S.E.X buzzing

[mcandmar]

Thanks for posting your findings and the schematic.  Its good to know i'm not the only one who had this issue with noise and solved it this way. I don't think people believed me on how bad it was.

I'm going to experiment with your version as you ended up with the voltages better centered than mine, and probably quieter because of it.  I suspect having the resistor on each polarity is why.

Enjoy!

Mark

 

[mauroj]

I hooked up the amplifier to a distortion meter today and came up with some great results. My SEX measured 6% THD at 1W and 2W RMS. The signal to noise measured between 89 and 90db. It did even better than I thought it would, thanks to my power supply modification performed by Donovan Stenger of Can-Tech Microsystems here in Brooks, Alberta. He enjoyed working on it so much that he is thinking about building tube amplifiers in his spare time.

 

[Lar]

Curious what the air quality is like theses days in Brooks? 

 

[mauroj]

Better than some, worse than some others. Luckily, where I live in town, is out of the normal wind path from that place you are alluding to. Have you been here before, Larry?

 

[Lar]

Back in the late 80`s i bought a new motorcycle there, lived in Cowtown for a stretch, but thats what I remember about Brooks, the smell. 

 

[mauroj]

Most days, there is no smell but once in a while, because of the packing plant and the feedlots attached, it stinks pretty bad. It's not a bad place to live, but certainly there are few people here that share my love of diy tube audio.

 

[mauroj]

Just reposting the schematic and pictures.

 

[mauroj]

Now pictures