grataku,
--If the windings for the transformer are unequal in any way, then the two opposing phases will be lop-sided, favoring either the top or bottom of the signal. Equal turns (this is probably pretty close, actually), stray capacitance, equal coupling to the core...etc.
--As long as the DC (i.e. bias) is close, then the effects will be minimal on the AC signal. DC becomes more of interest as it becomes larger in magnitude.
--Differing AC gain between the two devices. If they're only matched for DC Vgs, then they could still vary in the AC realm. Slightly more bias on the device with lower gain could offset this a bit.
Short on time at the moment...I'll try to come up with some more possibilities later.
Grey
--If the windings for the transformer are unequal in any way, then the two opposing phases will be lop-sided, favoring either the top or bottom of the signal. Equal turns (this is probably pretty close, actually), stray capacitance, equal coupling to the core...etc.
--As long as the DC (i.e. bias) is close, then the effects will be minimal on the AC signal. DC becomes more of interest as it becomes larger in magnitude.
--Differing AC gain between the two devices. If they're only matched for DC Vgs, then they could still vary in the AC realm. Slightly more bias on the device with lower gain could offset this a bit.
Short on time at the moment...I'll try to come up with some more possibilities later.
Grey
Bridged Zv5?
Getting closer to start assembly of Zv5, boards should come in by friday, realized i´m beginning to get short on transformers and still a pile of unfinished projects, then the cat got stuck in my first diaphragm attempt for the diy AMT´s, this cat´s got a flair for spreading the mess all over the place in notime!
So as i´ve not yet started the buildprocess i was thinking, this looks easily bridgable as it´s already floating, but as i have to lift it from ground both ends, what happens with noise? Should i keep supply´s for the "oposing channels" totally separated or should they have common gnd.
Realy gratefull for advice and comments.
Getting closer to start assembly of Zv5, boards should come in by friday, realized i´m beginning to get short on transformers and still a pile of unfinished projects, then the cat got stuck in my first diaphragm attempt for the diy AMT´s, this cat´s got a flair for spreading the mess all over the place in notime!
So as i´ve not yet started the buildprocess i was thinking, this looks easily bridgable as it´s already floating, but as i have to lift it from ground both ends, what happens with noise? Should i keep supply´s for the "oposing channels" totally separated or should they have common gnd.
Realy gratefull for advice and comments.
With Toroidal transformers, as long as they are bifilar wound the coils inductance should be extremely close. The larger you go the tighter the regulation tolerance gets, hence you would expect the closer the coils are to being equal. With Bifilar windings if you hook the coils up out of phase to one another the combined output sums to zero, is that what the circuit is trying to achieve Mr. Pass?
The reactive currents induced can be in or out of phase depending on the coil configuration of the transformer, surely there must be a consideration given to this factor?
Regards
Anthony
The reactive currents induced can be in or out of phase depending on the coil configuration of the transformer, surely there must be a consideration given to this factor?
Regards
Anthony
I have a different idea of "phase" that applies to AC only. For DC I prefer to talk about polarity. Basically by attaching the trafo to the center tap DC current flows in opposite directions producing almost equal and opposite magnetic fulx that null each other out and therefore there is no static DC flux that do not saturate the nucleus.
I can think of a number of reasons why EI nucleus would work better and be more tolerant is slight mismatch in current among that the fact that o the EI bobbin the wiring is better organized that on a toroidal nucleus also a little bit of air in the EI core helps as Nelson said.
The tuning is needed to optimize both the mosfet mismatch, I guess, and the slight magnetic mismatch. Apparently minimizing the distortion also get you the best compromise of current flowing in each side DC offset at the speaker.
I can think of a number of reasons why EI nucleus would work better and be more tolerant is slight mismatch in current among that the fact that o the EI bobbin the wiring is better organized that on a toroidal nucleus also a little bit of air in the EI core helps as Nelson said.
The tuning is needed to optimize both the mosfet mismatch, I guess, and the slight magnetic mismatch. Apparently minimizing the distortion also get you the best compromise of current flowing in each side DC offset at the speaker.
Well, of course it works one way, and not the other. If the
windings were two primaries labeled 0a and 120a and 0b and
120b, then you would attach either 0a and 120b (or) 0b and 120a
together and connect that to the positive supply. The remaining
leads go to the Drains of the Mosfets.
And Yes, bifilar winding improves the coil matching, but you will
still probably find yourself wanting to tweak it.
windings were two primaries labeled 0a and 120a and 0b and
120b, then you would attach either 0a and 120b (or) 0b and 120a
together and connect that to the positive supply. The remaining
leads go to the Drains of the Mosfets.
And Yes, bifilar winding improves the coil matching, but you will
still probably find yourself wanting to tweak it.
Is this a Pass Distributor in France or someone using the name for cache?
http://194.51.246.41/cgi-bin/passaudio/mpass.cgi
Anthony
http://194.51.246.41/cgi-bin/passaudio/mpass.cgi
Anthony