If you’re using low imped-

ance loads at high power

levels, we recommend that

you use the binding post

speaker outputs rather than the 1/4" TS jacks. Al-

though 1/4" jacks and plugs are convenient and easy to use, they are not designed to handle high-level currents.

Make sure that the amplifier is off before making connections or reconfiguring the signal routing.

INPUT

The M•800 gives you a choice of inputs — it has XLR as well as 1/4" TRS (Tip-Ring-Sleeve) input jacks. Sonically (and electrically) they’re identical, so choose either one. Since these two inputs are in parallel, don’t use both at the same time.

The amplifier expects to see a nominal signal level anywhere between the –10 dBV “semipro” and +4 dBu “pro” standards, meaning almost any line-level mixer or other device can be plugged into the amp’s INPUTs. Use the GAIN controls to adjust the gain of the amplifier to match the signal level you’re using.

Each type of input can be used with either balanced or unbalanced signals.

Balanced

Use the balanced connections if your source has balanced outputs. This will greatly reduce any noise picked up in your system.

When connecting a balanced signal using the XLR or 1/4" jacks, they’re wired thusly, per AES (Audio Engineering Society) standards:

 

XLR

 

TRS

Hot (+)

Pin 2

 

Tip

Cold (–)

Pin 3

 

Ring

Shield (Ground)

Pin 1

 

Sleeve

 

SHIELD

 

2

 

 

HOT

 

 

COLD

3

1

 

SHIELD

1

 

 

COLD

3

2

 

HOT

 

 

1

 

SHIELD

 

3

 

COLD

 

2

 

HOT

 

 

 

Balanced XLR Plug (prior to Lunar orbit insertion)

RING SLEEVE

SLEEVE RING TIP

TIP

RING (COLD)

TIP (HOT)

SLEEVE (SHIELD)

Balanced 1⁄4" TRS Plug

Unbalanced

Unbalanced TS (Tip-Sleeve) lines can be accommodated via the TRS jack. Make sure the cord terminates with a TS plug (like a guitar plug), or if it’s a TRS plug (like a headphone plug), make sure the ring is tied to the shield, preferably at the source end.

SLEEVE

SLEEVE

TIP

TIP

RING (COLD)

TIP (HOT)

SLEEVE (SHIELD)

Unbalanced 1/4" TS Plug

THRU

The THRU jacks allow you to feed the input signal to the inputs of other amplifiers. In this way, multiple amplifiers can receive an input signal from your single mixer or preamp. This is accomplished as follows:

•Make sure all your equipment is turned off before making any connections.

•Plug the signal source outputs into the first amp’s INPUTs.

•Patch from that amp’s THRU jacks to the next amp’s INPUT, and so on, daisy-chaining to other amps in your system (assuming your mixer has low impedance outputs).

To prevent excessive loading

of your source, a general rule

of thumb is to maintain a

load impedance 10 times or

more than the source impedance . If your console has an

output impedance of 100 ohms, then you can daisy-chain up to twenty M•800 amplifiers, which presents a load of 1000 ohms to the console (input impedance of 20 kohms divided by 20 amplifiers = 1000 ohms).

The THRU jacks can also be used to relay the input signals on to other devices such as a DAT or cassette recorder. They are wired in parallel with the XLR and TRS INPUTs, so the signals coming out of the THRU jacks are exactly the same as the signals going into the amp, unaffected by any of the amp’s switches and controls.

13