[mikebarney]

I'm having trouble understanding the indicators of the balance and impedance adjustment functions with only a single display.  The documentation is pretty clear for 2 displays, but not for a single.  The balance control appears to work okay with the Apple remote, but I don't understand what the display is indicating (left or right or alternating?) Can anyone provide some more info on how the single display works in those 2 modes?
Thanks,
Mike

[tortugaranger]

I'm having trouble understanding the indicators of the balance and impedance adjustment functions with only a single display.  The documentation is pretty clear for 2 displays, but not for a single.  The balance control appears to work okay with the Apple remote, but I don't understand what the display is indicating (left or right or alternating?) Can anyone provide some more info on how the single display works in those 2 modes?
Thanks,
Mike

Hi Mike,

The short but not very satisfying answer is running with a single display - although you can do it - leaves you running half blind on most of the adjustment modes and on auto-calibration of the LDRs.

When adjusting balance, the left/right displays diverge  from each other as volume balance swings left or right. With a single display - which only shows the right channel - you only see a change when the balance is skewed to the right.

In impedance adjust mode, the left display shows the impedance setting number (1-5) while the right shows the impedance level (1k-99k) for each impedance setting number.

To date, I've stopped short of insisting people buy dual displays or no displays all but perhaps it's time to rethink that. An alternative I've been considering is to modify the firmware to optionally operate mode-limited with no displays and only an LED indicator. While mode-limited, impedance adjustment mode, brightness adjustment mode, and max volume upon input change mode would all be inhibited. You could change volume, adjust balance, and change input only. The challenge with that is there's no obvious way to tell the V2.1 board to operate in such a mode. It really needs a mode jumper input.

In your case the best solution is just get the second display which is only $39 plus shipping.

[mikebarney]

Morten-
Thanks for your response (just not what I was hoping for!).
Unfortunately, adding a second display is problematic in my case.  My preamp layout (photos and description in link below) is built around the single display and to add another would require significant revisions to the chassis and a new faceplate, so thats probably not going to happen.
I chose a single display because 99% of the time, my preamp plays with the balance centered, so the two displays would show exactly the same thing, which I thought seemed redundant. 
I've lived with the 20K impedance level without playing around with the impact of changing the impedance, until I tried recently and discovered I basically couldn't use that feature at all. 
I have run the auto-calibration, but since I only need to see it shut down when its done, no problem there.
Anyhow, thanks for your help.
Mike
http://www.audiocircle.com/index.php?topic=135403.0

[mikebarney]

Morten-
One follow-up question:
I recall when I first built my preamp, on power-up it displayed the initial settings, including, firmware revision number, as a series of numbers on my single display.  Might it make sense, given the ease-of-use issues associated with a single display, to roll back to an earlier firmware release? 
I didn't see the earlier firmware downloads on the website, are they available if I want to experiment?
Thanks again for your help.
Mike

[tortugaranger]

Morten-
One follow-up question:
I recall when I first built my preamp, on power-up it displayed the initial settings, including, firmware revision number, as a series of numbers on my single display.  Might it make sense, given the ease-of-use issues associated with a single display, to roll back to an earlier firmware release? 
I didn't see the earlier firmware downloads on the website, are they available if I want to experiment?
Thanks again for your help.
Mike

Apologies for the slow response. Just noticed this was an open question.

Barring some serious firmware update problem I am loathe to leave earlier firmware versions available. Most of the updates have involved correcting a bug(s) and to a much lesser extent the addition/change of a feature.

One approach you might want to consider is leave your preamp as-is with a single display module which for most day to day use is adequate. But, add a connecting ribbon cable from the single display of sufficient length where you can access that cable perhaps through a hatch/opening in the bottom on the unit. That way those few times when you need dual displays you just temporarily plug in the additional module and when done detach it and put it away. Not the most elegant solution but gets the job done.

Best,
Morten