Thanks to everyone assisting by asking some great questions, 🙂
The somewhat strange performance of the Right channel regardless of the op amp on my former test was duplicated on a Sony CDPXE 300 a mid/ low price player tonight. It occurs regardless of the file type I tried PCM 16 bit as well. If you scope both channels together both running with 10Khz then 20Khz sine - you do not see it. Both waveforms look good.
However using Audacity to generate 20Khz and 10Khz Sine waves PCM or Flac strictly as Left, then Strictly as Right, the Right Channel regardless whether it is Track one or two on the CD ( I thought hard- eliminating every possibility of difference ) has a definite wobble,that my 60Mhz Philips scope with its Hold function has difficulty holding vs the Left which is very stable. Yes I swapped Test leads, and the result swapped to the other scope channel, inferring the lead was not contributing. Its a strange test in the first place, but it shows up anomaly. It involves the right channel only where the Left has no output, with the two CD players I have available to measure. So something which would be invisible in normal circumstances. In terms of the former test I believe its important to explain.
Cheers / Chris
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Hi,
So it is NOT the TDA1541 not being able to play 20KHz?
Have you tried any other software to generate the test tones? You generate as Wave Files and burn using a software that natively burns Wave files to CD without conversion (e.g. EAC Burn)?
I'll have to see, I think I have a copy of the original CBS Test CD somewhere on disk... If I find it I can send it to you.
Ciao T
So it is NOT the TDA1541 not being able to play 20KHz?
Have you tried any other software to generate the test tones? You generate as Wave Files and burn using a software that natively burns Wave files to CD without conversion (e.g. EAC Burn)?
I'll have to see, I think I have a copy of the original CBS Test CD somewhere on disk... If I find it I can send it to you.
Ciao T
No have not as yet tried other software to generate, I believe Audacity is a well written program, likewise K3B is well written. and Yes it is not the TDA1541 not being able to play 20Khz where both channels have output, there is indicated to me equal ability with both channels from the TDA1541.
At the moment though it indicates on both the Marantz and the Sony CD players a unique and probably rarely measured condition that where no signal 0% from the Left occurs the Right channel containing 100% of the signal both the Marantz and the Sony have difficulty processing a sine wave at 10Khz and 20Khz that shows on my scope as wobble of the waveform - rapid movement only repeat only just to be controlled by the scopes hold function.
Whereas the left channel on both players is rock solid where the Right channel has no signal.... indicating a strange anomaly confined to the right channel in the tests I have done.
Yes Thanks would appreciate trying a test Disc🙂, will send you a PM
Cheers / Chris
Hmm.... could be Audacity, but...
20Khz is very close to half the sampling frequency of 44.1Khz (for CD), so unfiltered output would have "wobble" on the amplitude. If the brick-wall filter isn't sharp enough (for whatever reason), that would get through to the audio output.
You could try stabilize that by using a tone at exactly 1/2, 1/3 or 1/4 of the sampling frequency i.e. 22.05Khz, 14.7Khz or 11.025Khz.
22.05Khz could give you zero output, depending on blind luck, but the other two should be good.
Welcome to digital.
20Khz is very close to half the sampling frequency of 44.1Khz (for CD), so unfiltered output would have "wobble" on the amplitude. If the brick-wall filter isn't sharp enough (for whatever reason), that would get through to the audio output.
You could try stabilize that by using a tone at exactly 1/2, 1/3 or 1/4 of the sampling frequency i.e. 22.05Khz, 14.7Khz or 11.025Khz.
22.05Khz could give you zero output, depending on blind luck, but the other two should be good.
Welcome to digital.
Hmm.... could be Audacity, but...
20Khz is very close to half the sampling frequency of 44.1Khz (for CD), so unfiltered output would have "wobble" on the amplitude. If the brick-wall filter isn't sharp enough (for whatever reason), that would get through to the audio output.
You could try stabilize that by using a tone at exactly 1/2, 1/3 or 1/4 of the sampling frequency i.e. 22.05Khz, 14.7Khz or 11.025Khz.
22.05Khz could give you zero output, depending on blind luck, but the other two should be good.
Welcome to digital.
That was partly the reason for the "strange" frequencies in post #238 (did anyone try them... I hadn't a CD-RW handy to double check them) although for this test it shouldn't really make any difference as it's really for extremely low distortion tests that these "odd" values are used.
Chris,
There is equally no problem with TDA1541 having one channel digital silence and the other any funloving level of 20KHz. Trust me, I know. I also know that there is absolutely no conceivable mechanism inside the circuit of the TDA1541 to cause that.
Given that you also have a cheap Sony Delta Sigma DAC Player producing the same result I would suggest the problem is elsewhere.
Sorry, I cannot send you the test-disk, only a digital copy via the net. And only if I can find it. Things are in a bit of a disarray right now, so it will take a bit.
Ciao T
There is equally no problem with TDA1541 having one channel digital silence and the other any funloving level of 20KHz. Trust me, I know. I also know that there is absolutely no conceivable mechanism inside the circuit of the TDA1541 to cause that.
Given that you also have a cheap Sony Delta Sigma DAC Player producing the same result I would suggest the problem is elsewhere.
Sorry, I cannot send you the test-disk, only a digital copy via the net. And only if I can find it. Things are in a bit of a disarray right now, so it will take a bit.
Ciao T
Meanwhile, listening tests confirm the use of transistors in the manner of each polarity collector to base connected with 2K4 and emitter feeding relative supply pin as improving audio experience particularly with stereo spatial ability with op amps AD825, opa627 and opa1611.
It would be really nice to receive some comment from persons who have tried this in their audio system. 🙂
Cheers / Chris
It would be really nice to receive some comment from persons who have tried this in their audio system. 🙂
Cheers / Chris
While this could be actually true, I have another concerns that placing the transistors beneath some high-bandwidth OpAmps with higher stability requirements like AD797 might rise other issues with noise/stability/performance, etc.
Primarily by hearing the difference between op amps that lacked transistors AD825 , for op amps that were installed with transistors AD825 in a marantz Cd80 and hearing with Sennheiser headphones, if there was any difference between each. Secondly by comments received from persons trying op amps constructed with transistors, which all supported that there was audio improvement and merit in this unique implementation.🙂
Cheers / Chris
Since Chris seems to talk from his experience alone, scientific rigour is not likely on the menu.
For the average dude, if he feels a chill in the air, he just says so and maybe other people go for their coats. In audio wonderland, a dude hears an affect he likes and maybe other people want it too. I believe that's how audio goes these days and this forum is often no different.
Ordinarily, I'd say the cost of a bottle of the snake oil on sale would not justify the expense of say, a 6-pack of Quantum Purifiers or 20 feet of Megabuck speaker cable. Here, the cost of the widely available parts is not going to set the world on fire or raise suspicions of commercial fraud for a product seen here as just a free design.
IMHO, it's an entertainment that may satisfy some people but not such a risk to one's time or money concerns as to get upset about. There are thousands of worse promotions in the audiophile market that boil down to products probably doing much less for much greater cost to the ill-informed user who has to pay for them, their marketing glitz and the promoter's loud suit. 😀
That's what I was trying to determine: whether or not it was likely that he actually heard anything at all. 😀
Which is why I have asked you to try it... with that knowledge having tried it you will know if it has the attributes I have described. However if you continue on professing its incapable etc then really what is the purpose of the DIY aspect of this Forum.
Cheers / Chris
Cheers / Chris
Chris,
From what you have said here, you do not understand the limitations of an individual stating that "I did this and heard that". without any controls, e.g. level matching or blindness to what was being tested.
A big diversion was wandering off to testing with 20Khz sine waves!! WTF was that all about?
However, since you are earnestly seeking confirmation of what you claim to hear, I shall have a go tomorrow morning with some op-amps I have.
I will report back.
From what you have said here, you do not understand the limitations of an individual stating that "I did this and heard that". without any controls, e.g. level matching or blindness to what was being tested.
A big diversion was wandering off to testing with 20Khz sine waves!! WTF was that all about?
However, since you are earnestly seeking confirmation of what you claim to hear, I shall have a go tomorrow morning with some op-amps I have.
I will report back.
I'm also willing to test. Can you recommend a sine-wave generator software? I'll be using BC546/556 though.
Hi Gloop
If you want to test with Sine waves I have used Audacity that is readily available for all O/S platforms, once there go to generate for sine wave selection at selected frequency, then file export selection as PCM or Flac. Music is also a nice alternative to assess.🙂
Cheers / Chris
If you want to test with Sine waves I have used Audacity that is readily available for all O/S platforms, once there go to generate for sine wave selection at selected frequency, then file export selection as PCM or Flac. Music is also a nice alternative to assess.🙂
Cheers / Chris
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