KSA100 MKII Class A 100-Watt amplifier board
KSA100 upgraded version of the CPI amplifier
This link is not include heatsink
DIY KIT (need buyer weld yourseft)
Technical parameters:
Output power: AB Class is 300W / 4 ohm load; A Class is 100W/4 ohm load (Total harmonic distortion THD + N <0.3%)
Speaker Impedance: Available 4-8 ohms.
PCB size: 61 * 236MM.
Power supply: DC Dual 18-50V transformer 400 watts or more, the need to replace withstand higher voltages higher capacitance.
Discrete Tube: 2SA1943 2SC5200 OR NJW0302 NJW0281, classics on the tube(Actual delivery of boards).
The default is 2SC5200 2SA1943, you can leave a message to change of NJW0281 NJW0302, the same price
About KSA100MK2:
Upgraded version handed down generation crew KSA100 of this kit from the US Nilfisk KRELL line of the original line KSA100 MKIIPart of the road after the class; line architecture is very good, two complementary input differential symmetry by T oshiba supervisor 2SC2240 / 2SA970As the stability of the effect is very good Actual audition bass permeability effect is very good, there is heavy penetrate the heart feelingEvery detail of the high-frequency performance is very crisp, four pairs of tube output to cope with it&39;s home speakers, floor boxes pushing big appetiteMoving too ease, of course, the premise is enough power in case of power transformer ...
The speaker line added protection, instant shut off the machine delay, the midpoint of DC protection and overcurrent protection functions such as improving
Energy, installed for customers which is very convenient, integrated speaker protection simply add a filter to the power board
Description:
1 There are 1% precision resistors metal film resistors (apart from 1W to 5W 5% accuracy and no external sense resistor), the use of CBB capacitor P hilips Cbb capacitors, mica capacitors.
2 electrolytic capacitors have a Black Edition, there ELNA and Nichicon, R ubycon and other famous capacitance. To ensure the stability of the circuit, and noise removal clean.
3 Select the audio coupling capacitor 1uF Weimaraner capacitors imported from Germany, to ensure that each channel to ensure that the small signal clean and clear sound.
2SC5171, 2SC1930 T oshib a bipolar transistors, the role is to promote the tube.
A970, C2240 T oshiba is a low noise, high power audio transistors dedicated amplification.
2SD669 H itachi imported NPN silicon tube, 2SD669 is working in a single-ended Class A status, the positive and negative half-wave signal alone by 2SD669 completed, so there is no crossover distortion, but also rich in even harmonics, timbre there are some moist role, and thus enlarged board very resistant, while 2SD669 is working in a big 50mA current status (normal op amp, amplification integrated only a few milliamps), to deal with large dynamic music signals easy to get the most realistic sound performance Play limit the effect .
Technical Parameters:
Output power: 300W (4Ω) 250W Mono class AB CPI 100W, 150W (8Ω) 150W Mono Class A 300W class AB
Frequency Response: 20Hz ~ 20kHz3Hz ~ 150kHz (1W output)
Total harmonic distortion: 0.05% (20Hz ~ 20kHz)
Damping: 200 (8Ω, 50Hz)
SNR: 110dB (RCA inputs)
93dB (balanced input)
123dB (input stage)
Gain: 128dB (after stage amplifier section)
Stereo headphone output impedance: 8 ~ 100Ω
Parts DIY Commissioning notes :
1) After completion of welding installed heatsink (note tubes and fins to be well insulated), adjust VR2 (5K) Precision canTransfer resistance makes ab board above two points (located next to the Omron Relay) voltage of 22mV, where the quiescent current100mA / tube (22mV divided by 0.22 resistance), and so on ...
KSA100 MKII original design for the CPI 100W, quiescent current is adjusted to about 550MA (ie, two of the line abVoltage Regulators about 120MV), customer heatsink if large enough, then (a channel needs 3KG above) can self-adjust to
Class A amp; amp except CPI attention should be sufficient cooling power transformer should be large enough, and the filter capacitor20000 microfarads at least one channel, the proposed 40 000, otherwise the current consumption due to Group A larger, inadequate power supply, and filtering,Will result in increased distortion Adjusting for Class A and B (about 200MA) sound is a good choice;
2) the midpoint zero, adjusting VR1 (5K) close adjustable resistor so that the output (OUT) to ground (i.e., the output terminal of the amplifier
Both ends) is close to zero mV; debugging.
High Voltage matters:
If the customer wants a high-voltage power supply (greater than DC +/- 50V), simply decoupling capacitors C18, C19, C23, C24(Kit for 1000uF / 50V) and C16, C21 (suite 220uF / 50V) can be replaced by high pressure points, other electricWithout changes to the content and parameters, high voltage suitable for Class A and B, if the customer wants the CPI machine voltage should not exceed 45VOriginal A machine voltage is 45V, the voltage is too high fever CPI huge plus instability, A low-pressure machines are the majority
Parameters:
PCB size: 61X236MM
Supply voltage: DC dual 30-50V (higher voltage required to change the filter capacitor voltage value), recommended + -45V (original line voltage)
Power output: 300 watts (total harmonic distortion THD + N <0.1%), DC + -45V, 4 ohm load was measured;
Product pictures:
Note that this amplifier power is rectified and filtered DC power supply after a double, not directly connected to the transformer oh
Recommend shop rectified and filtered with a trumpet-protected power strip:
List of components, including all components of the board
New PCB board
PCB as shown above, where large current tin processing were done to ensure that a large current through
The true picture:
US KRELL KSA100 generation of crew upgraded version KSA100 MKII original line
Signal Input
Powered speaker protection, output amplifier power supply interface as shown above, speaker protection from imported OMRON G2R-1
10A relay silver contacts and UPC1237 composition.
The overall layout of each tube, material fever, decoupling capacitors for four imported ruby 1000uF / 50V
Output for the import of non-inductive resistor 0.22R / 5W * 8 .
Four pairs of tube output, strong power, bass shock
Overall rational layout, 0 low noise
Circuit diagrams below for your reference (see incomplete, please open the Save As computer enlarge)
Circuit design for reference
Friends interested in the reference circuit for learning and communication