FOR SALE

B&K 500

B&K 500 Tube Tester, rebuilt and calibrated – $250 + Ship. Includes our remastered reprint of the manual and latest version of tube setup chart
B&K 500 dynamic mutual conductance tube tester.  Cosmetically, this unit is original and reasonably nice.  Electrically rebuilt — a lot of shop time went into the rebuild and calibration.

• The vast majority of resistors were replaced with new
• new bias and signal controls
• new bridge balance resistors, and bridge balance calibration performed (meter perfect balance at zero)
• new 6AX5GT rectifier tube
• sensitivity pot cleaned, and every socket pin (for all 28 sockets) has been cleaned and shines like new
• UPGRADE: grid leakage circuit upgraded to adjustable sensitivity, and currently set to detect leakage greater than 20 meg.  I chose 20 meg sensitivity since it is the default for later B&K models.  Sensitivity can now be adjusted as high as 100 meg.  For the B&K 500, the manual instructs that a “0″ meter reading indicates “no leakage”, and that “[i]f the meter shows any reading other than zero, the technician immediately knows that the tube his this defect [grid leakage] and a replacement is indicated.” (Source: B&K 500 instruction manual, page 11.)   Therefore, the machine is calibrated to read upscale for leakage in excess of 20 megohms.
• B&K 500 has a meter scale that will read actual micromhos (Gm) score
• Photos below show three different calibration tubes testing accurately using the TRUE Gm scale (NOT the Good-Bad scale, so you must interpret the photos correctly).  New 6L6 testing at 5500 micromhos (6000 reference new), new 6V6GT testing at 4100 micrmohos (4100 reference new), and new 12AX7 testing at 3400 micromhos (both triodes tested simultaneously on this model, with 3200 reference new).

BK 500 testing 6V6 (Gm scale)

BK 500 testing 6L6 (Gm scale)

BK 500 testing 12AX7 (Gm scale)



The B&K 500 features:

• 28 built-in sockets quickly test many common tubes, such as 6L6, 6CA7 – EL34, 6V6, 12AX7, 12AT7, 12AY7, 12AU7, 12BH7, 12BZ7, 6AN8, 6U8, 5U4, 6AU6, 50C5, 6AQ5, 6SN7, 6SL7, 5Y3, 6SJ7, 6AV5, etc.
• optional B&K socket panel (sold separately) greatly expands test capability for testing other tubes, such as compactrons, magnovals, and many others.
• Dynamic mutual conductance test circuit
• 2 quality metal tube pin straighteners built-in (one for 7-pin-min, and one for 9-pin-min)

FOR SALE: Complete set of 3 vintage USA Pomona socket savers. $55 + $3.75 S/H (USA/CAN). Email for foreign shipping quote.

SS-7, SS-8, SS-9 Pomona socket savers

Excellent condition, tight grip, all pins (male and female ends) meticulously cleaned and shined like-new for perfect continuity. Selling as a set only. One each:

• SS-7 = 7-pin-miniature
• SS-8 = Octal
• SS-9 = 9-pin-miniature

B&K 707 Mutual Conductance Tube Tester. $379 + S/H. Recapped and calibrated. Photo shows testing 6L6 calibration tube.

Improvements of note are: * 8 * socket savers installed (approx $80 of value in socket savers right there), several new sockets installed to replace worn-out original sockets, the pins in all 45 sockets have been individually cleaned for excellent continuity, solid-state #83 upgrade ($10 value), new 6BN8 internal tube ($15 value), ALC bulbs soldered into the circuit to avoid ALC continuity issues, new copy of manual and modern tube setup chart ($14 value), all control pots treated with deoxit, and new quality rubber feet on the bottom AND backside. Cabinet is very good condition, front panel is reasonably nice.

Coletronics B-16 socket adapter

COLETRONICS TUBE TESTER SOCKET ADAPTER Model B-16 – $65 + S/H.  Super-addition for Eico 625, Knight 600, Heathkit TC-1 or TC-2, Triplett 3413, and many other models!

Excellent condition, all socket pins cleaned and shine like new. This Coletronics socket adapter expands the capability of your tube tester by adding test sockets for Compactron, Novar, Nuvistor, Magnoval, and 10-pin. Works with most tube testers that use a standard RTMA “1 to 1″ pinout wiring scheme and have a 9-pin-miniature socket, such as most models by Hickok, Eico, Precision, Superior, NRI Professional, Conar, Heathkit, Triplett, Knight and probably others that I have not mentioned. Basic iInstruction sheet included, but not tube setup data — setup data should be found with your tester or sometimes can be freely download.

FYI – this is a clone of the Precision-branded socket adapters (such as A-15, G-140, and etc) and EICO-branded socket adapters, so this unit is super-useful when used with Precision and Eico testers. For example, Eico model 625 has downloadable setup charts with tube setup data ranging from the early 01-A style tubes up through modern compactrons such as 6GE5, when used with this socket adapter.  And since Heathkit TC-1 and TC-2, Triplett 3413, and Knight 600 are practically identical to Eico 625, those models can also readily use this Coletronics adapter. Other testers, such as Hickok, may require the user to create his own test data because setup data may not be as easy to find.

OHMITE USA-made Little-Devils Resistor Storage Tray with assortment of resistors – $25 + Flat-Rate Priority Mail (approx $11 USA).

This is a classic Ohmite Little-Devils resistor storage tray, traditional 5-drawer configuration. Good condition. An assortment of resistors is present and will remain included; these resistors are vintage carbon-comp type, many of them 2-watts. This is a BARGAIN for your money.



Technipower 12V Regulated Power Supply

Technipower regulated 12V-3A DC power supply.
Technipower is the BEST of the best. Made in USA, true military & high industrial grade, “repeatable and precise”. Built like a tank. Looks like a transformer, but it is a complete regulated 12 VDC power supply. Sealed construction except for a single voltage adjustment pot accessible on the underneath. Rated at 0-3A output. Input is 105-125 VAC, 50Hz-400Hz. I can tell you that I ran it up on a variac, and it had strong stable output even with much lower AC input voltages. Rock solid and extremely low ripple (less than 0.2 mV measured with Fluke 179). Dimensions 7-inch tall, 5-inch wide, 4.25-inch deep. Date code 22nd week of 1983.

Original price for this power supply would have been insanely expensive. Offer?

Precision 10-15, large countertop model

Precision model 10-15 large countertop tube tester – $250 + S/H, nice original cosmetics, has not been cleaned, not rebuilt, not serviced or calibrated. Exactly as-found.

If you want to impress your friends or walk-in customers at your repair shop, and show them that you mean business, here is a tube tester that will make quite an impression. The Precision Apparatus model 10-15 is a countertop version of model 10-12, and it is operated standing up, and it makes for a quite visual spectacle. It’s large and imposing size measures approx 26-inches tall, 18-inches wide, 11-inches deep. The meter is huge, and could easily be read across the room. The meter is 11.5 inches diameter, with 9-inch window of visibility. The photo to your left shows the 10-15 for sale, and compares the size in relation to a model 10-12 to its right.

Model 10-15 also has an incandescent light mounted on the top of the unit, shining downward upon the meter and controls. Electrically, models 10-12 and 10-15 are identical, and share the same manual and schematic. This sale is for model 10-15 only in the left side of the photo. Buyer will need to rebuild and calibrate. I will thoroughly check the meter and transformer, but otherwise unserviced. Rebuilding, service and calibration can be arranged at additional cost for serious buyer.