But as long as the feedback system has enough phase margin, that delay does not matter at all. I think your views stem from the whole TIM controversy from the 1970's. Yes, TIM (really a special case of SID, slew-induced distortion) was an issue with some badly designed solid state amps back in the day. Once the concept of phase margin was well-enough understood by audio amp designers (and not just industrial, telecommunications and control theory people), it became a non-issue.
never heard a monarchy but i have heard the audionote dac2 in stock form and with a tube rectified choke / black gate filtered psu for the output stage,
my friend has the audiolab m-dac, modified tube output eastern electric, audionote dac2,
4 of us have been listening to them,
in blind listening tests the three of us who had no clue which dac we were listening to picked the audionote dac2 in stock form,
at first i thought he was just playing the audionote and i was having a real hard time hearing any change from what i was used to hearing,
then he switched dacs and i heard something i had not heard on his digital before,
"switch back" i said, "switch back again" "thats weird i like that one a lot",
i opened my eyes and looked across at him, he was grinning, "that's the audionote"
i already knew it must be,
to me it sounds more holographic, its easier to imagine a real person or guitar the skin of a drum real sax etc is in front of you and you are there at the recording venue not sat listening to a hifi in your house, everything in the music seems to be a little more easily defined in space,
its more vibrant, closer to his vinyl setup,
its more tappy, ie i can't keep as still, it makes me tap my foot or fingers more than the other two dacs, it does not bring tears to my eyes like his vinyl can but its very good for digital imho,
of the three dacs the audionote is the one that im less likely to tell my friend to turn it off and put the vinyl on,
im the only one of the three listeners not counting the owner that has heard it with the new psu setup and imho it sounds a little smoother with a wider sound stage, it is now a little wider/deeper than the eastern electric and retains the more vibrant holographic presentation,
yesterday we rolled 3 sets of tubes through the audionote, russian , nos telefunkens and the stock tubes without altering anything to optimise the new output tubes,
me and my friend hear the russians as dry with a narrower stage, the telefunkens came somewhere between the other two,
the stock tubes sound warmer or more lush a little less smooth or is that more textured hmm whatever it is we both prefer the stock tubes,
i know i like them best because my foot refused to keep still,
the solid state m-dac comes last to all the listeners in this system in blind listening tests with or without different software,
for the record i use my ears and that's all i use, i don't give two hoots which measures best,
just telling it how i hear it, ymmv.
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No, sir, I am not confusing anything. If you do a bit of reading about Pass's stasis amp development, you would know that I am not. "Delay does not matter at all" is true with nice, repetitive sine/square/etc.-waves, but think about the very non-repetitive & complex waveforms of actual audio, and suddenly delay does matter. "On paper", the quality of metal & physical arrangement of an audio cable "doesn't matter at all", unless very, very poorly designed, and yet, it does, unless you hold that hundreds of thousands of buyers of cables are all self-delusioned(not impossible, considering that many seem to think Bose makes good speakers).
As for testing, I do not trust just my own ears, as I'm now 50, male, and have tinnitus. I use the ears of much younger friends, male & femaie, some of them musicians and/or recording engineers(of which I know many, as ribbon microphones are my primary field). So, I have more than independently verified to my own satisfaction that feedback in at least a dac i/v stage is audibly degrading to sound, regardless of what opamp or discrete circuit is used, and removing feedback not only reveals hidden layers of tone & clarity, regardless of whether tube or ss, but also reduces the audibility of jitter artifacts by a huge margin.
An amplifier does not know the difference between a sine wave and a music waveform. It just has a varying input voltage, a varying output voltage, and feedback to get the latter to track the former. "Delay does not matter" just happens to be true, because the delay is far too small to do anything. As I said, people often confuse delay with filtering. People often say that delay affects feedback: they are just wrong (whoever they are). Delay would affect feedback, which is why feedback cannot be used effectively for UHF and microwave amplifier but delay is entirely negligible for audio. Filtering can affect feedback, and may require careful design of the part of the circuit before the dominant pole to avoid slew rate limiting (or an approach to slew rate limiting) - but this is not delay.stephensank said:
"Self-delusioned" - yes, that is how I would put it. Some expensive (and DIY) cables will affect the sound, by degrading it. Most will make no difference, as tests have shown.
Curious here Stephen how you manage to change only feedback in your comparisons? I haven't so far seen a circuit where just the feedback can be removed and no other salient circuit details get altered as a result. Care to share two example schematics?
yet another person who fools himself that he has no feedback in a circuit. I really wish people would say what they mean here of all places; perhaps no/low global feedback? the dac chip itself of course will have plenty of feedback and there wil be local feedback on tubes, discrete SS whatever.
good chance lowering feedback reduces the audibility of jitter by masking it with harmonic/frequency based distortion products.
good chance lowering feedback reduces the audibility of jitter by masking it with harmonic/frequency based distortion products.
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Obviously, yes, when I refer to feedback, I mean feedback around more than one single semiconductor or tube.
I'm done being insulted on this thread. And I apologise if anyone has felt insulted by me. I've simply been attempting to help the OP with his decisions, not get into a formal debate.
I'm done being insulted on this thread. And I apologise if anyone has felt insulted by me. I've simply been attempting to help the OP with his decisions, not get into a formal debate.
OK stephensank: its a pet peeve of mine the 'no feedback' thing, many like yourself use it to mean something else and it leads the less informed to believe there is such a thing. feedback can be overused, but it can just as easily be under utilized; thinking that lower is always better is IMO fallacy.
A common mistake, sadly, but not obvious. I assume that when someone says "no feedback" that is what they mean. It sometimes turns out that they actually mean something else.stephensank said:
People have disagreed with what you said. It seems that in some cases what you said is not what you meant. If you regard disagreement as a form of insult then debating is not for you.
Hey hey hey! If wanted a debate on this thread, I would have asked for it at the beginning. I asked for experiences and recommendations, and since those are always subjective matters, there shouldn't be anything to debate for. If someone really wants to debate on something, I would kindly ask for he/she to start an own thread for it.
And; Stephensank was one of the few that actually answered my original question, and he did it really well. So if some one gives up with this discussion, I surely hope that it is not Stephensank. :=)
It's quite surprising how often basic manners seem to get lost in the internet world. One of the most basic rules is to respect the OP's wishes, and stick in to the subject. If you feel that you just can't, it's always better to be silent or start an own discussion on your own topic. Or otherwise, the original discussion gets lost in the middle of the secondary issues, like it has pretty much happened in this thread.
But hey, we are just humans, and surely no hard feelings for anyone; I have learned a lot from this thread. About the original topic, and few other things just well.
Not really. Diesel and petrol are both vehicle fuels, and both work when used in the appropriate engine. People may have a preference, for all sorts of reasons. What they can't do is claim things like "petrol degrades steering and so causes accidents"; it isn't true.
Similarly, people may have preferences for valve or SS buffers after a DAC. What they can't say is things like "SS feedback can't correct all errors because of time delay"; it isn't true.
Similarly, people may have preferences for valve or SS buffers after a DAC. What they can't say is things like "SS feedback can't correct all errors because of time delay"; it isn't true.
Thanks for the kind words. I am still impressed with that unit even after all these years.
I do also like this DAC a lot as well. No tubes in the analog stage, but no transistors either:
Sheldon’s World Blog Archive Another Audio Digital-to-Analog (DAC) is Born
Sheldon
I habe build a couple of dacs, with tube output and without. Modified as well a couple of commercial products. My current preference in my system and my room:
- buffalo iii in dual mono with broskie unbalancer and Ian's fifo and usb-input. jj803s and 12bh7. No electrolytics anywhere and many selected parts like z foil, v-caps, wirewounds prec. resistor, silber wiring etc.
- very musical as well: ee max plus, but only if you tune it heavily, the eletrolytic in the output is not needed, discrete opamps needed etc. here the solid state output is clearly netter than the tube one.
- i ran many dacs like pcm63 with 6922 output in srpp, rakk dac with tube and solid and transformer output, borbely with all-jfet, tda1543, buffalo ii and bufallo iii. I compared them with commercial products like accuphase dc701 etc.
The top currently for me is the one mentioned in the beginning. I will change the stage to fully balanced though to get rid of the phase splitter in my power amp though.
tentlabs used the tubes to do i/v conversion as well (not the resistor to ground method). I have the stage here, but still busy with other stuff. hope this helps. I would always go with the sabre and tubes. But i am build the sen, the d1 and othe solid stages as well, maybe they change my mind.
- buffalo iii in dual mono with broskie unbalancer and Ian's fifo and usb-input. jj803s and 12bh7. No electrolytics anywhere and many selected parts like z foil, v-caps, wirewounds prec. resistor, silber wiring etc.
- very musical as well: ee max plus, but only if you tune it heavily, the eletrolytic in the output is not needed, discrete opamps needed etc. here the solid state output is clearly netter than the tube one.
- i ran many dacs like pcm63 with 6922 output in srpp, rakk dac with tube and solid and transformer output, borbely with all-jfet, tda1543, buffalo ii and bufallo iii. I compared them with commercial products like accuphase dc701 etc.
The top currently for me is the one mentioned in the beginning. I will change the stage to fully balanced though to get rid of the phase splitter in my power amp though.
tentlabs used the tubes to do i/v conversion as well (not the resistor to ground method). I have the stage here, but still busy with other stuff. hope this helps. I would always go with the sabre and tubes. But i am build the sen, the d1 and othe solid stages as well, maybe they change my mind.
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Hello Blitz,
Have you been able to compare the following two tube output stages ?
1) The Differential Parafeed Line Stage with the LL1674 like used in the RAKK dac and the DAC END
2) the Broskie unbalancer
Both seem nice for getting single ended out of current out balanced DACs.
Regards,
Danny
Have you been able to compare the following two tube output stages ?
1) The Differential Parafeed Line Stage with the LL1674 like used in the RAKK dac and the DAC END
2) the Broskie unbalancer
Both seem nice for getting single ended out of current out balanced DACs.
Regards,
Danny
Well,
The Rakk-DAC II was my previous DAC, which I really like a lot. I tried it with: the LL1674-passive output stage, with RAKK-TUbeoutput and Borbely-Allfet-Out. I liked the tube-output not too much, not transparent in my view. I did not compared it directly withe the unbalancer using the same dac, but the unbalancer is very transparent and natural in combination with the BIII. All depenents extremly on the right selection of passive parts and tubes though.
Regards
The Rakk-DAC II was my previous DAC, which I really like a lot. I tried it with: the LL1674-passive output stage, with RAKK-TUbeoutput and Borbely-Allfet-Out. I liked the tube-output not too much, not transparent in my view. I did not compared it directly withe the unbalancer using the same dac, but the unbalancer is very transparent and natural in combination with the BIII. All depenents extremly on the right selection of passive parts and tubes though.
Regards
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