In short, no and no
. I am a hobbyist... and I don't claim any expertise in this area, just enough knowledge to be dangerous perhaps The point is though, unless you can be sure how each measurement correlates with perception/hearing you can run everthing in the menu, show some graphs and figures, and you still won't know whether you have a better sounding amplifier.
Walt Jung has demonstrated how to measure some of these "unmeasureable" artefacts. I linked to some of it earlier in this thread.
I am not too quick to agree with Mr. Self's comments either. I can hear too.
I would like to know why you think it's "strangling" the music too. I wholeheartedly support your quest to improve this circuit. I haven't built it. But I've used some of the concepts employed in it. And these circuits worked very precisely too.
I am working on improving my "state of the art" too.
I will take a second look, and see if I see any room for improvement.
Glad to hear we have some common ground then - I didn't get that impression from your initial post
It does work very precisely in every way as designed and the variable tone controls are brilliant. If only it didn't mildly stangle my music as well I'd be a convert
Perhaps it is because I used polypropylene decoupling caps instead of the specified polyester as suggested earlier, but somehow I doubt it. Thanks for the WJ articles link. I've read some of his later ones on opamps before but had never noticed the earlier ones and they look very interesting - some more reading for me to do now.
the evidence is in what you said, you confirmed you did not adopt the recommended decoupling.
You have only just recently told us you modified the design.
"Strangling" is such a subjective term. What I think of as "strangling" is really dynamic compression. However, this is a trait of loudspeakers typically. A properly designed line level circuit should not do this in any way.
Another subtle phenomenon that's hard to put your finger on is a noise floor of complex harmonics. Since some harmonics are musically related to fundamental tones, it doesn't really stand out like IM distortion does. But even at 60 or 80 dB down, many people are aware of it, even if they can't consciously hear it. Such is the nature of psycoacoustics. It can "veil" the sound. In a power amp it can go from a subtle "veil" to what I call "mud" as you drive it harder. (we've all heard "mud" at one time or another. ) But this shouldn't be a major issue with a line level circuit.
Lazy or inadequate power supply bypassing can introduce IM distortion in power amplifiers. Going the extra mile with the power supply design can make a huge difference in an otherwise ordinary circuit. But this shouldn't be an issue with line level circuits.
Have you looked at a square wave? I sometimes tweak feedforward compensation to "clean up" a square wave. But it's easy to get in trouble with feedforward compensation. I try to use as little as possible or skip it altogether if I can. On fast, wideband SS amplifiers it can get cumbersome. It can put a lot of "snap" back into tube amps without getting in too much trouble though.
Another subtle phenomenon that's hard to put your finger on is a noise floor of complex harmonics. Since some harmonics are musically related to fundamental tones, it doesn't really stand out like IM distortion does. But even at 60 or 80 dB down, many people are aware of it, even if they can't consciously hear it. Such is the nature of psycoacoustics. It can "veil" the sound. In a power amp it can go from a subtle "veil" to what I call "mud" as you drive it harder. (we've all heard "mud" at one time or another.
) But this shouldn't be a major issue with a line level circuit.Lazy or inadequate power supply bypassing can introduce IM distortion in power amplifiers. Going the extra mile with the power supply design can make a huge difference in an otherwise ordinary circuit. But this shouldn't be an issue with line level circuits.
Have you looked at a square wave? I sometimes tweak feedforward compensation to "clean up" a square wave. But it's easy to get in trouble with feedforward compensation. I try to use as little as possible or skip it altogether if I can. On fast, wideband SS amplifiers it can get cumbersome. It can put a lot of "snap" back into tube amps without getting in too much trouble though.
Last edited:
So he messed with the decoupling? Decoupling for line level circuitry is not trivial.
My recommendation is to verify that the circuit works as intended first before tweaking.
I have followed this thread closely and read every post. I appreciate your comments and some of the counter-points that have been made. Just to be clear, the pre-amp you built was the original, roughly 1996 design of D.S. pre-amp? I vaguely remember reading that you mentioned it earlier in the thread, but wanted to be sure.
I have no knowledge of, or listening experience with the original D.S. pre-amp, so I cannot make any 'sonic' comparisons between the two. But despite the similarities in design, it seems to me we should not rush-to-judgement or even anticipate what the 'sonic signature' will sound like, however subtle it may or may not be in the new design - some ~15 years later. Isn't it fair to suggest that there may be enough subtle changes to either component values, placement, or even the whole topology of the design - that includes upward to 25 op amps -
that the cumulative impact of those changes may help to improve the sound over the original design?I'm in the process of completing this new pre-amp, but have not fired it up yet. I'm being lazy and waiting for Elektor to either offer and publish a custom enclosure, or make a decision to roll my own. But this thread might help to motivate me to finish it sooner.
One more thought.... I strongly believe in the science and math of electronics. And for the most part believe that generally speaking, better specs produce better sound. We also know that lousy specs on certain measurements will surely yield a crappy sound - whether it's a pre-amp, amp, speakers, source device, etc.
how true....i get call from some guy asking me to modify an equipment or how to improve the sound of the gear.......asked where the gear was, and the guy said he is still to purchase the gear.....so i told him, listen to it first and give it some time....
owdeo seems to be asking for something i think no one here can give....we can only point to clues, the rest is up to him....
All that circuitry? just to replace (poorly imo) a Stepped attenuator and a very few short wires.
Fill yer boots
Except I don't quite see how that is going to:
1) Provide the gain for the MC and MM inputs
2) Perform the RIAA equalisation
3) Implement the balanced line inputs
4) Perform the balance and tone control functions
Do tell us how.
DouglasSelf,
I am new to the DIY site and this is the first time I have seen one of your postings. I do have two of your books and I am studying them intently. It seems funny to me that so many find a tone control sacrilegious as they do so many other things to overcome this aversion. The room treatments, speaker placements, shelving and sloping of crossover networks to get the sound correct are all forms of tone control to me, just in another domain. I for one still think that there is nothing wrong with a proper tone control. If everything was absolutely perfect in the reproduction chain we would still have different rooms and the effects on frequency response. Thank you for all your knowledge and sharing it with the rest of the world.
Steven
I am new to the DIY site and this is the first time I have seen one of your postings. I do have two of your books and I am studying them intently. It seems funny to me that so many find a tone control sacrilegious as they do so many other things to overcome this aversion. The room treatments, speaker placements, shelving and sloping of crossover networks to get the sound correct are all forms of tone control to me, just in another domain. I for one still think that there is nothing wrong with a proper tone control. If everything was absolutely perfect in the reproduction chain we would still have different rooms and the effects on frequency response. Thank you for all your knowledge and sharing it with the rest of the world.
Steven
Use a ceramic cart. Nice high output. Forget the MM or MC. They're just gimmicks.
Not needed with the ceramic cart. (Or use a strain gauge)
Use a transformer as a stepped attenuator.
Move the speakers back and forth. Use blankets or old quilts over them to change the tone.
See? Easy!
I have determined that no 1k stereo (dual gang) linear pots with a .5w power rating exist affordably in north america. omeg has no dealers that i can find, vishays at newark are only available from farnell for a $50 shipping charge. no one has the bournes pots in stock. alps doesn't make 1k. man oh man. i am frustrated!
Many high-end audio products are lauded for their carefully tailored harmonic distortion rather than the lack of it, so have you considered that you might be describing the effect of eliminating something from your audio chain that had been affecting the music programme? The clue to me is in your use of the term "strangled" which to me implies flat response and very low HF distortion. I've seen DestroyerX refer to it as "muffled" and there it infers no sweetening harmonics. Combined with intentionally flat response monitors, that could well add up to a purity of sound that perhaps you hadn't anticipated.......I'm posting here because I think the preamp I've built is subjectively "mildy strangling" the music. I find this interesting and was hoping to learn something by working out why. After all, this is a forum for DIY, not manufacturers, is it not? The recent spate of last minute comments implying that I have no basis for this opinion is pointless as everyone here must be aware of the debate over subjective vs objective and no matter which part of the spectrum you sit in no single person has all the answers. No one could prove that I can't hear what I'm hearing any more than I can prove that I can. The design must be audibly perfect as it measures so well.This is good science for anyone who uses an amplifier to display waveforms on a 'scope or generate impressive looking specs on paper, but for the rest of us who use them for enjoying music I think it's pretty questionable science...
I think few of us us really want technically perfect reproduction, though it is the basic principle of high fidelity audio, which we somehow feel obliged to uphold, even though it doesn't mean we'll enjoy it most. On the other hand, if I wished to process the audio for broadcast, recording, relay, PA etc, I wouldn't hesitate to go for the most linear equipment available. You can get funky at the listening end any time without affecting other uses.
I think few of us us really want technically perfect reproduction, though it is the basic principle of high fidelity audio, which we somehow feel obliged to uphold, even though it doesn't mean we'll enjoy it most. On the other hand, if I wished to process the audio for broadcast, recording, relay, PA etc, I wouldn't hesitate to go for the most linear equipment available. You can get funky at the listening end any time without affecting other uses.
Yes, yes, yes !!!!!!! finally
a comment I 100% agree with and have said many many times myself.What use is technical perfection when you don't actually like sitting and listening to it.
Ian,
I find your answer to be an interesting read. Yes I think that most of us as manufacturers and designers are always thinking of making a device wherever it is in the chain as close to technically perfect as possible with no significant acoustic signature of its own. But your argument that perhaps we are missing something has a valid point also. I would say this goes to why some people are so enamored of vacuum tube equipment though most of this will just measure as an inferior reproducer. I am not saying that you can't go the extra mile and also have very technically correct design, but that is not what I am getting at. I think that it is the distortion of harmonics that those people find so attractive, minor changes to the reproduced sounds that make them feel that the sound is more natural or inviting. We think of instruments in music as being pure and simple creators of sounds but it is really all of the side bands that are making that sound, not just the pure tones that you can never recreate through a synthesizer. Why we like one guitar over another that are made by the same manufacturer from the same wood in the same manner. The subtle differences that we listen for. I assume that this is what Owdeo is missing, something that gives the sound character. Perhaps an increase in second harmonic distortion would make him happier, but how to do that in a controlled manner is not something I could answer.
Steven
I find your answer to be an interesting read. Yes I think that most of us as manufacturers and designers are always thinking of making a device wherever it is in the chain as close to technically perfect as possible with no significant acoustic signature of its own. But your argument that perhaps we are missing something has a valid point also. I would say this goes to why some people are so enamored of vacuum tube equipment though most of this will just measure as an inferior reproducer. I am not saying that you can't go the extra mile and also have very technically correct design, but that is not what I am getting at. I think that it is the distortion of harmonics that those people find so attractive, minor changes to the reproduced sounds that make them feel that the sound is more natural or inviting. We think of instruments in music as being pure and simple creators of sounds but it is really all of the side bands that are making that sound, not just the pure tones that you can never recreate through a synthesizer. Why we like one guitar over another that are made by the same manufacturer from the same wood in the same manner. The subtle differences that we listen for. I assume that this is what Owdeo is missing, something that gives the sound character. Perhaps an increase in second harmonic distortion would make him happier, but how to do that in a controlled manner is not something I could answer.
Steven