I can tell you for me, in my experience, in order of preference would first come a ladder attenuator on a high quality switch(silver contacts), a relay controlled R2R ladder, and lastly a series attenuator on a good quality switch.
There is no reason why a series att. would sound "thinner' than say a ladder. In fact, I would think with all the added resistor noise and solder joints it'd be closer to a carbon or plastic pot.
If I thought I was getting fuller sound from a carbon pot as compared to one of the above I'd have to a.) question what I mean by fuller and b.)look at the rest of the component/equipment.
Hope that helps.
There is no reason why a series att. would sound "thinner' than say a ladder. In fact, I would think with all the added resistor noise and solder joints it'd be closer to a carbon or plastic pot.
If I thought I was getting fuller sound from a carbon pot as compared to one of the above I'd have to a.) question what I mean by fuller and b.)look at the rest of the component/equipment.
Hope that helps.
Pano, Conrad, thanks for the input, guys.
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It seems I agree with you both. I'd welcome the transparency of a sepped-attenuator any day. However, in my system, I will not tolerate the thinness Conrad admits to hearing, from atts. But since I already have a reasonable facsimile of the tonality of live instruments, as supplied by my carbon ALPS, I cannot support the theory that a thinner sound may be more accurate.
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The good news for me, and perhaps you too, Pano and Conrad, is that LDRs offer perhaps even more transparency, without the penalty of the thinner sound of atts, which you both seem to recognize.
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I guess what I'm trying to suggest is that the choice is not limited to carbon-pots and stepped atts, with their strengths and weaknesses, LDRs seem to combine the best of both, and then some.
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Just a thought.
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It seems I agree with you both. I'd welcome the transparency of a sepped-attenuator any day. However, in my system, I will not tolerate the thinness Conrad admits to hearing, from atts. But since I already have a reasonable facsimile of the tonality of live instruments, as supplied by my carbon ALPS, I cannot support the theory that a thinner sound may be more accurate.
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The good news for me, and perhaps you too, Pano and Conrad, is that LDRs offer perhaps even more transparency, without the penalty of the thinner sound of atts, which you both seem to recognize.
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I guess what I'm trying to suggest is that the choice is not limited to carbon-pots and stepped atts, with their strengths and weaknesses, LDRs seem to combine the best of both, and then some.
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Just a thought.
CdS cells are horrifically non linear and are amongst the worst "resistors" one can find, if one is measuring them... how they sound to the ear is a different matter...
_-_-bear
_-_-bear
Yeah, I've heard that issue raised before. Yet, all who've tried them seem captivated by their sound - no issues with thin mids or edginess.
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However, back on the stepped-attenuator front, I seem to have stumbled upon hints of some encouraging news for those considering atts, but are also wary of rumored idiosyncracies. I should first mention that several of those, who complained of problems, were actually using DACT atts. Could it be that the problems are limited to DACT, only?
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Here's a testimonial I found, in my research, over at the Goldpoint site. [SIZE=-1][FONT=Arial,Helvetica]http://www.goldpt.com/success.html [/FONT][/SIZE]
[FONT=Arial,Helvetica][SIZE=-1]Ladder Attenuator Assembly and Use - [June, 2002][/SIZE][/FONT]
[SIZE=-1]"[FONT=Arial,Helvetica]Just a quick note to let you know how I got on with the ladder attenuator. Assembly took me about 3 hours in total over a few weeknights - I took it slowly and was careful with the soldering. It works beautifully - no clicks or pops at all, so no need for the big ground resistor. I'm using it in my DIY preamp which is a scratch-built version of Bruce Rozenblit's "Grounded Grid" preamp. As for the sound - superb! A real improvement on the previous volume control, and I couldn't be happier. [/FONT][/SIZE] I had a DACT stepped attenuator before[SIZE=-1][FONT=Arial,Helvetica], and although it works well I had the distinct feeling that it had a "cold" and "brittle" sound with a recessed midrange. I know subjective terms like that aren't very helpful, but that was my impression. The Goldpoint is much nicer to listen to, and I can't imagine wanting to change to anything else." [/FONT][/SIZE].
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.The experiences of users of the different brands of off-the-shelf atts. should be interesting.
I think the stepped attenuator is probably clean and uncolored and your pot is the thing that sounds wrong. That said, I seriously doubt the difference between the two is that marked that on an AB test the majority of people would say 'oh my god, that other one sounds TERRIBLE. Take it away, please'
Perspective folks. Perspective.
Perspective folks. Perspective.
Only problems I see with carbon pots are poor channel balance, and wear
technically I see no other problem
might even be superiour
wear !
well, they are cheap to replace
channel balance !
how about using mono pots
with a balance meter
I'm tempted to try it
but the balance meter?
I have no idea how it works
hmm, maybe a couple of leds would work, somehow
technically I see no other problem
might even be superiour
wear !
well, they are cheap to replace
channel balance !
how about using mono pots
with a balance meter
I'm tempted to try it
but the balance meter?
I have no idea how it works
hmm, maybe a couple of leds would work, somehow
There was a time long long ago when good carbon pots were cheap. I don't think that's the case today, if you can even find really good ones. I know enough about LDRs to know that I'd never consider using one in an audio circuit. There are a lot of myths about attenuators concerning impedances and shunt types that I think are nonsense. Every individual situation needs to be looked at separately to be sure the chosen values don't load the previous stage excessively and provide sufficient drive to the next stage. Buffers solve many problems, but aren't always necessary if the driving and driven impedances are flat with frequency. In fact, if that's the case you can often get away with a rather low value attenuator that's less subject to pickup and response problems.
If an ARC preamp displays any desirable traits, then your point of reference is likely very different from mine. No experience with LS3 but some with SP10, LS15, LS25, REF3 and REF5. As far away removed from neutral or musical as i can possibly imagine but capable of interesting sound effects. Would rather live with a passive (shudder) than any of the above.
Not sure why anyone would use different type of resistors in an attenuator than what the rest of their amplification chain uses. The switcher is much more problematic. Most relays are just not suitable for music.
Electromechanical switches also vary a lot but luckily Shallco are cheap and readily available for the not-so-obsessed. Or one can apparently take them apart and polish the contact surfaces to perfection.
Direct replacement of a pot in an existing design is likely to upset the tonal balance. It is much better to start with an excellent, very transparent attenuator and build the rest of the preamp to suit its transparency while maintaining a natural tonality.
Maybe there are differences due to the frequency-dependent characteristics of the resistor noise that all resistors generate, depending on the current levels, wattage rating, materials, and the types of construction of the resistors and pots.
Here is a pretty-good short article about the different types of resistors:
Resistor Types--Does It Matter?
Apparently, one should use the lowest R values, and use the largest wattage ratings that are practical, and keep the current levels as low as possible. (Sounds like a buffer or active preamp stage would be a must.)
Is everyone using 1/4-Watt resistors in their stepped attenuators? Has anyone tried using 2-Watt resistors? That should greatly-improve the low-frequency noise problems.
Another potential problem with lower-wattage resistors, not mentioned in the article, is that their value can actually be modulated by the signal, since their value changes with temperature, which changes with the voltage across and current through them. Using high-wattage resistors would also alleviate that risk.
Tom
Here is a pretty-good short article about the different types of resistors:
Resistor Types--Does It Matter?
Apparently, one should use the lowest R values, and use the largest wattage ratings that are practical, and keep the current levels as low as possible. (Sounds like a buffer or active preamp stage would be a must.)
Is everyone using 1/4-Watt resistors in their stepped attenuators? Has anyone tried using 2-Watt resistors? That should greatly-improve the low-frequency noise problems.
Another potential problem with lower-wattage resistors, not mentioned in the article, is that their value can actually be modulated by the signal, since their value changes with temperature, which changes with the voltage across and current through them. Using high-wattage resistors would also alleviate that risk.
Tom
600mW resistors are widely available in E24 values to +-1% tol & +-50ppm/C
If we could modulate the resistive film temperature over a range of 50C then we get ~0.25% of total range of value change.
Do you really think we could get more than few C degrees of change in film temp on a ceramic substrate of a 600mW resistor running at 50mW continuous and an AC power of 10mW?
If we could modulate the resistive film temperature over a range of 50C then we get ~0.25% of total range of value change.
Do you really think we could get more than few C degrees of change in film temp on a ceramic substrate of a 600mW resistor running at 50mW continuous and an AC power of 10mW?
AndrewT,
Man, you're everywhere. 🙂
OK, maybe my last paragraph is ridiculous, especially for those resistors. And I'm too lazy to go find a worst-case type.
That wasn't the main point of my post, anyway, and I should not have thrown it in since it's very unlikely to have any significant effect in this type of application.
Tom
Man, you're everywhere. 🙂
OK, maybe my last paragraph is ridiculous, especially for those resistors. And I'm too lazy to go find a worst-case type.
That wasn't the main point of my post, anyway, and I should not have thrown it in since it's very unlikely to have any significant effect in this type of application.
Tom
I thought this would be interesting, for those of us contemplating the best stepped-attenuators. Found at a discussion forum, here:
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One of the other benefits of the TKD is that it has 40 steps of 0.5 to 1dB.
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In late 2002 I was trying to figure out whether to go with DACT, a Goldpoint ladder or something else in my GK-1. I exchanged a number of emails with the late, great Bob Crump on the matter. He had spent some years evaluating just about every attenuator under the sun, including pots, shunts, series and ladders with a variety of resistors and bypasses etc etc. In the end, the TKD with S102 bypasses was the best he found and it became the attenuator of choice for the cost no object CTC BlowTorch pre-amp (~US$15k). I believe it was also used in the $$$$ LAMM Reference 2 (I think that was the model).
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Bob's advice was that if I was considering an attenuator solution anywhere the cost of the TKD/S102 combo, I may as well spend the bit extra and get the best. He also advised that he had tried a large number of different bypass resistors but none approached the Vishay S102 on the TKD. After a series of emails with Bob through 2003 I eventually pulled the trigger in March 2004 and did just that.
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A word of warning though, it does need a fair bit of space to mount and it mounts with 3 machine screws through the front panel (hidden behind the volume knob). It also has a fairly lengthy break-in period to sound its best, though Hugh and I thought it sounded excellent from new. I heard a while back that the price had gone up even further and Michael Percy wasn't going to stock them any more as a result. However, last I heard they were still available from Japan where they are made.
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How much better does it sound than the likes of the DACT or GoldPoint ladders etc? I have no idea. I didn't have the time, money or energy to repeat for myself the evaluation studies performed by Bob. I trusted Bob and have never regretted it.
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One of the other benefits of the TKD is that it has 40 steps of 0.5 to 1dB.
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In late 2002 I was trying to figure out whether to go with DACT, a Goldpoint ladder or something else in my GK-1. I exchanged a number of emails with the late, great Bob Crump on the matter. He had spent some years evaluating just about every attenuator under the sun, including pots, shunts, series and ladders with a variety of resistors and bypasses etc etc. In the end, the TKD with S102 bypasses was the best he found and it became the attenuator of choice for the cost no object CTC BlowTorch pre-amp (~US$15k). I believe it was also used in the $$$$ LAMM Reference 2 (I think that was the model).
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Bob's advice was that if I was considering an attenuator solution anywhere the cost of the TKD/S102 combo, I may as well spend the bit extra and get the best. He also advised that he had tried a large number of different bypass resistors but none approached the Vishay S102 on the TKD. After a series of emails with Bob through 2003 I eventually pulled the trigger in March 2004 and did just that.
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A word of warning though, it does need a fair bit of space to mount and it mounts with 3 machine screws through the front panel (hidden behind the volume knob). It also has a fairly lengthy break-in period to sound its best, though Hugh and I thought it sounded excellent from new. I heard a while back that the price had gone up even further and Michael Percy wasn't going to stock them any more as a result. However, last I heard they were still available from Japan where they are made.
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How much better does it sound than the likes of the DACT or GoldPoint ladders etc? I have no idea. I didn't have the time, money or energy to repeat for myself the evaluation studies performed by Bob. I trusted Bob and have never regretted it.
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I'm in the same camp. The lower mids are where speakers sound most like speakers to me, not live instruments. I've heard very few speakers that sound right in the range, but when they do, it's amazing. One of those "Wow! I didn't know speakers could do that!" moments. When the lower mids are right, then the speaker will get out of the way of the music and stop sounding like a speaker. At least to my ears.
Agree. I've heard a lot of highly regarded systems like that. A lot of audiophiles seem to be afraid of bass. One can easily understand why, most bad systems have plenty of it, and it's awful. Getting away from that muddy lower midrange sets you apart. But maybe they also hear things the way we do, bad lower mids/upper bass bothers them, too. So if you simply attenuate that register, you've also attenuated the problem. Presto! The system sounds more "Neutral" or "Precise" because the problem is suppressed. But now the tonal balance is wrong - a new problem.
Getting things right in the lower mids can't be easy, or there would be a lot more speakers doing it. To my ear and experience, those that get it right are very rare. It's easy to recognize when you hear it.
Just my own 2cnts. I have had and presently do have (ain't the English language wonderfull!) passive pots. The Vishay-based one I now use in my amp does have a buffer but years ago I had dual-mono ones using Shinko. If my memory serves me right the were the sweetest sounding resistors ever for this implimentation. They are getting rare since no longer made. When I last looked PartsConnection has some. There may yet be other sources. Neither then nor now have I heard any drawbacks as reported by others. Synergy?
Well, a bit more back on topic. If I were going to spend serious money on a volume control, it would be transformer based. No doubt about it. They are anything but "thin" sounding. But I'm a transformer fan-boy, so take that with a grain of salt. 😀
Excellent choice. A little too cumbersome for my purpose, though - a pity!
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Thanks for the comfirmation, btw.
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http://wajonaudio.webs.com/
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Thanks for the comfirmation, btw.
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http://wajonaudio.webs.com/
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