Tracy Electronics output transformer

[astouffer]

Has anyone heard of output transformers made by a company called Tracy Electronics? I have a pair of 8k PP transformers (model TS-142A) and the quality looks pretty good. Can't find any references to them.

 

[Vintage Fart]

Only couple of pics available on web...

 

[Palustris]

That looks like a Triad S142-A. I would guess that the Tracy is an OEM product by Triad.

BTW: I use the Triad S142-A transformers on my push pull 5516 amplifier and they are excellent.

 

[directdriver]

Palustris is right. Tracy and Triad look like the same thing.
Here's a circuit that employs such transformer.

 

[astouffer]

Mystery solved! They seem physically large for only being rated at 15 watts.

 

[Palustris]

The BW specs. are impressive: 7Hz to 50kHz, but they are only rated for 50mA current per tube. I run my 5516 at 60mA and they make full power at 20Hz.

The chassis is made for Dynaco ST70 outputs so I had to mount the Triads on standoffs so the wires would not be crushed where they go through the chassis.

 

[6A3sUMMER]

astouffer,

Wow! . . . What a nice find.

Those are 50% UL taps.
That is half way from Pentode or Beam Power Mode (0%); to Triode Mode (100%).

You might try one of my favorites, very well matched JJ 7591S
I drive right over to eurotubes.com, they are very completely re-tested, and very well matched.

Whatever type of output tubes you use:
Be sure to exactly match the quiescent currents (the output transformer will love you for that).
Either Adjustable Fixed Bias;
Or individual Cathode Self Bias resistors and individual bypass caps, does the job if the tubes are very well matched.

Have fun designing, building, and listening!