|
AC
Outet: Utility outlet that remains on despite position of AC
switch. This is very useful on stage. When linking Boogies,
it is best to use isolated AC sources as one can run into the radio
phenomonon where the amps act as radio receivers picking up FM! Make
sure that you use high quality coaxial cables. The amps are very
high gain and can pick up all sorts of radio frequency (RF), but NEVER
let any amp head try to cure your amp of RF. Boogies as a rule
don't suffer this curse, but if you combine them in certain configurations
and use cheap cables, some RF will result. RF is staus quo in
lesser amps, especially Fender, don't let someone sell you a line
of crap that your Boogie is like all amps and needs "holy water"
to cure it!
Slo-Blo
Fuse: Generally never an issue unless there is a bad power
tube. If it goes, replace the power tubes first and then fuse
to prevent further blowouts.
Ground
Switch: A three position switch with the center position being
off, A to left, B to right. Useful in reducing buzzes that originate
from AC power wiring outside the amp. Best to leave in center
off position unless either A or B helps. When in the center,
the Boogie cannot be the source of ground shocks to micrphones.
Slave
Out & Level: Provides a direct output feed the faithfully
captures the preamp and amp sound. The level allows one to ensure
the adequate signal strength. This output is useful when slaving
to another Boogie's Preamp out/Power Amp in, or to a mixing board. Start
with the level off and increase as needed. Higher Slave settings
with lower Master 1 result in less overall line noise.
Generally set to about 25%
Effects Send&Return:
A useful feature to hook up external effects, or other Boogies. Modified
from the Mark II, the new patch points offer a low noise connection
without overloading of effects. The output is desingned to have
low impedance to ensure low signal noise and hum. The signal
comes in before the Graphic EQ. so shaping of the effects is possible. Input
will interupt signal so a loop must be completed. Output however
works alone and can be used to send a preamp signal to another Boogie. A
know issue is when the internal switching jack fails and cuts the
signal. To test this, place a cable from send to return. If
this solves the problem, the jack should be repaired by bending the
contacts or replacing it with a Switchcraft 12A.
Post
Effects Level: This Mark IIB had the effects loop modification
performed by Mike B. at MESA. This modification addresses the problems
of effect loop overloading and reverb level inequality between lead
and rhythm modes. At the time of the modification, Mike B. marks the
unity gain level that is optimized for the amp. It is usually
around 8. At this level, the amp will be the same volume as
before the mod was perfomred. Thus all front panel controls are pre-effect.
The front panel masters can now be considered effect send levels,
hence the Post Effects Level ascts as a Master Volume to control the
overall volume.
Set-up
Info:
1.
Set all front panel controls as one would normally do
2.
Adjust POST EFFECTS LEVEL for desired volume
3.
Connect SEND to input of effect unit(s)
4.
Connect RETURN to output of effect unit(s)
5.
Set effects controls to normal
6.
Effects with level indicator lights should be set for unity gain,
then adjust master(s) on amp so loudest playing almost indicates overload.
7.
Effects without level lights must be set up by ear. Follow steps
1-5. Upon unplugging the effects return cable at the back of
the amp, the volume should NOT increase. IF it does, plug the
effect back in and then turn the master(s) down a bit and the POST
EFFECT LEVEL up to regain volume and compare once again with the cable
pulled out.
Presence:
The presence acts to affect
the overall brightness of the amp. At low setting a very warm,
mellow tone is obtained, at full, a more robust gain tone is heard.
Speaker
Outputs: Three outputs are available for different configurations
and if so desired, speaker mismatches. No harm can come to the
Boogie or the speaker, save that a mismatch in the wrong direction
will cause the powertubes to run down faster. EVM and Altec speakers
are able to handle the 100 Watts and 8 Ohm. For other speakers,
MESA suggests 60 Watt and 4 Ohm. Lower power setting with the
4 Ohm jack gives a mellow sound with distortion at a lower volume. 8
Ohm adds more clarity and crispness, and 100 Watt adds even more volume.
Preamp/Amp
Juntion: Located on the undersurface of the chasis to the right,
provides a juntion out of the preamp/Graphic EQ. signal to slave other
Boogies or a signal in to use the Boogie as a Power Amp only. When
doing this, only the Master 1 functions and it is suggested all other
pots are turned to zero. Best way to link the Slave Out or Effects
Send of one Boogie to another for a Power Amp effect.
Gain
Boost/Reverb Dual Footswitch: Located to the left, this outlet
works with a Stereo cable and footswitch to control the Gain Boost
and the reverb. Very useful in adding a "third mode"
to the rhythm with the significant boost and adds a "fourth mode"
to the gain of the lead mode.
Lots of players are buying
up old Mark II and Mark IIB amps for their clean channel sound that
is very bold and punchy. For more information, see the on-line
archives of Boogie Manuals,
especially for the IIB.
4x12
Boogie Cabinet : A straight
4x12 rectifier closed back cabinet, with slated upper baffle done
in Bubinga hardwood. The cabinet houses two EVM 12L 200 Watt speakers
in the lower ports and two MESA Black Shadow 150 Watt speakers by
Eminence in the upper ports. The cabinet is wired in series
parallel for a total speaker load of 8 ohms, and a power capacity
of 700 watts. The stock MESA jack plate allows the cabinet to be run
with all four speakers at once with an 8 ohm load, or in stereo, with
the cabinet split into two EVM / MS-150 pairs, each running at 4 ohms.
Thus, one can run the cabinet with one amp and run either all four
speakers, or run only one side and just run two speakers. Alternatively,
one could run two amps through the one cabinet in a stereo rig or
split set-up.
|