Z A P pulse 2.2 Special E dition
A n d Z A P p u ls e 2 . 2 S t a n d a r d
COOKBOOK |
P u l s e F i e l d |
T e c h n o l o g y |
A s s e m b led a nd t e s t ed P W M A m p lifie r m o d u le for D IY A u d io!
C r e d it C a rd sized footprint!
[up to 580 Watts RMS in 4 Ohms]
ZAPpulse amplifiers represent the best in PWM (Pulse Width Modulation) amplifiers. Based on a single integrating modulator stage, the ZAPpulse has the shortest feedback delay of any PWM amplifier available on the market, allowing for best possible sound quality. These modules are ultra efficient at some 96% of the applied power is usable audio power! This means almost no heatsinking
is necessary. Despite the small size these modules are incredibly rugged and will drive 2 Ohms and even lower impedances with no hazzle! Power exceeding 1 kW per module is fully supported! The input stage is fully balanced, without conversion circuits, so both balanced and unbalanced signals are equally usable. Sound quality is on level with market leading Class A amps!
L C A u d io T e c h n o l o gy Inc.
Content.
A c t i v e C r o s s o v e r w ith Z A P p u l s e 2 . 2 |
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B r id g e T i e d L o a d , a n d d i s a b l i n g o f p r o te c t i o n |
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C o m p e n s a t e d M o d e |
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C o m p le te A m p lifier S c h e m a tic |
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C o n n e c t i o n o f in p u t / o u tp u t |
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C o n n e c t i o n o f p o w e r s u p p l y |
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C o o ling R e q u i r e m e n ts |
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E ffe c ts o f s w i t c h i n g f r e q u e n c y |
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M e c h a n i c a l p ro p e r t i e s |
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M o r e Z A P p u l s e te c h t a l k |
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M in i m a l i st S y s te m |
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P a s s i v e V o l u m e C o n tro l |
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P r in c i p le o f O p e r a t io n |
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P r o f e s s i o n a l u s e (PA ) |
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S h o p p i n g L i s t |
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S u r r o u n d S y s t em |
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S y n c r o n o u s M o d e |
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Ta b l e o f O u tp u t p o w e r v s . P ow e r S u p p ly V o l t a g e |
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Te c h n i c a l D a t a |
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1 . 0 |
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2 .2 S E |
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2 . 1 S E |
2 . 0 |
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2 . 0 |
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2 . 1 S E |
ID E |
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2 . 2 S E H a r d d i s k |
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1 .0 |
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Z A P p u l s e S o u n d Q uality v s . V e r s i o n |
Z A P p u l s e E m i s s i o n s |
v s . V e r s i o n |
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More Informations: www.lcaudio.com
Z A P p u lse 2 .2S E 2 L C Audio Technologl yy ApSInc
T h is b o o k l et is i n t e n d ed for n o n c o m m e r c i a l u s e b y D IY a u d io c o n s t r u c t o r s . C o n t e n ts m a y b e c o p i ed a nd distributed freely for private o r n o n c o m m e r c i a l u s e . N o c o p y i ng f or c o m m e r c i a l p u r p o s e s is a l l o w e d . C o p y r i g h t 2 0 0 4 - 2 0 0 5 L C A u d i o T e c h n o l o gy Inc.
Principle of Operation.
In a conventional amplifier the input signal is amplified through various analog stages to a progressively higher amplitude. In the final stages of the amplifier, the output stage, high current capability is added to enable the amplifier to drive loudspeaker loads. When current is drawn out of the output stage to the load, heat is dissipated in the output stages, since the load current multiplied with the voltage drop over the output device gives a power value (of average 60% of the max. output power) that needs to dissipate in heat sinks. 60% is not the power loss
at maximum output power, but the average heat dissipated at various output power levels (except very small levels below 1W). So a 100 Watt amplifier will as average need to dissipate 60 Watts power into heat sinks. The ZAPpulse operates in a different way, the output devices are either off or on with no significant voltage drop. So even when the load draw large amounts of current, there is only minimal power to be dissipated. To control the signal amplitude, the pulse width of the output square wave is controlled very accurately.
Filter
+60V
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P u l s e F i e l d |
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Out |
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G n d |
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T e c h n o l o g y |
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Integrator |
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Gate Driver |
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Gnd |
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Differential |
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Comparator |
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Output Filter |
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-60V |
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Power Stage |
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After the output devices the square wave need to be filtered with a choke and capacitor. This filter regenerates an analog signal that can be fed to the loudspeakers. The choke and capacitor's quality is paramount in order to get a good sound quality, so we use an oversized (1.5 kW) ultra high speed ferrite core with silver conductor and TEFLON insulator. This choke has a very low impedance (only 5 milli Ohms), and allows for a good damping factor in any speaker load. To get an output signal of say 30V, the output devices are made to switch high 75% of time, and 25% of time low. In this case
the Pulse Width is 75%. SinceV+ to V- voltage is 120V, the output voltage seen from V- is 75% of 120V = 90V as seen from the minus rail. Translating to 30V, above GND. (As wanted in our example. Operating from +60V to -60V allows for any output voltage in this range, including 0V. Thus a total DC coupled system for highest possible sound performance. Pulse Width Modulation is often shortened to PWM. A very important stage in a PWM amplifier is the modulator. It can be made i various ways, with different properties. We have selected and optimized the balanced integrating type.
ZAPpulse 2.2SE |
3 L C Audio Technology Inc |
This booklet is intended for non commercial use by DIY audio constructors. Contents may be copied and distributed freely for private or non commercial use. No copying for commercial purposes is allowed. Copyright 2004-2005 L C Audio Technology Inc.
More ZAPpulse Techtalk!
The heart of the ZAPpulse amplifier is a balanced integrating PWM modulator. It basicly integrates the DC level of one switching cycle of the output stage, including any switching noises, slope differences etc. Then this value is compared, and corrected in the next switching cycle to create an output signal of exactly 0 Volt. This correction is performed every switching cycle, which is about 500.000 times per second.
The input signal is injected directly into the integrator to keep signal paths ultra short. No signal conditioning, such as DC blocking, HF blocking or other limiting factors are present on the ZAPpulse module. So if this is required by your application, you have to add these functions outside the module. When signal is applied to the input, the integrator no longer corrects the output signal level to 0 Volts, but to the audio signal.
The feedback group delay is kept very low, only around 1 uS, to allow for TIM free operation. The analog integrating feedback loop has a lower group delay of any completely digital (DSP based) feedback loop. And since output switching noise products are the same no matter the modulator type, the analog feedback loop gives a much better rejection of noise products than a true digital approach. It's all about speed, and how fast the noise can be cancelled.
The output square wave has a base frequency of typ. 460 kHz, and rise times of some 10.000 V/uS. The slopes are minimised to around 80nS to keep
switching losses low at heavy speaker loads. However at low signal amplitudes the main power loss comes from capacities in the MOSFET's, so transitions are slowed to reduce EMI, noise and idle loss. This is controlled by the PulseField circuit in the Gate driver.
A simple rule says that at no signal, a ZAPpulse loses some 9.5 Watts power to capacities in the MOSFET's, and at full power it loses another 9.5 Watts to serial resistance. So at 500 W out you only have to dissipate around 19 Watts to the heat sinks.
One great advantage PWM amplifiers have over conventional analog amplifiers is, that PWM amplifiers have exceptional ability to expand the sound stage with added sound level. An analog amplifier would typically collapse the soundstage at higher levels, depending on the size of the power supply (why we have huge power supply banks in all our analog amplifiers). The PWM will play with wide and deep sound stage at any listening level, even with a very (almost too) small power supply. We have made tests with a 2 x 250 W RMS ZAPpulse amp, running with only two 2200 uF 100V main caps. And it still has plenty of bass control, definition, width and depth. Opportunities for interesting experiments in this field are obvious.
ZAPpulse 2.2SE |
4 L C Audio Technology Inc |
This booklet is intended for non commercial use by DIY audio constructors. Contents may be copied and distributed freely for private or non commercial use. No copying for commercial purposes is allowed. Copyright 2004-2005 L C Audio Technology Inc.
Connection of a Power Supply
To make ZAPpulse 2.2SE work, simply connect a typical Audio Power Supply of +/-35V to +/- 72V. (max. 60 V for the standard version). The output power depends on the voltage of the power supply. The 2.2 standard version uses 63V capacitors, on the board, while the 2.2SE uses 100 V caps. This is why the SE can be made to deliver much higher powers than the standard modules. In the standard version, the sound quality of the main caps must be considered.
The midrange and treble sonic properties of these caps, will interact with the overall sound performance of the amplifier, so we recommend using very high quality caps with standard modules. With the SE modules the mid and high frequency performance is fixed at the highest level by the BC Vishay series RLI136 (100uF 100V). So PSU caps only need to have good bass props. Always use short and heavy wire between PSU caps and modules (less than 4-5 inches).
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+ 6 0 V |
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S H O R T ! |
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S H O R T ! |
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P o w e r |
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G N D |
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1 0 . 0 0 0 u F |
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P o w e r |
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6 3 V |
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G N D |
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1 0 . 0 0 0 u F |
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O U T |
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- 6 0 V |
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S H O R T ! |
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+ 6 0 V
P o w e r G N D
- 6 0 V
There is no need to use huge capacitor banks, like with Class A or A/B amplifiers. Almos all the power of the PSU will be translated to audio power, so smaller caps will work just as well. 10.000 uF is adequate for driving 2 channels at full power.
External Gate Drive.
R e m o v e b u b b l e
+ 6 0 V |
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S H O R T ! |
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S H O R T ! + |
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1 0 . 0 0 0 u F |
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1 0 . 0 0 0 u F |
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O U T |
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S H O R T ! |
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- 6 0 V |
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+ 6 0 V
P o w e r
G N D
G a te Drive
- 6 0 V
T h e Z A P p u l s e 2 . 2 S E m o d u le h a s a n o n - b o a rd G a t e Drive regulator. It d e riv es it's
v o lta g e from the n e g a t iv e - 6 0V rail ( w h y t he n e g a t i ve rail h a s a h i g h er c o n s u m p tion
t h an the p o s itive rail). By f e e d i ng a s e p a r a te g a te drive v o l t a ge from the pow e r s u p p l y ( 1 5 - 20 V D C 2 0 0 m A ) you c a n r e d u ce the idle loss o f a Z A P p u ls e m o d u l e from 9 . 5W to 5 W . T h is w ill m a k e y o ur a m p lifie r e v e n c o o l e r! I M P O R T A N T ! T h e G a t e drive v o l t a g e ( m in u s ) m u s t b e tied to the - 6 0V rail N O T to G N D !
ZAPpulse 2.2SE 5 L C Audio Technology Inc
This booklet is intended for non commercial use by DIY audio constructors. Contents may be copied and distributed freely for private or non commercial use. No copying for commercial purposes is allowed. Copyright 2004-2005 L C Audio Technology Inc.
Output Power vs. Power Supply Voltage.
The Output power can be calculated as a function of the max. signal amplitude, which depends on the supply voltage.
At +/- 60V Supply Voltage the amp can ideally deliver 120 Vpp. To calculate the output power we need the RMS value, which is simply 120 / 2pi = 120 / 2,82 = 42,6 Vrms (in this example).
Output power is then calculated using Ohms Law:
In this example 223 watts RMS.
This was ideal values, in ZAPpulse the practical values are corrected with a serial loss of 1 - 3 VDC depending on load impedance (1 V @ 8 Ohms).
At +/- 60 VDC you will get a practical output power of: some 210 Watts RMS.
P = |
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P = Output Power RMS
U = RMS Voltage (42,6)
R = Speaker Impedance (8)
See below for output powers at other transformer voltages, and load impedances.
Bottom table shows bridge mode ZAPpulse modules operating at very high power!
T r a n s f o r m er A C V |
D C V o l t a g e |
8 O h m s P o w e r |
4 O h m s P o w e r |
2 x 2 4 V A C |
+/- 3 2 V D C |
6 0 W |
1 0 6 W |
2 x 2 7 V A C |
+/- 3 6 V D C |
7 8 W |
1 3 7 W |
2 x 3 3 V A C |
+/- 4 5 V D C |
11 9 W |
2 2 2 W |
2 x 3 6 V A C |
+/- 4 9 V D C |
1 4 4 W |
2 6 6 W |
2 x 4 0 V A C |
+/- 5 5 V D C |
1 8 0 W |
3 4 0 W |
2 x 4 2 V A C |
+/- 5 8 V D C |
2 0 0 W |
3 8 0 W |
2 x 4 5 V A C |
+/- 6 2 V D C |
2 3 0 W |
4 3 8 W |
2 x 5 0 V A C |
+/- 6 9 V D C |
2 8 6 W |
5 4 8 W |
You can also Bridge-tie your speaker loads to get higher output power. For this you need 2 ZAPpulse modules per audio channel.
T r a n s f o r m er A C V |
D C V o l t a g e |
8 O h m s P o w e r |
4 O h m s P o w e r |
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2 x 2 4 V A C |
+/- 3 2 V D C |
2 1 9 W |
3 9 7 W |
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2 x 2 7 V A C |
+/- 3 6 V D C |
2 8 6 W |
5 2 6 W |
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2 x 3 3 V A C |
+/- 4 5 V D C |
4 4 8 W |
8 3 7 W |
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2 x 3 6 V A C |
+/- 4 9 V D C |
5 4 2 W |
1 0 1 9 W |
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2 x 4 0 V A C |
+/- 5 5 V D C |
6 8 2 W |
1 2 9 1 W |
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2 x 4 2 V A C |
+/- 5 8 V D C |
7 5 8 W |
1 4 3 9 W |
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2 |
x 4 5 |
V A C |
+/- 6 2 |
V D C |
8 7 9 W |
note |
2 |
x 5 0 |
V A C |
+/- 6 9 |
V D C |
1100 W |
note |
note: N o t r e c o m m e n d e d for s afe o p e r a t i on o f m o d u les.
ZAPpulse 2.2SE |
6 L C Audio Technology Inc |
This booklet is intended for non commercial use by DIY audio constructors. Contents may be copied and distributed freely for private or non commercial use. No copying for commercial purposes is allowed. Copyright 2004-2005 L C Audio Technology Inc.
Connection of Inand Outputs.
Here you can see how inputs and outputs are connected to the ZAPpulse module .
Unbalanced Input.
+ 6 0 V
P o w e r
G N D
S T R I P L I N E
O U T
- 6 0 V
-Out
+Out
Balanced Input
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S T R I P |
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L IN E |
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X L R F E M A L E C h a s s is p l ug as
s e e n from r e a r s i d e .
+ 6 0 V
P o w e r
G N D
O U T
- 6 0 V
-Out
+Out
If you want to ensure safe operation of your ZAPpulse module, dont let the input wires close to loudspeaker cable,power line cable, power transformers or the Ferrite coil. Dont leave long input wires unconnected.
Passive Volume control
P o t e n t i om e t e r 2 2 k log.
S e e n f r o m
F R O N T
+ 6 0 V |
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P o w e r |
-Out |
G N D |
O U T
+Out
- 6 0 V
ZAPpulse 2.2SE |
7 L C Audio Technology Inc |
This booklet is intended for non commercial use by DIY audio constructors. Contents may be copied and distributed freely for private or non commercial use. No copying for commercial purposes is allowed. Copyright 2004-2005 L C Audio Technology Inc.
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