S.E.X buzzing

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Offline J. Mauro

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Reply #75 on: February 15, 2014, 08:06:56 AM
This is a picture of the handwritten schematic. I will post a pic of the actual section when I can tear myself away from listen. Maybe later today.

Jeremy Mauro

So long, and thanks for all the fish.

Offline J. Mauro

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Reply #76 on: February 17, 2014, 05:03:15 AM
These are the pictures of the modified power supply.

Jeremy Mauro

So long, and thanks for all the fish.

Offline J. Mauro

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Reply #77 on: February 17, 2014, 05:04:18 AM
And another shot of the whole thing.

Jeremy Mauro

So long, and thanks for all the fish.

Offline Paul Joppa

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Reply #78 on: February 17, 2014, 11:22:25 AM
Excellent - really clever approach! It keeps the filament power grounded at AC and centered through the big 4700uF caps.

Paul Joppa

Offline J. Mauro

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Reply #79 on: February 17, 2014, 11:34:32 AM
Yes, I was surprised with the remarkable difference in noise from before and after this change. Like night and day. Needless to say, I was also very pleased with the result.

Jeremy Mauro

So long, and thanks for all the fish.

Offline mcandmar

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Reply #80 on: February 17, 2014, 12:09:34 PM
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

M.McCandless

Offline J. Mauro

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Reply #81 on: February 24, 2014, 01:38:50 PM
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.

Jeremy Mauro

So long, and thanks for all the fish.

Offline Lar

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Reply #82 on: February 24, 2014, 04:01:50 PM
Curious what the air quality is like theses days in Brooks?  ;)

Larry V

Offline J. Mauro

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Reply #83 on: February 24, 2014, 04:29:06 PM
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?

Jeremy Mauro

So long, and thanks for all the fish.

Offline Lar

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Reply #84 on: February 24, 2014, 04:57:59 PM
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.  :o

Larry V

Offline J. Mauro

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Reply #85 on: February 25, 2014, 02:55:14 AM
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.

Jeremy Mauro

So long, and thanks for all the fish.

Offline J. Mauro

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Reply #86 on: March 20, 2014, 03:55:46 AM
Just reposting the schematic and pictures.

Jeremy Mauro

So long, and thanks for all the fish.

Offline J. Mauro

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Reply #87 on: March 20, 2014, 03:57:36 AM
Now pictures

Jeremy Mauro

So long, and thanks for all the fish.

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