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Tu b e
Replacement
FIG. A
Tube life span depends upon things such as amplifier load and
playing style. Power amplifier output tubes have a shorter life
span than pre-amplifier tubes and usually need attention first.
A simple way to check if your tubes are noticeably worn, is to
replace them with a spare new set and listen for any
improvement in tone quality:
ALWAYS unplug the amplifier when replacing tubes.
Replace
tubes
ONLY
with
the
proper
type
(see “Specifications” below).
CAUTION: let tubes cool before handling, they get HOT...
1. Replace the OUTPUT tubes (V9, V10, V11, V12 in FIG. A)
with a new set. Set BIAS and BALANCE. Listen for any
improvement.
2. Keep the new OUTPUT tubes in place. Replace the PREAMPLIFIER tubes (V1, V2, V3, V4, V5, V6, V7, V8 in FIG. A)
with a new set. Listen for improvement.
3. Keep the new PRE-AMPLIFIER tubes in place. Put the
original OUTPUT tubes back in the amplifier. Set BIAS and
BALANCE. Listen for any improvement.
If there is a noticeable improvement in sound quality after any
of the 3 steps above, keep the tube arrangement that sounds
the best. Obtain new spare tubes for future testing and tube
replacement.
Specifications
TYPE :
PR 449
PART NUMBER :
021-5700-000 (120V, 60Hz) USA,
021-5760-000 (230V, 50Hz) Europe
021-5740-000 (230V, 50Hz) UK,
021-5730-000 (240V, 50Hz) Aust
021-5770-000 (100V, 50/60Hz) Japan
POWER REQUIREMENTS :
360W
POWER OUTPUT :
100W RMS (Full Output), 25W RMS (1/4 Output)
1kHz sine into 4 ohms @ <5% THD (Presence @ “1”)
INPUT IMPEDANCE :
1M ohm
TUBES :
Four 6L6GC (P/N 053980), Two 12AX7A (P/N 023572),
Five 12AX7WA (P/N 013341), One 12AT7 (P/N 023531)
FUSES
F200:
F201:
F1 & F2:
T4A 250V (110V, 120V units), T2A 250V (230V, 240V units)
T5A 250V (Internal Filament Fuse, 230, 240V units)
T100mA (all units)
SPEAKERS :
Fender 12 in., 8Ω, (P/N 037617)
FOOTSWITCH :
4-Button: Channel, Effects Loop, Reverb, Tremolo (P/N 057025)
DIMENSIONS
WEIGHT :
Height:
Width:
Depth:
19 7/8 in.
26 3/8 in.
12 27/32 in.
(50.7 cm)
(67.3 cm)
(32.8 cm)
80 lbs.
(36.3 kg)
Product specifications are subject to change without notice.
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