Roll Call: Who's building, built, or thinking of building a beta22?

[DefQon]

2 trafo's and 2 S22 is plenty even for the most demanding speaker duty.
 
4 S22's will be a waste of money and just plain silly.
 
Standard heatsinking according to the BOM on AMB is fine for speaker duty but make sure the PSU enclosure has plenty of holes of ventilation especially above crucial areas such as the tip of the heatsink shrouds.
 
For balanced/single ended headphone duty, 2 S22/2 trafos is overkill. 

 

[joeyjojo]

  Does anyone know if it will be ok if I just use 2 Sigma 22 boards supplied by 100VA transformers instead of using 4 in balanced configuration to power speakers.  If I read things correctly, if I set everything up correctly I can output 50W into 8ohms.  

 
AMB says one S22 per B22 board for speakers (regardless of 2 or 4 board).  Deviate from that and you'll be deviating from the official word.  Anyway, 50 W into 8 ohms would imply a current of over 6 A, which is going to dissipate far too much heat in the MOSFETs for the stock heatsinks.  You should make a thread on the AMB forum and TK will go over the calculations with you.  Offboard heatsinks will be needed, negating some of the gains from cheaping out on the PS.

 

[Xovaan]

Just got my 2ch b22 and lcduino up and running! Gotta say that the sound is surreal, even through my ATH-AD900's! I'll post pics once I order my front panels

 

[alota]

  Just got my 2ch b22 and lcduino up and running! Gotta say that the sound is surreal, even through my ATH-AD900's! I'll post pics once I order my front panels

too many peoples sais that the beta-22 is not a great deal, the boards are na old design, etc. etc.
in my opinion(of course i´m a beta-22 owner)this amplifier deserves a lot.
is not 100% neutral but is near to the neutral and drives very well a lot of headphones
and the beta-22 improves with better components

 

[cans4dessert]

Does anyone here have much experience with single ended (2-Ch or 3-Ch) B22 paired with HE-6? If you found yourself liking the pairing, how much biasing and gain were you running? I am thinking of getting a new pair of headphones, either HE-6 or LCD-3. Leaning towards HE-6 at the moment for its lower price...

 

[Zashoomin]

  Does anyone here have much experience with single ended (2-Ch or 3-Ch) B22 paired with HE-6? If you found yourself liking the pairing, how much biasing and gain were you running? I am thinking of getting a new pair of headphones, either HE-6 or LCD-3. Leaning towards HE-6 at the moment for its lower price...

Honestly I think that if you are going to power the HE-6 with a beta 22 I would go balanced.  I have heard it with a 2 channel and I thought that it could use a bit more power.  The LCD3's on the other hand sound superb with just 2 channel.  

 

[cans4dessert]

Thx Zashoomin. I have no plan of going balanced with my Beta 22 (i've got a 3-Ch setup) any time soon. Just can't find the time =P
So it seems it would be logical for me to go with LCD-3 based on the recommendations from you and other forum members. No one has yet to suggest pairing with HE-6 over LCD-3. But then again, in the thread "Amps that can drive the HiFiMan HE-6 planar headphones", the OP thought the 3-Ch Beta 22 drove the HE-6 very well. And I wonder if he felt it that way because of the bias current setting of the amp. Perhaps people have varying opinions because of different bias settings??

 

[Zashoomin]

  Thx Zashoomin. I have no plan of going balanced with my Beta 22 (i've got a 3-Ch setup) any time soon. Just can't find the time =P
So it seems it would be logical for me to go with LCD-3 based on the recommendations from you and other forum members. No one has yet to suggest pairing with HE-6 over LCD-3. But then again, in the thread "Amps that can drive the HiFiMan HE-6 planar headphones", the OP thought the 3-Ch Beta 22 drove the HE-6 very well. And I wonder if he felt it that way because of the bias current setting of the amp. Perhaps people have varying opinions because of different bias settings??

I am not tech exert so I have no idea if you can bias the amp for just as much or close to as much power as a stock 2 or 3 channel beta 22.  But last time I heard the pairing I felt it was a bit lacking. But it is also an opinion so that is just my two cents.  

 

[cans4dessert]

Thx for your input. I am far from an expert. I just know how to follow instructions just enough to build a beta 22 =p

 

[alota]

  Does anyone here have much experience with single ended (2-Ch or 3-Ch) B22 paired with HE-6? If you found yourself liking the pairing, how much biasing and gain were you running? I am thinking of getting a new pair of headphones, either HE-6 or LCD-3. Leaning towards HE-6 at the moment for its lower price...

i tried only in balanced mode with a higher output source.
in my opinion, this is the minimal requirement for the he-6.
with audeze(i never tried the lcd-3)the situation is different

 

[fishski13]

on paper, a B22 should have no problem powering the HE6.
 
if you go with 2.5" heatsinks in both the O22 and B22, and size the TX appropriately,  200-225mA quiescent current bias should be achievable, or 400-450mA Class A swing.  i think there are sonic differences between 160mA and 200mA.  depending on preferences, you may like one better than the other.  balancing doesn't double the Class A current delivery since the outputs are in series with one another.
 
assuming a source of 2Vrms, a gain of 5x or 10Vrms v-swing isn't enough for the HE6.  to achieve the full 15Vrms the B22 is capable of, you need to go with a gain of 8x.  for balanced/4Vrms this means you need a gain of 4x.  if you want to swing the full 30Vrms that a balanced B22 is capable of, then a gain of 8x would be appropriate.
 
just because your pot may be sitting at 3-5 o'clock doesn't mean the amp is "under-powered".  it's a function of gain.

 

[alota]

  on paper, a B22 should have no problem powering the HE6.
 
if you go with 2.5" heatsinks in both the O22 and B22, and size the TX appropriately,  200-225mA quiescent current bias should be achievable, or 400-450mA Class A swing.  i think there are sonic differences between 160mA and 200mA.  depending on preferences, you may like one better than the other.  balancing doesn't double the Class A current delivery since the outputs are in series with one another.
 
assuming a source of 2Vrms, a gain of 5x or 10Vrms v-swing isn't enough for the HE6.  to achieve the full 15Vrms the B22 is capable of, you need to go with a gain of 8x.  for balanced/4Vrms this means you need a gain of 4x.  if you want to swing the full 30Vrms that a balanced B22 is capable of, then a gain of 8x would be appropriate.
 
just because your pot may be sitting at 3-5 o'clock doesn't mean the amp is "under-powered".  it's a function of gain.

really interesting.
i came to the end of the pot without any distorsion but is too dangerous for the ears.
i think that the beta is good for the he-6.
the problema is the presentation of the bass frequencies with the he-6.
this headphone does not have a boom boom bass

 

[fishski13]

as long as the gain is within what the max v-swing is, clipping shouldn't occur. driving the HE6 with an unbalanced amp that can only swing 7Vrms, but with a gain of 8x, will clip when the HP requires more voltage than what the amp can deliver and there's still more play on the pot to go "louder".

the 25W B1/F5 is definately not a bassy combo when driving loudspeakers. this combo turns the K701 into bass monsters - i get more bass than any Audeze driven by a typical HP amp. the T50RP turns into mud. i'm sure there's something similar going on with the HE6, albeit maybe not to the same extent.

 

[jc9394]

With my 2x gain balanced beta22 and 2.7V source, it is still lack of power when driving the HE-6 but it sound really really good with LCD-3.

 

[fishski13]

With my 2x gain balanced beta22 and 2.7V source, it is still lack of power when driving the HE-6 but it sound really really good with LCD-3.

 


no doubt. you need mucho more gain than 2x. the voltage requirements for the HE6 or K1000 usually require a dedicated amp with gain structure optimized, especially with a stepped attenuator.