believe.

They also have a transistor and diode tester.
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Hi Cliff,

Those prices at Elenco for these aren't too bad.

Up to now, when playing with circuits, I've been using one of the 4 Radio Shack so-many projects in one kits I have in my shack. Just run a couple of jumper wires to the spring clips and I'm usually good to go.

Having a couple of these ready made boxes would be nice though. I might even have enough parts around to make my own too. What's the tolerances on the resistors and caps in these boxes Cliff, do you know right off hand?

Substitution boxes are not to easy to find, but find I did.
Elenco has both cap and resistor boxes assembled and in kit form.

they are hard to find but they have them, radio kits, test equipment, capacitor and resistor kits too.

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Amazon dot com