Bob Carver CHERRY 180 User Manual

Bob Carver CHERRY 180 User Manual

Cherry 180 watt vacuum tube amplifier

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CHERRY 180 WATT VACUUM TUBE AMPLIFIER
This manual provides general, ongoing use and safety information of the Cherry 180
Mono Block Amplifier.
General
The new series of mono block amplifiers are the perfect blend of form and function and the ideal choice
for serious music listeners. The Cherry 180 is conservatively rated at 180 Watts rms into 8 ohms and was
designed to drive the most demanding speakers. These amplifiers offer extreme performance that is
difficult to believe, and each amplifier features a high impedance input, an automatic DC
a
"set and forget" bias adjustment, and low idle current which greatly increases output tube life. They
have ultra-wide bandwidth output transformers with interleaved windings capable of the most nuanced
voice as well as huge peak output capacity. Selectable feedback control allows the user to change the
sound of the amplifier from vintage classical to modern contemporary.
From a listening perspective these amplifiers provide a warm, rich sound with a sumptuous and
enveloping sound stage, a great front to back depth of field, and very tight, pin-point imaging within that
larger acoustic. A special current feedback circuit allows the amplifier to "listen to the room" via
feedback from the speakers acting as microphones (using the law of reciprocity). The room-speaker-
amplifier interaction provides a sense of believable ambience and acoustic space that is thoroughly
realistic and quite enjoyable. Additionally, the transformer output impedance allows the signal to follow
the impedance curve of the speaker system, allowing more voltage to be delivered to the loudspeaker at
very low frequencies – providing an exceptional and satisfying low end response.
Safe Operating Conditions
Because of the high power available it is necessary to emphasize some prudent and safe operating
conditions.
1. Be cautious when lifting the amplifier. It weighs 42 pounds. Make certain that what it is placed
on can support the weight.
2. The amplifier should be situated so that its location or position does not interfere with its
proper ventilation. The amplifier should never be placed near or over a radiator or heat
register. The amplifier should not be placed in a built-in installation such as a bookcase or
(VTA180M)
restorer
circuit,
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Summary of Contents for Bob Carver CHERRY 180

  • Page 1 The new series of mono block amplifiers are the perfect blend of form and function and the ideal choice for serious music listeners. The Cherry 180 is conservatively rated at 180 Watts rms into 8 ohms and was designed to drive the most demanding speakers. These amplifiers offer extreme performance that is...
  • Page 2: Circuit Description

    cabinet that may impede the flow of air around the unit. Do not place this amplifier directly on carpeted floors. 3. Do not operate the amplifier plugged into an ordinary extension cord. Heavy duty extension cords (14 ga. or heavier) have adequate wire size and will not overheat. 4.
  • Page 3: Volume Control

    FEEDBACK SWITCH The small switch mounted on the top front of the chassis controls the amount of negative feedback. When the toggle handle is pushed LEFT (classic), the feedback is approximately 20 dB, a value used by most vintage amplifier designers and is my personal preference. When toggled RIGHT (contemporary), feedback is limited to about 11 dB.
  • Page 4: Speaker Connections

    ADJUSTING THE OUTPUT TUBE BIAS The front panel incorporates a bias meter. Turn the volume control all the way down (full counter clockwise) while performing bias adjustments. Use a small screwdriver and adjust the bias control (located on the rear of the amplifier, “Tube Bias Adjustment”) for 100 mA after the unit has warmed-up for 20 minutes.
  • Page 5: Power Switch

    Replace one-by-one, until a fuse blows or one of the tubes does not show a bias current. Replacement tubes are available for free from the Bob Carver factory if one blows under the one year tube warranty period. If a tube blows beyond the warranty period we recommend you purchase a replacement from us as we purchase large amounts of tubes and provide a very competitive price for a tested, known good tube from our preferred tube supplier.
  • Page 6 TUBE TESTER The front panel meter may be used to test the tubes. Remove all the large power output tubes; plug the amp into the AC wall socket with the main rear panel power switch OFF. Insert the tube you wish to test into socket #6 (the far right front socket).
  • Page 7 Cherry 180W Mono Block Amplifier Specifications Number of Line Inputs Input impedance 100 k ohms Input Stage 12AX7 current sourced long tailed balanced pair Pre-driver Stage 12AT7 current sourced long tailed balanced pair Automatic DC Restoration 6AL5 Nominal Voltage Gain 30 dB (into 8 ohms) Output Stage Configuration 3 complimentary sets of KT88s in a push-pull configuration (6 total)
  • Page 8 Servicing — Do not attempt to service these amplifiers yourself, as opening or removing the bottom cover WILL expose you to dangerous high voltages. Refer all servicing to Bob Carver LLC. Damage Requiring Service — These Amplifiers should be serviced by Bob Carver LLC when:...
  • Page 9 Lightning Storms — Unplug this amplifier during lightning storms or when unused for long periods CAUTION: - Changes or modifications not expressly approved by BOB CARVER LLC will void the manufacturer’s warranty. P a g e...
  • Page 10 WARRANTIES: Bob Carver LLC warrants that all equipment manufactured by us to be free from defects in materials and workmanship for seven (7) years (vacuum tubes – one (1) year). This warranty shall not apply (a) to equipment not manufactured by Bob Carver LLC (b) to...

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