Tone King Ironman II User Manual

Tone King

1

User’s Manual

Note from the Builder

Thank you for choosing Tone King’s Ironman II precision power attenuator. The
Ironman II is a new generation of power attenuator, with a sophisticated design that
preserves the tone and feel of your amplifier quite well, while reducing the volume level
at the speakers.

There are two important components to the Ironman II design that make it unique and
particularly effective - the tuned reactive load and the transformer coupled power
division circuitry.

The idea was that the load seen by the amplifier should always have the appropriate
complex impedance curve so that it responds as it does to a real speaker load. A real
speaker load varies greatly with frequency. For example, the impedance of a typical "8
ohm" speaker may rise to 60 ohms or more at its resonant frequency (usually around
60-80Hz), and then rise again to many tens of ohms at high frequencies. An amplifier
responds a lot differently when driving a complex load like this, compared to a simple
resistive load (as is used in most attenuators). We developed the Ironman II's reactive
load circuit by matching the results of impedance curve measurements we ran on an
actual speaker in typical cabinet. The resulting design was then tweaked through
empirical methods, in order to create a load circuit that is most effective at preserving
the tone and feel of your amplifier.

The second part of the equation is the circuitry that divides the power from your
amplifier between the speaker and the load. In other attenuators, this is often done
with a resistor ladder. There are two problems with this approach - first, the resistor
ladder itself can become part of the load, which means that the amplifier sees a simple
resistive load. Second, in dividing the power this way, a voltage divider is effectively
formed between the dividing network and the speaker. Since the speaker has a
complex impedance that varies with frequency, the result is that the frequency response
at the speaker is altered, usually dulling the top end and muddying the sound.

The scheme we chose involves 100% transformer coupling, using a set of custom
transformers, so that the connection between the amplifier to load, and between the
amplifier to speaker, is purely transformer coupled at every step of the attenuation dial.
This is an expensive and elaborate design (each step of the dial requires its own tap on
one of the custom transformers), but is significantly more effective at preserving the
tone and feel of your amplifier more than other methods.

In this new Iron Man II design, we added an analog speaker cabinet simulation for DI
purposes (balanced XLR). Included is a level switch (line and microphone inputs), an
option to select between speaker center or edge micing and a ground-lift to avoid
ground loops in conjunction with other equipment.

2

Safety Instructions (Important !)

Please keep this instruction manual for future reference and for the duration of owning
this Tone King product. Please carefully read and understand the instructions inside
this user’s manual before attempting to operate your new amp. This instruction manual
includes essential safety information regarding the use and maintenance of the
amplifier. Take special care to heed all warning symbols and signs inside this manual
and those printed on the amplifier itself.

WARNING!
TO PREVENT FIRE OR SHOCK HAZARD, DO NOT EXPOSE THE AMPLIFIER TO
WATER OR MOISTURE. DO NOT OPERATE NEAR ANY WATER SOURCE

WHAT’S THE MEANING OF THIS?
The lightning flash with an arrow triangular symbol is intended to alert the user to the
presence of non-insulated “dangerous voltage” within the products enclosure, and may
be of sufficient magnitude to constitute a risk of electric shock

WHAT’S THE MEANING OF THIS?
The exclamation point triangular symbol is intended to alert the user to the presence of
important operating and maintenance (servicing) instructions in the user manual
accompanying this amplifier!

1. Read Instructions – All the safety and operating instructions should be read before
this product is operated.

2. Retain Instructions – The safety and operating instructions should be retained for
future reference.

3. Heed Warnings – All warnings on the amplifier and in the operating instructions
should be adhered to.

4. Follow Instructions – All operating and use instructions should be followed.

5. Water and Moisture – The amplifier should not be used near water – for example, a
bathtub, washbowl, kitchen sink, laundry tub, wet basement, or near a swimming pool,
and the like.

6. Heat – Amplifier should be situated away from heat sources such as radiators, heat
registers, stoves, or other amplifier (including amplifiers) that produce heat.

7. Power Sources – This product should be operated only from the type of power source
indicated on the rating label.
If you are not sure of the type of power supply to your home, consult your product
dealer or local power company.

8. Grounding or Polarization
– This product may be equipped with a polarized alternation-current line plug (a plug
having one blade wider than the other). This plug will fit into the power outlet only one
way. This is a safety feature. If you are unable to insert the plug fully into the outlet, try

3

reversing the plug. If the plug should still fail to fit, contact your electrician to replace
your obsolete outlet. Do not defeat the safety purpose of the polarized plug.

9. Power-Cord Protection
– Power-supply cords should be routed so that they are not likely to be walked on or
pinched by items placed upon or against them, paying particular attention to the cord
in correspondence of plugs, convenience receptacles, and the point where they exit from
the amplifier.

10. Cleaning – The amplifier should be cleaned only as recommended by the
manufacturer. Clean by wiping with a cloth slightly damp with water. Avoid getting
water inside the amplifier.

11. Non-use Periods – The power cord of the amplifier should be unplugged from the
outlet when left unused for a long period of time.

12. Object and Liquid Entry
– Care should be taken so that objects do not fall and liquids are not spilled into the
enclosure through openings.

13. Damage Requiring Service
– The amplifier should be serviced by qualified service personnel when:
A. The power-supply cord or the plug has been damaged; or
B. Objects have fallen, or liquid has been spilled into the amplifier; or
C. The power attenuator has been exposed to rain; or
D. The power attenuator does not appear to operate normally or exhibits a marked
change in performance; or
E. The power attenuator has been dropped, or the enclosure damaged.
F. The power attenuator needs tube replacement or biasing

14. Servicing – The user should not attempt any service to the power attenuator beyond
that described in the operating instructions. All other servicing should be referred to
qualified service personnel.

15. Ventilation – Slots and openings in the cabinet are provided for ventilation and to
ensure reliable operation of the product and to protect it from overheating, and these
openings must not be blocked or covered.

16. Attachments – do not use attachments not recommended by the product
manufacturer as they may cause hazards.

17. Accessories – Do not place this product on an unstable cart, stand, tripod, bracket,
or table. The product may fall, causing serious injury to a child or adult, and serious
damage to the product. Use only with a cart, stand, tripod, bracket, or table
recommended by the manufacturer, or sold with the product.

18. Lightning – For added protection for this product before a lightning storm, or when
it is left unattended and unused for long periods of time, unplug it from the wall outlet.
This will prevent damage to the product due to lightning and power line surges.

19. Replacement Parts – When replacement parts are required, be sure the service
technician has used replacement parts specified by the manufacturer or have the same
characteristics as the original part. Unauthorized substitutions may result in fire,
electric shock, or other hazards.