Simply the Best - LiveWave AMP

[Stee]

this amplifier have a very good sound
is modified from MCM 100 Watt Subwoofer Amplifier Module

http://www.mcmelectronics.com/product/50-6272
with big Sanken final stage
and 8x 4700uF/50V little capacitors on PSU

also using digital input DAC: 8 x TDA1543 in parallel
another lucky idea

http://www.diyfidelity.com.au/product_info.php?cPath=0_35&products_id=41
modified without AD847 I/V converter and filter
+ 3uF capacitor output + potentiometer for volume adj

 

[fizzard]

Something looks very wrong with the amplifier schematic. Are you sure it's correct?

As far as the DAC goes NOS == NFG.

 

[Stee]

sure is correct

this lucky idea is use a good op-amp (fet inp)
like fully-differential one
takes current from supply

sound better of NAD YAMAHA and ROTEL

i have DENON 1500 series DAC...
this Australian TDA1543 NOS have "LiveWave"
like no other

 

[whoandcar]

Your are using a TL072 with a 43 Volt supply????

 

[CBS240]

 

[djk]

He didn't draw it correctly.

http://www.mcmelectronics.com/content/ProductData/Spec Sheets/50-6272.pdf

 

[Stee]

if you see pdf drawing

there are transistor on supply just for enable circuit
two resistor made voltage shunt

also i have reduce NFB with a potentiometer
there is a little distorsion
but more and more armonics

 

[Stee]

Version "2" ---> Cap-Out

see this modification

short the capacitor of voltage balance in NFB
and add 6X 4700uF capacitors on OUT

this solution expand your sound like a tube amp
because don't force the zero point on output
similar of transformer push-pull

next upgrade Ver. 3
fully complementary bipolar input...

 

[Stee]

Version 3 ---> Complementary IN

from Rotel RB981
this will be the upgrade
on mirror stage

 

[Stee]

Conclusions:

the traditional method to adjust automatically the dc offset outgoing from solid state audio amplifiers
is completely wrong from the point of view of the dynamic behaviour and integrity of musical timbre
because it adds compression emphasis to signal depending on the area described by the same

viceversa, the method of Free Run Mode®
allows through a decoupling of balanced capacitors
a proper transfer of information
and returns a natural sounding.

 

[AndrewT]

Re: Conclusions:

the traditional method to adjust automatically the dc offset outgoing from solid state audio amplifiers
is completely wrong from the point of view of the dynamic behaviour and integrity of musical timbre
because it adds compression emphasis to signal depending on the area described by the same

viceversa, the method of Free Run Mode®
allows through a decoupling of balanced capacitors
a proper transfer of information
and returns a natural sounding.

What does that mean?

 

[fizzard]

What the idea? Use the current in the power pins to drive the circuit?

 

[Stee]

Negative input must be pure

see the figure belove

if you have an average voltage rating
which subtracts the input signal
the result is a compressed wave

Furthermore, the ramp climb
will never behave equivalent
to ramp down

 

[whoandcar]

Re: Conclusions:

...viceversa, the method of Free Run Mode®
allows through a decoupling of balanced capacitors
a proper transfer of information
and returns a natural sounding.

You simply have translated thi input capacitor to the output. The effrect is the same. Bass cut.

 

[Stee]

OCN - Output Capacitor Ness

put in the output two or more capacitors
in balanced configuration
to decopuling DC on loudspeakers
don't create emphasis

if you have a pair of bipolars
with the same gain (selected)

you can feel the difference
when connect ground to the central point:
nothing

viceversa
have a resistor + single capacitor on input (integrator)
sure force your offset on zero voltage
but need time to discharge this value

try to short and listen LiveWave

 

[whoandcar]

It is only a matter of time constants - (freq response).

 

[Stee]

frequency response is sufficient

the difference
at a glance
is the architecture :

the output capacitors regenerating another
because in parallel on the load

in the serial configuration instead
(the negative input integrator):

the load is in series
then suffers a delay
therefore involves a deflection

you can feel difference just with a simple test
trusted me, is not a detail

 

[Stee]

example

STD DC OFFSET

 

[Stee]

NAD Solution

automatic DC offset ADJ
with diodes limiter

 

[AndrewT]

Re: NAD Solution

automatic DC offset ADJ
with diodes limiter

no that limits the voltage across the electrolytic cap to prevent it blowing up.
Normally this cap sees little or no audio voltage across it, since the two input filters limit the bandwidth of the amplifier.