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VSSA Lateral MosFet Amplifier

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#2,041
Hi,
thank,
Originally Posted by tritosine
BYRTT 8 PCB set
CaféNoir 6 PCB set
ColinAlex 8 PCB set
DavorXXL 6 PCB set
DuffyDawg 4 PCB set + 4 SMPS400
electromf 4 PCB set
badrisuper 2 PCB set
volavola 2 PCB set
JethroTull 2 PCB set
kp93300 2 PCB set
momomo67890 4 pcb set
ua3grn 6pcb set
mj777 2pcb set
mkusan 2pcb set
Odysseas 4pcb (2 pairs)
hcbonfim 2pcb set
Albrerta 2pcb set
dw1narso 2 pcb set (1 stereo) + extra output device pairs & isolators (for stereo if possible)
supernet 2 pcb set
milandks 4pcb set
tjencks 2pcb set
quanghao: 2pcb set
audionootje: 4pcb set (2x stereo)
tritosine 4pcb (2 pairs)
Bobo le Chat 2 pcb set
AP2 2pcb set+2pcb empity (i need this also)

regrds
 
#2,042
Hi
BYRTT 8 PCB set
CaféNoir 6 PCB set
ColinAlex 8 PCB set
DavorXXL 6 PCB set
DuffyDawg 4 PCB set + 4 SMPS400
electromf 4 PCB set
badrisuper 2 PCB set
volavola 2 PCB set
JethroTull 2 PCB set
kp93300 2 PCB set
momomo67890 4 pcb set
ua3grn 6pcb set
mj777 2pcb set
mkusan 2pcb set
Odysseas 4pcb (2 pairs)
hcbonfim 2pcb set
Albrerta 2pcb set
dw1narso 2 pcb set (1 stereo) + extra output device pairs & isolators (for stereo if possible)
supernet 2 pcb set
milandks 4pcb set
tjencks 2pcb set
quanghao: 2pcb set
audionootje: 4pcb set (2x stereo)
tritosine 4pcb (2 pairs)
Bobo le Chat 2 pcb set
AP2 2pcb set+2pcb empity (i need this also)
Meganinja 2 set ( stereo )

regrds
 
#2,045
On my experience, bridged amplifiers present some real sonic advantages.

First, if you can achieve symmetrical cabling, the rejection remove a lot of unwanted parasitic informations due to ground current leakeages.
Second,, at the same levels, you divide by two the currents from each rail of the power supply, witch is good for dynamic.
Third, the perfectly symetrical function remove some distortions.

The price we pay is a reduced damping factor, that you can cancel with a motional feedback compensation of each loudspeaker driver, witch is a plus, both for linearity of the passive filters, and linearity of the impedance curve, with VERY positive result on the reproduction of instant dynamic details.
 
#2,046
Hi Esperado thanks for valueable information
Yes use the same precision ekstern symmetrical wiring as in VSSA module itself i can imagine would benefit the setup.
Last two lines i have not knowledge for understanding at moment, maybe by research later.
But looks like one can bring performance in VSSA even higher with such setup, even if power is not needed.
BR Ricky
 
#2,047
Meganinja said:
Hi
BYRTT 8 PCB set
CaféNoir 6 PCB set
ColinAlex 8 PCB set
DavorXXL 6 PCB set
DuffyDawg 4 PCB set + 4 SMPS400
electromf 4 PCB set
badrisuper 2 PCB set
volavola 2 PCB set
JethroTull 2 PCB set
kp93300 2 PCB set
momomo67890 4 pcb set
ua3grn 6pcb set
mj777 2pcb set
mkusan 2pcb set
Odysseas 4pcb (2 pairs)
hcbonfim 2pcb set
Albrerta 2pcb set
dw1narso 2 pcb set (1 stereo) + extra output device pairs & isolators (for stereo if possible)
supernet 2 pcb set
milandks 4pcb set
tjencks 2pcb set
quanghao: 2pcb set
audionootje: 4pcb set (2x stereo)
tritosine 4pcb (2 pairs)
Bobo le Chat 2 pcb set
AP2 2pcb set+2pcb empity (i need this also)
Meganinja 2 set ( stereo )
coolewater 2 pcp set
regrds
Click to expand...
 
#2,048
BYRTT said:
Last two lines i have not knowledge for understanding at moment
Click to expand...
May-be i will open a topic on this subject, as it seems a lot of people had not experienced (and used) this easy tip to get the best from the best amps ( Vssa being one of them).
It is out of topic here, i think i will open a topic about impedance compensation of loudspeakers.
Just few words about, if L.C. do not disagree.The typical impedance of a moving coil loudspeaker look like this:

IMAGE1%202.GIF


Here, you can see the resonance peak (at 75Hz) , followed by an increase of impedance due mainly to the inductance of the coil. (Little accidents due to membrane fractioning and suspension resonances).
Lot of people know (and use) Zobels in order to flatten the impedance in the treble, canceling the inductance by a parallel network ( simplified datas about this here : TA Speaker Topics - Neutralizing L(e) with a Zobel)
You can achieve the same with the main resonance, by a compensation net work (an inductance+a capacitance+ a resistance in serial, wired in // with the speaker).
Not enough room, here to explain why such a network, because it change the Smalll an Thiele parameters continue to work as well once the speaker is in its enclosure (closed or bass reflex), despite the changes in resonance frequency.
The result can be near flat on the all range of the speaker.
Just to say that it increase a lot the damping of the speakers, and help to calculate the filters, as they are charged to a now flat impedance.
Good for phase response too.
The result for the amp is it has no more to deal with non constant current/voltage ratios. You can achieve this way a near totally flat impedance curve of your enclosures, and an more linear charge for the amplifier.
 
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#2,051
Hi Christophe, thanks.
My research now unnessesary than you made here vere nice understandable explanation.
with motional feedback compensation I now have new small error in system to try to cancel. If we can hear the timing this error cancel is doing will show, but once again as with other circuits in audio line if not wideband enough we always get the highs shouted out with arrival before lover (here because of higher z=lighter load for amp) + speaker/cabinet resonans a much speedier bass SPIKE.
Is attached picture circuit in the direction to go for motional feedback compensation, because else if the induktor or cap gets active signal trace we also get those 90° fase deviation ?
BR Ricky
 

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#2,054
BYRTT 8 PCB set
CaféNoir 6 PCB set
ColinAlex 8 PCB set
DavorXXL 6 PCB set
DuffyDawg 4 PCB set + 4 SMPS400
electromf 4 PCB set
badrisuper 2 PCB set
volavola 2 PCB set
JethroTull 2 PCB set
kp93300 2 PCB set
momomo67890 4 pcb set
ua3grn 6pcb set
mj777 2pcb set
mkusan 2pcb set
Odysseas 4pcb (2 pairs)
hcbonfim 2pcb set
Albrerta 2pcb set
dw1narso 2 pcb set (1 stereo) + extra output device pairs & isolators (for stereo if possible)
supernet 2 pcb set
milandks 4pcb set
tjencks 2pcb set
quanghao: 2pcb set
audionootje: 4pcb set (2x stereo)
tritosine 4pcb (2 pairs)
Bobo le Chat 2 pcb set
AP2 2pcb set+2pcb empity (i need this also)
Meganinja 2 set ( stereo )
coolewater 2 pcp set
mikvous 2 pcb set
 
#2,055
BYRTT 8 PCB set
CaféNoir 6 PCB set
ColinAlex 8 PCB set
DavorXXL 6 PCB set
DuffyDawg 4 PCB set + 4 SMPS400
electromf 4 PCB set
badrisuper 2 PCB set
volavola 2 PCB set
JethroTull 2 PCB set
kp93300 2 PCB set
momomo67890 4 pcb set
ua3grn 6pcb set
mj777 2pcb set
mkusan 2pcb set
Odysseas 4pcb (2 pairs)
hcbonfim 2pcb set
Albrerta 2pcb set
dw1narso 2 pcb set (1 stereo) + extra output device pairs & isolators (for stereo if possible)
supernet 2 pcb set
milandks 4pcb set
tjencks 2pcb set
quanghao: 2pcb set
audionootje: 4pcb set (2x stereo)
tritosine 4pcb (2 pairs)
Bobo le Chat 2 pcb set
AP2 2pcb set+2pcb empity (i need this also)
Meganinja 2 set ( stereo )
coolewater 2 pcp set
mikvous 2 pcb set
still4given 2 PCB set
 
#2,056
BYRTT said:
Hi Christophe, thanks.
My research now unnessesary than you made here vere nice understandable explanation.
with motional feedback compensation I now have new small error in system to try to cancel. If we can hear the timing this error cancel is doing will show, but once again as with other circuits in audio line if not wideband enough we always get the highs shouted out with arrival before lover (here because of higher z=lighter load for amp) + speaker/cabinet resonans a much speedier bass SPIKE.
Is attached picture circuit in the direction to go for motional feedback compensation, because else if the induktor or cap gets active signal trace we also get those 90° fase deviation ?
BR Ricky
Click to expand...

You must know the L of the speaker and then the easiest way is to use these formulas (you don't need inductor, just R and C):


C=L/RxR (I do not know how to type superscript, therefore RxR)

R=Rdc+Rdc/2

Praxis showed that R must be higher that Rdc of voice coil. If R = Rdc (of voice coil), impedance of speaker flattens at too low value, hence +Rdc/2.
 
Last edited:
#2,057
Hi ivanlukic very much thanks for tips.
I guess i also can check/measure reallife result with the DATS unit from Dayton Audio, i bought this device in januar from Intertechnik.de for other purposes with goal for bringing my speaker projekt SQ higher (See Picture for DATS device).
If this unit can inspire others for having big small helper in speaker solution see Dayton Audio website (think the unit is born by John Murphy at TrueAudio and eaylier branded WT3, but now with new software and more purposes, eg making ThieleSmall data on unknown unit).
BR Ricky
 

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#2,058
ivanlukic said:
You must know the L of the speaker...
Click to expand...
I was talking of motional feedback compensation, not Zobel (L compensation).
Motional compensation need you measure the -3db frequency points at each side of the resonance peak of the (broke in) speaker.
About Zobel (inductance compensation), it is better to measure too, as Pure L compensation is not flat enough (Eddy currents etc.). Need a more complex circuit than simple rc. Usually an other serial R+C in // with the main C.
But, as i said, it is off topic in this thread, and was just about how to compensate better for not losing damping when bridge operation. Also beneficial, of course with a single mode amplifier.
 
Last edited:
#2,059
Esperado said:
I was talking of motional feedback compensation, not Zobel (L compensation).
Motional compensation need you measure the -3db frequency points at each side of the resonance peak of the (broke in) speaker.
About Zobel (inductance compensation), it is better to measure too, as Pure L compensation is not flat enough (Eddy currents etc.). Need a more complex circuit than simple rc. Usually an other serial R+C in // with the main C.
But, as i said, it is off topic in this thread, and was just about how to compensate better for not losing damping when bridge operation. Also beneficial, of course with a single mode amplifier.
Click to expand...

I prefer the solutions where diy-er does not need expensive lab instruments and complicated measurements, simple working solutions that satisfy diy-ers needs.
Solutions that do not require complex multi element circuits. Zobel inductance compensation (RC) is such circuit. This is because I do not have lab, scope, etc. I believe that many diy-ers do not have lab, so it's pointless to suggest complicated solutions that are possible to only very small number of diy-ers. I am glad that some forum members have good labs and are willing to share some of their experiences and results, but most forum members do not have lab. Most of us are amateurs without lab.
 
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