Tube Testers and Test Equipment


Quality Test Instruments for Technicians or Hobbyists

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Knight deluxe substitution box

Knight deluxe substitution box

Knight deluxe Resistor-Capacitor Substitution box, real nice model – $59.99 free ship USA

Very good condition. This is an excellent choice for any technician.

  • Dual simultaneous operation – you can use the Resistor side and the capacitor side at the same time!
  • 36 resistor substitution options (each at 1W or better) from 15 ohms to 10-Meg
  • 18 capacitor substitution options from 100pf to .22uf
  • Silicon diode substitution
  • 40uf @ 450v electrolytic filter capacitor substitution

I have checked out the entire box, and all values are within common-sense tolerance in my opinion.  I also replaced several of the capacitors with new, and installed a new 40uf @ 450v filter cap.  Cleaned the box inside & out.  Cleaned switches.  Resoldered quite a number of bad solder joints.  Installed 2 nice sets of heavy duty vintage USA test leads (alligator ends).  Size dimensions: (approx) 7.5 x 8.5 x 3 inches.

Knight R-C substitution box

Knight R-C substitution box – $59.99 free ship USA


t2Heathkit T2 Signal Tracer, rebuilt, with RF/AF probe – $79 free ship USA.

A signal tracer is one of the most useful test instruments you can own. The uses are endless. This quality Heathkit T2 has been rebuilt and has rebuilt RF/AF probe (probe is not Heathkit, but is custom-built and very nice).

This model is probably the easiest signal tracer to use, extremely simple, no-frills.

  • new capacitors (including 500v rated, brand-new electrolytics in the power supply)
  • Murata X1Y2 class safety line capacitor
  • new polarized line cord
  • new 6K6 power output tube
  • new output transformer
  • all switches properly cleaned for perfect continuity, including AC power switch
  • I built a probe for you using the Heathkit T2 design schematic, works great
Heathkit T2 - $79 free ship USA

Heathkit T2 – $79 free ship USA

For simplicity and because one of the transformers was replaced, the signal tracer is now hard-wired as a signal tracer, which means that the seldom-used “substitution” features are not available.  Honestly, no one uses those features — such as trying to use the signal tracer as a temporary output transformer, etc.  In 20+ years, I never once felt compelled to use a signal tracer in that manner.  If anything, eliminating those “features” increases reliability (less chance of burning out the internal transformers) and increases simplicity of use.

Photos below show me using this signal tracer to trace signals in a typical All-American-5 tube radio.  (Radio not included, obviously).

tracer signal at one RF coil

tracing RF signal at one coil

tracing signal at another RF coil

tracing RF signal at another coil

tracing AF signal at volume control

tracing AF signal at volume control


massive 45A filament transformer

massive 45A filament transformer

powerful 45-AMP Filament transformer 6v – $39 free ship USA

Here is a whopper for your tube projects! A massive 45-amp filament transformer. Nominal input 115vac, nominal output 6.5vac @ 45A. Want to build a massive tube warmer/heater? Now is your chance. With this transformer, you can power the filaments of almost *50* (yes, fifty…) 6L6 tubes at the same time! Size: approx 4L x 3.25W x 4.5H inches.


Filament transformer 45A - $44 free ship USA

Filament transformer 45A – $39 free ship USA



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