OK, since this thread seems to have run its course, perhaps it'd be a good idea to summarize my findings (here and elswhere, in the course of my 'research') for the benefit of those who're, like me, new to the in-depth subject of volume-control. (Understandably, technically-oriented, and long-standing, fans of passive 'pre-amps' are the undisputed experts on this topic. And my own comments should, ideally, be viewed in the context of the recent discoveries of a long-standing audiophile who may be reasonably learned in most areas of high-end audio, but relatively new to this one - a novice in this particular field).
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Stepped-attenuators are, in my view the standard-bearers in the field of volume-control. For those of us seeking the very best in transparency, and overall sound-quality, all other means of V-C (volume-control) must be measured against (the best of) this standard. However, there's a caveat in the fact that some seem to believe that atts tend to thin-out the sound, as compared to other means of V-C, which do not display this trait. The results of my investigation, in this regard, are inconclusive. The fact is that most of those, who aired such a concern, were using DACT attenuators, though other brands were also implicated. On the basis of my findings, I'd be inclined to believe that there is a ligitimate concern, regarding a thinner midrange conveyed by DACT atts. Fuller mids seem to be a feature of both the Goldpoint, and TKD atts. As to whether these eradicate the problem completely, I'm not sure. Nevertheless, according to a comprehensive study done by John Curl, designer of the Blow-Torch pre-amp, the very best stepped-attenuator of all is, in his view, the top TKD. (A reference to his findings is linked elsewhere in this thread).
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Potentiometers (carbon-based, or plastic) generally speaking are less transparent than atts. However, the very expensive, $1k, ALPS RK50 is THE EXCEPTION, with reputed transparency comparable to the best atts (but at much higher cost). At a lower level, the best TKD pot is alleged to be close (but not quite there) to the quality of the better atts. Citing a few of the popular examples, the consensus seems to be that the sound-quality of pots, in ascending order of ranking, would be; Blue-ALPS, PEC, and the afore-mentioned TKD (Based on what I've gleaned, I'd guess that the Black-ALPS would be either equal to the PEC, or somewhre between PEC and TKD).
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Transformer-based volume-controls (TVC and AVC) are, generally, much more expensive than atts. The sound-quality is usually comparable, with the best of these alleged to be slightly better than stepped-attenuators - a claim hotly debated by att-advocates.
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Light-Dependent Resistors (LDR) volume-control, by all consensus, seems to be the very best means of V-C, with singular regard to sound-quality. Many, who had previously used atts, now attest to slightly more transparency and resolution of low-level detail, with their current use of LDR V-Cs. The same applies to those who'd previously used TVCs. There are several LDR passive 'pre-amps' avalable in the form of the likes of LightSpeed, WarpSpeed, Eva, etc. However, though perhaps all can be used in the context of a replacement volume-control for an active pre, perhaps the most attractive, in terms of physical-fit and cost (comparable to an att in both regards, effectively) is the OptiVol LDR volume-control by Ska. With regard to its sound-quality (in the context of passive and active applications, respectively) here are two example of the prevailing sentiments - from a thread at that site:
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Example A: Greg's SKOptVol is actually better (and cost less) than the passive Ladder Volume switch that I was using 😎 With Greg now using a 27K series resistor, the minimum volume is -54.5db 🙂 My Speakers are 92db and -54.5db is sufficient for them. Here's what I wrote a few months ago about Greg's SKPre c/w SKOptVol ... Quote: Hi All I have just completed an SKPre c/w SKOpticalAttenuator and thought that I would give a short report on it. This is a very transparent and neutral preamp. The stage is very open, deep and wide. It is very musical and detailed. The highs and mid-range are very detailed and have no edge to them. The bass is very detailed and full, also. Everything has a very "there" feel to it. Nothing seems to stand out or be out of place ... very nice Also, the SKOpicalAttuator is also very good sounding ... 🙂 Actually, I would say that Greg's SKOptVol is fantastic and will be my choice of volume pot in the future 8- ) :thumbsup.
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Example B: Title: Re: Simple LDR volume control! Post by sfox52 on Apr 5 th , 2008, 11:06pm Me Three! 😉- I shoehorned my Optivol into a Bottlehead Foreplay Tube linestage pre-amp, powered via a wallwart dc supply. It's the best attenuator I've had in it, including a stepped switch!.
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Far-be-it from me to advocate any particular means of volume-control. I embarked on this venture with a view to finding an upgrade for a noisy pot in my own pre. The result is that my choices have now been short-listed to a few probable candidates. I've posted my findings with the hope that this will assist others who're engaged in a similar quest (and, with a similar aim, these findings will also be incorporated into a revised version of a recent article at my little site linked below). That's it!
.
Thanks to all who participated, for the most part. This forum is great!
.
Peace!
.
____________________________
.
WAJ on AUDIO
.
Stepped-attenuators are, in my view the standard-bearers in the field of volume-control. For those of us seeking the very best in transparency, and overall sound-quality, all other means of V-C (volume-control) must be measured against (the best of) this standard. However, there's a caveat in the fact that some seem to believe that atts tend to thin-out the sound, as compared to other means of V-C, which do not display this trait. The results of my investigation, in this regard, are inconclusive. The fact is that most of those, who aired such a concern, were using DACT attenuators, though other brands were also implicated. On the basis of my findings, I'd be inclined to believe that there is a ligitimate concern, regarding a thinner midrange conveyed by DACT atts. Fuller mids seem to be a feature of both the Goldpoint, and TKD atts. As to whether these eradicate the problem completely, I'm not sure. Nevertheless, according to a comprehensive study done by John Curl, designer of the Blow-Torch pre-amp, the very best stepped-attenuator of all is, in his view, the top TKD. (A reference to his findings is linked elsewhere in this thread).
.
Potentiometers (carbon-based, or plastic) generally speaking are less transparent than atts. However, the very expensive, $1k, ALPS RK50 is THE EXCEPTION, with reputed transparency comparable to the best atts (but at much higher cost). At a lower level, the best TKD pot is alleged to be close (but not quite there) to the quality of the better atts. Citing a few of the popular examples, the consensus seems to be that the sound-quality of pots, in ascending order of ranking, would be; Blue-ALPS, PEC, and the afore-mentioned TKD (Based on what I've gleaned, I'd guess that the Black-ALPS would be either equal to the PEC, or somewhre between PEC and TKD).
.
Transformer-based volume-controls (TVC and AVC) are, generally, much more expensive than atts. The sound-quality is usually comparable, with the best of these alleged to be slightly better than stepped-attenuators - a claim hotly debated by att-advocates.
.
Light-Dependent Resistors (LDR) volume-control, by all consensus, seems to be the very best means of V-C, with singular regard to sound-quality. Many, who had previously used atts, now attest to slightly more transparency and resolution of low-level detail, with their current use of LDR V-Cs. The same applies to those who'd previously used TVCs. There are several LDR passive 'pre-amps' avalable in the form of the likes of LightSpeed, WarpSpeed, Eva, etc. However, though perhaps all can be used in the context of a replacement volume-control for an active pre, perhaps the most attractive, in terms of physical-fit and cost (comparable to an att in both regards, effectively) is the OptiVol LDR volume-control by Ska. With regard to its sound-quality (in the context of passive and active applications, respectively) here are two example of the prevailing sentiments - from a thread at that site:
.
Example A: Greg's SKOptVol is actually better (and cost less) than the passive Ladder Volume switch that I was using 😎 With Greg now using a 27K series resistor, the minimum volume is -54.5db 🙂 My Speakers are 92db and -54.5db is sufficient for them. Here's what I wrote a few months ago about Greg's SKPre c/w SKOptVol ... Quote: Hi All I have just completed an SKPre c/w SKOpticalAttenuator and thought that I would give a short report on it. This is a very transparent and neutral preamp. The stage is very open, deep and wide. It is very musical and detailed. The highs and mid-range are very detailed and have no edge to them. The bass is very detailed and full, also. Everything has a very "there" feel to it. Nothing seems to stand out or be out of place ... very nice Also, the SKOpicalAttuator is also very good sounding ... 🙂 Actually, I would say that Greg's SKOptVol is fantastic and will be my choice of volume pot in the future 8- ) :thumbsup.
.
Example B: Title: Re: Simple LDR volume control! Post by sfox52 on Apr 5 th , 2008, 11:06pm Me Three! 😉- I shoehorned my Optivol into a Bottlehead Foreplay Tube linestage pre-amp, powered via a wallwart dc supply. It's the best attenuator I've had in it, including a stepped switch!.
.
Far-be-it from me to advocate any particular means of volume-control. I embarked on this venture with a view to finding an upgrade for a noisy pot in my own pre. The result is that my choices have now been short-listed to a few probable candidates. I've posted my findings with the hope that this will assist others who're engaged in a similar quest (and, with a similar aim, these findings will also be incorporated into a revised version of a recent article at my little site linked below). That's it!
.
Thanks to all who participated, for the most part. This forum is great!
.
Peace!
.
____________________________
.
WAJ on AUDIO
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I use a TKD stepped attenuator in my AKSA preamp. This is the same one selected by the late, great Bob Crump for the "Blowtorch" preamp.
No thin lower mids, I can assure you - obviously those posters who said this, hadn't bothered to try the TKD. 😉
Regards,
Andy
My sentiments too - to an extent. Been leanin' towards that said TKD meself. Lamm uses it in the LL1, Audio-Note too, and we all know about the Blow-Torch - no reports of thinness in the mids of either of these pre..s. But this is the reason I worded that segment as I did. I'm reasonably convinced that this is a concern with at least one or two over-the-counter atts (including the DACT), but people have a tendency to generalize, inadvertently clouding the issue. I simply reported what I found, as I found it, leaving people to interpret for themselves and further investigate because, as I said, this segement of my own research was inconclusive - to this moment, at least - for the reasons cited. (The samples of opinion were not just from this forum, btw, but from a wider cross-section of available opinion).
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Oh, and you're right, of course, Bob Crump is the one who did the att research (re; my post #37) not sure how John Curl became mixed-up in my brain. Perhaps this is because he's also associated with this pre - I think.
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Thanks!
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______________________
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WAJ on AUDIO
Somewhere around post 5000 on the current blowtorch site I posted resistor distortion measurements. They show carbon comp, carbon film and various others distortion. It may shed some light on what people claim to hear. I am too lazy to look up the exact post numbers.
If the topic seeks to establish whether atts display a thinner sound, then this implies that other means of volume-control are not so afflicted. If pleasant harmonic-distortions (or whatever other reasons) account for a 'fuller' sound from carbon pots/resistors and LDR (or even TVCs, for that matter) compared to that of atts, then I'd have imagined that this'd be relevant to the topic - in some sense - since atts do not exist in a vacuum, there are alternatives.
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My original post included this sentence: 'Others, elsewhere go further to claim that the atts' clarity border on 'edginess', made more obvious by the atts thinner mids, compared to carbon pots, and other forms of volume-control.' I may very well be intellectually-challenged, but I fail to see how pots can be relevant to this debate, while TVCs and LDRs are not - all are forms of volume-control, to my understanding, though all can be utilized as the main components in passive pre..s. From my perspective, I've no interest in passive pre..s (been there, and done it - and done with it).
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Unfortunately, in the context of this thread, perhaps some only view TVCs and LDRs as passive pre-amps - hence, the call for a separate thread. I see them differently (indeed, a reflection of the reality) in the context of their use as volume-controls in active pre-amps, such as Coincident (TVC) and darTZeel (LDR) along with countless other diy active pre-amps, and upgrades to existing active pre..s (as is my intent with my own active pre).
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Therefore, in the context of their use as volume-controls in active pre-amps, any concerns with atts would necessarily be considered against the alternatives (as my OP indicates) including carbon or plastic pots, TVCs, and LDR volume-controls - not passive pre-amps.
.
Perhaps I'm wrong!
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________________________
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.WAJ on AUDIO
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My original post included this sentence: 'Others, elsewhere go further to claim that the atts' clarity border on 'edginess', made more obvious by the atts thinner mids, compared to carbon pots, and other forms of volume-control.' I may very well be intellectually-challenged, but I fail to see how pots can be relevant to this debate, while TVCs and LDRs are not - all are forms of volume-control, to my understanding, though all can be utilized as the main components in passive pre..s. From my perspective, I've no interest in passive pre..s (been there, and done it - and done with it).
.
Unfortunately, in the context of this thread, perhaps some only view TVCs and LDRs as passive pre-amps - hence, the call for a separate thread. I see them differently (indeed, a reflection of the reality) in the context of their use as volume-controls in active pre-amps, such as Coincident (TVC) and darTZeel (LDR) along with countless other diy active pre-amps, and upgrades to existing active pre..s (as is my intent with my own active pre).
.
Therefore, in the context of their use as volume-controls in active pre-amps, any concerns with atts would necessarily be considered against the alternatives (as my OP indicates) including carbon or plastic pots, TVCs, and LDR volume-controls - not passive pre-amps.
.
Perhaps I'm wrong!
.
________________________
.
.WAJ on AUDIO
Last edited:
There seems to be a joke in here, somewhere. Somehow it eludes me, though. I'm done - absolutely!
Yes, I see those all as well within the scope of your original question. Especially as a reference to the sound of the stepped attenuators. What does a S.A. sound like in comparison to X,Y or Z? Not off topic.
This thread has outlived its usefulness and is now closed- Status
- Not open for further replies.