Thule Audio PR-250-B Brochure

SPACE PA250B / PA350B / IA350B

These are the most advanced amplifiers offered by Thule Audio. You can choose between two power

amplifiers, PA250B and PA350B, or the integrated version, IA350B, with volume control.

[ thule audio introduces virtual class a® ]

PA250B, PA350B and IA350B contain a brand-new circuit technology that we call Virtual Class A®.

You may have heard of class

AB amplifiers, the usual type of amplifier design. One of the most

notable problems with class

AB amplifiers is that the output transistors “open and close” when

you play music. This switching gives a very unmusical distortion that is quite detrimental to

sound quality. In the class

A amplifiers, this problem is solved by raising the so-called idle current

to a high level that prevents the output transistors from switching.The disadvantage to class

A

construction is a high degree of heat generation due to the increased idle current – and there-

fore a significant waste of energy. Hardly any amplifiers are class

A in practice, even though a

few manufacturers claim that they are.

Thule Audio wanted to achieve the advantages of a class

A amplifier, particularly the lowered

distortion, but did not want to accept the disadvantages: a large degree of heat generation and

power consumption. That’s why Thule Audio has developed an intelligent control circuit that

has a built-in, custom-made IC that measures the output current to the speakers and sets the

so-called control bias voltage to the output transistors – so that the transistors no longer switch.

IA350BPA350B

[ technical specifications ]

CONNECTIONS IA350BPA250B/PA 350B

Stereo line inputs 300mV / 10kohm / phono 1V / 10kohm / phono

Multi chan. inputs 300mV / 10kohm / phono 1V / 10kohm / phono

Tape in 300mV / 10kohm / phono

Tape out 300mV / 10ohm / phono

Balanced input 600mV / 20kohm / XLR 2V / 10kohm / phono

Pre out 0-600mV / 5ohm / phono

Sub out 0-600mV / 10ohm / phono 0-600mV / 10ohm / phono

Loudspeakers 4-8ohm, screw terminals 4-8ohm, screw term.

TECHNICAL QUALITY IA350B / PA350BPA250B

Power output, 1kHz,8ohm 2 x 350W / 5 x 120W 2 x 250W / 5 x 100W

Power output, 1kHz,4ohm 2 x 500W / 5 x 160W 2 x 380W / 5 x 150W

Peak current capacity 0.6ohm,1ms + / -45A + / -35A

Frequency range 20-20.000Hz +0dB,-0.5dB 20-20.000Hz +0dB,-0.5dB

THD 20-20kHz, -10dB, 8 ohms 0,005% 0,005%

S/N 112dBA 112dBA

GENERAL

Size (W x H x D), net weight 420 x 120 x 375mm, 21kg 420 x 120 x 375mm, 21kg

Max. power consumption 1000w 750w

THULE AUDIO reserve the right to alter design and specifications without notice

Thule Audio ApS

Hørkær 14

2730 Herlev

Denmark

Tel

[phone]

Fax

[phone]

[e-mail]

www.thule-audio.com

Thule Audio’s custom made

integrated control circuit ( yellow )

for Virtual Class A®

In this way, Thule Audio has created a new type of class

A amplifier, but without the well-known

physical disadvantages. And for that reason, we think this new amplifier technology merits the

name “Virtual Class

A®”.

Thule Audio has also developed a new “high efficiency technology” for

PA250B, PA350B and IA350B.

When you play music, most of the music signals are on a relatively low level,and the music

peaks only occasionally. The amplifier must support the reproduction of both signal sizes so that

the voltage peaks are reproduced without any compression or distortion. Musical peaks require a

high supply voltage but at the lower levels you can lower the voltage supply and thereby reduce

the generation of heat.

Thule Audio has developed a dynamic power supply for

PA250B, PA350B and IA350B that uses

this principle. The norm is to use a lower voltage supply, but with musical peaks a higher voltage

supply is used. The voltage supply thereby changes in tune with the music, and the changes

occur very rapidly – much faster than the musical signals can change.

With musical signals,Thule Audio’s “high efficiency technology” reduces heat generation by

approximately 60% compared to class

AB amplifiers. This means that PA250B with 250W generates

no more heat than a normal 100

W amplifier.

As opposed to class

D amplifiers where the output transistors themselves switch and thereby

influence the signal path directly, Thule Audio’s “high efficiency technology” has no connection

to the actual signal path.

Class

D is only a little more effective than Thule Audio’s “high efficiency technology”, but class D

requires a great deal of signal processing and output filters in order to function, particularly at

higher frequencies, and even here only a few very expensive products have succeeded in creating

sound good enough to be used for things other than subwoofers and car radios.

The combination of Thule Audio’s “high efficiency technology” and Virtual Class

A® has created

a new way of making amplifiers. For the first time ever, you get class

A sound: crisp, clear and

with a superb dynamic performance without any hardness – and the heat generation is even

significantly lower than traditional class

AB amplifiers.

SPACE PA250B, SPACE PA350B and SPACE IA350B are all both stereos and surround sound products.

Thule Audio has many years of experience designing high-end sound products for music. And

we have used this experience to create the ultimate sound reproduction for music: the

PA250B,

PA350B and the IA350B. The best possible sound reproduction for music actually gives the best

sound reproduction of surround sound for film, if the amplifier is equipped with sufficient

power to handle the explosive sounds.

That’s exactly why you do not need to compromise by choosing either stereo or surround – you

can have both. One minute the

PA350B is a highly powerful stereo amplifier using 2x 350 W with

a fully balanced signal path, the next,it’s a state of the art surround amplifier using 5x 120

W.

It’s a simple but brilliant principle.

If five channels are not enough, in connection with, e.g. DTS ® 6.1 or Dolby ®

EX the PA250B and

PA350B can be equipped with extra plug-in cards so that you can reach up to 7x 100W for the

PA250B and 7x 120W for the PA350B.

The new amplifiers in Thule Audio’s Space series are all equipped with solid power supplies

with 120,000uF capacity and 2x 500

VA / 2x 350VA transformers for PA350B, IA350B and PA250B

respectively, and in addition, the power supply is utilised to an even greater extent in the PA350B,

IA350B and PA250B due to the “high efficiency technology”: The power supply’s capacity is used

for music signals instead of for generating heat.

The output transistors are generously equipped with 36pcs 20

A transistors in the IA350/PA350B

and 24pcs 20A transistors in the PA250B.

With the

PA350B, IA350B and PA250B, only the best components are used, for example Burr Brown

operational amplifiers and high quality relays for signal exchange. PCB tracks are made with

extra-thick copper.

[ “high efficiency technology” sized right for the living room ]

PA250B

, PA350B and IA350B are extremely powerful amplifiers with up to 2x 350W. Normally,

amplifiers of this strength are physically very large and space-intensive, because they require

a lot of cooling. Thule Audio has used “high efficiency technology” in order to construct more

moderate, smaller-sized cabinets with an elegant, timeless design. The back plates of the

amplifiers are equipped with genuine WBT® speaker plugs, The Platinum Series.

[ more operating possibilities ]

The IA350B can be operated both with and without remote control.

Shifting between two- or multiple-channel operation for

PA250B/PA350B can be done in three

different ways: You can use a single knob directly on the front of the amplifier.Or, the shift can

occur automatically with the help of an internal control circuit in the amplifier which senses

which channels carry signals. If you have connected a Thule Audio

PR250B, the control can take

place through a data connection between your equipment.

[ put together your thule audio equipment
so that you can gain a fully balanced signal path ]

PA250B or PA350B will both be the strong cornerstone of your home cinema, and the obvious

solution is to pair one of these amplifiers with the processor/preamp Thule Audio

SPACE PR250B,

so you are assured a fully balanced signal path.

Perhaps you want to start by acquiring a

IA350B that goes with stereo products such as Thule

Audio

CD150B and Thule Audio TU100, so you are secured for the future and can later change to

multiple channel operations in connection with the building of your home cinema system.

IA350B

can also be connected to PR250B with a data interface, and will automatically convert into a

power amplifier with same performance as

PA350B.

PA250B / PA350B Rearpanel IA350B Rearpanel