Gamut M250 User Manual - Page 5
Browse online or download pdf User Manual for Amplifier Gamut M250. Gamut M250 10 pages. Mono power amplifier
Print Page
The red terminals go positive when there is a positive signal on the Pin 2 on the input XLR. In other
words, GamuT amplifiers are non-inverting. Some other brands of amplifiers do not follow this standard.
Take care if you want to bi-amp. Do also note that JBL speaker units are wired inverted.
WARNING!
Do not use this direct output for tests with square waves or sine waves and a capacitor across
the output terminals, as you may damage the amplifier.
Do not connect output ground to input ground. Do not connect any output grounds together.
Do not connect headphones to this amplifier without using protecting resistors.
Make sure, that you do not let any tiny part of the speaker cable going to a terminal touch the
other terminals. Only connect this amplifier to loudspeakers, and only one loudspeaker on each
channel. Do not connect the output of this amplifier to another amplifiers outputs or inputs.
DO NOT CONNECT A RED TERMINAL TO ANOTHER RED TERMINAL!
DO NOT BRIDGE THE AMPLIFIER!
DO NOT USE BOTH CHANNELS TO DRIVE ONE LOUDSPEAKER!
Loudspeaker impedance
Most loudspeaker are 8 or 4 Ohm, and they are specified so by the manufacturer.
Unfortunately, some loudspeakers have an impedance, which is much lower than specified. They will not
damage the GamuT power amplifier, because it will simply mute.
In the GamuT M250 MkIII, we use a gem of a MOSFET transistor. It handles 500W, and a peak current
of 400 Ampere and 100 Ampere long-term.
Such high currents will destroy any HiFi loudspeaker we know of.
The lower the impedance, the higher the current will be.
Somewhere, we have to draw a line between what is a loudspeaker load, and what is a short circuit. We
have set this line at 1.5 Ohm, which will draw about 47 Ampere peak.
The impedance of a few electrostatic loudspeakers does go down below 1.5 Ohm at high frequencies.
The protection circuit will not allow this long-term on test signals. However, it works well with Quad ELS-
63 and most Martin Logan electrostatic loudspeakers.
Please also note that a Quad ELS-63 electrostatic loudspeaker cannot handle more than 55V peak, and
the GamuT M200 MkIII can give more than 70V peak. So be careful.
A lifetime of enjoyment
So far, our oldest amplifiers from 1982 still work in professional recording studios, often doing their job
16 or 24 hours a day. So we expect our GamuT amplifiers to do likewise.
A more likely cause for change would be your wish to upgrade in some years time. Here our modular
approach serves to keep the upgrade cost low, and you avoid selling with a loss on the second hand
market.
The cabinet should last a lifetime, and the GamuT Logo is engraved down into the surface; wearing the
text out will be quite difficult.
Apart from being good economy, this long term approach is also better for the environment. Most parts
of the cabinet are made of aluminium, which is easy to recycle.
All parts are screwed together to enable easy disassembly. Your grandchildren will be pleased with your
choice.
5