Hi All,
I need Nakamichi AV-1 service manual please share it
Problem Speaker protect relay not working ( first it work and off immediately ) All AMPs are OK
Regards
MANOJ
I need Nakamichi AV-1 service manual please share it
Problem Speaker protect relay not working ( first it work and off immediately ) All AMPs are OK
Regards
MANOJ
Thank you for your valuable information mr manoj. I recently tried your aud600 and a class B amplifier with the same transformer. Dc rail 2 * 50v. Your aud 600 is more powerful than the other with the same feed !!!!. I measured the output power with a 4ohm resistive load with 20hz sine wave. With aud600 I measured 27v rms at clipping and with class b 2 pair 2sa1943 2sc5200 I had 30v at clipping !!. I do not understand anything less voltage and more power how!
Sorry but I'm going crazy. Thank you for spending your precious time and please help me to understand.
Sorry but I'm going crazy. Thank you for spending your precious time and please help me to understand.
Hi,
I think 20Hz sine signal not fully supported your class AB AMP.check with 1KHz SINE signal for both amp
regards
MANOJ
I think 20Hz sine signal not fully supported your class AB AMP.check with 1KHz SINE signal for both amp
regards
MANOJ
thank you for your reply. I measured the voltage at 1khz. Class b amplifier gives 32v and aud600 29v. Class b is always superior in number but your class d seems more powerful listening !! Still I did not get anything !! C abnormal no
Hi Julia,
still 3v difference its amazing are you check the supply rail its still +/-50V DC or +/- 47V when its on clip both AMP
Regards
MANOJ
still 3v difference its amazing are you check the supply rail its still +/-50V DC or +/- 47V when its on clip both AMP
Regards
MANOJ
hi mr manoj. voltage decrease. class b 45 v and aud600 47v at 20hz. with smps 2kw 4*1000uf at one rail
i test aud600 with +-95v irfp250n 200khz 100r gate 30uh ring core from china with no broblem. heat sink aluminium 1cm *10*10
Hi,
It means both AMP working good.Your doubt is why Class D is so powerful
Class AB give TRMS 253W@4R load at +/-45v on clip (Class AB eff. is 65% so your wattage is 165W@4R)
Class D TRMS 276W@4R load at +/-47v on clip ( Class D eff. is 88% (min) 243W@4R )
Peak watt 550W@4R D AMP
Peak watt 500W@4R AB AMP
Regards
MANOJ
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Class AB give TRMS 253W@4R load at +/-45v on clip (Class AB eff. is 65% so your wattage is 165W@4R)
Class D TRMS 276W@4R load at +/-47v on clip ( Class D eff. is 88% (min) 243W@4R )
Peak watt 550W@4R D AMP
Peak watt 500W@4R AB AMP
Thank you mr manoj. Sorry but I do not agree. Class b 32v eff 4 ohm load gives 256w. Class d 29v rms gives 210w. It is standart the power calculation rms. I'll tear out my hair I do not understand. Class d seems more powerful
Class D TRMS 276W@4R load at +/-47v on clip ( Class D eff. is 88% (min) 243W@4R )
Peak watt 550W@4R D AMP
Peak watt 500W@4R AB AMP
Thank you mr manoj. Sorry but I do not agree. Class b 32v eff 4 ohm load gives 256w. Class d 29v rms gives 210w. It is standart the power calculation rms. I'll tear out my hair I do not understand. Class d seems more powerful
Class AB give TRMS 253W@4R load at +/-45v on clip (Class AB eff. is 65% so your wattage is 165W@4R)
Is what you mean that power is given by: u * i * power factor?
Is what you mean that power is given by: u * i * power factor?
Many things are wrong here. 253 W is the maximum clean theoretical output power of an ideal amplifier with 45V power rail. If you divide it by efficiency, then you can get the power input of the amplifier. But if you multiply it with efficiency, then nothing. 165 W is a meaningless quantity here. And 65% is actually also wrong. Certainly there is some amp with this efficiency, but absolutely not a characteristic value. Ideally it is pi/4=0.78 for class B. And this has no relation to loudness, only to dissipation. Also in case of ClassD there is no relevance of efficiency to loudness. And 88 % is not a minimum value actually.
Protech!
What related to loudness differences with the same speaker and acoustic environment are:
- gain (included freq and load dependancy)
- input signal
- overdrive and overcurrent behaviour
- power supply drop (dynamic one, not static!)
...in this order. Check these factors first!
Thanks pafi. The measures are taken with the same condition. Same power supply same speaker with same song. I do not understand why class d is more powerful listening but less powerful in measure. Please help me. Is what is calculated differently the power in class d
Hi,
Thanks pafi. I am not fully agree with your notes.all cases, we taken from voltage and current, the same way for loudness
and my calculation was 253W-35% = 164W
Regards
MANOJ
Thanks pafi. I am not fully agree with your notes.all cases, we taken from voltage and current, the same way for loudness
and my calculation was 253W-35% = 164W
I fully agreed with this
Regards
MANOJ
Manoj!
Efficiency is power output per power input. Power output is 253W. Why do you subtract anything from output power? Output is output, no conversion here, we are already at the destination.
If you wanted to calculate input power from output power, then you should add the loss (or equivalently divide by efficiency), but this is not the case here.
Efficiency is power output per power input. Power output is 253W. Why do you subtract anything from output power? Output is output, no conversion here, we are already at the destination.
If you wanted to calculate input power from output power, then you should add the loss (or equivalently divide by efficiency), but this is not the case here.
Check gain first!
gain ? I increase the volume until you hear the distortion in the music! My preamplifier is half its power. It comes out 1.2 v and it can offer up to 3v rms !! You are moving away from my question. It is nevertheless very clear. I measure more power rms with class b but listening I feel that class d is more powerful on my speaker ????????????
I did not understand. Please
gain ? I increase the volume until you hear the distortion in the music! My preamplifier is half its power. It comes out 1.2 v and it can offer up to 3v rms !! You are moving away from my question. It is nevertheless very clear. I measure more power rms with class b but listening I feel that class d is more powerful on my speaker ????????????
I did not understand. Please
Protech!
I wrote checking gain for good reason. You refused it, this way making more difficult to get the answer. Hard to help if you dont let it. I know many different possible reasons that can lead to lower volume despite of higher measured sine power, but I will not list all of them.
Nothing can be clear about your situation if you don't write it.
The first thing to check:
Is the distortion at lower volume is caused by amp, or the preamp? You wrote 1.2 V but nothing about how you measured it. And with which amp. An average voltage of 1.2V with undistorted music signal may imply a 5...10 V peak voltage or even more. So your measurement tells nothing about the source of the distortion. If you used oscilloscope and checked if peaks are not distorted on input then you could say the problem is with amp, not the preamp, and in this case you could say gain is not important. But without any correct measurements...
Do you want to start real debugging, or you are affected to your confusement?
The answer is for sure in the details you don't want to talk about or ignore. I listed many factors.
I wrote checking gain for good reason. You refused it, this way making more difficult to get the answer. Hard to help if you dont let it. I know many different possible reasons that can lead to lower volume despite of higher measured sine power, but I will not list all of them.
Nothing can be clear about your situation if you don't write it.
The first thing to check:
Is the distortion at lower volume is caused by amp, or the preamp? You wrote 1.2 V but nothing about how you measured it. And with which amp. An average voltage of 1.2V with undistorted music signal may imply a 5...10 V peak voltage or even more. So your measurement tells nothing about the source of the distortion. If you used oscilloscope and checked if peaks are not distorted on input then you could say the problem is with amp, not the preamp, and in this case you could say gain is not important. But without any correct measurements...
Do you want to start real debugging, or you are affected to your confusement?
The answer is for sure in the details you don't want to talk about or ignore. I listed many factors.
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thanks pafi. preamplifier output is 3.2 v 20hz with 100 ohm resistiv load without clipping. impedance class d 2.2k and class b 10k . i mesure output preamplifier at 10k resistiv load more than 3.5 v
sorry i get the solution by a professiinnel. it is the dynamic headroom it s easy no? thank you all for the help
Do you really think I asked this? Are you able to answer a question instead of telling everything else? Your question was about music, but you are continuously talking about sine ratings, and nothing about the real situation with music.