I have an Alps 6 channel motorised pot after a DCX2496, perhaps that, or something similar, would be better? This is the issue, who in their right mind still only uses 2 channels? 🙂
Yes, but those are much more benign in perception plus they only appear with very non-mono signals. Mono content remains smack center at any time. IMO M/S should be used throughout the whole line level analog chain from DAC to power-amp inputs, it cleans up the soundstage stability big time.
[OT]
The speakers can actually be included in this, by using the simple trinaural rematrixing from two source to three output channels/speakers. Trinaural renders the soundstage much better than two speakers in that it produces a more stable sound field around the head. With two speakers, image collapses when you turn/move your head, with trinaural much less so, almost an experience like true wave field synthesis.
Trinaural matrix is simple and somewhat related to M/S:
Lout = L - R/2
Rout = R - L/2
C = (L+R)/2
[/OT]
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Ah understood. I'm currently digesting the Gerzon papers on stereo shuffling and realising that M/S has a lot going for it.
Trinaural I like the idea of but cannot implement it in my current house as there is a piano in the way.
Trinaural I like the idea of but cannot implement it in my current house as there is a piano in the way.
Jan Didden designed a very nice 6 channel volume board for the DCX DCX2496 active output mod & 6-channel vol control | Linear Audio NL. Something similar will hang off my miniDSP at some point when I send Jan some money.
Yep, Gerzon and Barton, with their "Trifield" matrixing, were geniuses. Trinaural is Trifield stripped down to the core and extremely easy to implement.
Yes, he gave me a link to that yesterday in the DCX thread..................
If using dsp, just use an optical encoder... There's lots of cheap, nice ones out there, with good "feel"...
Today's midFi discovery is Alfredo Campoli on Decca mono from 1954. The performance more than makes up for all the technical issues.
@Gpauk: What use is an optical encoder for me? I fail to see the link.
@Gpauk: What use is an optical encoder for me? I fail to see the link.
As usually it depends, but the Penny & Giles Chris719 mentioned are strong contenders. 25 years back they offered two different rotary faders (RF15 and the smaller brother RF11), the latter already very expensive (i had a quote in 1993 of 173 DM / pcs / lot 100) while the RF15 was 263 DM (same conditions).
Specified interchannel deviation was 0.5dB (+ or - ) from 0 to -60dB.
At that time they were still offering special selected ones down to ~0.1dB deviation (additional costs though).
Today the RF15 is still available (up to 8 channels) but i don´t know about their prices today. Their standard spec for matching accuracy is a bit higher today (+- 1dB - same range as above).
Beautiful construction, completely sealed and the famous honey pot feeling when operated.
In the more affordably range there once was a japanese pot callled "noble", dimensions very similar to the ALPS RK27, but 4 pins instead of 3, aluminium housing less sensitive to dust intrusion and every single one i measured with a matching accuracy of +-0.5dB (0 to -60dB).
Unforunately none of these offered a motorized version ......
Nah its a bit ornery to control*, which is why not many people have tried to DIY it. Jan is stubborn and doesn't like admitting defeat 🙂.
*For the DIY type. For those who do embedded control and love writing bit banging routines all day its easy.
*For the DIY type. For those who do embedded control and love writing bit banging routines all day its easy.
Here you go https://www.diyaudio.com/forums/construction-tips/315561-diy-pot-ganging-2.html#post5264528 😀 It's a fun thread 🙄
Nice looking switch Howie.
I am using the Alps RK27 motorized with great results on the commercial stuff. The QuantAssylum 401 tells me the tracking is very tight and no matter what the volume setting, I don't get more than 2-3 ppm distortion into 600 Ohms.
I've designed a compact 64 step relay based attenuator but need to assemble the PCB and write the code - too busy for now through.
I am using the Alps RK27 motorized with great results on the commercial stuff. The QuantAssylum 401 tells me the tracking is very tight and no matter what the volume setting, I don't get more than 2-3 ppm distortion into 600 Ohms.
I've designed a compact 64 step relay based attenuator but need to assemble the PCB and write the code - too busy for now through.
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Will you include a Balance Control function in this collection of relays? Balance control external to the volume control relays? No Balance control at all?
Balance appears to introduce uncomfortable tradeoffs involving latching vs nonlatching relays, 2xSPDT versus 1xDPDT relays, and perhaps more.
Perhaps I misunderstood, but if your audio is in the digital domain, then a rotary encoder read by the dsp is the perfect volume control - steps as small as you like, or related to speed of movement etc... Someone mentioned minidsp so I assumed digital domain...
Yes my miniDSP has digital volume control, but this has some problems not least no way of telling what the setting is!!!
Also: No balance control, potential loss of resolution etc.
It works but is it ideal?
Also: No balance control, potential loss of resolution etc.
It works but is it ideal?
I bought a Goldpoint stepped attenuator a while ago and it always seemed fine to me. Our ATE guys threw several 100 $35 Teledyne miniature RF relays in the bin and I have never raised the energy to use them in an attenuator.
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