[kendrab]

I am fairly new to headphone based audio. A move to a smaller apartment made my speaker based system impractical. I started off with a used Sugden Headmaster amplifier and a set of AKG K240 II headphones. I was fairly happy, but the sound could't match what I was used to through my speakers.
 
I decided to order a better set of headphones. My dealer sells Beyerdynamic products, so I had him order in a set of their T90 Tesla headphones. While I was waiting, a used Three channel Beta 22/Sigma 22 headphone amp and power supply came on the market. I was torn about whether to purchase it, and because it was three provinces away, I couldn't actually listen to it.
 
But the price was good ($700 delivered), and what I read about the amplifier and power supply combination convinced me. I expected this to be a nice step up from the Sugden Headmaster amplifier I was using, but didn't think it could ever be as good as I have been hearing. 
 
This amplifier is really delivering the goods (and that is with a set of used AKG K240 Mk II headphones). I am hearing more in my recordings than I ever thought possible. After comparing the two headphone amplifiers, I sold the Sugden Headmaster with no feelings of remorse.
 
I cannot say this is the best headphone amplifier on the market. In fact, I am sure that is NOT true (there is always something better if you are willing to spend enough). But given I paid just under $700 Canadian for it, I have zero complaints. I am now hearing more detail through the Beta 22 amplifier and AKG headphones than I was with my $15,000 speaker based system.
 
The performance of the B22/S22 combination has me all fired up. I am impatiently waiting for my new headphones to arrive. If a fairly mid-line headphone can sound this good, what will the T90 Teslas sound like?
 
My Beyerdynamic T90 headphones had been backordered, but they finally arrived at the main distributors Canadian location last Friday. They have now been shipped to my dealer, and I was assured that I should receive them by the end of the week. I will write back once I have spent a little listening time with them. 
 
Kendrab

 

[milosz]

It's quite interesting that you heard a rather significant improvement from the Beta 22 over the Sugden Headmaster.  I thought the Headmaster was a pretty highly rated product, I would have thought it's sound would be closer to the Beta 22 than you experienced.  
 
 
Interesting, indeed.  I know the Beta 22 design is one of the VERY BEST, I'm not surprised that you like the Beta.  I have a three channel Beta and am building another to sell.  I've tried a few innovations in the new one I'm building, including an internal isolated Sigma power supply; it's electrically equivalent to a two-chassis design but occupies only one chassis.  The power supply, from AC inlet to DC output is isolated from the amp chassis by Delrin and rubber. My older single-chassis Beta 22 does not have an isolated supply, and there is a tiny bit of AC line buzz audible.  The new one is dead silent, so isolating the PSU got rid of that last little bit of noise, just like a two-chassis build.
 
Isolated Power Supply
 

 

[senson]

I am not sure if it's appropriate if I post this here. If it's not please let me know.
I'm looking for a person who can do some work on my 3CH B22(New chassis prefer double chassis, rewiring and possibly upgrade it to 4CH if it's possible.)
I prefer a person in local area but I'll ship it if it's necessary.
BTW please do not offer me "my friend or my uncle or my someone can take a look" I'll feel comfortable to deal with a person on this forum.

 

[milosz]

I think this is an OK place to post your request.
 
However, given the cost of the labor involved, you might be better off to sell your Beta 22 and buy one in the configuration you want.  
 
Converting a single chassis 3-channel Beta 22 to a two-chassis fully-balanced amp involves a considerable amount of work.

 

[ericfarrell85]

Milosz,

What about combining a 3 channel and 4 channel Beta into a 6 channel animal. I have two Betas and have considered consolidating them into a single unit. Any interest in the work?

 

[milosz]

Milosz,

What about combining a 3 channel and 4 channel Beta into a 6 channel animal. I have two Betas and have considered consolidating them into a single unit. Any interest in the work?

Hmmmm
 
Could be done.  The chassis could be expensive.  Labor is not low cost either. And I am building a DIY T-2 at the moment so wouldn't be able to get to anything for a few months.
 
 
Here's my latest Beta 22; aluminum with tiger-maple trim; 3 channel, with isolated PSU (so it's wired  like & performs like a 2-chassis build) and Goldpoint attentuator.

 

 

[milosz]

WOOD!

 
Isolated power supply - as quiet as a 2-box Beta 22

 
Pilot light is white but not garishly bright

 
Front panel is machined from 3/4" thick aluminum

 

 
 
Very clean build; power supply rail wiring is 12 ga Teflon insulated silver-plated wire; ground lines are 10 ga. This ensures a very low impedance connection to the power supply, helping to lower noise.

 
Goldpoint attenuator and special coupler- no play, super-smooth, positive operation, solidly mounted near input jacks using Delrin block. Leads from attenuator to amp boards are Teflon-insulated, silver plated OFC coax.

 
Isolated power supply - subchassis containing transformer is isolated from main chassis by Delrin and rubber; power subchassis is bonded to power line safety ground, but power line ground is 100% isolated from signal ground.  Every bit as quiet as a 2-chassis build without the hassle and also without the electrical compromises necessary when using long cables and connectors to bring the DC from a second chassis to the amp chassis. 

 
High quality gold-plated solid copper RCA input jacks.

 
I really enjoyed building this. 

 

[picopa]

Congratulations! great build!

 

[fishski13]

beautiful milosz!  the maple on natural metal looks great.  kudos on the wiring and layout.  no wonder it's quiet.  the GP is my fav for attenuation in the B22 these days.

 

[milosz]

The Goldpoint sure is nice but costs a bunch! Ouch!

 

[milosz]

For the maple, I used one light coat of boiled linseed oil to bring out the figure a little, then five coats of Minwax wipe-on poly, sanding with 600 grit between coats.  The maple will turn a nice honey color over the years.

 

[xevman]

I've been planning on building a beta22 for a while. Upon further research I discovered this. 

http://www.ebay.com.au/itm/Finished-ZEROZONE-Class-A-B22-headphone-amplifier-base-on-22-beta-22-AMP-/222062320931?hash=item33b3f21d23:g:1KwAAOSwI3RW8i2q

Not sure what to think about it. It seems to be a single ended (2 channel version of the beta 22 in a small enclosure. Anyone here tried it?

 

[amb]

It's a Chinese fake, not based on genuine boards, and most likely uses inferior parts. Also, that big power transformer situated so close to the amp boards will surely cause magnetic interference.

 

[xevman]

thought so, it seems to cheap for an assembled beta22

 

[milosz]

NEW BUILD
 
Compact 2-chassis ß22 / σ22 2-board amp with built in DAC  (note: Genuine AMB / Glass Audio parts)
 
DAC is Curryman - ES9023 DAC with discrete FET output buffers ( https://www.minidsp.com/products/minidspkits/curryman-i2s-dac )
DAC has separate power supplies
USB reciver is Amanero ( https://docs.google.com/viewer?url=http://www.amanero.com/drivers/combo384-D.pdf )
USB receiver and DAC are in a copper shielded subchassis inside the amp.
Switch selects onboard DAC or RCA line inputs
 
Knob is ground from semi-precious tigers-eye stone, side panels are Shedua wood.
 



 
Here's the amp insides, you can see the copper-shielded DAC and USB receiver 

 
The σ22 power supply on/off switch has a soft white pilot light ring