The question was already answered. Go with series. Fewer mechanical contacts = greater reliability and it's as audibly transparent as a ladder. The Acoustic Dimension attenuators go one better by using one less mechanical contact than typical series attenuators.
se
Thanks Steve. That was the equation. If the only advantage for the ladder attenuator was the idea of more transparency due to a shorter signal path (less resistors) not exist, because it is equal in the most important parameter to the series: the sound....not worth. All other parameters are in disadvantage. But, it is a bit strange that if this equality is audible objectively, why have both models.
Take a look at this circuit (without the balance control). Choose R as a low value that your source can still properly drive,
for example 10k for non-tube sources. At any setting it has two resistors and one switch contact. Yes, the input impedance does vary,
but that really isn't a problem in most cases. I would have the switch contacts at the ground ends of the shunt resistors, though.
The technical description of Model 5
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I have to agree with SE.
Far too much neurosis over nothing. I use Alps RK27 and Goldpoint. They work just fine.
Far too much neurosis over nothing. I use Alps RK27 and Goldpoint. They work just fine.
The funny thing is that people who obsess over tiny details like attenuator distortion are often quite oblivious of major issues like the need to use coupling caps and ground leak resistors to keep DC away from the switches and so avoid switching clicks. Such people sometimes turn out to be Faradaphobes too.
sorry bonsai, this is not the subject. transparency/reliability if you read. overreaction is more like neurosis, btw.
Well no I do not mean a fixed volume. I do not even recommend 12 steps as I think it is too little. What I meant was that the experiment with two resistors soldered in signal path show how important is quality of the switch connectors. I put the switch in with same two resistors and degradation is sound is clearly hearable. That is also why very often passive preamplifiers with stepped attenuator suck. Even if the impedance matching (which is rare for passive) is fine another cable, connectors and solder joints kill the sound.
I do not say there are no good switches. But for example Elma, not talking about it's sonics as I have never had another 4 deck switch to compare it to, did pops and clicks when switching even though it was meant to be make before brake version and was lubricated well. This was only in ladder type wiring obviously as series wiring never brakes ground connection. Another thing is one of my Elmas never used sitting in box parts for 5-6 years got the gold connectors totally oxidated, instead of gold they look like smoked bronze right now. I mention all of this becouse these are not cheap. The price point of around $200 for the 4 deck switch alone needed to wire ladder type for stereo RCA single ended connection I paid few years back is rather high and with good resistors jumps even higher. I have also had a local company custom made so called very high quality metal firm resistors made for me to my values specification to get the perfect ladder type steps. Extremely low tolerances and precision metal film resistors a the end appeard to be sonically quite inferior to cheap Vishay/Dales. That also tells something especially to those who only consider electrical parameters, it's not all about it, or proabably it is measurable but it's not about the simple basic parameters. I attach the photo of Elma with custom made resistors I made few years ago for some preamplifier.
I once had this idea to buy single deck 24 position switch and just make it to drive 48 relays. The relays could be pick out of many for sonics (easy made tests), so the resistors, all could be wired p-2-p with no odd PCB and it's unneeded connection and traces with high quality wiring, realays aligned one next to another soldered directly to signal wire in ladder type configuration where the realy would just switch in to "an open part of cable going to inside connectors" the right value of resistors for given loudness. Simple and no need for expensive switches, also flexible with personal choice of favourite realys and resistors. Never done that though, but I bought single deck 24 position Elma for that purpose at some point.
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Chris, confine your promotion efforts to the Vendor's forum.Have we forgotten shunt attenuators? Perhaps they are out of scope of dicusssion because they have varying input impednace, but if you have a well designed DIY system you can take this into account.
I use Broskie balanced shunt attenuator. Although they have 66 positions, in practice I only use 2 or 3 positions. Maybe I have tin ears, but really, when my wife asks me to turn it down, there is no point reducing level by 0.5dB. When she asks me to turn it down, what she really means is reduce level by 3dB at least. And do it NOW. So using the coarse controller on the Broskie attenuator is just fine. I never touch the fine control.
Shunt attenuators have best of both worlds. If its a single end version, its got 2 resistors in series and one switch. Just don't worry about varying input impedance.
I use Broskie balanced shunt attenuator. Although they have 66 positions, in practice I only use 2 or 3 positions. Maybe I have tin ears, but really, when my wife asks me to turn it down, there is no point reducing level by 0.5dB. When she asks me to turn it down, what she really means is reduce level by 3dB at least. And do it NOW. So using the coarse controller on the Broskie attenuator is just fine. I never touch the fine control.
Shunt attenuators have best of both worlds. If its a single end version, its got 2 resistors in series and one switch. Just don't worry about varying input impedance.
It appears some people worry about the audibility of switch contacts, and indeed it appears all these attenuator contacts are exposed to the air (and possibly affecting the OP's decision of two-contact Ladder vs. one-contact Series). Aren't there better and more reliable contacts available in relays, such as reed switch relays?
This brings up microprocessor control, which brings several advantages (and yes, the chip and its clock oscillator would turn off in between switching levels, eliminating it as a possible noise source). This technology has been available for decades - I'm surprised mechanical stepped attenuators are still so popular. Perhaps the straightforward and more easily understood switches make them look "better."
I see many relay-based designs with this Google search (and no, I don't have a design I'm selling! Maybe someday...):
microcontroller relay audio attenuator
This brings up microprocessor control, which brings several advantages (and yes, the chip and its clock oscillator would turn off in between switching levels, eliminating it as a possible noise source). This technology has been available for decades - I'm surprised mechanical stepped attenuators are still so popular. Perhaps the straightforward and more easily understood switches make them look "better."
I see many relay-based designs with this Google search (and no, I don't have a design I'm selling! Maybe someday...):
microcontroller relay audio attenuator
Too big and messy and complicated. Why not just hermetically seal a regular attenuator?
se
Regarding pops and clicks from one step to the other, some people advise me to use a "make before break" type, but what happens with impedance when two steps are connected at the same time?:
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Regarding pops and clicks from one step to the other, some people advise me to use a "break before break" type, but what happens with impedance when two steps are connected at the same time?:
You mean "make before break." And it would depen on whether it was a series or ladder.
se
yes, I committed a typo mistake (solved).
Well, I read that noises are related with the ladder attenuators, but some say that happens on all stepped attenuators.
The input impedance typically halves in a ladder attenuator using a MBB (make before break) switch.
Output impedance is affected too.
I've been using a ladder attenuator on one amp for many years, and connected to many different sources, and no ill-effects are observed in any of them.
It's highly likely that during the actual volume change operation some effect is audible in the system due to the moving impedance, but the click of the switch is usually louder than any of that.
Series attenuators do not show this specific effect (you can think about what happens when a series resistor is disconnected, for example, versus two different values being connected at the same time) - though in both ladder and series you should always use a make before break as the input typically goes open in BBM.
Output impedance is affected too.
I've been using a ladder attenuator on one amp for many years, and connected to many different sources, and no ill-effects are observed in any of them.
It's highly likely that during the actual volume change operation some effect is audible in the system due to the moving impedance, but the click of the switch is usually louder than any of that.
Series attenuators do not show this specific effect (you can think about what happens when a series resistor is disconnected, for example, versus two different values being connected at the same time) - though in both ladder and series you should always use a make before break as the input typically goes open in BBM.
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You will get switching clicks whatever type of switch you use and whatever type of resistor arrangement you use if there is DC present. However, make before break will give quieter clicks than break before make.
The only clicking I hear with my Acoustic Dimension attenuators is the mechanical clicking of the switch.
But who really cares? I don't listen to music while continuously fidgeting with the volume control.
se
as you said, was a "philosophical" question.
So you have an acoustic dimension attenuator, I supose the series, right?
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