One very neat relay attenuator I've seen in a preamp at an audio show in Montreal was using a hybrid type volume control. They were using digital or PGA type volume control when changing volume (slow or fast), so it was totally silent during this operation and when set, they where calculating the exact same value on the latching relay R-2R ladder so only one "click" would be heard. Sounded really good as well.
I don't know if anyone has attempted this here?
Ciao!
Do
I don't know if anyone has attempted this here?
Ciao!
Do
seems to me the attenuator would be several times the size of the amp =D
as for Titan, i'm not entirely sure they are for general sale yet. its the same tech as in the davinci, but the USB board by itself is multichannel 8 x 32/192, 4 x 32/384
the cost will probably be about the same as the rest of your dac, think its about 500EU I have a prerelease prototype, but i understand its same as the final one
yeah i thought of using the PGA to drive something else with a control voltage too, seems to me it would make a good solution and avoid putting 2 opamps in the signal for no reason
as for Titan, i'm not entirely sure they are for general sale yet. its the same tech as in the davinci, but the USB board by itself is multichannel 8 x 32/192, 4 x 32/384
the cost will probably be about the same as the rest of your dac, think its about 500EU I have a prerelease prototype, but i understand its same as the final one
yeah i thought of using the PGA to drive something else with a control voltage too, seems to me it would make a good solution and avoid putting 2 opamps in the signal for no reason
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Hi,
about volume control and complexity. I can see that people here are trying totally different things for volume control - and anything pre-WIRE, actually.
I don't seem to fit right into the minimalist approach of leaving out every non-essential component, like avoiding additional opamps or pots. See attachment.
I'm still in the stage of finding that out, but there certainly won't be a number of devices in front of it. It'll of course go as close to the DAC as possible.
Seeing that my headphone amp (ultimately) will have a volume control (pot on the right, see pic), I don't know why not having separate gain presets for each input would be a big problem in general.
Considering a DAC like a BII/BIII as the single (i.e. only) source of analog signals, isn't having a relay-type attenuator with predefined input levels the functional equivalent of telling your controller to switch both channels and volume in the digital domain simultaneously?
Then again, I own a record player...
Would you please explain? What flexibility did you have to give up that was caused by digital volume control in the BII per se (and not by different topology of signal routing and management in your shunt volume control device).
Haha, glad you didn't put "no volume control" right at the top of that list.
I was always under the impression that the general culprit (going from larger to smaller influence, assuming quality gear) are things like the number of devices (as in: interconnected units) involved, the number of plugs, the length of cabling, the degree of pollution outside and inside the devices, etc.
Considering the above I'd favor a PGA close to the amp over a separate unit just for volume control...
Cheers,
Sebastian.
about volume control and complexity. I can see that people here are trying totally different things for volume control - and anything pre-WIRE, actually.
I don't seem to fit right into the minimalist approach of leaving out every non-essential component, like avoiding additional opamps or pots. See attachment.
I'm still in the stage of finding that out, but there certainly won't be a number of devices in front of it. It'll of course go as close to the DAC as possible.
Seeing that my headphone amp (ultimately) will have a volume control (pot on the right, see pic), I don't know why not having separate gain presets for each input would be a big problem in general.
Considering a DAC like a BII/BIII as the single (i.e. only) source of analog signals, isn't having a relay-type attenuator with predefined input levels the functional equivalent of telling your controller to switch both channels and volume in the digital domain simultaneously?
Then again, I own a record player...
Would you please explain? What flexibility did you have to give up that was caused by digital volume control in the BII per se (and not by different topology of signal routing and management in your shunt volume control device).
Haha, glad you didn't put "no volume control" right at the top of that list.
I was always under the impression that the general culprit (going from larger to smaller influence, assuming quality gear) are things like the number of devices (as in: interconnected units) involved, the number of plugs, the length of cabling, the degree of pollution outside and inside the devices, etc.
Considering the above I'd favor a PGA close to the amp over a separate unit just for volume control...
Cheers,
Sebastian.
Attachments
functionally yes, but adding 7 components in each phase, including 2 integrated circuits (at least one of which has THD numbers worse than the dac) and a transformer, with what is likely not a small amount of feedback, where nothing at all is needed; is hardly the same thing.
i'm not against opamps, i quite like them (obviously), but cleverness for cleverness sake is not what i consider clever. adding extra components can only degrade performance and in your circuit, linearity, noise and expense are all increased for no reason.
i'm not quite sure what you mean....separate unit just for volume? nothing in my list is a separate unit and my top 3 are actually part of the transport/source signal path whether any attenuation is applied or not. titan is a usb-i2s convertor of the highest order that happens to have 64bit floating point volume control, puremusic is player software and sabres volume, well thats obvious.
When you say integrated circuits, are you referring to the IC's that control the relays? In a relay attenuator, the specs of any ICs in the attenuator control circuit shouldn't matter since they're not in the signal path.
I think in the end it depends on our own needs/priorities. I'll probably build a wire amp without a volume control for fun, but I like to have the flexibility that having a volume control in the amp provides.
I believe by separate unit, he means a volume control that is external to the amp. I know that's kind of the point, but that brings us back to that whole personal priorities thing
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afaik the PGA volume control is buffered with at least 1 OP internally; but i think 2, one before and one after and it is this I object to, any efforts to create an individual high performance dac and amplifier combination are thrown away and rather limited to the performance of the internal opamps. i was referring to his schematic, in fact the whole post was directed at sek, no relay attenuator there. i presumed by PGA we are talking about the Ti electronically controlled analogue attenuator ICs; if i'm mistaken my apologies. i'm certainly not having a shot, i just dont understand the need/want to add such a complicated circuit to accomplish something you already have covered.... rather well
indeed one of the MAJOR points of the controls i favor are they are not external or separate to anything, they are integral to a device that is in the critical signal path whether you like it or not, but happen to provide completely transparent volume control hat has no effect on channel matching, input or output impedance, allows simultaneous control of multiple channels and also practically free for as many channels as you like.
sure you have the disadvantage that you cant use the amp with other peoples gear that doesnt have volume control, but for me, who gives a toss! I build gear for me. with my bal-bal its taken another step, it'll be integrated into the dac itself as the IV stage that happens to drive headphones very well
indeed one of the MAJOR points of the controls i favor are they are not external or separate to anything, they are integral to a device that is in the critical signal path whether you like it or not, but happen to provide completely transparent volume control hat has no effect on channel matching, input or output impedance, allows simultaneous control of multiple channels and also practically free for as many channels as you like.
sure you have the disadvantage that you cant use the amp with other peoples gear that doesnt have volume control, but for me, who gives a toss! I build gear for me. with my bal-bal its taken another step, it'll be integrated into the dac itself as the IV stage that happens to drive headphones very well
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More photos
I just thought I would add some photos of my build. This is a BAL-SE. I was very careful with the ICs when soldering them since they are so freaking expensive. The small residual amounts of flux remaining are non-reactive rosin type, meaning it is 100% safe to leave on for centuries. The tiny 0805 chip parts are a quite a challenge - some of mine look a little drunk, but I assure you, they are rock solid in place and the sound obviously speaks for itself. Another high five to OPC!
Shown below in daylight on a ESD safe bag - taken with an ancient digital camera with a nice macro mode. Remember, this amp is tiny (like I could probably hold ten of them in my palm)!
I just thought I would add some photos of my build. This is a BAL-SE. I was very careful with the ICs when soldering them since they are so freaking expensive. The small residual amounts of flux remaining are non-reactive rosin type, meaning it is 100% safe to leave on for centuries. The tiny 0805 chip parts are a quite a challenge - some of mine look a little drunk, but I assure you, they are rock solid in place and the sound obviously speaks for itself. Another high five to OPC!
Shown below in daylight on a ESD safe bag - taken with an ancient digital camera with a nice macro mode. Remember, this amp is tiny (like I could probably hold ten of them in my palm)!
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
nice work, pictures taken before the wonderous sounds sprang forth i take it? =P or you are commenting on the superbly black background?
also sek, i think i misunderstood your statement back there but i cant edit it, still not quite sure i follow, i think i was just reeling from your volume control schematic that shows 2x more parts (and of lower performance) than the amp its attenuating!
it seems totally against the theme of the amp, but i didnt mean it to be snarky with the cleverness thing. more flexible maybe, but its a bottleneck
anyway i'm just waiting for the epoxy to cure on the mini T connectors i'm lashing together for the low impedance battery umbilical, i'll grab some pics of the build on the bench tomorrow and some impressions
also sek, i think i misunderstood your statement back there but i cant edit it, still not quite sure i follow, i think i was just reeling from your volume control schematic that shows 2x more parts (and of lower performance) than the amp its attenuating!
it seems totally against the theme of the amp, but i didnt mean it to be snarky with the cleverness thing. more flexible maybe, but its a bottleneck
anyway i'm just waiting for the epoxy to cure on the mini T connectors i'm lashing together for the low impedance battery umbilical, i'll grab some pics of the build on the bench tomorrow and some impressions
Are you referring to my post? Just to clarify, what you were looking at in my schematic is an RFI filter. No reason to bash...
The schematic served the purpose of making clear that priorities and use cases can vary with each of us. It has nothing to do with my other point about volume control. Buffer and pot could of course be replaced with something else, like a relais ladder or a rotary switch.
I just wanted to make it a point that THE WIRE can also be built by not going with the flow, as being minimalist for the sake of being minimalist can be wrong, likewise. Say, for example, you use the amp for serious things, like, working with people in something that could be called professional audio. You have this amazing, minimalistic gear that looks and sounds all fancy, wired to some other gear (that you might not have control of). And then someone puts their cell phone into close proximity. Booom bzzr bzzr bzzr, credibility lost.
Wrong statement, and subjectivist on top. I can easily prove that an EMI filter improves performance (with regard to EMI). Can you prove your statement that it degrades performance (with regard to sound quality)? But I'm not here to argue.
You see, leaving out components can degrade performance, too. As long as there's an improvement, the added complexity is justified. You can't interface THE WIRE to absolutely anything, anywhere you go. But the EMI filter you see in above schematic (common mode choke, X2Y caps, ESD protection using TVS diodes) is such a tiny SMD circuit that it can be bypassed with a simple jumper on the PCB in case it is not required...
Yes, it's so small that I seriously think about reflow soldering it in my oven.
Considering thermal transfer of the LME49600 and all...
Cheers,
Sebastian.
sek, you are the one talking about magic devices. higher THD (the PGA) improves THD now? the filter is perfect and thus only effects the higher frequencies? the inductor is linear? this is a rhetorical post, because neither can possibly be true. lets get back on topic, you can argue with reason by PM if you must
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qusp, are you referring to my post again?
How do you come up with PGAs when looking at my schematic and reading my text?
I never considered you the kind of DIYer calling RFI filters magic devices. Or cell phones. There are scenarios where you better have your equipment ruggedized, depending on what you want to do. Just saying...
About getting back on topic, well, I was merely picking up the topics of pre-WIRE volume control and tinyness, when someone started to argue with me about some TI chips.
Cheers,
Sebastian.
PS: I got your PM, thanks.
How do you come up with PGAs when looking at my schematic and reading my text?
I never considered you the kind of DIYer calling RFI filters magic devices. Or cell phones. There are scenarios where you better have your equipment ruggedized, depending on what you want to do. Just saying...
About getting back on topic, well, I was merely picking up the topics of pre-WIRE volume control and tinyness, when someone started to argue with me about some TI chips.
Cheers,
Sebastian.
PS: I got your PM, thanks.
i took the pot/opamp on the output as a PGA, i'm actually not sure how you would represent the pga in a simplified schematic being a combined 4 channel attenuator, MCU and opamp, but if its just a couple of lower performance dual opamps and a pot, sorry for the misunderstanding, but my position stays the same as the 2211 is inferior as well. it seemed in theme with the schematic of too many parts for the job, if it isnt representing the pga, but instead just as it appears, why would you need the wire? given youde be getting a pcb made up for the attenuator, wouldnt you just put a couple of lme49600 on the output of the 'pot' and call it a day?
anyway lets just agree to disagree, you have a completely different preference for design than i do and we'll never agree and thats cool..thats audio
i'm surprised the wire appeals to you TBH
anyway lets just agree to disagree, you have a completely different preference for design than i do and we'll never agree and thats cool..thats audio
i'm surprised the wire appeals to you TBH
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Interesting projetc. Would love to read more about it and of course to see some photos!
Qusp's posts about digital volume control really got my attention, I always dismissed this atten method because in the old days there wasn't enough bit depth. I'm putting together this hifidino controlled WM8741 DAC and looked at the wolfson datasheet it mentions 32bit (unfortunately it is rather vague as far wether the WM8741 actually uses 32bit calculation with its attenuation.) But I think I will include a set of wire amps inside the DAC enclosure for a headphone output.
It looks like I will have 1 SE-SE pcb and 2x re-work PCB's. I vaguely remember some info on the Frankenwire with it operating as a a bal-bal but with more VRMS output capability, but I couldn't find the info in the big thread.
Is anyone building the unofficial Frankenwire and is it OK if we include discussion of it here ?
It looks like I will have 1 SE-SE pcb and 2x re-work PCB's. I vaguely remember some info on the Frankenwire with it operating as a a bal-bal but with more VRMS output capability, but I couldn't find the info in the big thread.
Is anyone building the unofficial Frankenwire and is it OK if we include discussion of it here ?
Need help. What value of potentiometer should i choose for The Wire SE-SE? I want to buy DACT 21 step 1% smd resistor attenuator and there are values: 10K, 20K, 50K, 100K, 250K. As I understood more resistance gives better control at low level of volume and low resistence like 10K gives better control at high volume. So maybe I should take something like 20K or 50K ? Suggestions are welcome.
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