Just in case something misunderstand. 5mV measurement point is on the power supply filter caps, not at the output.
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I misunderstood.
5mV ripple on the supply lines is well within "normal". Look at this using your AC coupled scope probe. As you turn down the output bias, it will reduce. As you turn up the output bias it will increase.
As you send more current to a dummy load, the ripple will increase.
A very spiky ripple indicates a lot of high frequency content. You might be able to see the droop in the rail just after the peak when the rectifier has not yet turned off. This is the kick that can turn on supply rail ringing.
A rounded ripple indicates that lower harmonics dominate.
An rCRC PSU will be more rounded than an rC PSU. An rC(L+R)C PSU will be more rounded than an rCRC PSU.
I read your output measurement as "at the output".
5mV ripple on the supply lines is well within "normal". Look at this using your AC coupled scope probe. As you turn down the output bias, it will reduce. As you turn up the output bias it will increase.
As you send more current to a dummy load, the ripple will increase.
A very spiky ripple indicates a lot of high frequency content. You might be able to see the droop in the rail just after the peak when the rectifier has not yet turned off. This is the kick that can turn on supply rail ringing.
A rounded ripple indicates that lower harmonics dominate.
An rCRC PSU will be more rounded than an rC PSU. An rC(L+R)C PSU will be more rounded than an rCRC PSU.
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Hi Terry ,you need a personal computer running a software like ARTA or equal, a good sound card is absolutely necessary.
The sound card line out would be connected at the input of the amplifier under test
The sound card line in would be connected at the out (via voltage divider)of the amplifier under test.
Then,when software run ,test signals from line out comes to the amplifier inp,like a signal generator, and the amplifier out comes (via line inp.)inside for analyzing and computing
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I wonder ,if someone except me,has built the bonsai SX amplifier.
It will be useful if someone can measure THD of this amplifier.
Bonsai, is THD of this amplifier a simulation result, or a real measurement result?
It will be useful if someone can measure THD of this amplifier.
Bonsai, is THD of this amplifier a simulation result, or a real measurement result?
Thimios unfortunately I have not been able to get my test set up working. Looks like I can only get it solved with a new sound card which I will get when I make a trip to Europe at the end of July.
The sx- Amp is NOT a low distortion design. That said, the levels you are seeing look to be on the high side: 0.1 % on a practical amplifier would be the kind of result I would expect. The figures in my article (nx amp and e-Amp also) are all simulated.
For comparison please see the Hiraga design referenced in my article and the JLH.
The sx- Amp is NOT a low distortion design. That said, the levels you are seeing look to be on the high side: 0.1 % on a practical amplifier would be the kind of result I would expect. The figures in my article (nx amp and e-Amp also) are all simulated.
For comparison please see the Hiraga design referenced in my article and the JLH.
Bonsai, thanks for your answer.
The only reason for my question...i want know if something go wrong to My amplifier. I don't believe that ultra low THD is the goal for a good amplifier.
That is an important news!
Never i have listened a Hiraga amplifier.
Thanks Terry.
Mr.Bonsai
Thanks for sharing such great project for diy ... please do you mind uploading the PCB files .. it's not available at the site now " New file to be added shortly" besides if it's available in PDF .. i'm not good dealing with gerber files i think it's for mass production or to be manufactured .. i will just DIY my own use...
Regards
M.H
Thanks for sharing such great project for diy ... please do you mind uploading the PCB files .. it's not available at the site now " New file to be added shortly" besides if it's available in PDF .. i'm not good dealing with gerber files i think it's for mass production or to be manufactured .. i will just DIY my own use...
Regards
M.H
NX amplifier PSU testing
Hi bonsai I was just building your NX amplifier.I have one doubt regarding the PSU testing. I have completed the PSU and is now tested with a testing transformer of 22-0-22 ac .I can see the D15 speaker engage LED blinking when the power applied I cannot see any time delay there.Is this issue with the input voltage which is less applied here instead of 34v ac or any other can you guide me on this.
Hi bonsai I was just building your NX amplifier.I have one doubt regarding the PSU testing. I have completed the PSU and is now tested with a testing transformer of 22-0-22 ac .I can see the D15 speaker engage LED blinking when the power applied I cannot see any time delay there.Is this issue with the input voltage which is less applied here instead of 34v ac or any other can you guide me on this.
Hello hifiramr
Unfortunately the solid state speaker relay will NOT engage with 22-0-22 VAC transformer rails. You need at least 30-0-30 rails and my recommendation is 34-0-34 Vac. After rectifying and smoothing, you should have 50-0-50 VDC.
Also, running the nx-Amp of such a low supply voltage (22-0-22) will mean very limited power, and probably much higher distortion than necessary.
(Apologies for the late reply BTW)
Unfortunately the solid state speaker relay will NOT engage with 22-0-22 VAC transformer rails. You need at least 30-0-30 rails and my recommendation is 34-0-34 Vac. After rectifying and smoothing, you should have 50-0-50 VDC.
Also, running the nx-Amp of such a low supply voltage (22-0-22) will mean very limited power, and probably much higher distortion than necessary.
(Apologies for the late reply BTW)
Thank you Bonsai for your prompt reply.I will arrange 34v Ac transformer and will check it.I will post the update here
35-0-35Vac is the normal retail transformer voltage.
This is very easily available.
Since I am on a nominal 240Vac supply I find that a 230:35-0-35Vac transformer gives about +-50.5Vdc when the amplifier is adjusted to normal bias current.
Users in Europe where the nominal supply is 220Vac will get considerably less. Maybe around +-48Vdc.
This is very easily available.
Since I am on a nominal 240Vac supply I find that a 230:35-0-35Vac transformer gives about +-50.5Vdc when the amplifier is adjusted to normal bias current.
Users in Europe where the nominal supply is 220Vac will get considerably less. Maybe around +-48Vdc.
Thank you Andrew for the reply.As the power supply was tested with 22-0-22 the delay settings is working fine now I have replaced 2n7002 diode and PDTA114ET.I use this voltage only for testing PSU the protection circuit was not tested.I have done a mistake in getting one parts that is PSMN4R3-100PS 100V 4.3mΩ TO-220AB N-channel NXP.I ordered a compatible one with 44mΩ.
Any comparable part is available for PSMN4R3-100PS
close mach
please let me know
Also for power supply please let me know below speck is fine or not
PRIMARY : 0---230 VOLT.
SECONDARY : 0---34 V./ 10 Amp.
0---34 V./ 10 Amp.
Total of ( 680 VA.)
Any comparable part is available for PSMN4R3-100PS
close mach
please let me know
Also for power supply please let me know below speck is fine or not
PRIMARY : 0---230 VOLT.
SECONDARY : 0---34 V./ 10 Amp.
0---34 V./ 10 Amp.
Total of ( 680 VA.)