CeriaTone Overtone Special 20W Mini “Lunchbox” Amplifier User Manual

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Ceriatone

Overtone Special

20W Mini “Lunchbox”

Amplifier

User’s Manual

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Thank you for the purchase of your Ceriatone Overtone Special 20W Mini guitar amplifier!

Here, we hope to explain how best to use your new amp.

Table of Contents

1) About the Overtone Special…………………………………………………………………………………………page 2

2) Quick setup……………………………………………………………………………………………………………page 3

3) Front Panel controls………………………………………………………………………………………………….page 4

4) Rear Panel controls…………………………………………………………………………………………………..page 7

5) Tube compliment and bias adjustment……………………………….……………………………………………page 10

6) Frequently Asked Questions………………………………………………………………………………………...page 14

7) Settings templates…………………………………………………………………………………………………….page 17

1) About the Overtone Special 20W Mini “Lunchbox”

The release of our Overtone series of amplifiers has been overwhelmingly popular, and the support of customers such as you
has instigated the release of over a dozen different versions within the series. We have been pleased to provide many players
access to our unique take on these legendary amplifiers.

Most recently, we offered our first foray into the “lunchbox” format – the OTS Mini 20W. Not only is this amplifier a completely
different format for us, it is also a unique design that capitalizes on the expressive, sweet power section centered on classic
American-style 6V6 tubes. Many fantastic sounds are possible with this unassuming, but completely serious amplifier

While our work could not have been possible without the gracious information shared over the last decade in the public domain,
we hope you appreciate our modifications, component selection, and construction techniques. Most of all, we hope the OTS
becomes an integral part of your tone equation to exhilarate your playing and music.

Rock on!

- Nik Azam

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2) QUICK SETUP (for instant gratification)

1) Plug your guitar using a 1/4” instrument cable into the INPUT on the far right of the front panel

2) Plug a suitable power cable from the OTS’s rear panel MAINS cable inlet to your wall power receptacle

3) Plug the OTS into your speaker cabinet using 1/4” speaker cable

4) Set the IMPEDENCE selector to the match the impedance of your speaker cabinet

5) Plug the footswitch cable into the FOOT PEDAL jack on the rear panel of the amplifier

6) Set the OD TRIM control on the rear panel to 12:00 (clock face)

7) Set all rotary controls on the front panel to 12:00 (clock face)

8) Turn MASTER control to about 9:00 (clock face)

9) Set front panel MID BOOST switch in the down position (OFF)

10) Set front panel ROCK / JAZZ switch in the up position (ROCK)

11) Set front panel POWER switch in the upward ON position (with adjacent switch to STANDBY) for 30 seconds to allow
tube filaments to warm up

12) Set front panel STANDBY switch upward to the ON position

13) ROCK!!!!!!

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3) FRONT PANEL CONTROLS

On the front panel of the Overtone Special, you can see fourteen items of interest.

From left to right:

1) POWER two-way toggle switch

2) STANDBY two-way toggle switch

3) INDICATOR LED

4) PRESENCE control

5) MASTER control

6) RATIO control

7) LEVEL control

8) BASS control

9) MIDDLE control

10) TREBLE control

11) ROCK / JAZZ two-way toggle switch

12) MID BOOST two-way toggle switch

13) VOLUME (PULL BRIGHT) control

14) INPUT ¼” instrument jack

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POWER two-way toggle switch powers the OTS on and off. With the toggle switch in the UP position, the OTS is ON. In the
DOWN position, the OTS is OFF.

STANDBY applies high voltage to the vacuum tube anodes (and screen grids) during use of the OTS. To ensure long tube life,
first power the unit on with the toggle switch in STANDBY position for approximately 30 seconds. Then place switch upward to
ON position to use the OTS. With the toggle switch in the UP position, the OTS is in operate mode. In the DOWN position, the
OTS is in standby mode.

INDICATOR will illuminate when the OTS is powered by turning the rear panel MAINS toggle switch to the ON position. If
INDICATOR does not turn on, check your power cable connections, and then the 2A slow-blow fuse on the rear of the unit.

PRESENCE adjusts the high frequency response of the power amplifier using negative feedback. Use this control to add
sparkle and clarity to your tone.

MASTER sets the overall volume of your amplifier.

RATIO serves a sort of volume control for the overdrive channel. However, just like this version of the original amplifier, there

are not individual master volume controls for the clean and overdrive channels. Instead, the RATIO control serves to balance
out the volume of the overdrive channel with the clean channel.

LEVEL adjusts the amount of gain, and in turn distortion in the overdrive mode.

BASS adjusts low frequencies in your amplifier for both clean and overdrive modes.

MIDRANGE adjusts the mid frequency response for both clean and overdrive modes.

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TREBLE adjusts the high frequency response for both clean and overdrive modes. At near-maximum settings, you may also
notice an increase in gain.

ROCK / JAZZ adjusts the overall frequency response and voicing of the amplifier. ROCK has a fatter midrange and a deeper,
spongier bottom end. You might find ROCK more familiar territory. JAZZ tightens up the bottom end and adjusts the contour of
the midrange, giving the amplifier more of a hi-fi response. Experiment with both, as great sounds rest in each. With the toggle
switch in the UP position, ROCK is on. In the DOWN position, JAZZ is on.

MID BOOST is a midrange-frequency boost. You can use this to add fatness to your clean or overdrive tones, or even make
single coil guitars sound thicker and less scooped. We particularly like MID BOOST with the overdrive mode. With the toggle
switch in the UP position, MID BOOST is on. In the DOWN position, MID BOOST is off.

VOLUME adjusts the signal strength coming out of the tonestack, and going into the second tube stage. Think of this as a gain
control primarily for your clean channel, but note it will impact the overdrive mode as well.

BRIGHT is a high-frequency boost that can be used to add sparkle to your tone in both clean and overdrive modes. This high
frequency boost is more prominent as VOLUME is turned down. To engage this feature, pull out the VOLUME control. To turn
BRIGHT off, push the VOLUME control inward.

INPUT jack provides a typical, 1megaohm input impedance as seen on most guitar amplifiers. The FET input has been
removed from the 20W Mini, as in most circumstances the regular input provides the best results in clean and overdrive modes.