TEKTRONIX 570 Tube Characteristic-curve Tracer
Rare, in excellent shape and one of the last units produced: ser. no. 005580

This Tektronix Model 570 Characteristic-Curve Tracer lived its entire working life in the Southern Alberta Institute of Technology where it couldn't have seen more than a few hundred hours use. It is in perfect, spotless and immaculate condition. Although it didn't need it, has been completely calibrated and meets the original, factory specification with ease. It comes with a complete and original copy of the user's/service manual containing the full calibration procedure and all the schematics. As well, two of each the socket adapters for octal, 7- and 9-pin tubes and a full complement of interconnecting leads are included.

As you can see from the photos, this unit is equipped with a "blue" phosphor CRT (rather than the earlier, green phosphor.) Originally and as a cost cutting move on Tek's part, it was equipped with black vinyl-covered lifting handles rather than the sewn, blue leather-covered handles typical of Tek scopes and curve tracers of an earlier era. By an amazing coincidence I saw a sale on eBay a while back for some of the original Tek, blue leather handles that were brand new! It turned out that the seller had worked for Tek and had contacted the original supplier of the part and had them make up several pairs to the original spec. So, I bought some and this unit has been retrofitted with those.

It's hard to describe how completely perfect this unit is, it has seen so little use that the air filter is as clean as new. Possibly, this is the finest example extant.

To see a large page of pictures of the inside of the unit,click here.

To download a PDF of the of the operator's and service manual click here.

The unit will be properly crated in a braced and 1" Styrofoam lined solid plywood crate for which there will be a an additional $US75.00 charge. Short of an all-out disaster during shipment, we guarantee that the unit will arrive, intact, undamaged, in "plug and play" condition and meeting, as previously stated, the original, factory specification.

To see a page of pictures of the unit as it was being crated, click here.

Over the last 15 years I have owned 8 Tek 570s and of these one was sold to Roger Modjeski of RAM Labs, two went to David Manley of Manley Labs who shipped one to Ei (Electronska Industrija) in what was then Yugoslavia. For lack of a 570 Ei fouled up the anode/screen geometry in the first of the now legendary KT90s and, using one of my '570s I sorted out the problem for David.
Another 570 went to Mr. Yeung, a reviewer for the Hong Kong publication "Audiophile" while yet another went, as I recall, to the folks at VAC in the USA.

Some Specifications and Features of the Tektronix 570 Characteristic-curve Tracer
Vertical Deflection (click for a large page of close ups):
200uA to 50mA per div, 11 steps in a 1,2,5 sequence.
Display of one of: plate, screen or control grid current is switch selectable.

Horizontal Deflection (click for a large page of close ups):
100mV to 50V per div, 9 steps in a 1,2,5 sequence.
Display either: plate or control grid voltage is switch selectable.

Plate Sweep
(click for a large page of close ups):
0 to: 5, 10, 20, 50, 100, 200, 300, 500V full wave AC @ 120Hz. and a max. current of 250mA avg. and 1A peak.

Grid Step Generator (click for a large page of close ups):
The number of steps per family is selectable from 4 to 12 with grid voltage steps in a range from 100mV to 10V per step with 3% accuracy.
The maximum current is 50mA avg. and 100mA peak.
This generator's output may be offset in the positive direction by as many as 8 steps (+80V) thereby allowing the investigation of operation in the "grid current" region as long as the supply's current limitations are respected.

Positive DC Voltage (click for a large page of close ups):
This regulated supply provides five calibrated steps from 0 to: 20, 50, 100, 200, 300VDC @ 3% accuracy.
Continuously variable, uncalibrated, from 10 to 300V.
Maximum current of 50mA avg. and 150mA peak.

Negative DC Voltage (click for a large page of close ups):
This regulated supply provides a continuously variable output through the range of 0 to -100VDC and is used to set bias voltages i.e. to vary the voltage on suppressor grids in pentodes where the G3 connection is brought to a separate pin.

The Type 570 Characteristic-Curve Tracer presents a graphic analysis of vacuum-tube characteristics under a wide range of operating conditions.

Calibrated horizontal and vertical deflection make it possible to measure the characteristics directly or the curves may be compared with preselected tube characteristics that have been reproduced on a mask over the cathode-ray tube.

Front panel switching between two test sockets permits rapid comparisons between two tubes or between two sections of the same tube.

By means of various switch settings for the vertical and horizontal deflections the following displays are possible:

  • Plate current vs. plate voltage
  • Screen current vs. plate voltage
  • Grid current vs. plate voltage

  • Plate current vs. control grid voltage
  • Screen current vs. control grid voltage
  • Grid current vs. control grid voltage

The 570 can configured to provide displays of the characteristics of tubes connected in cascode, active plate load, compound connection such as the triode/tetrode operation of two output tubes or -- with an easily built additional sweep supply in series between the output of the +DC supply and the screen of a beam tetrode or pentode -- the characteristics of a tube with variable "percentages" of ultra-linear operation.

Additionally, the 570 can display the characteristics of solid state devices such as zener diodes, N-channel small-signal depletion-mode JFETS and MOSFETs used in differential stages and high voltage, high power, N-channel, depletion- and enhancement-mode MOSFETS.