Genz-Benz STREAMLINER 900 - Manual (Page 3)

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EQUALIZATION – The Streamliner™ 900 contains a 3 band equalizer with a user switchable midrange center
frequency control. This equalizer is best described by breaking it into its component parts, the shelving bass/treble
section and the midrange band-pass section. The Bass and Treble shelving filters are modified passive designs
based on the classic Baxandall topology that was developed in the 1950’s by Peter Baxandall. This type of eq is
nicely suited for instrument amplification (in addition to classic professional recording consoles) due to its gentle
slopes and musical transition between the two bands. Our modified design keeps the interactive nature of a
Baxandall design to a minimum while retaining all of the benefits.
The Bass frequency is a shelving type with approximately +/-12dB of effective cut/boost at 55 Hz.
The Treble frequency is a shelving type with approximately +8/-12dB of effective cut/boost at 4K Hz and
approximately +/- 12 db at 12.5K Hz. In the boost position it offers the advantage of boosting the highs for clarity,
without drastically increasing the upper mids, providing a more tonally balanced top end. In the cut mode it acts
much like an instruments passive tone control.
The active tube driven mid frequency filter features +/-12 dB of effective cut or boost with a bandwidth approximately
1 octave wide. The center frequency of this filter is user adjustable to 220Hz, 600Hz or 2.5kHz with the Mid Freq
switch.
MASTER VOLUME – The Master Volume control adjusts the overall volume of the amplifier and the effects return.
Typically, best results are obtained when this control is operated between the 9:00 and 3:00 positions. The Master
Volume control adjusts the signal level after the Effects Return jack.
POWER SWITCH - The Power switch provides the power to the amplifier from the AC mains source. The
Streamliner™ contains a fully automatic turn-on time delay (approx. 20 seconds) of the output power amplifier to
allow the high gain tube preamp to fully bias up and stabilize before audio is allowed to pass. This is similar to the
standby procedure recommended on classic all tube bass and guitar amps. The RED WARM-UP LED will illuminate
during this period. The amp is ready to play as soon as the LED disengages.
MASTER SECTION STATUS INDICATORS -
• The BLUE “POWER” light indicates that the amplifier is ON and the high voltage power supplies are active.
• The RED “WARM-UP/PROTECT” LED provides 2 functions. During the Turn-On process of the Streamliner™
this light will illuminate for approx 20 seconds while the tube preamp is allowed to bias up and stabilize. When
the amp is in use, after the Warm-Up period, the LED also can indicate when the amp enters “protect” mode. It
will illuminate during any internal fault condition such as thermal and overcurrent faults. If this happens, first turn
the amp off, check for a blocked cooling fan, wait 1 minute and try again. It the amp remains in protect, remove the
speaker cable and try again. If the amp now comes out of protect this is an indication of a short circuited load and
your speaker cable is the most likely problem. If the Protect LED remains on, consult a service technician.
• The AMBER “PEAK” LED indicates that the power amp is near its maximum power. Under high output conditions
it is normal for this LED to light with the strongest pulses of the signal. Driving hard beyond this point will cause the
amplifier to gradually begin to clip which may become audible. If using a very mid focused bass tone and while
driving the amp hard, it may be possible to hear some distortion before the PEAK LED is lit. This is normal and is a
result of the harmonics generated by the preamp tubes during the overdrive process being more audible since the
ear is more sensitive to upper midrange frequencies.
3DPM™ -- 3 DIMENSIONAL POWER MANAGEMENT – Our proprietary 3DPM™ technology insures greater and
more solid sounding output while retaining the feel and playability of a more traditional tube based power amplifier.
When driving the power amp hard, the result is increased heft and girth while maintaining the dynamics and
articulation of the individual notes. This circuitry achieves a more 3 dimensional tone and feel, like a tube amplifier
power section, without the anemic flatness other amplifier designs can exhibit.