Tube DIY Asylum Do It Yourself (DIY) paradise for tube and SET project builders.

---

[ Follow Ups ] [ Post Followup ] Thread: [ Display  All  Email ] [ Tube DIY Asylum ]

---

[ Alert Moderator ]

---

RE: Switcher Filter

Posted by vinnie2 (A) on November 21, 2016 at 13:14:19

In Reply to: Switcher Filter posted by Triode_Kingdom on November 21, 2016 at 09:05:29:

Ok, before we go any further I need to bring you up to date on what I got done this morning. I would have posted it sooner, but my honey do list got enforced priority about mid morning. : )
Anyway, I was working at tweaking things a bit and noticed that the hum pots were no longer doing anything when I had the meter on the wings of the pot and set to mV. I got the lowest reading when I had it cranked hard to port or starboard, and I was still getting about 25 mV. Not good. So I decided to try taking the pots out of from 813's and replacing them with a couple of 50 ohm resistors tied to the filament pins and each other with a wire going to the cathode cap and resistor. Well how 'bout that sports fans, the ripple dropped to 1.7mV at the filament pins! So then I change the filter on the 26 to match the filters on the 813's, and danged if that ripple doesn't drop to 1.7 mV too. Haven't removed the hum pot on the 26 yet but will try that next. I was feeling pretty cocky by now, so I checked the ripple at the speaker terminals and get slapped in the back of the head. It was 105 mV. Phooey says I, and decide to put a shorting plug in the amp input, and when I check it this time at the terminals I get 0.5mV! Couldn't hardly believe it. I double checked everything to make sure it was correct, and it was. So that means I have a problem with my preamp, but I will work on that later. Just to be sure, I turned the volume up and put my ear right next to the speaker with the shorting plug still in and it was dead quiet.
So to get back to the rest of your post, I am not sure why, but my filter seems to be working pretty well, at least as far as hum goes. What would be the symptoms of the 50kHz if it is still there? Right now it sounds as if all my troubles are gone with this right channel and it sounds good to boot.

Edits: 11/21/16 11/21/16 11/21/16 11/21/16

This post is made possible by the generous support of people like you and our sponsors:

Signature Sound

[ Signature Sound Lounge ]

---

[ Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2024, Audio Asylum, all rights reserved ]

---

[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]

---