Published/DIY ultra-low THD designs?

leadbelly · 1st April 2007, 03:29 AM

I know that THD doesn't carry much weight in this forum, and those designs which feature low THD using large NFB and such are not too popular, however if you would be kind as to point such designs out and save me some tedious searching, that would be appreciated.

Miles Prower · 1st April 2007, 03:35 AM

Quote:

Originally posted by leadbelly
I know that THD doesn't carry much weight in this forum, and those designs which feature low THD using large NFB and such are not too popular, however if you would be kind as to point such designs out and save me some tedious searching, that would be appreciated.

Try Googling for the Williamson amp. That was a high gNFB, low THD design.

leadbelly · 1st April 2007, 06:38 PM

Thanks.

Any SE designs?

Wavebourn · 1st April 2007, 07:52 PM

Quote:

Originally posted by leadbelly
Thanks.

Any SE designs?

Higher THD, terrible transciens?

janneman · 1st April 2007, 08:16 PM

Quote:

Originally posted by leadbelly
I know that THD doesn't carry much weight in this forum, and those designs which feature low THD using large NFB and such are not too popular, however if you would be kind as to point such designs out and save me some tedious searching, that would be appreciated.

Bob Cordell's desing is both - www.cordellaudio.com , http://www.cordellaudio.com/papers/MOSFET_Power_Amp.pdf .

Jan Didden

Jeb-D. · 1st April 2007, 08:29 PM

If you want low THD in a Single Ended amp, screw the feedback loops and go cathode follower. It's a more natural form of feedback, opposed to loops which arn't quite phase correct. Especially in transformer coupled amplifiers.

Just my .02, as I'm sure some will disagree.

Wavebourn · 1st April 2007, 10:03 PM

Quote:

Originally posted by Jeb-D.
If you want low THD in a Single Ended amp, screw the feedback loops and go cathode follower. It's a more natural form of feedback, opposed to loops which arn't quite phase correct. Especially in transformer coupled amplifiers.

Just my .02, as I'm sure some will disagree.

I agree.

phn · 1st April 2007, 10:30 PM

What do you mean by low THD?

Ken Shindo promises the following for his 300B SET:

Total Harmonic Distortion: 0.1%.
Signal to Noise Ratio: 110dB.
Intermodulation Distortion: 0.09%

But the question makes little sense.

All of the old Leak amps have a THD of around 0.1 pct. Everybody who has heard them say the TL/12 and TL/25A are the best-sounding Leak amps. Anyone can make a poor sounding amp, be it tubes or whatever.

And there's no tube amp without NFB. A triode has internal NFB, which is the reason it operates different from pentodes and all other components.

Edit: Fixed weird characters thanks to ultra slow, instable, bug infested piece of junk IE7.

sorenj07 · 1st April 2007, 10:48 PM

Quote:

Originally posted by phn
ultra slow, instable, bug infested piece of junk IE7.

use firefox.

phn · 1st April 2007, 10:52 PM

Quote:

Originally posted by sorenj07

use firefox.

And lose the privilege of bitching and moaning? Where's the fun in that?

1st April 2007, 03:29 AM	#1
leadbelly diyAudio Member Join Date: Dec 2002 Location: Calgary, Alberta	Published/DIY ultra-low THD designs? I know that THD doesn't carry much weight in this forum, and those designs which feature low THD using large NFB and such are not too popular, however if you would be kind as to point such designs out and save me some tedious searching, that would be appreciated. __________________ Aerodynamics are for people who can't build engines. Enzo Ferrari

1st April 2007, 06:38 PM	#3
leadbelly diyAudio Member Join Date: Dec 2002 Location: Calgary, Alberta	Re: Re: Published/DIY ultra-low THD designs? Thanks. Any SE designs? __________________ Aerodynamics are for people who can't build engines. Enzo Ferrari

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Ultra High-End DAC designs for DIY?	steaxauce	Digital Line Level	61	27th February 2009 06:54 PM
Published designs on DIYAudio and Copyright, Patent and etc issues...	Ultima Thule	Everything Else	59	4th February 2008 06:25 PM
Any published line array designs?	mazeroth	Multi-Way	10	18th April 2006 09:46 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read

1st April 2007, 08:29 PM	#6
Jeb-D. diyAudio Member Join Date: Nov 2005 Location: SoCal	If you want low THD in a Single Ended amp, screw the feedback loops and go cathode follower. It's a more natural form of feedback, opposed to loops which arn't quite phase correct. Especially in transformer coupled amplifiers. Just my .02, as I'm sure some will disagree.

1st April 2007, 10:30 PM	#8
phn diyAudio Member Join Date: Oct 2004	What do you mean by low THD? Ken Shindo promises the following for his 300B SET: Total Harmonic Distortion: 0.1%. Signal to Noise Ratio: 110dB. Intermodulation Distortion: 0.09% But the question makes little sense. All of the old Leak amps have a THD of around 0.1 pct. Everybody who has heard them say the TL/12 and TL/25A are the best-sounding Leak amps. Anyone can make a poor sounding amp, be it tubes or whatever. And there's no tube amp without NFB. A triode has internal NFB, which is the reason it operates different from pentodes and all other components. Edit: Fixed weird characters thanks to ultra slow, instable, bug infested piece of junk IE7.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)