beta22 - a real interesting headphone amp

peranders · 25th February 2007, 09:44 PM

http://www.amb.org/audio/beta22/

Have you seen this design? It looks real interesting, don't you think?

blip1882 · 26th February 2007, 03:37 AM

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.

peranders · 26th February 2007, 07:41 AM

Just looking at the schematic, it seems to be designed according to known well-functioning circuits, probably a massive overkill but this is my style also.

Nordic · 26th February 2007, 07:43 AM

Peranders, anyone who has seen your circuits knows that!

They were freaky scary when I started.

Workhorse · 26th February 2007, 04:01 PM

Quote:

Originally posted by Nordic
Peranders, anyone who has seen your circuits knows that!

They were freaky scary when I started.

PA is also scary I think....No Offence PA

Andersonix · 25th October 2007, 05:48 PM

Everyone who's heard it has been very impressed (including me!). And it's available as an almost complete parts kit from glassjaraudio. Nice to have option to build a desktop integrated amp and headphone amp.

Bootstrapper · 26th October 2007, 02:59 PM

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.

Daveis · 10th January 2009, 06:11 AM

Has anyone compared the sound of the b22 to M3?

h_a · 10th January 2009, 04:53 PM

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

MOSFET follower headphone amplifier

and Patrick's (EUVL) DAO headphone amp

http://www.diyaudio.com/forums/showt...43#post1130743

Have fun, Hannes

26th February 2007, 07:41 AM	#3
peranders Electrons are yellow and more is better! diyAudio Member Join Date: Apr 2002 Location: Göteborg, Sweden Blog Entries: 4	Just looking at the schematic, it seems to be designed according to known well-functioning circuits, probably a massive overkill but this is my style also. __________________ /Per-Anders (my first name) or P-A as my friends call me

26th October 2007, 02:59 PM	#7
Bootstrapper diyAudio Member Join Date: Sep 2007	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. __________________ -Juha

10th January 2009, 04:53 PM	#9
h_a diyAudio Member Join Date: Sep 2006 Location: Graz, Austria	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 MOSFET follower headphone amplifier and Patrick's (EUVL) DAO headphone amp http://www.diyaudio.com/forums/showt...43#post1130743 Have fun, Hannes __________________ fresh matched IRFP240/IRFP9240 fets \|\| AlephJ/JX-kits F5 transistor kits \|\| Burning Amp BA-1/2/3 transistor kits

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26th February 2007, 03:37 AM	#2
blip1882 diyAudio Member Join Date: Sep 2005	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.

26th February 2007, 07:43 AM	#4
Nordic diyAudio Member Join Date: Sep 2005	Peranders, anyone who has seen your circuits knows that! They were freaky scary when I started.

25th October 2007, 05:48 PM	#6
Andersonix diyAudio Member Join Date: Jan 2004 Location: Silicon Valley	Everyone who's heard it has been very impressed (including me!). And it's available as an almost complete parts kit from glassjaraudio. Nice to have option to build a desktop integrated amp and headphone amp.

10th January 2009, 06:11 AM	#8
Daveis diyAudio Member Join Date: Dec 2003 Location: Des Moines, IA	Has anyone compared the sound of the b22 to M3?

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