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EA IAmp
4400 |
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The basic Marantz PM4400 is
a very musical and great platform to mod.
Its weakness is mainly lost of control of the bass (due to
under-rated original transformer) and loss of transparency, due to the
various tone controls and balance used.
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| Green
Boxed Section |
| Original
puny EI transformer changed to 2 transfomer;
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| Big
Toroidal for power stage |
| EI for
Preamp stage. |
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| Yellow
Boxed Section |
| Critical
Caps and diode changes |
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| Blue
Boxed Section |
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All non essential
functions that will deteriorate the sound like source direct and
bass/treble boost is bypassed. The
signal from the source selector gets to pass thru a resistor (not the
potentiometer!!) in a shunt circuit and straight to the amp section. |
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Effective Audio Amp 4400A Mod
Details
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Original
under-rated single transformer changed to 2 transformer.
1 over-rated (2 times over-rated!!) Toroidal transformer for
power stage and 1 EI type for pre-amp stage for maximum isolation.
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All
tone control and balance control bypassed.
The signal from the source selector goes to the amp stage
directly thru 1 resistor only. The
volume circuit is changed to a shunt type.
This allows the signal to travel thru 1 resistor only and does
not pass thru the volume control.
The volume control still controls the volume but not directly  ;
Remote volume control still works
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Original
generic diode bridge changed to discrete FRED diodes.
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Main
Caps for power amp changed to Elna special Audio Grade(black series)
type. Input coupling caps
changed to Blackgate BG N series.
Elna cerafines and Rubycon ZL types used at other critical
locations. Film caps bypass at critical locations.
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Circuit
and grounding changes to improve sound and lower noise.
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Chasis
Damping with Damping sheets.
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IEC
cut for using external power cord.
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Input
mains filtering with solen film caps.
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| Total
Mod Cost w/o amp |
SGD 600.00 |
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| Total
Mod Cost with amp |
SGD 900.00 |
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| Additional
Options |
| Eichmann
Pure Copper Cable Pods |
SGD 100.00 |
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Change
of Speaker connectors to above
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Loan set
available for your trial in the comfort of your home.
Please contact
me for
arrangement.
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