Carol-Ann Tucana 3 75W Head

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Tonally the Tucana 3 is designed to cover many styles and is very suited to session players and players who need a very wide palette of excellent tones. With 3 channels, the Tucana 3 can stray into higher gain levels, yet still retain full note definition and separation even with complex chords all while exhibiting an ultra-quiet noise floor.

The New Tucana 3 boast some impressive new features including a programmable foot controller, Carol-Ann's new updated tube driven effects loop and CA's next generation AutoBiasMon!

This is an update of Alan Phillips' own personal favourite amplifier model, the Tucana. The updated Tucana 3 features 3 channels with separate gains and masters on the OD channels, KT88 power tubes running at 75 W (150w version available), a new foot controller but with the addition of a new footswitcble efx loop bypass that is programmable on a per channel basis right from the foot controller. This allows the efx loop to be setup to be active on only on certain channels or all of them or completely off.

The Tucana model is the Swiss Army knife model designed for players who need access to many tones. Typical users will be Session Players and Cover Band Players.

Tucana 3 Model Specs:

• Separate Input Level Controls for Clean and OD channels
• Independent three band eq on Clean and OD Channels (CHB and CHC share the same eq as on the Tucana 2)
• Separate Gain Controls for CHB and CHC
• KT 88 Power Tubes
• 75W (150W version available)
• Separate Master Volumes for all three channels
• Shared Presence Control
• Tube buffered efx loop using NOS 12AU7 tube
• efx Send Level Control
• AutoBiasMon system
• 5 Button Foot controller with programmable efx loop assignment connected via a 3 pin XLR mic cable
• Available in 100V, 120V and 240V versions
• 20.75"(width) x 11"(height)  X 10.25" (depth), 45 to 47 lbs

AutoBiasMon:

Introduction

The AutoBiasMon is an original design from Carol-Ann Custom Amplifiers that is the next step from our manual BiasMon system which was released in 2013 and has proven to be highly successful. This new design takes the BiasMon to the next level with automatic biasing, tube state indication, low voltage controlled Standby Switch as well as the ability to select different tube types to run in the same amplifier.

Features and Description

The AutoBiasMon is a microcontroller based software/hardware system built into the amplifier that monitors various tube parameters and voltages inside the amplifier and computes the best operating bias point to ensure the amplifier sounds and plays as designed and it also provides several mechanisms to extend tube life and protect the tubes.

Traditional biasing methods typically give a figure in cathode current (mA) for the bias point. However, cathode current is a variable that depends on the plate voltage and ultimately the wall voltage that can be drastically different from one location to the next and even at the same location during various times of the day, which is the biggest factor that makes an amplifier sound and feel different from room to room.

The TRUE bias point is actually a measure of idling power in Watts. This idle point is not a fixed point as such, but you hear different opinions for a Class AB1 amplifier that range from 50 to 75% idle dissipation, with 100% being the maximum plate power dissipation for the tube, (i.e. 25W for an EL34).

We have selected the idle dissipation point (bias point) for our designs that gives the correct feel and tone and also ensures great tube life.

The AutoBiasMon includes all the circuitry to produce and control the negative bias voltage, which is the voltage applied to the grids of the power tubes to set the idle dissipation power. A traditional bias system consists of a negative voltage supply that uses a potentiometer to set this voltage. The problem is that as the amp is driven harder that voltage goes more positive running the tubes hotter at a point where they are already running hard. This has both tonal and tube life implications, but was just an accepted norm of any fixed bias tube amplifier. However, AutoBiasMon controls that negative voltage within +/- 0.1V at all times regardless of how hard the tubes are being pushed. It does this by using a voltage control system that can be thought of as similar to a DC Motor Controller. The AutoBiasMon circuit is protected from grid conduction and tube faults.

Another age old problem this system eradicates is that of Standby Switch Transients. Despite thoughts to the contrary, the Standby Switch can often cause more problems than it protects from. Almost all Standby Switches used in the Industry are rated for 250V AC switches but in this application being used to switch up to 500V DC. In reality the Standby Switch really does not protect from any problems at all, creates some new ones of its own and is a legacy feature from transmitting tube circuits that was never specified for receiving tubes like those used in a guitar amplifier. However, it has evolved to become a feature many players use and don't want to live without.

The Standby Switch on an AutoBiasMon amplifier only switches 5V DC. The AutoBiasMon circuit controls the negative grid voltage to turn on and off the power tubes in a slow controlled manner. You will notice no pops or thumps at all when operating this switch.

Finally, probably one of the most important features of this system is the users ability to bias their own tubes and carry out a rebias at any time without ANY experience or tools.

Programmable Foot Controller:

The Tucana 3 features a 5 button foot controller with programmable assignment of the efx loop. The controller connects to the amp via a standard 3 pin XLR mic cable, making for easy field replacement. Can reliably be used with up to 500 feet of cable.

Channel changing is a simple one button affair to select between the three channels. The controller also features a lead master function which can switched in and out on either of the OD channels (B,C).

THe efx loop modes of operation are as follows:

Mode 1: efx loop can me switched in and out manually via the footswitch
Mode 2: efx loop is assigned to channel A, the clean channel.
Mode 3: efx loop is assigned to the Overdrive channels , B&C, plus Lead Master
Mode 4: efx loop is assigned to the Lead Master only

Programming is simple and the controller stores the programmed mode in memory.

The actual physical switching inside the amplifier is still done using relays and none of this technology affects the tone allowing for Instant, tonally transparent and noise free switching to be achieved.

New Updated Effects Loop Circuit (Upgrade)

This Tucana 3 has been upgraded to include Carol-Ann's lates Effects loop circuitry.
Here's what Allan Phillips has to say about it:

"While the 5751 driven efx loop has been a staple in almost all our amps since 2005, it was time for a redesign. This is partly due to issues with some effects units and partly due to the difficulty of obtaining 'quiet' 5751 new production tubes. I now reject 2 out of every 3 I buy.

So....the new loop uses an NOS 12AU7 high current tube. This tube is way more capable of driving long cables with much less High frequency roll off due to cable capacitance. The signal to noise ratio is also much improved from the 5751 based design.

The send control on the back of the amp has always been able to be used as a master volume control for the entire amp, with 'unity' being at the 11 O clock position. The new system also allows this control to be used as a master volume for the entire amp, the 'unity' position is now 2 O clock, giving much more available range to bring the overall volume down if required."