|
Tweakers' Asylum Tweaks for systems, rooms and Do It Yourself (DIY) help. FAQ. |
|
|
|
Tweakers' Asylum Tweaks for systems, rooms and Do It Yourself (DIY) help. FAQ. |
|
In Reply to: Class A single-ended requires a transformer or coupling capacitor. posted by Al Sekela on October 22, 2010 at 15:15:28:
Single ended transistor circuits can be designed using plus and minus supplies. The Pass Labs Aleph series is like this. You have a differential front end and a single ended output that has a current source for the other half. You bias it as high as you like and with a cap in the feedback to ground you get around 40mv offset. Amps like this can sound fantastic. The Aleph series has a sliding bias output stage to give it more current as the load demands. While this makes for more power into lower impedances it messes up the sound. A pure fixed bias output stage sounds best. I have done it both ways.
The trouble with single ended class A circuits is that they are so inefficient. I was biasing my amp at 3 amps bias and so I was using 150 watts a channel to get 25 watts.....ridiculous. Tons of heat and tons of heat-sinks and tons of capacitance in the power supply to get rid of the hum.
I would go with the Tripath. I heard a Vinnie amp that ran off batteries and with a few mods was guite good. I am done with class A single ended (at least for now).
This post is made possible by the generous support of people like you and our sponsors:
Follow Ups
- Really? - Ric Schultz 16:35:07 10/22/10 (1)
- Thanks. I did not know this had been done. - Al Sekela 15:04:55 10/23/10 (0)
Top of Page ]
[ Contact Us ]
[ Support/Wish List ]
[ Copyright © 2025, Audio Asylum, all rights reserved ]
