Planar Speaker Asylum

Welcome! Need support, you got it. Or share your ideas and experiences.

Return to Planar Speaker Asylum

Message Sort: Post Order or Asylum Reverse Threaded

anyone ever try a JFET Transconductance Amplifier with a Maggie ?

172.56.241.187
Posted on April 17, 2023 at 10:52:24
trioderob
 I know that years ago folks were doing back flips over a few Transconductance amps that Nelson Pass designed - particularly for use with Lowther full range speakers ,,,,,, anyone ever try them with a Magnepan ?

ref info: "Its output of a current contrasts to that of standard operational amplifier whose output is a voltage." - wiki

 

Hide full thread outline!
    ...
If you refer to the F4..., posted on April 17, 2023 at 11:18:23
E-Stat
Audiophile

Posts: 40769
Joined: May 12, 2000
Contributor
  Since: April 5, 2002
 it's shy on power for Magnepans.

"It is suitable for driving a high sensitivity loudspeaker with the output voltage of a preamp or other line-level audio source."

First Watt F4

 

RE: anyone ever try a JFET Transconductance Amplifier with a Maggie ?, posted on April 17, 2023 at 12:34:31
SoundMann
Audiophile

Posts: 650
Joined: October 21, 2015
 May you be referring to an amp such as Jim Stricklands Transnova (TNT).

 

RE: If you refer to the F4..., posted on April 17, 2023 at 14:06:11
Davey
 The only thing Pass has done that would even be close (and not very) to a transconductance amplifier is the F1.

Strictly speaking, an actual transconductance amplifier is completely unsuitable for 99% of speaker systems. And certainly not suitable Magnepan's. :)

Dave.

 

I was honing in on the Lowther reference, posted on April 17, 2023 at 14:08:12
E-Stat
Audiophile

Posts: 40769
Joined: May 12, 2000
Contributor
  Since: April 5, 2002
 which is mentioned on the F4 page.

 

open baffle single full range driver ,,,,,, posted on April 17, 2023 at 14:22:24
trioderob
 yesterday I was at a friends who built a simple open baffle speaker with a full range driver .... maybe a Tangband .....

he has been trying all kinds of amps with it - oncluding a pass lab design - and it reminded me about the pass labs amp that is a current rather than voltage source

the idea popped into my head about using it with Maggies but I dont remember reading about using it with a speaker with a passive cross over

 

RE: If you refer to the F4..., posted on April 17, 2023 at 15:14:14
SoundMann
Audiophile

Posts: 650
Joined: October 21, 2015
 "Strictly speaking, an actual transconductance amplifier is completely unsuitable for 99% of speaker systems."

And yet the Transnova circuit can theoretically drive any speaker in existence.

 

RE: If you refer to the F4..., posted on April 17, 2023 at 15:37:41
Davey
 The Transnova is not a transconductance amplifier.

Dave.

 

RE: I was honing in on the Lowther reference, posted on April 17, 2023 at 16:27:10
Davey
 Yeah, I understand.
But he was asking about transconductance amplifiers for Magnepan usage, not for Lowther's.

For the benefit of all posters, there are TransXXXXX labeled amplifiers where the 'transconductance' is used for marketing purposes.
And then there are 'real' transconductance amplifiers.
That's why I said "strictly speaking" in my other post.

Dave.

 

Sure, posted on April 17, 2023 at 16:37:33
E-Stat
Audiophile

Posts: 40769
Joined: May 12, 2000
Contributor
  Since: April 5, 2002
 The common ground for my question was his "amps that Nelson Pass designed - particularly for use with Lowther full range speakers" comment.

 

There is some truth to the claim, posted on April 17, 2023 at 17:07:38
E-Stat
Audiophile

Posts: 40769
Joined: May 12, 2000
Contributor
  Since: April 5, 2002
 "TheTNT-200's first stage is a "transconductance amplifier"- that is one in which the output current is proportional to the input voltage (and,implicitly,one in which the output voltage does not affect either)"

 

It's not a claim. :), posted on April 17, 2023 at 17:11:45
Davey
 ...

 

Exactly, posted on April 18, 2023 at 06:06:45
E-Stat
Audiophile

Posts: 40769
Joined: May 12, 2000
Contributor
  Since: April 5, 2002
 The first stage is.

 

Page processed in 0.026 seconds.

[ Top Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2025, Audio Asylum, all rights reserved ]
[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]