Mesa/Boogie BASS STRATEGY Eight:88, Руководство пользователя

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Owners - it is not necessary to remove the Bottom Cover on your PRODIGY to set the BIAS when replacing Power Tubes. Located
on top of the chassis are two 2-position mini-toggle switches, one for each quartet of KT-88s, along side two precision Trim Pots and
two LEDs. The BIAS ADJUST circuit allows for precise setting of the Bias for the Technician using a Current Meter—or—a “near
perfect” setting of the Bias for the not-so-technically-minded Musician/Owner with a very small “flathead” screwdriver. Owners and
non-technicians can adjust their Bias when re-tubing by setting the BIAS ADJUST Switch to SET BIAS and following the Bias Adjust-
ment Instructions below.
Like some other amplifiers, this system measures current at the cathodes which, with no signal running through the amp, is the same
as plate current (plus the minute screen current). But unlike other systems, the BIAS ADJUST switch entirely removes the adjustment
circuit and its cathode resistors from the audio chain when adjustment is complete and it is set back to OPERATE.
OPERATE: This position is for playing your amplifier. The BIAS ADJUST switch should be set here at all times unless you are adjust-
ing the BIAS after replacing a worn set of power tubes.
Technicians—you know what to do. Set BIAS ADJUST SWITCH to SET BIAS Position—Check and Adjust Cathode Current: Set
both rows to 120 – 125 mA.
This Bias Adjust Mode also allows for a near-perfect Owner Achievable Bias Setting with nothing more than a small jewelers flat-head
screwdriver. Again—adhere to the directions below and adjust your Bias ONLY after replacing worn power tubes with a new set.
NOTE: When the Bias switch is in the Set Bias position, the Mute LED will be on and the amp will be muted. This is to prevent the
amp from passing signal while the Bias circuit is engaged.
Owners—the following simple procedure is also printed on the chassis top (Tube Deck) and consists of the following steps:
SET BIAS (For Non-Technicians)
1. Set both BIAS SWITCHES (located on the upper Rear Tube Deck) to OPERATE. Make sure the amp is set to FULL POWER—
setting the Bias while in HALF POWER will give an incorrect measurement.
2. Follow the Cold-Start Procedure under POWER in the Front Panel Section of this manual and Switch the PRODIGY to STAND-
BY ON after three minutes. Then allow the amp to warm up for another 5 minutes (POWER and STANDBY ON).
3. Set one row’s BIAS SWITCH to SET BIAS (leave other row set to operate). The MUTE circuit is activated by this setting and you
may proceed with the procedure with no load connected to the SPEAKER OUTPUTS. BUT DON’T FORGET TO CONNECT A
LOAD when you are finished with the BIAS setting procedure!
4. Using a small flat screwdriver, twist the trimmer pot for that row counter-clockwise until the LED just goes dark... then:
5. Twist the trimmer EXACTLY ONE HALF turn clockwise toward greater brightness—Stop there. You’re Done!
6. Repeat the SET BIAS procedure for the second row of KT-88s.
7. Set the BIAS ADJUST switch back to OPERATE and Play! Your BIAS is set for optimum performance and Tone. CHECK YOUR
SPEAKER OUTPUTS! Don’t forget to connect a load (cabinet) BEFORE playing!
NOTE: IMPORTANT! It is important when re-tubing your STRATEGY, to make sure that all the power tubes are matched to each
other. This is critical to achieving a proper Bias Setting and also for obtaining the best performance from your amplifier. If your local
dealer doesn’t have a complete set of identically matched KT-88s (Preferably MESA Tubes), you may order perfectly matched sets
direct from us at www.mesaboogie.com or, by calling 707-778-6565 and asking for a Product Specialist - who will be happy to assist
you with your purchase of these matched sets of KT-88 Power Tubes.
NOTE! Original STRATEGY OWNERS! MESA offers a HALF-PRICE DISCOUNT on your FIRST SET of Replacement Power Tubes.
This can be obtained by ORDERING DIRECT FROM THE FACTORY ONLY and the order must be accompanied by your ORIGINAL
SALES RECEIPT as proof of ownership.