Tube DIY Asylum

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

Return to Tube DIY Asylum

Message Sort: Post Order or Asylum Reverse Threaded

Magnequest RH40 transformers

142.119.47.168
Posted on September 22, 2020 at 19:00:36
vetmedrobert@gmail.com
Audiophile

Posts: 453
Location: Ontario
Joined: September 20, 2007
 These have 2 solder tabs on the high voltage side labelled "plate' and AC Ground" Do I connect the tab marked plate to the output tube's plate and the AC Ground to the B+? or does it really matter as long as both channels are connected the same way?

 

Hide full thread outline!
    ...
RE: Magnequest RH40 transformers, posted on September 22, 2020 at 19:35:45
Tre'
Industry Professional

Posts: 17294
Location: So. Cal.
Joined: February 9, 2002
 It matters.

The reason the B+ connection is labeled AC ground is because that's what the output of your power supply is. A capacitor is a dead short for AC and the last thing in your power supply before the output transformer is a capacitor connected to ground.

If you hook them up backwards the winding capacitance of the output transformers will have a very bad affect on the frequency response of your amplifier.

Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"

 

RE: Magnequest RH40 transformers, posted on September 22, 2020 at 19:49:25
vetmedrobert@gmail.com
Audiophile

Posts: 453
Location: Ontario
Joined: September 20, 2007
 Greatly appreciate you clarifying that. Not wanting to seem contradictory but why is it inadvisable to connect the transformer the "wrong" way? You say it has to do with winding capacitance but if you could explain a bit more it would be appreciated:)

 

RE: Magnequest RH40 transformers, posted on September 22, 2020 at 20:11:45
Tre'
Industry Professional

Posts: 17294
Location: So. Cal.
Joined: February 9, 2002
 When a output transformer is designed and wound, there are certain unavoidable capacitances between the windings. Depending on where these capacitances are located within the windings (close to a AC ground point vs. clear at the other end of the winding, etc.) that capacitance will short the high frequencies to ground. If a transformer designed for one end to be close to AC ground (the B+ connection) and the other end connected to the plate of the output tube is wired backwards, the winding capacitance that would not do harm (because of how it's placed) to the FR of the transformer is now placed where it does the most harm to the FR.

Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"

 

RE: Magnequest RH40 transformers, posted on September 23, 2020 at 07:26:32
vetmedrobert@gmail.com
Audiophile

Posts: 453
Location: Ontario
Joined: September 20, 2007
 Makes sense, thanks.

 

You're welcome. Dave Slagle and others could give you more detail. nt, posted on September 23, 2020 at 10:44:38
Tre'
Industry Professional

Posts: 17294
Location: So. Cal.
Joined: February 9, 2002
 .
Have Fun and Enjoy the Music
"Still Working the Problem"

 

Page processed in 0.017 seconds.

[ Top 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 ]