Hafler 9505 Transnova Black

DESCRIPTION
The 9505 model sets a new standard of sonic excellence for professional
applications. Utilizing Jim Strickland’s JFET input/MOSFET output trans•nova
circuitry along with his brilliant DIAMOND driver stage creates the ultimate
balanced amplifier.
The TRANSconductance Nodal Voltage Amplifier
(patent #4467288) is a simple three-stage design
delivering unparalleled speed and accuracy. The
Dynamically Invariant Amplification Optimized
Nodal Drive combines the linearity of Class A op-
eration with the current headroom of a Class B sys-
tem, resulting in a significant advancement in the
art of power amplifier design. The sonic result of all
this unique technology presents a deep, wide sound stage with in-
credible musical transparency and detail.
Many so-called “balanced” amplifiers are merely conventional unbalanced
designs with a balanced-to-unbalanced converter (usually IC op-amp based)
preceding the power amplifier. The 9505, however, is a true differential input
power amplifier.

ARCHITECT’S AND ENGINEER’S SPECIFICATIONS
The audio power amplifier shall be a fully balanced, discrete solid state
design employing JFET inputs and 16 lateral power MOSFET output devices. It
shall be constructed on a 16 gauge steel chassis utilizing convection air
cooling.
Each channel shall be rated for a minimum of 250 watts into an 8 ohm load and
375 watts into a 4 ohm load with both channels driven. In bridged mono mode,
the amplifier shall produce at least 750 watts into an 8 ohm load. A switch shall
be provided for stereo or bridged mono operation and all power ratings shall
be measured from 20Hz-20kHz with less than 0.2% THD.
The amplifier’s back panel shall provide a switch to select Unbalanced inputs
via gold-plated RCA jacks or Balanced inputs via combination XLR and 1/4”
phone jacks. The back shall also utilize gold-plated 5-way binding posts for
output connectors and a switch to isolate or connect the signal ground to the
chassis ground. The amplifier shall include a 3-wire grounded AC line cord
and a switch to operate the UI power transformer on 120V/60Hz AC mains. An
optional transformer for 230V 50-60Hz operation shall be available.
The amplifier’s front panel shall incorporate a lighted main power switch and
have rack handles. The amplifier shall fit standard 19” EIA rack mounting
requirements utilizing 3-rack spaces. The dimensions shall be 19” Wide, 121
⁄2”
Deep* (plus 1” for handles), 51
⁄4” High (excluding feet), and be finished in black
with a net weight of 50 pounds. It shall be a Hafler 9505.
Starting with the much acclaimed trans•nova amplifier core, each (+) and (–)
port of the input differential stage has been buffered with a high impedance
buffer pair. This allows direct signal access to the differential amplifier, with-
out conversion to unbalanced form. Deactivating the balanced mode is ac-
complished via a rear panel switch that grounds the (–) balanced inputs,
effectively converting the amplifier to unbalanced operation.