beta22 - a real interesting headphone amp

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.

Attachments

  • b22_assy.jpg
    b22_assy.jpg
    88.1 KB · Views: 1,165
I've been pondering the B22 for a while as a replacement for my PIMETA. Not much to say about it beyond that the few people who have built it seem pretty enthusiastic about it. Also, I really dig the concept of having modular boards and being adaptable into a speaker amp...

Anyway, it seems really intriguing but I want to hear more testimonials from early adopters over on head-fi... and I'd love one of the gurus over here to give the circuit diagram a critical examination and report back about its theoretical performance.
 
Has anyone tried to simulate this B22? Perhaps with PSpice? I tried, but I cannot get proper output voltage even if all the bias currents and voltages are like tehy should be (at least those which are mentioned with the schematics)

The only difference between my sim model and the original circuit is the mosfets, since PSpice doesn't have models for IRFZ24N & 9Z34N, I'm using IRFZ22 & 9Z32. According to datasheets, they shouldn't differ too much for the sim not to work. Maybe PSpice just cannot handle that circuit..

EDIT: Looks better if reduce that input-to-ground resistor down to 47k instead of previous 1 Meg.
 
I'm always wondering why people build small power amps for their headphones instead of thinking of something much simpler. Headphones have much lesser requirements, a factor 1000 reduced power needs, their much higher impedance does not need extremely low output impedance for reasonable damping factor and so on.

Yet still a lot of designs are of the general opamp topology, I really think that's a missed opportunity to create very simple designs that work really well.

Just as an example,
Grey's mosfet follower

http://www.diyaudio.com/forums/showthread.php?s=&threadid=95841&highlight=

and Patrick's (EUVL) DAO headphone amp

http://www.diyaudio.com/forums/showthread.php?postid=1130743#post1130743

Have fun, Hannes
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.