No, that is not the correct way to measure bias. Bias is measured "across" emitter resistor. + or red Probe to emitter side of the resistor and - or black probe of DMM to "speaker out" side of the resistor..
dear, Prasi
please read #1599
To check DC out: Connect input GND to PSU GND and place your DMM test probes black to PSU GND and red or positive probe to Speaker out (reading should be in mV DC).
Bias setup: Place your DMM negative probe to Gnd. and Positive to R33/5W or Emitter of 2SC5200/2SA1943 and adjust 1K trimmer to 15mV DC.
Hope this will help…
No,this is nothing to do with bias adj.
Look at the picture,you can see the bias setting voltmeter position.
Short amplifier's input.Connect the voltmeter as at the picture.Turn amplifier on,read the voltmeter,adjust according manufacturer guides.
You MUST do this AFTER the first power on ADJUSTMENT USING PROTECTIVE RESISTORS.
This procedure is common for all amplifiers bias adjustment.
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Look here,R8=1K instead of 560R for higher gain amplifier.
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Hi Thimios, can you please confirm for me, short input. Are you saying connect positive input to ground? What effect does this have on the input circuit related to output stage. Thank you very much, I appreciate your knowledge.
Apex A40 - The beginning
My first step towards the wonderful Apex A40. Got the PCB ready(Alex's v1.4 layout). P30, A Class PSU and TB3 PCBs are under construction. Would like to setup a home music system with all these combinations
Thanks to both Mile Sir and Alex Sir.
Regards
Sha
My first step towards the wonderful Apex A40. Got the PCB ready(Alex's v1.4 layout). P30, A Class PSU and TB3 PCBs are under construction. Would like to setup a home music system with all these combinations
Thanks to both Mile Sir and Alex Sir.
Regards
Sha
Hi Mile Sir,
I would love to build the Apex combination A40 + P30 + TB3 + A Class PSU, almost similar to Mr Terry's build. I have couple of queries, could you please help me out on that.
1. My main trafo is 40-0-40 10Amps (800VA), is this good enough for a A40 stereo setup?
2. Can 'A Class PSU' feed TB3 and P30 together, for stereo setup?
3. Is it possible to control the gain of P30 using a trim pot?
4. What should be be the ideal bias voltage between the 0.33R resistor for A40?
I know my questions are little lengthy .. please forgive as I am a beginner
Thank you for being with us.. and for all the designs and support.
Regards
Sha
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Hello zoky2
Nice build
I read your post #3361 on page 337
Can you share your two Pair AX-14 Schematics And Layout
Because I want to build it, I already make AX-14 with one pair, But wanted More power On 8Ohm load. Can Your two Pair AX-14 Amp gives you 120 To 130W on 8-ohm load, What is maximum Rail voltage it can handle, on 53Vdc+/- I think it gives you about 115W on 8Ohm load.
Please help me in details with your Two pair AX-14 Schematics And LAyout
Thanks
Best regards
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Hi!
How to change the input sensitivity? I want to decrease it. But I have noticed that there is one scheme with R8 = 560r, R2 = 22k and one with R8 = 22k, R2 = 560r. Which one is correct?
Thanks!
