Absolare Push-Pull User manual

ABSOLARE Push-Pull Mono Amplifier
User Manual

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ABSOLARE Push-Pull Mono Amplifier User Manual 1.2

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ABSOLARE Push-Pull Mono Amplifier User Manual 1.2
Contents
1. General Description ...............................................................................................................4
2. Safety Issues and Warnings ...................................................................................................4
3. Unpacking and Placement .....................................................................................................5
4. Installing the Tubes ................................................................................................................6
5. Connecting the Cables ...........................................................................................................9
5.1. Power cables ...................................................................................................................9
5.2. Signal Cables....................................................................................................................9
5.3. Speaker Cables ................................................................................................................9
6. Operating the Unit ...............................................................................................................10
6.1. General Operation.........................................................................................................10
6.2. Setting the Bias Levels...................................................................................................10
6.2.1. 845 Bias Levels........................................................................................................11
6.2.2. EL34 Bias Levels ......................................................................................................12
7. Troubleshooting and Maintenance .....................................................................................13
8. Technical Specifications .......................................................................................................13

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ABSOLARE Push-Pull Mono Amplifier User Manual 1.2
1. General Description
The Absolare Push-Pull Mono Amplifier is a transformer coupled, zero feedback,
monoblock power amplifier, supplied in matched pairs for stereo amplification. It
features an all tube, point-to-point construction signal path. It is available in both
transformer balanced (XLR) and unbalanced (RCA) input versions.
2. Safety Issues and Warnings
- Be sure the voltage setting of the unit matches the applied voltage to power
input. Operating voltage is fixed and must only be changed by an authorized service
agent.
- Do not touch tubes while operating. Tubes are extremely hot devices and also
contain very high voltages.
- Do not open bottom covers. There are no user serviceable parts inside the units.
-Do not operate the amplifier without an output load. 4 –8Ωspeaker or
equivalent load should be connected to speaker terminals when the Amplifier is
operating.

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ABSOLARE Push-Pull Mono Amplifier User Manual 1.2
3. Unpacking and Placement
Each monoblock amplifier comes in a separate box.
After opening the top cover of each box, remove the upper layer of hard foam
material. You can then lift each Amplifier from its box cradling them with the cloth
that is underneath the chassis. Retain the cloth and all packing materials for future
use.
Each Push-Pull Mono Amplifier may become very hot during operation. You should
always place them on support feet and leave at least 2 inches (5 cm) clearance
above each Amplifier to allow sufficient ventilation.
Each Push-Pull Mono Amplifier is designed to be supported by separate support
feet. They do not have support feet fixed in place. Feet can affect the sound quality
significantly. Feet must be positioned underneath each unit in direct contact with the
aluminum base plate –not the leather clad MDF covers. There are three areas
where the aluminum base plate is exposed through openings in the leather clad MDF
bottom plate. You can use either three or four feet.
After each Amplifier has been placed in its final position, it can be lifted in turn to
locate the support feet –firstly lifting the back (for 2 feet) and then the front (for 1 or
2 feet) to be placed underneath the chassis. Adjusting their position will also affect
the sound to varying degrees, depending on the type of rack, location or interaction
with other equipment. For the most situations, the arrangement as shown in the
diagram below is a good starting point.

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ABSOLARE Push-Pull Mono Amplifier User Manual 1.2
4. Installing the Tubes
There are total of 5 tubes in each monoblock. Placement of tubes is shown below:

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ABSOLARE Push-Pull Mono Amplifier User Manual 1.2
The large 845 output tubes must be installed in correct orientation. The small
indicator pin on the lower side of the tube base must be aligned with the small hole
on the right-side of the tube socket, as illustrated in the figure below.
CAUTION: Incorrect positioning of 845 tube may seriously damage the amplifier!

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ABSOLARE Push-Pull Mono Amplifier User Manual 1.2
EL34 tubes have a small bump in the center as a key for correct positioning. Align it
with the corresponding notch in the tube socket while inserting.
The 12AT7 / ECC81 tube has one missing pin acting as a correct positioning key.
Align the missing pin with the missing hole in the tube socket while inserting.

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ABSOLARE Push-Pull Mono Amplifier User Manual 1.2
5. Connecting the Cables
5.1. Power cables
AC power input is via a standard IEC inlet socket. Operating voltage must only be
changed by an authorized service agent.
The quality of the power cable will affect the sound quality accordingly.
5.2. Signal Cables
RCA only version has only one RCA input connector.
Balanced (XLR) version has both RCA and XLR input connectors. There is a
selector switch (marked as SEL) that lets you connect desired input.
GAIN switch at HIGH setting lets you by-pass the 4:1 input transformer. When the
input transformer is by-passed, the sound level will increase due to level differences
of balanced and unbalanced connection standards, but you lose true balanced input
features and the system may become more susceptible to noise. This setting is
supplied to connect unbalanced XLR preamplifier outputs. Preamplifiers with true
balanced XLR outputs should be matched at the LOW gain setting.
5.3. Speaker Cables
Speaker binding posts can handle spade lugs, banana plugs or bare wire.
Polyethylene knobs are chosen instead of metal ones to reduce extra conductor
mass and eddy currents. Do not overtight them, the higher friction of the
polyethylene should safely secure the cables in place.
There are two impedance options for speaker connection. You should use the
closest matching output with your speaker manufacturer’s recommended value.
Since the output is transformer coupled, there is no output power difference when
using 4 or 8Ωspeakers.
Always use a combination of either 0 + 4Ω, or 0 +8Ωbinding posts. NEVER connect
speaker cables in a combination of 4Ω + 8Ω terminals.

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ABSOLARE Push-Pull Mono Amplifier User Manual 1.2
6. Operating the Unit
6.1. General Operation
Before turning on each Absolare Push Pull Mono Amplifier, be sure that all tubes are
installed and all cables connected correctly.
If you have changed 845 output tubes you should first minimize the bias settings (by
rotating to counter-clockwise) before turning-on the amplifiers and re-adjust the bias
settings. Please refer the bias settings section (6.2.1).
After turning each Amplifier on, the power indicator LED on the front face plate will
start to blink. You will not hear any sound until the indicator LED stops blinking to
illuminate continuously which indicates all the capacitors are charged and internal
voltages are stabilized.
Absolare Push-Pull Mono Amplifiers will be ready to operate approx. 40 seconds
after turning on the power and attain full sonic performance in 15 to 30 minutes.
6.2. Setting the Bias Levels
Measurement points for the bias levels are at the back panel:

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ABSOLARE Push-Pull Mono Amplifier User Manual 1.2
6.2.1. 845 Bias Levels
You have to adjust left and right 845 tube bias levels in each Amplifier separately.
Measurement is done via a multimeter at 2V DC (or 2000mV DC) setting. Insert the
black (-) probe into black socket and red (+) probe into one of the green sockets on
the rear panel. You should read a value about 0.500V (500mV) for each tube. If the
readings are different, then adjust the bias level via potentiometers near the EL34
tubes. A small flat screwdriver will be necessary to access internal bias trim pots.

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ABSOLARE Push-Pull Mono Amplifier User Manual 1.2
6.2.2. EL34 Bias Levels
There are no separate manual bias adjustments for the two EL34 tubes, but the
push-pull symmetry is important. With a multimeter at lowest DC volt measurement
setting, insert black and red probes into blue sockets. The adjustment point is in
between the EL34 tubes. You should aim for as close to 0.0V as possible by turning
the adjustment pot with a small flat screwdriver. If you cannot cross the zero value
(i.e. you only get positive or negative values in entire adjustment range) you should
turn off the unit, wait until tubes are cooled down, swap EL34’s and repeat the
adjustment procedure above. This will occur when one of the EL34 tube’s gain is
very different than the other one. If swapping the tubes does not solve the issue then
you should replace at least one of the tubes or use a ‘gain-matched’pair.

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ABSOLARE Push-Pull Mono Amplifier User Manual 1.2
7. Troubleshooting and Maintenance
Surface of the unit is dirty
Clean with a slightly damp cloth.
No power light
- Check AC line voltage.
- Check the main fuse.
Power light is on but 845 tube heaters
are not glowing
- Tube orientation is wrong, turn-off unit
immediately and correct the installation.
- Tube(s) are defective.
Power light is on, tube heaters are
glowing, but no sound
- Check the input cables, speaker cables
and source.
- Internal fuse for 845 tubes may be
blown out. Call your dealer.
Noise / hum in the sound
- Check grounding of power, input cables
and source.
If the problem is persistent, contact your nearest ABSOLARE dealer.
8. Technical Specifications
- Zero Feedback, Push-Pull Architecture
- Point-to-point construction
- Tubes: 2 x 845, 2 x EL34, 1 x 12AT7 / ECC81 (for each unit)
- Output power: 85 Watts
- Input: 1 x RCA (transformer balanced XLR optional)
- Input Sensitivity: 1.5 Volts (balanced input 1.5 / 6 Volts)
- Input impedance: 100 kΩ
- Speaker impedance: 4 –8Ω
- Bandwidth: 15 Hz –25 KHz +/- 1.0 dB
- Dimensions: 38.2 x 64.8 X 29.7 cm / 15" x 25.5" x 11.7" (W x D x H), excl. feet
- Weight: 42 kg / 92 lbs., net (each monoblock)

ABSOLARE USA LLC
40 Pemberton Road, Nashua New Hampshire, 03063
Phone: [phone]
E-mail: [e-mail]
ABSOLARE SERVICE EUROPE
Mozartstraat 157, 1962AL Heemskerk, Netherlands
Phone: [phone]
E-mail: [e-mail]

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ABSOLARE Push-Pull Mono Amplifier User Manual 1.2
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