Sheldon TrueTone Series User manual

Issue 6 1/2/2007
1
Handbook
TrueTone

Issue 6 1/2/2007
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About your TrueTone Amplifier
The
TrueTone range is a hand built, high quality range of all valve amplifiers originally designed
for the discriminating Blues/Rock guitarist. They are however extremely versatile and can fulfil
a range of roles from country clean to rock via jazz, blues and all points in between.
All amps in the range benefit from an unprecedented Unlimited Lifetime Warranty.
The
TrueTone 1
The TT1 range are 35-50W class AB amplifiers that give the player an unprecedented ability
to tailor their own sound by selecting the type of output valve used in the amplifier, and a
choice of two pre selected factory set pre-amp configurations one HOT one COOL!
We deliberately chose this path to get the best tone, performance, and long maintenance
from the amp.
The output section can be selected by the player to suit his own style. This can be done by
either the factory, dealer or even easily by the player themselves simply by following the
simple procedures set out in this handbook, giving a freedom of choice rarely encountered in
other amplifiers.
Front panel controls:
•Input: standard input using a single jack socket.
•Volume: controls the input gain level set low for a clean sound and higher for
more overdrive.
•Compass: this is a variable tone rotary, set at North it will not overly emphasise any
particular frequency. Heading SW will bring in a little sparkle, heading SE will
bring in sparkle and grind, with an emphasis on the upper mid range, and it will
also boost gain slightly.
•High: Controls the high frequency content, as in a normal treble control but with a
much wider response.
•Middle: Controls the middle frequency content. With the middle control set low or
off the tone controls are voiced to be able to give a similar response to the fabled
clean tone of a blackface Fender, with more Mids introduced as the control is
increased. With the middle control set high the response is more 'Marshall' like.
•Low: This controls the low frequency content, again with a much wider response
than conventional guitar amp tone controls.
•Special Sauce: With the accompanying footswitch or the panel mounted switch,
(which both select this feature), this control gives a boost by lifting the tone stack
from ground via a potentiometer, this allows a pre-set level boost that can be
used for soloing. A LED beneath the control and on the footswitch, indicate when
this control is active. (Plugging in the footswitch bypasses the panel-mounted
switch). With the control set fully clockwise the tone controls are effectively
bypassed and the natural tone of the amplifier is dominant. This can be fine tuned
using the compass and freeze controls, which remain in circuit.

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•Freeze: Essentially a hi-cut control which is located within the power amp section
and can be used to tailor the overall high frequency response of the amp from icy
sharp to smooth and mellow.
•Master: The master volume is a subtle but effective variation on the standard type
used in most guitar amps and uses a technique called 'Boot strapping' to increase
the apparent impedance of the control pot used. This has the benefit of reducing
the tonal change often associated with Master volume controls on low settings.
Although part of the power amp, for maximum effectiveness the master is not
included in the feedback loop as in some designs.
•Ready…: This is the power switch and turns on the amplifier
•Go!: This is the amplifier stand-by switch and can be set to off when the amplifier
is on but not in use for longer periods. This can lead to longer power valve life.
Rear panel controls:
•Mains inlet: A standard IEC connector allows connection to the mains supply.
•Voltage selector: Allows a choice of mains input voltages either 230v or
115v.NOTE: for UK use this must be set to 230v.
•Mains fuse: This is a 2A slo-blo 20mm fuse(UK only).
•HT fuse: This is a 500mA slo-blo 20mm fuse(UK only).
•Triode /Pentode: This switch configures the output valves to either full power
(pentode) mode or half-power (triode) mode. In triode mode even harmonics are
emphasised and will give a sweeter and rounder overall tone.
•Impedance selector: Allows matching to the correct impedance of the cabinet to
be used.
•Speaker outlets: Two parallel wired jack sockets are provided to allow more than
one cabinet to be used.
•Bias controls: Two test points allow monitoring of the bias levels of both sides of
the push-pull output circuit using a simple voltmeter. The centre ground
connection allows a meter to be connected between the cathodes of each side of
the push -pull output section power valves, (TP1 & TP2), and ground across a 1
ohm resistor. This will indicate in millivolts on a test meter what the bias current
flowing through each side is. This can then be adjusted by using the Range and
Balance pots located beneath the test points. A more detailed procedure is set
out later in this user manual.
•Footswitch: The supplied footswitch is connected here and selects the Special
Sauce feature. Any two-connector cable such as speaker cable can be used here,
as no audio signal is present.
•Optional Effects send and return and Reverb controls are located on the rear
panel.

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Table 1
The following table shows the available options for the TT1’s output section.
Output valve
configuration Output power
& Voltage
Settings
Characteristics
4 x Sheldon-6V6 30-35w
40 -42 mV
Sweet clean tones, which move easily into a
super creamy overdrive. So nice it’s what the
amps come with as standard!
2 x Sheldon-EL34 40-45W
30 – 35 mV
Characteristic British rock/blues tones with
crisp highs and plenty of midrange grit and
grind.
2xSheldon- 6L6/5881 40-45W
35 – 45 mV
Sweet chiming clean tones with solid bass and
top end. More detail in the tone and a smooth
overdrive tone.
4 x Sheldon-EL34 45-50W
70 – 80 mV
Even more of that Classic Brit rock tone! But
with more headroom. Like a 100W plexi but at
50w volumes!
4 x Sheldon-6L6/5881 45-50W
70 – 90 mV
More of that great 6L6 tone!
Better headroom, very suited to the clean
blues player but will break up very nicely when
pushed moving into a smooth driven tone!
2xSheldon-6L6
2xSheldon 6V6
35-40W
45 – 55 mV
A best of both worlds combination! The clear
top and bottom of the 6L6’s complementing
the smooth creamy break-up of the 6V6’s
gives probably the best blues tone you will
hear!
2xSheldon - KT88/6550 45-50W
55 – 60 mV
The ultimate in solid bass and crystal clear
highs, late break up but boy when it does!! For
the cleaner style of playing this is probably
one of the best set ups.
Choosing your output configuration has never been easier or more versatile! The TT1 gives
the player a wider choice than previously available in all but a very few amplifiers and puts the
power of choice in the hands of the player or tech.

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Biasing your TT1 amplifier.
To get the best performance from any amplifier it must have its output section correctly
‘biased’. Our amps use fixed bias to put the player and technician in control of the valve.
The bias of the output valves is vital in deciding not only the operating class of the amplifier
but also in maximizing performance, tone and valve life. Ours is by far the better option
between cathode and fixed bias……….Without question!!!!!
The TT1 is a class AB amplifier and can be biased over a range of settings depending upon
the type of output valves selected and the tone desired.
All
TrueTone amplifiers are fitted exclusively with Sheldon valves, which in themselves can be
selected for the type of tone required.
To bias your TT1 you will need:
•A digital multimeter set to mV.
•A trim tool or small flat bladed screwdriver (we can supply the correct tool).
•And……………….
•Your brain in gear or the number of your local tech.
•Us on the other end of the phone!
CAUTION VALVE AMPLIFIERS CONTAIN HIGH VOLTAGES WHICH CAN BE FATAL!
WHILST BIASING YOUR TT1 IS NOT IN ITSELF DANGEROUS. ALL INSTRUCTIONS
MUST BE FOLLOWED CORRECTLY AND CAREFULLY!
The first step in biasing your TT1 for best operation is to select the desired valve type (6V6,
6L6, EL34 etc). Then chose the grade of Sheldon valve. These range from 1 to 10 with 10
being hot and giving early distortion, and 1 being cooler and moving into power amp distortion
much later.
Now follow these steps exactly:
•ENSURE YOUR TT1 AMPLIFIER IS SWITCHED FULLY OFF AND DISCONNECTED
FROM THE MAINS SUPPLY.
•From the table chose your desired output section configuration (2x 6L6, 4 x 6V6, etc.)
then look up on the table the correct bias setting.
•Allow your amplifier to cool right down if it has been in previous use. VALVES GET VERY
HOT IN USE AND CAN BURN YOUR FINGERS IF TOUCHED.
However, you can use a tube glove or other blunt instrument if time is an issue!
•With the rear panel removed, carefully take out the output valves fitted. Do not use a
twisting motion as this will damage them!
•DO NOT REMOVE THE AMPLIFIER FROM THE CHASSIS FOR ANY REASON.
APART FROM EVERYTHING YOU MIGHT DO IN THERE, YOU MAY INVALIDATE
YOUR WARRANTY!!!!!
•Carefully fit your new selected set of Sheldon valves being careful to note that the
locating pip on the valve base is aligned with the slot in the centre hole of the valve base.
Push the valves firmly and fully home. Excessive force should not be required nor
applied. If it is, then something is wrong and the alignment may be incorrect.

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•On the rear of the amplifier there are two red test point sockets marked TP1 and TP2, and
one black socket which is connected to ground. You will be measuring a voltage between
each of the red test points and the black ground socket.
•Put the BLACK or COMMON probe of your multimeter into the BLACK socket on the rear
of the amplifier. Then put the RED test probe into the RED test point marked TP1. This
will indicate the bias setting of the left hand pair of valves as viewed from the rear. Repeat
this process for the right hand pair and off you go! Both values should be identical.
•To do this first use the Range to get to the figure & the Balance pot to get the values
equal. REMEMBER do not exceed the top value in the range. It may sound hotter, but it
also has higher voltage.
•Use the
Range pot also to determine how cold you wish to run the amp. For example at
the bottom of the table value or below is where your amp will run coldest. If you prefer
this, then you can do no real harm. Let your ears decide!!
•Reconnect your TT1 to the mains. AT NO POINT SHOULD YOU NOW TOUCH THE
OUTPUT VALVES OR ATTEMPT TO TOUCH ANYTHING INSIDE THE AMPLIFIER
ITSELF.
•Switch on the Ready… switch located on the front panel. You will see the heater filaments
inside the valves begin to glow. Ensure that they are all on. And allow them to warm up
for a few minutes.
•Now switch on the Go... switch located on the front panel. You will notice that you now will
get a reading on your multimeter. Allow a few seconds for this to stabilise. IF AT ANY
POINT AFTER SWITCHING ON THE Go... YOU SEE ANY GLOW ON THE MAIN
PLATE STRUCTURE WITHIN THE VALVE OTHER THAN THE HEATER FILAMENT,
DOWN BIAS TO RUN THE VALE SET COOLER OR SWITCH OFF THE Go…AND
TALK TO US OR YOUR LOCAL TECHNICIAN……………………….IMMEDIATELY!!!

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The TrueTone 2 TTSpecial 112 TTSpecial Plus 112
The TT2 and the Special and Special Plus are 18/35w class AB blues monsters!
Designed for use in smaller venues and studios they are a big amp in a compact package!
The difference is that the TT2 is only available in the larger volume cab sizes whilst the
Special and Special Plus are in the TT3 size box and are plus Reverb.
Whilst most available amps in this class claim to be class A, in reality most are simply hot
cathode biased class AB amps.
We decided to set the record straight and tell things the way they really are! Let your ears be
the judge, don’t let ‘class ‘ prejudice get in the way of good honest tone!
The TT2 uses a combination of fixed bias and cathode bias. Unlike most other amps which go
for cathode bias when using these types of output valves. So why be different?
Well, whilst cathode biased amps can sound very sweet, in some cases particularly with
EL84’s they can get a bit muddy sounding when driven to their limits.
Fixed bias lets us get the most out of them, squeezing every last bit of tone out and making
the most effective use of the available power.
The TT2 can be fitted with a range of Sheldon – 6V6’s or 6L6’s depending upon which style
you prefer. Simply chose the grade of Sheldon - valves which suit your playing style and your
dealer or the factory will adjust the bias to get optimum performance from the chosen set.
Then when you wish to replace them simply use the same grade of valve and no further
adjustments will be necessary. Should you wish to change the grade of valve used then ask
your dealer or the factory to make the very simple adjustment.
Front panel controls:
•Input: standard input using a single jack socket.
•Volume: controls the input gain level, set low for a clean sound and higher for
more overdrive.
•Compass: This will take you around the tonal spectrum from resonant deep lows
towards the West and beyond to singing highs towards the East. This is easily
the most effective tone control available today. In a live situation this amp will get
you there quicker!
•Freeze : This allows you to dial in up to 35Watts by using one or two pairs of
output valves.
•Master: Takes the output of the amp and changes nothing throughout the volume
range leaving your tone intact!!
Rear panel controls:
•All valves, fuses and mains inlet are easily accessed at the rear of the unit via the
rear panel for fast and trouble free maintenance.
•Optional Effects send and return and Reverb controls.

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The TrueTone 3 TrueTone 3R
If there ever was an amp that you couldn’t quit playing then this is it!
Don’t be fooled by the simple control layout there’s an amazing range of sounds in there just
waiting to get out! Every turn of each control can yield a new sound and setting the controls
anywhere will give a useable tone-full sound.
The TT3 is virtually unique in using pre-amp valves throughout its construction. The output
section uses three cathode biased Sheldon12AU7 valves with option of fitting 12AT7’s or
12BH7’s for a different tone and output volume.
A pair of Sheldon 12AX7’s fulfils pre-amp duties.
Using the ‘Freeze’ control you can go from 1W in single ended mode to just over 3W in Push-
Pull mode and all points in between using the rotary control.
Perfect for those late night bedroom moments of inspiration to being able to get a full throated
sound in the studio or practice room with out losing any of that precious tone.
The ‘Compass’ control is a unique and amazingly wide ranging tone control that can take you
from deep resonant lows to needle sharp highs with the turn of a single control. We are
confident that it is the widest ranging single tone control you have ever heard.
‘Gain’ and ‘Master’ control let you tailor the TT3’s tone from clean to mean and beyond.
A further feature of these amps is that when used in conjunction with our forthcoming adaptor
module the amp can be turned into a super pre-amp/chain for use with larger amps.
Optional reverb controls are accessed from the rear panel to the left hand side.
The TT3 has the following standard features:
•12AU7 output section for cranked power amp overdrive at 1 - 3 watts.
•Cathode bias allowing the option of fitting a range of different output valves
(12AT7 -12BH7 etc)
•2x Sheldon 12AX7 preamp. Similar to the TT1 and TT2 but maximized for a little
more drive tone.
•Unique
‘Compass’ control for maximum tone choice.
•‘Freeze’ control enables a choice of output power, tone and style. From 1W in
SE mode to over 3W in PP mode.
•Master and Gain controls allowing quiet cranked amp tone at all volume levels.
•Ultra fast rectifier diodes with special noise reduction circuit to ensure maximum
response and quiet operation.
•Eyelet board construction, with thick Glass epoxy circuit board for a super tough
construction.
•Custom wound transformer.
•Specially selected Sheldon valves.
•Celestion Vintage 30 or Greenback speaker.
•Reverb on TT3R.

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The TTJunior
Don’t be fooled by the simple control layout there’s an amazing range of sounds in there just
waiting to get out! Every turn of each control can yield a new sound by setting the controls
anywhere.
It may be the baby of the range but it’s an amazingly versatile and tone-full tool!
The TTJunior is unique in using pre-amp valves throughout its construction. The output
section uses one cathode biased Sheldon12BH7 valve. One Sheldon 12AX7 fulfils pre-amp
duties. Perfect for those late night bedroom moments of inspiration to being able to get a full
throated sound in the studio or practice room with out losing any of that precious tone.
The ‘Compass’ control is a unique and amazingly wide ranging tone control that can take you
from deep resonant lows to needle sharp highs with the turn of a single control. We are
confident that it is the widest ranging single tone control you have ever heard.
We have introduced some extra grind from NE to SE for that Rock moment!
Separate Line out and volume control let you use it in the front end of another amp or for
direct into a DI box/Mixer for live and recording without a safety net!
A further feature of these amps is that when used in conjunction with our forthcoming adaptor
module or powered cabinets the amp can be turned into a super pre-amp/chain for use with
larger amps.
Optional reverb controls are accessed from the rear panel.
The TTJunior has the following standard features:
•12BH7 output section for cranked power amp overdrive at 1 watt.
•Cathode bias.
•1x Sheldon 12AX7 preamp. Similar to the TT2 and TT3 but maximized for a little
more drive tone.
•Unique
Compass control for maximum tone choice.
•Mastercontrol allowing quiet cranked amp tone at all volume levels.
•Ultra fast rectifier diodes with special noise reduction circuit to ensure maximum
response and quiet operation.
•Eyelet board construction, with thick Glass epoxy circuit board for a super tough
construction.
•Custom hand wound transformers.
•Specially selected Sheldon valves.
•Celestion Vintage 10 speaker.
•Attenuated line out located on the rear panel.

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The TrueTone 4
The TT4 is an 18W Class A blues monster!
Designed for use in smaller venues and studios for Harp/Pedal Steel/Acoustic Guitar, the TT4
is a big amp in a compact package!
Whilst most available amps in this class claim to be class A, in reality most are simply hot
cathode biased class AB amps (for a more detailed explanation see our web site at
www.sheldonamps.com
The TT4 uses a cathode bias design to optimise the characteristic tone that is required for a
dedicated amp of this type.
You will be surprised just how loud and proud18W can be! The TT4 can be an
educational experience!
The TT4 can be fitted with a range of Sheldon – 6V6’s/6L6’s or EL 84’s depending upon
which style you prefer. Simply chose the grade of Sheldon - valves which suit your playing
style and your dealer or the factory will get optimum performance from the chosen set. Then
when you wish to replace them simply use the same grade of valve and no further
adjustments will be necessary. Should you wish to change the grade of valve used then ask
your dealer or the factory to make the very simple adjustment.
Front panel controls:
•Input: standard input using a single jack socket.
•Volume: controls the input gain level, set low for a clean sound and higher for
more overdrive.
•Compass: This will take you around the tonal spectrum from resonant deep lows
towards the West and beyond to singing highs towards the East. This is easily
the most effective tone control available today. In a live situation this amp will get
you there quicker!
•Freeze : This allows you to dial in 9-18 Watts by using one or both output valves.
•Master: Takes the output of the amp and changes nothing throughout the volume
range leaving your tone intact!!
•Celestion – Fane or other OEM Driver as required.
Rear panel controls:
•All valves, fuses, mains inlet and operational switches are easily accessed and
labelled at the rear of the unit via the rear panel for fast and trouble free
maintenance.
•Optional Effects send and return and Reverb controls.

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Product Warranty User Agreement
Subject to the Obligations and Exclusions listed below, Sheldon warrants this product
against manufacturing defects in material and workmanship, to the original owner and all
subsequent owners.
Obligations
1. This warranty will be honoured only on the presentation of a copy of the invoice or bill of
sale as proof of purchase.
2. Transportation of the product to an authorized service facility or Sheldon is the
responsibility of the user. Sheldon shall supply all parts / labour to affect warranted work at
no charge and payment for return carriage will be the responsibility of the owner in all cases
and without exception.
Limitations of Implied Warranty
ANY IMPLIED WARRANTIES, INCLUDING WARRANTIES OF MERCHANTABILITY FOR
A PARTICULAR PURPOSE SHALL BE NEITHER EXPRESSED OR IMPLIED.
Exclusions
1. This warranty shall not cover adjustment of customer operated controls, or products that
have been altered, replaced, or have missing or defaced serial numbers, the appearance of
accessory items including, but not limited to, cabinets, cabinet parts, covers, footswitches, or
knobs.
2. This warranty shall not apply to unpacking, setup, installation, or removal and reinstallation
of products for repair by authorized service personnel.
3. This warranty shall not apply to repairs or replacements necessitated by any cause beyond
the control of Sheldon including, but not limited to, any malfunction, defects, or failures
caused by or resulting from the unauthorized service, accidents, abuse, neglect, loss of parts,
lack of reasonable care, incorrect use or failure to follow instructions, incorrect line voltage,
damages resulting from improper packaging, improper maintenance, modification or repair by
the user, fire, flood, or other Acts of God.
4. This warranty shall not apply to vacuum tubes, fuses or any loudspeakers or horn drivers
that have been damaged due to thermal destruction or physical destruction by this unit.
The foregoing is in lieu of all other expressed or implied warranties, and Sheldon does not
authorize any party to assume for it any other obligation or liability. In no event shall Sheldon
be liable for special or consequential damages arising from the use of this product, or for any
delay in the performance of this warranty due to causes beyond our control. Some states /
territories do now allow limitations on how long an implied warranty lasts and/or do not allow
the exclusion or limitation of consequential damages, so the above limitations on implied
warranty and consequential damages may not apply to you. This warranty gives you specific
legal rights. You may have other rights that vary from state to state / territory.

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Sheldon Amplification © 2007 Please note that any specification may change at the discretion of the company without prior notice. Unlimited
Lifetime Warranty is subject to activity undertaken within the manufacturing process and within the current specification. Any use found that is
not as intended, any third party intervention with parts or process outside specification will cause the warranty to be invalid without further
reference to the company.
Serial Number
Certificate o
f
O
wnership
You are now the proud owner of a Sheldon Amplifier.
We all wish you well with your product, and extend this
open invitation to contact us direct if you have any questions
or issues which you feel we could help you with.
It is only with the continued support of you, our customer,
that we continue to grow and develop and we thank you for
that opportunity…...
From us all ….
Sheldon Amplification
Birmingham
England B26 3PN
Tel ++44 121 743 1504
Fax ++ 44 121 246 8887
Email : [e-mail]
www.sheldonamps.com
First User
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Model
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