[Amps] Dummy load oil

[Dave Haupt]

When I was in the power amp business, we had a mix of loads - Bird, MFJ, Heathkit, etc.  At one point, I felt it necessary to find out just what was "transformer oil"...Bird had said "use only transformer oil", until they switched to recommending silicone based oils somewhere about 1990...the loads had not changed, only the recommended oil had.

I think it was Bird who finally led me to the sources of "transformer oil", at the time the two vendors referenced were Shell and Texaco.  I ended up on the telephone with technical reps from both companies.  They advised that if it was not the silicone-enhanced version, then it was, indeed, "refined mineral oil".  The refinement process was described as nothing more than simply heating the oil to higher than normal operating temperature to drive off the more volatile compounds...this decreased the flash point.

At one point, one of the oil company reps said basically if we used agricultural grade mineral oil, we'd probably be fine, as long as we did not seal the loads - when those volatile compounds are driven out, the seal might burst.

I've used ag grade mineral oil since.  A gallon at my local feed store is $15.00.  The normal application is as a horse laxative.

Dave W8NF