Manley SLAM! - Manual (Page 7)

6) PHANTOM POWER SWITCH: This simply turns on 48 regulated volts of phantom power that ‘rides’ on Pin 2&3 of
the BALANCED XLR INPUT. In this case, it is also only ON when you select one of the 3 Mic modes on the SOURCE
switch.
However, we do have several warnings:
a) Because you can and will have a typical line input often plugged into that XLR and because you can easily switch to
MIC, and because there is a chance some gear is not designed with DC blocking capacitors (or they are rated for less than
48 volts) there is a chance of doing damage to line level gear by ‘accident’. We don’t know of this ever happening but can
imagine that it is possible.
b) In general, patching mics with phantom turned on is a habit to break. Mic signals are typically 1/100th of a volt, and
phantom is 48volts so rather huge speaker killing pops are likely - unless monitors, headphones, etc are turned way down or
off. c) For the same reason as above, running mics through patchbays, intermittant cables and corroded XLRs with phantom
turned on may be extra noisy and crackley. If you need phantom, you need good solid connections. The only mics that need
phantom are most FET condensor mics, and some other internally preamplified mics and a few DI boxes. We don’t know of
any dynamic mics or tube condensor mics that require phantom.
d) Contrary to urban myth, we also don’t know of any mic that can be damaged by phantom, whether it needs it or not,
except a few ‘modified’ vintage ribbon mics that had their protective capacitors removed. Early Neve and Trident consoles
applied phantom power to every mic jack and offered no switch to turn it off. It is probably also a myth that some mics
sound better with phantom off, but not a myth that bad jacks and cables will sound better with it off. Use phantom power
only if its needed.
7) GROUND TERMINALS: These provide separate grounds for use in some installations, with special star grounds or
other grounding techniques to prevent hum. In most situations the two terminals are simply connected with a wire. The
top terminal marked CHASSIS is the AC third pin MAINS ground which also connects to the chassis’s, rack rails and can
internally connect to XLR pin 1. The bottom terminal marked CIRCUIT is the internal audio ground, which also connects to
the 1/4” jacks sleeves.
8) SIDE-CHAIN INSERTS AND LINKING. These are all regular Bantam jacks, like are used in most patch-bays. Why
these? Again size, space and they offer true, no-BS inserts like a patch-bay does. Most studios have Bantam to XLR adapter
cables (we used to chop long patch cables in half and solder on XLRs) and if they don’t, they should. All of the outputs are
impedance balanced (30 ohms), single ended +4 dBu signals. The inputs are single ended, high Z, with the ring connected to
ground through a 30 ohm resistor and should be compatible with most pro gear, balanced or unbalanced.
Some engineers like to patch in an EQ into the side chain of some compressors or limiters which alters how the limiter
responds. For example if the EQ is set to boost at 6K (or HP filtered at 3K), the limiter becomes more of a De-esser. Some
dynamic controllers seem to be extra sensitive to low frequencies and bass, so we filter out low frequencies to prevent
excessive pumping or squashing on bass heavy material. A text-book limiter would not have side-chain inserts because it is
supposed to accurately limit true signal peaks. The SLAM!’s Opto Limiter has a switch that provides some side-chain low
freq filtering at 100 and 200 Hz. The 200 Hz setting also boosts about 4 dB at 6K, for a bit of gentle de-essing to be the “vo-
cal setting”.
Because there are actually 4 limiters in the box, side chain inserts require 8 jacks (sends and returns). The two top jacks are
sends for the Opto limiter (L&R) and they are half-normalled to the two returns below them. Some may also use these as
alternative outs from the MIC PRE, but the Opto Limiter and, to a lesser degree, the FET Limiter will affect them, but it
avoids the final tube stages.
The next 4 jacks are similarly used for the FET Limiter. The Send is an op-amp isolated version of the unbalanced main
output. Any plug or patch cord in any of the ‘returns’ breaks the normal and unless there is a healthy +4 dBu signal inserted
there, you won’t see any limiting.
The jacks marked EXT LINK (5.1) are just intended for those lucky guys with 3 SLAM!s who need a way to link 5 or 6 lim-
iters for surround work. Two regular Bantom patch cables are required. These jacks are parallelled, and the rings carries the
Opto audio link, the tip carries the FET DC link. The LINK toggle on the front panel must be in the BOTH & EXT position
and all controls on all 3 units are used. The Opto Link blends all 6, the FET link uses the moment-to-moment highest signal
of the 6 channels.
The bottom two jacks are unused at present, but might be useful for mods and special versions. We had an idea to use them
for a ‘blend’ input because some guys like to use the drum sub-mix to ‘push’ the 2 buss limiters, but we felt this was a bit
excessive and can be done with the above side-chain inserts easily enough.
9) CHANNEL 2 BALANCED INPUT: Similar to Channel 1 described by 2) above.
10) CHANNEL 2 BALANCED OUTPUT: Similar to Channel 1 described by 3) above.
11) CHANNEL 2 INSTRUMENT INPUT: Similar to Channel 1 described by 4) above.
12) CHANNEL 2 UNBALANCED OUTPUT: Similar to Channel 1 described by 5) above.
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