So I finished a dac prototype I've been working on a few days ago using a very special I/V stage and amplifier I spent years working on. The sound is the sound I've been looking for, it sounds practically indistinguishable from a live performance, although even sub-par recordings have an errly holography and tangibility to them.
However, there is something I've come across which is puzzling the crap out of me. I cannot hear any difference between filters. I've spent almost the entire last 3 days trying. I'm using a TP buffalo dac and at first I thought the filter selection might be broken. I reflashed the firmware and still nothing. Even disabling the OSF has no effect on sound. So I kept the OSF off and downloaded HQplayer and starting playing with the different filters it offers and also converting files to DSD on the fly. No matter how hard I try I cannot hear a difference. I even tried looping a 2 second clip over and over for 30 minutes and I could not hear a difference.
For some context, I went to an ear doctor a couple of years ago for some tests and he said I have above average hearing. Also I can still hear the mosquito tone, so poor hearing is not part of the equation. I can't for the life of me figure out why there is no difference when people talk so much about the differences in filters. Also my analog I/V stage has no analog filtering at all because there was no difference in sound. I even turned the OSF off on the dac and also turned the digital filter off in the HQplayer, no difference in sound.
I'm thinking maybe the I/V stage and amp are responsible because they are the only odd duck variables here that I can think of. They have excessively low distortion and excessively high bandwidth. Is it possible for these two factors to enable inaudible filters or is it normal to not hear differences? Any other possible reasons?
However, there is something I've come across which is puzzling the crap out of me. I cannot hear any difference between filters. I've spent almost the entire last 3 days trying. I'm using a TP buffalo dac and at first I thought the filter selection might be broken. I reflashed the firmware and still nothing. Even disabling the OSF has no effect on sound. So I kept the OSF off and downloaded HQplayer and starting playing with the different filters it offers and also converting files to DSD on the fly. No matter how hard I try I cannot hear a difference. I even tried looping a 2 second clip over and over for 30 minutes and I could not hear a difference.
For some context, I went to an ear doctor a couple of years ago for some tests and he said I have above average hearing. Also I can still hear the mosquito tone, so poor hearing is not part of the equation. I can't for the life of me figure out why there is no difference when people talk so much about the differences in filters. Also my analog I/V stage has no analog filtering at all because there was no difference in sound. I even turned the OSF off on the dac and also turned the digital filter off in the HQplayer, no difference in sound.
I'm thinking maybe the I/V stage and amp are responsible because they are the only odd duck variables here that I can think of. They have excessively low distortion and excessively high bandwidth. Is it possible for these two factors to enable inaudible filters or is it normal to not hear differences? Any other possible reasons?
Absolutely. Nothing to worry about. Both doctor and mosquitoes have given you a clean bill of health.
Why then do people continually discuss the audible effects of digital and analog filters and DSD in dacs?
Spice says -3db point is about 1.7Mhz, I don't know what it is on the bench.
We can effectively say it is higher than average.
Can that have an such an effect on filter audibility?
We can effectively say it is higher than average.
Can that have an such an effect on filter audibility?
Oh looks like we seriously diverge in our respective meanings of 'excessively high'. My I/V stage at present does more than an order of magnitude better.
Actually 1.7M was the simulated -3db point when driving 4 ohms as an inverting amp.
In I/V duty the simulated -3db point is 14Mhz.
Can this cause filter inaudibility somehow?
In I/V duty the simulated -3db point is 14Mhz.
Can this cause filter inaudibility somehow?
I've been designing an ultra high performance amp for the last 3 years using a unique topology I came up with. The performance is off the charts relative to everything else out there so I figured why not use it in an I/V stage. The design is effectively a highly idealized opamp effectively speaking, so converting it from speaker amp to I/V stage is simple. However, I really don't want to get off topic here. I'll ask again. Can high effective bandwidth be responsible for inaudible filters? My understanding is that I/V stages usually have an audible defect when asked to reproduce high frequency content, most likely due to their limited linear bandwidth. However mine has no such issues within the expected range of potential aliasing. So, could this be a possible cause? I don't know of any other variable that could make all filters + DSD inaudible when there are countless anecdotes of filter audibility.
Clearly not in terms of bandwidth - AD8065 (for example) does quite a bit better than -3dB at 14MHz for G=2.
You use the AD8065 in your I/V stage I gather? Have you attempted to listen to the difference in digital or analog filters? Did you hear any?
No, I don't use AD8065 in my I/V stage. I tried it a while back. Yes I have listened to different analog filters and yes I hear some are better than others. Digital filters I haven't much listened to as my DACs have been NOS so far. I do plan to play with OS filters in future though.
So back to my earlier question - what's great?
So back to my earlier question - what's great?
Hmmm. I neglected using any analog filter because it sounded fine without it. I only attempted a simple first order filter but there was no audible change so I just left it out. There must be something I'm missing.
I was being sarcastic because I wasn't interested in discussing irrelevant topics. I'm not sure what you were attempting to gain via discussing the relative bandwidth of my design vs the AD806 without adding a relevant point.
I suspect there is but I know it'll be a waste of time to ask for specifics since you're not inclined towards sharing details, right?
I was observing the overabundance of hype on your thread, a pattern that I've noticed isn't simply an isolated incidence. You might find more contributions if you reduced that and shared more detail of your findings.
Depends on what you want to know. If you want to discuss irrelevant topics or ask for a schematic of my I/V stage then probably not. Notice how we are two pages in and nothing productive has been said. If you are going to waste my time then please say nothing. I have other things to do.
High bandwidth was not a goal of the design and the simulated bandwidth value is after heavy compensation is applied. Low distortion was my own goal of the design. In that respect nothing on the market comes close. I'm also not interested in the egotism. Your perceived 'hype' is imagined and unwarranted. It's really sad how obsessed you people get with my design that every thread I make gets immediately derailed at the mere mention of it. Just leave it alone please. Clearly if it is as bad as you people hope it is then there is nothing for you to be afraid of. I am only interested in Q and A and relevant discussion, not a ******* match. My secretive nature surrounding my design is due to the fact that I've wasted the last several years of my life on this design whilst also being on the bottom end of poverty. I would like to use it to recoup the money I've spent. I would hope you'd be understanding of that.
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Classic 😀 You use sarcasm and claim no interest in egotism? Best entertainment so far today.
Sarcasm in said context was meant to be dismissive due to irrelevance, not egotistic. I'm guessing English is not your first language. Please do not respond to my threads anymore. It's like dealing with a child. If anyone else wants to add something that is actually relevant to the intended topic I would appreciate it.
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