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Post by matt on Dec 18, 2010 1:34:50 GMT -5
... No change in the specs or sound quality. Just a different taper on the volume control. So then you are still just modifying the resistive ladder on the analog output? (i.e. not compressing the digital bits to pick up the resolution on the low end) I am currently using one of my XDA-1's with a pair of near field monitors. I bought the TC Electronic Level Pilot as a workaround, although now that I have placed the level pilot near my keyboard, I much prefer to use it over the digital control. It is a joy to use. I use the digital control to adjust the sensitivity of the level pilot. So I will not be RMA'ing my existing XDA-1s anytime soon. I just placed a reservation for 2 more XDA-1s. These will be used for speakers (as opposed to near-field monitors). Since I will be using the remote more, perceived volume control will be more important. I take it that I should call on Monday to have them reprogram the new ones to the log volume control prior to shipment. |
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MikeWI
Emo VIPs 
DC-1, ERC-1, USP-1, UPA-2, Sub 10, Emotiva 4S
Posts: 346
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Post by MikeWI on Dec 18, 2010 7:38:51 GMT -5
Will it be clear in online ordering which volume program is included?
Mike
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Post by matt on Dec 18, 2010 15:59:56 GMT -5
Will it be clear in online ordering which volume program is included? That would be the smart thing to do. Otherwise, Emotiva will have some people ordering the XDA-1 and sending it right back after they experience the volume control. I am guessing that the existing linear volume control "directly" modifies the resistive ladder and might be more ideal when a pre amp or passive volume control is used. |
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Post by Chuck Elliot on Dec 18, 2010 21:20:37 GMT -5
Will it be clear in online ordering which volume program is included? That would be the smart thing to do. Otherwise, Emotiva will have some people ordering the XDA-1 and sending it right back after they experience the volume control. I am guessing that the existing linear volume control "directly" modifies the resistive ladder and might be more ideal when a pre amp or passive volume control is used. I may be missing something, it wouldn't be the first time, and I ask the following with all due respect. Under what circumstances, in your opinion, would a linear taper volume control be preferable to a log taper. And, why? I can think of none! |
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Post by matt on Dec 19, 2010 17:57:53 GMT -5
Under what circumstances, in your opinion, would a linear taper volume control be preferable to a log taper. And, why? I can think of none! I would agree with you and say none, unless the log taper is implemented by using something other than the resistive ladder on the analog output, such as compressing the dynamic range of the digital signal. Even then, it might be fine if the analog resistive ladder did most of the work in conjunction with the digital alteration. Of course, this is speculation. I would like to hear about the actual implementation. I would not be surprised if they were able to add additional volume adjustment for the low end using the existing resistive ladder with a firmware update, but I do not know enough about it to know if that is possible. |
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Post by Chuck Elliot on Dec 19, 2010 18:44:03 GMT -5
Under what circumstances, in your opinion, would a linear taper volume control be preferable to a log taper. And, why? I can think of none! I would agree with you and say none, unless the log taper is implemented by using something other than the resistive ladder on the analog output, such as compressing the dynamic range of the digital signal. Even then, it might be fine if the analog resistive ladder did most of the work in conjunction with the digital alteration. Of course, this is speculation. I would like to hear about the actual implementation. I would not be surprised if they were able to add additional volume adjustment for the low end using the existing resistive ladder with a firmware update, but I do not know enough about it to know if that is possible. There is a 14bit register in the AD1955(The DAC). It can hold any number between 0-16383. 0 is off; 16383 is fully on. The %voltage out(gain) at any register value is n/16383. A gain of 1 (16383/16383) is fully on; gain = 0 (0/16383) is fully off. There is either a table or algorithm in the xda-1 that sets this register value such that n = a function of the volume control (0-80). This gain setting done by the above is analog and has no effect on SQ regardless of where it is set. This is not a DSP! |
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Post by sharkman on Dec 19, 2010 22:14:09 GMT -5
Something that I'm wondering about yet doesn't deserve its own thread. The XDA has trigger in and trigger out. Has anyone discovered if the trigger out can control another component by itself, or does it need 12 volts on the trigger input first.
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Post by BigV10 on Dec 19, 2010 22:29:07 GMT -5
I use the XDA-1 trigger out to turn on my UPA-2. Works fine and should also work fine relaying the signal.
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Post by mlrf18 on Dec 19, 2010 22:34:12 GMT -5
Yes it will. I use it to turn on my RPC-120 to power my amps.
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Post by sharkman on Dec 20, 2010 0:05:00 GMT -5
Sweet, thanks guys.
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Post by bobbyt on Dec 20, 2010 21:08:58 GMT -5
Under what circumstances, in your opinion, would a linear taper volume control be preferable to a log taper. And, why? I can think of none! Here's my best guess: under ideal listening circumstances, in a purpose-built room with no concern for sleeping family, neighbors, etc. I could be way off here, but I'm thinking maybe Emotiva was doing their designing & testing in a dedicated room and spent most of their time either at reference level or fairly close to it. So the super-fine adjustment from say 50-80 were probably very nice to have. But if they weren't doing casual background or nighttime listening, and didn't have families or neighbors to be concerned about, they could've overlooked the coarser control way down low. What I'm wondering is how the volume scale change works--I thought the volume levels were discrete resistors, like how those passive attenuators work. Isn't that what those internal pictures of the XDA were showing? |
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Post by jannick on Dec 21, 2010 5:41:26 GMT -5
Afaik the resistive ladder is inside the DAC chip, and the groups of resistors you see in the internal shots are the output stages. With XPA-1's 32db gain and the 89 db sensitivity of the ERT 8.3, they would have to be listening to some pretty serious volume levels before they use the top steps of the dac  I'm at 29db gain / 85 db sensitivity, and volume step 10 is absolute max I can stand. |
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rabi
Seeker Of Truth
Posts: 0
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Post by rabi on Dec 28, 2010 11:59:07 GMT -5
I have maggie smg's, upa-1's and xda-1 fed from IMAC digital out and concur with others in reference to the low end of the volume scale. Though I can play mine in the mid to high 30's low 40 without exceeding my 12 x 14 room pleasure center. Maggies are 86db.
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I'm at 29db gain / 85 db sensitivity, and volume step 10 is absolute max I can stand. 