!

 

Qualified Service Personnel Only

Class-G Trans•ana Amplifier

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The transistor Q8 is configured as a

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

+HV

 

 

 

 

 

 

 

 

 

 

 

 

switch, which controls the current

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

source Q5, of the input differential

 

 

 

 

 

 

 

 

 

 

+ 15V

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

POS

 

 

POS

 

 

 

 

 

 

 

 

 

 

 

amplifier Q11 and Q12. If the power

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

G

 

 

G

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

POS PRE-

 

 

 

 

 

 

 

 

 

 

+LV

 

 

 

 

 

On/Off, Signal Sensing, and Thermal

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DRIVER

 

 

DRIVER

 

 

Q9

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Q13

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Protection circuits have all stopped

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Q18

 

 

 

 

 

 

 

 

 

 

 

 

CR1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

I MIRROR

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

pulling to -15V, the turn-on process

 

 

 

 

 

 

 

 

 

 

Q6, Q7

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

begins, and the voltage at the emitter

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

POS

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

of O8 slowly ramps up to zero Volts

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

OUT

 

 

OUT

 

 

 

 

 

 

 

 

 

 

 

according to the charging time of soft

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BIAS

 

 

DRIVER

 

 

Q4

 

 

 

 

 

LOCAL

 

 

 

 

 

 

AMPLIFIER

 

 

 

 

 

 

 

DIFF

 

FB

 

 

 

 

 

 

 

 

Q37

 

 

 

 

 

 

 

 

 

 

 

 

 

out

 

start components R13, C93, and C94.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R9

 

 

Q19

 

 

 

 

 

 

 

 

 

FB

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AMP

 

R46

 

 

 

 

<out

 

 

 

Q21

 

 

 

 

 

 

 

 

 

C47

 

 

 

 

15V is divided between R40 and R65,

 

 

DC

 

 

 

 

Q11, Q12

 

C10

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NEG

 

 

 

 

 

R86

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

and imposed across the base-emitter

 

 

OFFSET

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

OUT

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

of Q5 and R35, causing current

 

 

U2B, R47, C22

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Q10

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

source Q5 to turn the amplifier on.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CR17

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R13

 

 

 

 

 

I

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The input signal is connected across

 

 

C93 SOFT

 

 

 

 

SOURCE

 

 

NEG PRE-

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

-LV

 

 

 

 

 

 

 

C94 START

 

 

 

 

R40, R65

 

 

 

DRIVER

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

the differential amp transistors Q11

 

 

Q8

 

 

 

 

Q5,R35

 

 

 

 

 

Q17

 

 

 

 

 

NEG

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NEG

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

and Q12. U2B is configured as a DC-

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

G

 

 

 

G

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DRIVER

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Q1

 

 

 

 

 

 

 

 

 

 

 

servo integrater to null any DC at the

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Q23

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

output.

 

 

 

 

 

 

 

 

 

 

- 15V

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

-HV

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The output of the differential amplifier

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

is fed to the positive pre-driver Q18,

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

and to the curent mirror which mirrors the inverted input current of Q6 into O7 and delivers it to the negative pre-driver

Q17. The pre-driver current is split between the three current paths of the bias and the driver circuit according to the factory bias setting of trimpot R9, and the temperature of Q37. Q37 is thermally linked to the heatsink, and compensates for the gate-voltage temperature coefficient of the output MOSFETs. Q19 drives the positive output MOSFET Q4, and Q21 drives the negative output MOSFET Q10. Local feedback components C47 and R86 help to stabilize this output stage.

At low output voltages, current flows to the woofer from the lower voltage rail +LV or -LV through the diodes CR1/CR17 and output MOSFETs Q4/Q10. When the output voltage approaches or exceeds these lower voltage rails, output current flows from the higher voltage rail +HV or -HV through CLASS-G MOSFET Q9/Q1 and output MOSFETS Q4/Q10.

Positive G driver Q13 turns on class G MOSFET Q9 when the base-emitter voltage exceeds 0.7V. This occurs when (OUT - 1.4 - 5.1V) - (+LV - 0.7 - 10) > 0.7V, which reduces to OUT > +LV - 3.5V. A similar equation can be applied to the negative class G driver Q23. The resulting behavior can be observed as the class G rail on the source of the output MOSFET tracking 3.5V higher (or lower) than the output signal.

Soft Start Circuit

The amplifier soft start circuit is controlled by three On/Off circuits: Power On/Off, Signal Sensing, and Thermal Protection. The "diode OR" connection of CR5, CR6, and CR3 causes the amplifier to turn off if power On/Off is low or Signal Sensing is low or the Thermal Protec- tion is low. The amplifier will turn on only if all these circuit outputs are high. In this all-high condition, CR5, CR6, and CR3 are open circuited or back-biased, allowing R13 to turn on Q2 and Q8, illumi- nating LED CR8 and turning on the amplifier. Q8 is turned on slowly, according to the time constant of R13 and C93 and C94. This "soft start" behavior eliminates audible turn on transients.

SOFT START CIRCUIT

 

 

 

ON / OFF

ON

R13

 

INDICATOR

SOFT

 

C93

CR5

LED

START

CR6

Q2

C94

DELAY

CR3

R50

Q8

 

 

CR8

 

 

– 18 –

Page 27
Image 27
Hafler TRM10S, TRM12S manual Class-G Transana Amplifier

TRM12S, TRM10S specifications

The Hafler TRM12S and TRM10S are two standout models in the world of professional studio monitors, designed to meet the demands of sound engineers, audiophiles, and music producers. Known for their exceptional performance and clarity, these monitors are integral to contemporary studio environments.

The TRM12S is equipped with a robust 12-inch low-frequency driver, ensuring deep bass response. This model has been tailored for larger spaces, delivering an impressive output that doesn't compromise on precision. It handles low-end frequencies adeptly, making it ideal for electronic music production, film scoring, and any genre where bass fidelity is paramount. The wide dispersion pattern of the TRM12S allows for a consistent listening experience across different positions in the room.

In contrast, the TRM10S features a slightly smaller 10-inch low-frequency driver, which is perfect for smaller studio setups or for users who prefer a more compact design without sacrificing sound quality. Despite the size difference, the TRM10S still offers profound bass response, making it versatile for various applications, from mixing to casual listening.

Both models utilize Hafler's proprietary technologies, including advanced, high-efficiency amplifiers that provide clean, high output with low distortion. This enables the monitors to produce a wide dynamic range, making it easier for sound engineers to make critical mixing decisions. The integrated DSP (Digital Signal Processing) allows for precise tuning of the audio output, which compensates for any deficiencies in the acoustics of the space.

Another key feature of the TRM series is the adjustable room compensation settings. This functionality empowers users to tailor their monitor settings based on room dimensions and placement, ensuring the optimal playback environment.

Moreover, both the TRM12S and TRM10S are built with durability in mind, featuring rugged enclosures that minimize resonance and vibration, resulting in a clearer audio reproduction. Their sleek design ensures they blend seamlessly into any studio décor, while providing professional-grade sound quality.

Overall, the Hafler TRM12S and TRM10S are designed for professionals seeking reliable, accurate monitors that excel in delivering unparalleled sound fidelity. Their combination of advanced technology, thoughtful features, and solid performance makes them a worthy investment for any serious studio setup.