balanced b22 questions

By design, it does not, but you can always add one.

Or you can add a switch and wire the negative signal rail to signal ground.

See the β22 website "Other options" section, at the bottom of the page for a simple solution that doesn't involve phase splitters.

The balanced β22 can't do that with single-ended sources. The best it can do by itself is to have the negative/cold boards act as individual ground channels for the balanced headphones.

Quote:

Originally Posted by deathg0d 

Quote:

Originally Posted by amb 

See the β22 website "Other options" section, at the bottom of the page for a simple solution that doesn't involve phase splitters.

 Hi amb, thanks for your reply but sorry i think i did not explain myself clearly. i was wondering if i have a SE source input into b22, can/does b22 able to work the signal and output it to balanced? meaning, if my cdp is SE and my headphones are balanced, so am i getting a balanced signal out?

I've often wondered myself about tweaking one input differential to drive 2 VAS differential stages. Take 2 B22 boards and drive both from one input differential. Bridging 2 boards for balanced drive, no matter the source.

a 2 or 3 channel amp doesn't have the bridged output configuration that many here call "balanced output"

I would claim that the 2 channel B22 is so good that the "advantages" of balanced output (really Bridged) are moot

just wire a 2 channel B22 with "balanced" output connectors and plug in your "balanced" headphones with single-ended source and justifiably believe you are at 99.8%+ of the performance of a Bridged output implementation

Bridged outputs can allow some cancellation of even order distortion products - but only to the extent that both half bridge amps are well matched in their distortion characteristics

in Bridged outputs the odd order distortion products are doubled compared to the Single ended drive case

with both half Bridged outputs running in Class A  their output stage's dynamic current demands are opposed in sign so they sum to 0 in the power supply rails - this potentially reduces power supply modulation by the audio current demand when the half bridges of each channel fed by the same supply 

The Bridged output currents also complete their local load current loops through the half bridge stages and the +/- ps rails - with correct ps and ground connection there is no load current flowing in the gnd reference plane

Basically all power supply related "advantages" of a 4-channel B22 implementation are meaningless - the B22 has C-multiplier sub regulation of the input/driver circuitry, Output bootstrapped Cascode output devices - and is usually ran from regulated power supplies to start with

with dual mono ps build and good signal gnd wiring you would be arguably technically better than a 4-channel build by credible estimates of audible error (those doubled odd order harmonic components should by most estimates be audibly worse than the reduction of the less subjectively objectionable even harmonics are an "improvement" )

this of course assumes your SE source is good - since you talk about sending SE signal to a phase splitter in the amp you really can't complain unless somehow the phase splitter circuitry can "improve" the signal

Thanks jcx, and if the source is balanced do these comments still apply?

Quote:

Originally Posted by digger945 

I've often wondered myself about tweaking one input differential to drive 2 VAS differential stages. Take 2 B22 boards and drive both from one input differential. Bridging 2 boards for balanced drive, no matter the source.

The Dynahi and Dynalo don't use the differential (-) signal at the input jfets and the inverted signal can be used to drive a second output stage for "balanced" output. No need for an additional phase splitter. I don't know about the Rudistor or HR products, maybe a similar input design? It appears as though the B22 uses both halves of the differential signal at the inputs. I actually looked at the input on the B22 schematic for quite a while but it is well beyond my level to hack out a usable inverted signal. The input design on the B22 appears to be a generation more complex than the Dyna series.

I'm slowly digesting the article on multiple feedback paths you linked me to "at the other place" (thanks much BTW). I haven't had much time for DIY fun between work and family holiday time lately, but hopefully I'll be proto'ing a couple ideas after the new year. I have a balanced bridged dynamid running well  (SE input > balanced out) and I am intending on modifying my Dynamite to the same topology. The downside is ~ as we discussed a bit ~ the lack of a negative feedback path on the inverted phase in the original Gilmore schematic. If there was an easy way for two balanced feedback loops, one from each output, to the one SE input, it seems to be a very compelling topology. I wish some of the smarter guys in the room would take it up as a project.

If you have a Balanced only source I would argue that world class Bal/SE conversion circuitry is cheaper than another pair of B22 amps - and that 2 Bridged Output SE amps driven with a balanced signal do not give the full noise immunity of a good differential receiver Bal/SE converter

the Dyna Balanced option requires buffers after the volume pot to drive the low differential impedance of the input resistors

it is common Pro Audio equipment practice to only use balanced signal for external cabling - internally a balanced to SE converter circuit is used and processing is often SE up to the output which is again converted to Balanced - the conversion circuitry is often monolithic SS Instrumentation Op Amp based

Xfmr based SE/Bal conversion does have some technical appeal in extreme noise environments - but audio bandwidth and distortion specs are measurably degraded by even good quality audio xfmrs

it is likely much commercial music will have gone through several Bal/SE/Bal conversions in the analog processing - of course nowadays it is possible to digitize at the mic/pre and process entirely in digital 

if you accept that adequate noise immunity is possible in SE home listening room setups then Balanced could be seen as just another Audiophile excess - more difficult, expensive = exclusive - so obviously it Has to be superior

of course there is fairly inexhaustible body of subjective commentary insisting that SE, op amps are evil and only discrete (preferably vacuum tube) based Balanced circuitry (except SE Triode==Nirvana) is "worthy" of audiophile consideration

I would suggest "just listen" is not adequate to decide - learn something about perceptual testing, psychoacoustics and you could save money and time rather than chasing every audiophile fashion that pops up on these boards

The Beta24 board has the right circuit.(for you also bada bing [SUSY])