
Home  Forums  Rules  Articles  diyAudio Store  Gallery  Wiki  Blogs  Register  Donations  FAQ  Calendar  Search  Today's Posts  Mark Forums Read  Search 
Vendor's Bazaar Commercial Vendors large & small hawking their wares 

Please consider donating to help us continue to serve you.
Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving 

Thread Tools  Search this Thread 
10th January 2014, 12:21 PM  #1 
diyAudio Member
Join Date: Sep 2007

First One M v1.4  mosfet power amplifier module
Hi guys
Finally the First One mosfet amplifier module is ready to go to travel the world. It has been a long testing and measuring period, just to make me sure the module is good enough to meet your expectations. First One M v1.4 amplifier is plug & play class AB module, current feedback type, ready made to the last detail, calibrated and tested. Technical specifications: Maximal power (20 Hz  20 kHz, THD 0,1 %) 160 Wrms/8 Ohm 250 Wrms/4 Ohm Maximal power (20 Hz  20 kHz, THD 0,05 %) 150 Wrms/8 Ohm 230 Wrms/4 Ohm THD (100 Wrms/4 Ohm, 10 kHz) 0,004 % THD (100 Wrms/4 Ohm, 100 Hz) 0,0034 % IMD (80 Vpp/4 Ohm, 19+20 kHz) 0,003 % THD (1 Wrms/8 Ohm, 1 kHz) < 0,0016 % Frequency response (3 dB) 3 Hz  3 MHz Slewrate 240 V/us Signal to noise ratio > 110 dB Voltage gain +27 dB Input impedance 10 kOhm Output impedance (20 Hz  20 kHz) < 10 mOhm Damping factor (100 Wrms/4 Ohm, 20 kHz) > 2000, measured on PCB output terminals Output DC offset < +/5 mV Supply voltage +/40 V to +/63 V Size  dimensions (W x D x H) 100 x 50 x 40 mm Net price for the module is 88,00 EUR Orders welcome to esl@siol.net Best regards, Lazy Cat Last edited by Lazy Cat; 20th February 2016 at 12:14 AM. 
10th January 2014, 12:36 PM  #2 
diyAudio Member
Join Date: Sep 2007

Plots of the First One amplifier, 40 ppm THD 10 kHz at 100 Wrms/4 Ohm
1. Input signal 10 kHz 2. Output signal 20 Vrms, no load 3. Output signal 20 Vrms on 4 Ohm 
10th January 2014, 12:39 PM  #3 
diyAudio Member
Join Date: Sep 2007

Plots of the First One amplifier, 34 ppm THD 100Hz at 100 Wrms/4 Ohm
1. Input signal 100 Hz 2. Output signal 20 Vrms, no load 3. Output signal 20 Vrms on 4 Ohm 
10th January 2014, 12:43 PM  #4 
diyAudio Member
Join Date: Sep 2007

Few square waves and rise time measurements of the First One amplifier module.
1. 50 kHz 2. 200 kHz 3. mid signal level rise time 4. high signal level rise time Calculation from picture 4, 60 V (90% Vpp) in 250 ns results in: Slew Rate of 240 V/us Last edited by Lazy Cat; 10th January 2014 at 01:05 PM. 
10th January 2014, 12:44 PM  #5 
diyAudio Member
Join Date: Sep 2007

Measurement showing the First One's behaviour at 2,77 MHz sine signal.
We can see 0,9 Vpp input sine signal present on CH2 and 14,3 Vpp output signal on CH1 Calculations from the plot: 1. Voltage gain is x15,89 or +24 dB at 2,77 MHz 2. Linear voltage gain of the First One is +27 dB, meaning that 2,77 MHz is exactly 3 dB gain point 3. Phase shift at 2,77 MHz is 76° 4. 10 Ohm zobel load (Zr+Zc) dissipates 2,4 Wrms at 2,77 MHz 
10th January 2014, 12:49 PM  #6 
diyAudio Member
Join Date: Sep 2007

The task was to find a proper output inductor and test the amp to all possible values of capacitance as a load, to be sure there are no chances for the amp to oscillate, no matter what kind of speaker cable is connected to its output terminals.
Lowest possible output serial inductance to fulfill upper demands is 0,2 uH, very practical small size still to be located on PCB. Few pictures attached as follows: 1. Plot of 10 kHz/20 Vpp square waves on 6 Ohm +1 uF load. Upper trace amp's output in front of inductor, lower trace behind the 0,2 uH inductor. 2. 32 ppm THD10k spectrum 20 Vrms on 6 Ohm load (60 Wrms/6 Ohm) 3. 24 ppm THD10k spectrum 20 Vrms on 6 Ohm + 1 uF (90 Wrms/4,3 Ohm impedance). We can see that 1 uF loading capacitor completely filtered out third harmonic and elevated the second for 5 dB. The whole THD droped for 8 ppm but since third harmonic is also present in the input signal, this THD reduction is actually bad, not preserving the input signal integrity. 4. 0,2 uH output inductor and 1 uF loading capacitor in series with on/off switch 5. Complete measuring assembly 
10th January 2014, 12:52 PM  #7 
diyAudio Member
Join Date: Sep 2007

As a conclusion of the measurements here's 19+20 kHz intermodulation distortion measurement
1. 30 ppm THD19+20k 80 Vpp on 4 Ohm load 2. Setup 
10th January 2014, 01:04 PM  #8 
diyAudio Member
Join Date: Sep 2010
Location: Singapore

Hi LC,
Interested for a pair. Thanks, James 
10th January 2014, 01:08 PM  #9 
diyAudio Member
Join Date: Sep 2007

Thanks chunek, you're the first one

10th January 2014, 01:21 PM  #10 
diyAudio Member
Join Date: Aug 2008
Location: Toronto

Class AB/D?

Thread Tools  Search this Thread 


Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
800 Watt MOSFET Amplifier Module  The Saint  Aussie Amplifiers  75  18th July 2013 11:16 AM 
MOSFET POWER AMPLIFIER MODULE IN EBAY INDIA  reji  Vendor's Bazaar  0  19th March 2013 01:52 AM 
class D amplifier module,power amplifier module  sunlight009  Vendor's Bazaar  2  19th October 2011 01:02 AM 
NX400  400W RMS@4Ohms Lateral Mosfet Power Amplifier Module by ClassD for sale  magnum_1  Swap Meet  16  13th June 2009 03:59 PM 
Help with Mosfet module please  Beejay  Solid State  6  11th September 2008 03:21 PM 
New To Site?  Need Help? 