TGA-3 100 Watt Guitar Amplifier User’s Guide
INTRODUCTION
Congratulations! You’ve just purchased one of the finest, best-sounding and most versatile amps on this planet!
Please be patient and read this manual before you power-up, and you will be richly rewarded.
OVERVIEW
The Demeter TGA-3 was designed by James Demeter as literally three amps in one. Therefore, a basic explanation
of the front panel controls and rear panel jacks is necessary to enable you to unlock the great potential of this
professional tool.
Looking at the front control panel, there are four colors of knobs: yellow, green, red, and blue. The blue knobs
are controls which are common to all channels: stereo effect returns and the presence control. We’ll talk more
about these later on.
The yellow knobs control the “clean” channel, reminiscent of a vintage Fender Deluxe or Bassman. This channel is
capable of delivering plenty of squeaky-clean volume for country or traditional Jazz styles. It also has a great
blues “bite” to it when you turn up the gain, similar to a Tweed Fender Deluxe with everything on “10.”
The green and red overdrive channels give you every possible combination of distortion, feedback and sustain.
From smooth to hard, from Vintage British Crunch to “ modded” super distortion, this amp has it all and more.
Rear Panel
Before you turn on the amp, let’s take a look at the rear panel, where you will make the proper connections to
your system.
Speakers
No tube amp should be powered up without making sure that the speakers are connected. If you have a TGA-3-
100 combo amp the speaker will come connected, but it is always a good idea to check anyway. A tube amp can
burn up its output transformer (an expensive repair) if operated without being connected to a speaker.
Impedance
Always observe proper impedance matching. The Demeter TGA-3-100 has 3 speaker output jacks: for 4, 8 and
16 ohm cabinets. If you don’t know what the impedance of your speaker cabinet is, you should find out! If your
cabinet or speaker is not marked (most are), you can try the following:
Connect an ohmmeter between the terminals or to the input jack of the cabinet, and set the meter’s range for
at least 20 ohms full-scale. The reading will usually be a bit less than the actual impedance (6 or 7 ohms for an
8- ohm speaker, 3 or 3.5 ohms for a 4- ohm speaker, 13 to 15 ohms for a 16 ohm speaker). Impedance matching
is necessary to get optimum volume and tone, and to avoid undue stress on your amp.
Note: most Marshall-type cabinets will have an impedance of 16 ohms, but some may be wired for 4 ohms.
6900 Kingsbury Road | Templeton, CA 93465 | 805-461-4100 | http://www.demeteramps.com/
