Post by Steve Deckert on 08/16/21 at 05:45:53
click image to view the larger high res version.
This is a SE84UFO2 being tested for channel balance and to make sure the tube harmonics match between the two channels as well as noise and hum.
I know there are a lot of you waiting in line to get one of these and thought you might enjoy knowing that since the web page was written, we have stopped using both the beeswax caps and the copper foil beeswax caps due to Covid Logistic issues with the manufacture. The Copper foil beeswax were an upgrade worth a couple hundred bucks. We have eliminated the option of two types of caps and are now shipping all amps with the MIFLEX Copper Foil caps which sound as good or better than the copper foil beeswax and will last forever without having to be replaced in 30 years.
So even though the wait is long, the sound of this amp will melt you face off and it will last forever. Output tubes are rated at 10,000 hours each, but if you clip them a lot it can be less.
We have also changed the speaker binding posts, again for logistics reasons and again to a little better model.
The graph is shown at 1 watt of output where most people listen to it. The first (even order) harmonic is the only one audible at this output level.
Here is the same thing but at a higher bin count to accurately show 60 and 120 cycle hum.
Again you have to click on the image to see it full size.
This shows the 60 cycle and 120 cycle hum at -64dB below the 1 watt listening level. In our tests, -54dB is actually the line of inaudibility on 100dB speakers, so -64dB would be if the speakers were inserted into your head. The smaller peaks are the harmonics of the first two peaks.
Steve