You could start with gushing 6moons reviews from the usual suspects. A days search could find rave reviews of any number of "deprecated" components. The only rational conclusion...
Hi,
I had a look at your LM4562 Pre. I do not wish to be insulting, so I will not comment much on it. Nor on what I see with the PGA2320 one.
If you like the results, that's all that matters.
It does put your comments into suitable context for evaluation on my side though, so thank you for being so open.
Ciao T
I had a look at your LM4562 Pre. I do not wish to be insulting, so I will not comment much on it. Nor on what I see with the PGA2320 one.
If you like the results, that's all that matters.
It does put your comments into suitable context for evaluation on my side though, so thank you for being so open.
Ciao T
Just had a quick look at your pdf download and I'm curious about a couple of things. You say the HF hash comes from various sources in your lab (fig 3), but how does it get in? Also why make 64 averages when measuring noise?
Its rather ironic I know, given your remarks to Thorsten but I'll say it anyway. I think you'd do well to consider your layout, particularly grounding.
Yes, there used to be a Wolfson product that had the ladders without the opamp, you had to put in your own opamp or discrete circuit. I would also prefer that. I *think* one of those small fabless IC houses has taken it up and does sell it now but I need to search for it.
Still, sound wise, they are pretty transparent. They're used by the hundreds in analog mixing consoles, especially the 8-channel CS3318. I ususally don't run them above 0dB so that may help.
jan didden
I don't think there's anything in the layout that's an issue. There is a lot of noise nowadays in the environment, and I could only do my measurements in the lab. You only have to clip your scope ground lead to the tip and hold it near some laptop adaptors or a CFL to pick some of this garbage up.
I would like to have done the measurements in one of the RF chambers, but as I mentioned that was not possible. The lab is primarily used for TV, SMPS and lighting river development.. It is a very noisy environment.
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Torsten, given your position on distortion, RIAA equalization and a whole lot of other things, I'll also refrain from being insulting. My stuff is simple, buildable and it generally measures up well. It sounds good and I don't pad comments about my designs with loads of b.s.
BTW Torsten, my comment was not meant as an insult. It was simply a question. Maybe you want tell us what you did and why.
BTW Torsten, my comment was not meant as an insult. It was simply a question. Maybe you want tell us what you did and why.
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Well the main thing is that you're happy with the sound you got. I agree with Thorsten.
You mean - Charles shared his secret list with you Scott?
Yeah, but not the secret handshake. So he won't be able to attend the meetings.
se
Yeah. But nobody believes me. All I have are some grainy black and white photos, but trust me, I was there. I saw it with my own eyes.
se
Hi,
Well, well.
It is competent on the basics, but with many subtle flaws in subtle areas.
Sure, it is buildable, but who wants to build it? Probably few that read or post on this thread for example.
It is also trivial to design (and even more trivial to improve upon objectively as well as subjectively).
I think one of the biggests improvements you can easily make is to replace the Op-Amp with one that uses cascoded J-Fet inputs (e.g. OPA627), seeing you use an Alps plastic track pot.
Given all the HF noise in your measurements, I'd have a look at both the layout and the powersupplies, there is room for improvement there. The 50Hz are unlikely from your testbench, but from your mains transformer.
Of course you may have fallen for the myth that cables don't matter and just measured using crappy cables which picked up all the noise that is around.
Anyway, these are very credible efforts for a beginner, as you build more you will learn more, as you learn more, you will change your designs. Maybe you will care more about HF noise and less about THD, and about interactions between base current and non-linear wiper impedance in potentiometers. Or maybe you simply will convince yourself that is all B$ and continue making stuff like this.
Ciao T
Well, well.
It is competent on the basics, but with many subtle flaws in subtle areas.
Sure, it is buildable, but who wants to build it? Probably few that read or post on this thread for example.
It is also trivial to design (and even more trivial to improve upon objectively as well as subjectively).
I think one of the biggests improvements you can easily make is to replace the Op-Amp with one that uses cascoded J-Fet inputs (e.g. OPA627), seeing you use an Alps plastic track pot.
Given all the HF noise in your measurements, I'd have a look at both the layout and the powersupplies, there is room for improvement there. The 50Hz are unlikely from your testbench, but from your mains transformer.
Of course you may have fallen for the myth that cables don't matter and just measured using crappy cables which picked up all the noise that is around.
Anyway, these are very credible efforts for a beginner, as you build more you will learn more, as you learn more, you will change your designs. Maybe you will care more about HF noise and less about THD, and about interactions between base current and non-linear wiper impedance in potentiometers. Or maybe you simply will convince yourself that is all B$ and continue making stuff like this.
Ciao T
This sort of 'club' behavior reminds me of the AES back in the late 1970's. Walt Jung and I both attended an officers meeting where there was a lot of insider 'hanky panky'. We were annoyed, because we had been invited to came to this meeting, and we hoped to contribute, or at least learn something. Later, we both left our positions with the AES, and I politely turned down a chance to be president of the AES. What was the point?
For the record, Charles Hansen and I have never met, except at audio functions, and that is usually a polite hello. We do talk to each other by phone, especially in recent times, as Charles and I hope to keep the 'stories' about us from deviating into unfounded criticisms, which they often do, without our interjection.
For the record, Charles Hansen and I have never met, except at audio functions, and that is usually a polite hello. We do talk to each other by phone, especially in recent times, as Charles and I hope to keep the 'stories' about us from deviating into unfounded criticisms, which they often do, without our interjection.
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