I know.
I just have not gotten around to it, been busy with real life stuff(christmas, planning new years eve, sleeping....).
But you are not forgotten, just give me a few days(maybe until Friday at the latest) if it is alright with you.
Hello,
Thanks for sharing your great work here!
How does it work that your attenuator is click free? I have heard similar attenuators and they always click...
Is the new small Omron G6K relay better than the older and larger ones?
How does it sound
Greetings,
Udo
The relays still make a click when you then them on/off, that is unavoidable with any kind of mechanical relay. So when switching volume you will hear a lot of clicking but that is just a result of using mechanical relays.
What I mean when I say pop and click free is that there are no popping or clicking sounds in the output when you switch volume.*
*However due to the fact that it is not possible to implement zero-crossing detection with mechanical realys, you will at times hear some very small pops in the sound and when I say small I do mean small. This is unavoidable and ALL, and I do mean ALL R-2R relay volume controllers on the market has this small issue.
In the end what matters is the sound when you are not changing the volume level and there this circuit really delivers.
Clear, detailed, distortion free, noise free, with almost perfect channel matching(maximum of 0.08dB difference between left and right channels) all the way from maximum to zero attenuation. So listening late at night with the volume turned down still gets you better that 0.08dB channel matching.
A R-2R attenuator really is the ultimate way to make a volume controller.
The current version is a 7-bit R-2R attenuator with 128, 0.65 dB steps for a maximum attenuation of -82dB but this means that the volume can never be muted 100%. -82dB should be quiet enough for most people but I am considering making a different version of my attenuator.
This would "only" be a 6-bit R-2R attenuator with 64, 1dB steps for a total attenuation of -64dB, however it will include a relay that disconnects the signal completely when hitting -64dB, giving the attenuator a true mute function when the volume is turned all the way down.
PCB size will be the same as the current version, since the seventh relay from the current version will be used as a mute relay.
If and when this would be available is hard to say, something like 6 to 12 months from now and that is IF I decide to go ahead with it. Which depends on if I want to build it for my own use.
This would "only" be a 6-bit R-2R attenuator with 64, 1dB steps for a total attenuation of -64dB, however it will include a relay that disconnects the signal completely when hitting -64dB, giving the attenuator a true mute function when the volume is turned all the way down.
PCB size will be the same as the current version, since the seventh relay from the current version will be used as a mute relay.
If and when this would be available is hard to say, something like 6 to 12 months from now and that is IF I decide to go ahead with it. Which depends on if I want to build it for my own use.
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Hi,
I'm working on my own implementation of R-2R attenuator http://www.diyaudio.com/forums/analog-line-level/267437-r-2r-attenuator-pcb-layout-question.html. I've been watching your thread with a lot of interest and I really like your approach.
Now you made me curious why would you reduce the number of attenuator steps and increase the step size? I can understand the reason to have less relays switching, but do you expect a significant difference between 6 and 7 bit implementation?
Thanks,
Oleg Sh.
I'm working on my own implementation of R-2R attenuator http://www.diyaudio.com/forums/analog-line-level/267437-r-2r-attenuator-pcb-layout-question.html. I've been watching your thread with a lot of interest and I really like your approach.
Now you made me curious why would you reduce the number of attenuator steps and increase the step size? I can understand the reason to have less relays switching, but do you expect a significant difference between 6 and 7 bit implementation?
Thanks,
Oleg Sh.
Thanks Andrew T,
I personally have no real experience with stepped attenuators but decided to have one for my system. On the one hand smoother attenuation feels right, on the other hand... I just checked how many volume control steps my computer implements... It is only 16 (+1 step to mute). So it is only 4 bit for attenuation and I must admit it is sufficient for most of my needs... It makes me thinking... I haven't made my boards yet and now I probably have to decide if I still want 7 bit...
By the way, what is "very quiet" in db?
Thanks,
Oleg Sh.
I personally have no real experience with stepped attenuators but decided to have one for my system. On the one hand smoother attenuation feels right, on the other hand... I just checked how many volume control steps my computer implements... It is only 16 (+1 step to mute). So it is only 4 bit for attenuation and I must admit it is sufficient for most of my needs... It makes me thinking... I haven't made my boards yet and now I probably have to decide if I still want 7 bit...
By the way, what is "very quiet" in db?
Thanks,
Oleg Sh.
if too loud = no attenuation, then the others become (very approximately)
loud = -6dB
normal = -12dB
quiet = -18dB
very quiet = -24dB (i.e. the absolute maximum output from the attenuator is 24dB BELOW the level that will clip the power amplifier).
This gives an average listening level ~ 40dB below clipping. 50W amplifier @ -40dB ref clipping will measure ~ 200mVac
Add on another couple of steps if you want even lower.
7steps @ 6dB/step gives -0dB to -36dB using a 3 relay attenuator.
This is where the Aikido comes in at. It has 6 steps that are coarse. and 6 fine steps for balance and fine adjustment.
loud = -6dB
normal = -12dB
quiet = -18dB
very quiet = -24dB (i.e. the absolute maximum output from the attenuator is 24dB BELOW the level that will clip the power amplifier).
This gives an average listening level ~ 40dB below clipping. 50W amplifier @ -40dB ref clipping will measure ~ 200mVac
Add on another couple of steps if you want even lower.
7steps @ 6dB/step gives -0dB to -36dB using a 3 relay attenuator.
This is where the Aikido comes in at. It has 6 steps that are coarse. and 6 fine steps for balance and fine adjustment.
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I have been thinking about it for some time now and I realised that 64, 1dB steps are more than enough, it gives me enough maximum attenuation and a 1dB stepsize is more than adequate. On top of that, it also means that the 7th relay can be used as a true mute when the volume attenuator reaches maximum attenuation.
But it is not somthing I am actively working on at the moment.
Is it possible to configure a setup for balanced (quad) attenuator? My preamp is fully balanced from input to output.
Using a dual(stereo) potentiometer should do the trick. You can't hook up 2 boards to the same single(mono) potentiometer.
But then you have to make sure that each channel in the dual potentiometer are closely matched so you get the same volume level from each board. Otherwise the excellent channel matching, at all volume levels, of my design will be lost.
So it is not really designed for balanced use, but it could be done.
But then you have to make sure that each channel in the dual potentiometer are closely matched so you get the same volume level from each board. Otherwise the excellent channel matching, at all volume levels, of my design will be lost.
So it is not really designed for balanced use, but it could be done.
Hi Neutrality, I like this design, I'm realy looking foward to the V2 of attenuator.
I meanwhile have the attenuator up and running. Currently there's a multiturn 10k lin wirewound pot installed for level control, which works fine for now. The supply voltage is taken from the 7812 reg on the DCB1 board.
Compared to the Alps blue velvet pot that I was using before, everything sounds tidier with the relay attenuator, and to my ears the bass has tightened up quite a bit. I'm very satisfied, thanks for having made your project available Neutrality!
Compared to the Alps blue velvet pot that I was using before, everything sounds tidier with the relay attenuator, and to my ears the bass has tightened up quite a bit. I'm very satisfied, thanks for having made your project available Neutrality!
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