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Multi-amplification PCB with three integrated amplifiers each PCB and 24 dB/Octave Linkwitz-Riley Electronic filters.
The professional alternative to a passive crossover in a low cost Do-It-Yourseft
Project.3-way tri-amplification system.
3-way biamplification with high-mid pasive filter and common bass amplifier.
Multiamplification offers many advantages over systems employing passive crossovers. One very serious problem with passive crossovers is the fact that the filters are terminated by loudspeakers rather than simple resistors. This means that the driver is an integral part of the passive filter and that the driver's electrical characteristics strongly affect the response of the filter. This is not the case with a multiamplified system where the active filter crossover terminates its own filters. The response of the active filters can be established quite precisely and is totally independent of the loudspeaker driver's electrical characteristics.
Also, some of the amplifier power will be wasted in the crossover resistance. In a multiamplified system the drivers are connected directly to the amplifiers and these problems are avoided.
Some of the other benefits of multiamplification are the result of using separate amplifiers for each driver. For example, high-frequency distortion products from the woofer amplifier are not reproduced by the tweeter. The woofer system can actually be driven into significant amounts of distortion and, as long as the tweeter system is not overdriven. Also, because each of the amplifiers handle only a portion of the complete frequency spectrum, the amplifiers intermodulation (IM) distortion will be reduced.
I am building three prototype PCB´s, two PCB´s for my tri-amped amplifier and the
other one for my bi-amped system. All board have independient power supply and
each amplifier have independient capacitors near the chip. I´m testing the first
prototype, you can download the PCB Layout to build your own PCB.
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PCB Layout |
Components layout |
Schematics
I want to make a profesional PCB´s if you are interested in them.
Bill of materials
D1,D2,D3,D4-P600M or similar 6A rectifier diode
D5,D6,D7,D8,D9,D10-1n4007
C1,C2,C6,C7,C42,C43,C44,C45-2200uF 50V
C3,C4,C5,C10,C11,C38,C39,C40,C41,C52,C53-100nF
R1,R62-10R 1w
R2,R3-220R
R4,R5-2.2K
R6,R7-R(HIGHPASS_1)
R8,R9,R10.R11-R(HIGHPASS_1)
C12,C13,C14,C15-C(HIGHPASS_1)
C16,C17,C18,C19-C(LOWPASS_1)
C20,C21-C(LOWPASS_1)
R12,R13,R14,R15-R(LOWPASS_1)
R16,R17-R(HIGHPASS_2)
R18,R19,R20,R21-R(HIGHPASS_2)
C22,C23,C24,C25-C(HIGHPASS_2)
C26,C27,C28,C29-C(LOWPASS_2)
C30,C31-C(LOWPASS_2)
R22,R23,R24,R25-R(LOWPASS_2)
C32,C33-1uF bipolar
R30,R31,R32,R33-15K
R26,R27,R34,R35,R36,R37,R38,R39,R40,R41-10K
R28,R29,R42,R43,R44,R45,R56-100K 1/4w
R46,R47-1M 1/4w
R48,R49,R58,R59-22K 1/4w
R50,R51-20K 1/4w
R52,R53-1R 1/2W
R54-R55,R57,R60-1K 1/4w
C34,C35-2.2uF OR (2 X 4.7uF)
C36,C37-22uF
C38,C39,C40,C41-100nF
C46,C47-.22uF
R61-47K 1/4w
C48-10uF tantalum
C49-220pF
C50-100uF tantalum
C51-47pF
Testing my first prototype.
The results of testing are better than expected. It seems to LM1875 sounds
better even TDA1514. This amplifier seems ideal for mid-high range. It has been
necesary some time for adjust crossover, but change crossover frecuency is very
simple operation with socket mounted resistors and capacitors.
Enclosures
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5" Studio Monitor
Frequency Range: 80 Hz - 20 kHz
High driver: Beyma T2030
Bass driver: Beyma 5MP60/N |
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8" Bass Reflex Subwoofer
Frequency Range: 40 Hz - 1000 Hz
Bass driver: Beyma 8WOOFER/P |
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6.5" Subwoofer
Frequency Range: 40 Hz - 1000 Hz
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Drivers
Beyma is a professional audio company, but there are some hi-fi products (studio
series) in their catalog, they are really good and really quality made (machined
aluminium tweeters and aluminium chassis woofers) with very big assortment and
attractive prices too. here are the drivers of my project:
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TWEETER MODEL - T2030 |
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| Specifications |
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Nominal Diameter |
1.25" / 32mm |
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Impedance |
8 ohms |
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Minimum Impedance |
6.2
ohms @ 2.5 khz |
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D.C. Resistance |
5.0
ohms |
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RMS Power Rating |
15
Watts |
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Program Power |
30
Watts |
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Sensitivity (1W/1m) |
95dB 1w @ 1m |
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Frequency Response |
1.5kHz - 20kHz |
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Recommended Crossover |
2.0
kHz - 12dB or higher |
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Dispersion (H x V) |
60° |
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Voice Coil Diameter |
1.0" / 25.4mm |
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Magnetic Assembly Weight |
1.16 lb. / 0.525 kg. |
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Flux Density |
1.44T |
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BL Factor |
3
N/A |
| Mounting Information |
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Overall Diameter |
3.9" / 102mm |
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Overall Depth |
1.65" / 42mm |
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Baffle Cutout Dimensions |
2.95" / 75mm |
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Net Weight |
1.54 lb. / .7 kg. |
| Materials |
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Diaphragm |
Aluminum |
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Voice Coil |
Aluminum |
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Voice Coil Former |
Kapton |
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Front Cover |
Aluminum |
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Magnet |
Ferrite |
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Parameters |
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Resonant frequency (fs) |
1050hz |
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Mechanical Factor (Qms) |
3.957 |
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Electrical Factor (Qes) |
1.567 |
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Total Q (Qts) |
1.122 |
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WOOFER/MID MODEL - 5MP60/N |
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| Specifications |
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Nominal Basket Diameter |
5" / 125mm |
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Impedance |
8 ohms |
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RMS Power Rating |
50 Watts |
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Program Power |
100 Watts |
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Frequency Response |
50Hz - 12.0kHz |
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Sensitivity (1W/1m) |
91dB |
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Voice Coil Diameter |
1" / 25.8mm |
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BL Factor |
6.4 N/A |
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Voice Coil Length |
14 mm |
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Air Gap Height |
6 mm |
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X Damage (peak to peak) |
20 mm |
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Magnetic Assembly Weight |
2.2 lb. / 1.0 kg. |
| Mounting Information |
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Overall Diameter |
5.28"/134mm x 5.28"/134mm |
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Bolt Circle Diameter |
5.4" / 137mm |
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Baffle Cutout Diameter- |
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- Front Mount |
4.72" / 120mm |
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No. Of Mounting Holes |
4 |
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Volume Displaced By Driver |
.019 ft3 / .5 Liters |
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Overall Depth |
2.68" / 68mm |
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Net Weight |
2.64 lb. / 1.2 kg. |
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Shipping Weight |
2.8 lb. / 1.27 kg. |
| Materials |
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Basket |
Die Cast Aluminum |
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Cone |
Polypropylene |
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Surround |
Rubber |
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Voice Coil |
Copper Wire |
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Magnet |
Ferrite |
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Thiele-Small Parameters |
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Resonant Frequency (fs) |
60 Hz |
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Impedance (Re) |
5.33 ohms |
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Coil Inductance (Le) |
0.4 mH |
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Mechanical Q (Qms) |
1.604 |
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Electrical Factor(Qes) |
.35 |
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Total Q (Qts) |
.29 |
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Comp. Equivelant Vol. (Vas) |
.35 ft3 / 9.8 Liters |
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Voice Coil Overhang (Xmax) |
4.0 mm |
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Reference Efficiency |
.5% |
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Displacement Volume |
34 cm3 |
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WOOFER MODEL - 8WOOFER/P |
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| Specifications |
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| Nominal diameter |
8" / 200 mm. |
| Rated impedance |
8 ohms. |
| Power capacity* |
50 w RMS |
| Program Power |
100 Watts. |
| Sensitivity |
92 dB, 2.83v @ 1m @ 2π |
| Frequency range |
30-3500 Hz |
| Recom. enclosure vol. |
20/50 l 0.7/1.77 ft.3 |
| Voice coil diameter |
25.8 mm. 1 in. |
| Magnetic assembly weight |
1 kg. 2.2 lb. |
| BL factor |
7.1 N/A |
| Moving mass |
0.02 kg. |
| Voice coil length |
15 mm. |
| Air gap height |
6 mm. |
| X damage (peak to peak) |
20 mm. |
| Mounting Information |
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| Overall dimensions |
214 x 214 mm. |
| Bolt circle diameter |
217.5 mm. 8.56 in. |
| Front mount cutout diameter |
182 mm. 7.16 in. |
| Rear mount cutout diameter |
185 mm. 7.28 in. |
| Depth |
86 mm. 3.38 in. |
| Volume displaced by driver |
1.5 l 0.056 ft.3 |
| Net weight |
1.5 kg. 3.3 lb. |
| Shipping weight |
2.46 kg. 3.53 lb. |
| Materials |
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| Basket |
Die Cast aluminium |
| Cone |
Polypropylene |
| Surround |
Rubber |
| Voice coil |
Copper |
| Magnet |
Ferrite |
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Thiele-Small Parameters |
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| Resonant Frequency, fs |
35 Hz |
| D.C. Voice Coil Resistance, Re |
5.37 ohms. |
| Mechanical Quality Factor, Qms |
2.33 |
| Electrical Quality Factor, Qes |
0.47 |
| Total Quality Factor, Qts |
0.38 |
| Equivalent Air Volume to Cms, Vas |
75 l |
| Mechanical Compliance, Cms |
940.2 µm/N |
| Mechanical Resistance, Rms |
1.97 kg/s |
| Efficiency, o (%) |
0.6 |
| Effective Surface Area, Sd(m2) |
0.022 m2 |
| Maximum Displacement, Xmax |
4.5 mm. |
| Displacement Volume, Vd |
100 cm.3 |
| Voice Coil Inductance, Le @ 1kHz |
0.6 mH |
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