Herve Deletraz (Mr. darTZeel) sent me an explaination of why we had some problems with battery power initially that i thought i would pass on to those interested.
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Herve's message;
"this is ONLY for the pre-serial machine you have:
The preamp is always drawing battery current, even when the preamp is switched off. So when you received it, maybe that the batteries were severely drawn out due to no AC connections for a while. Restoring the full charge would take several DAYS to recover, so the problem you had with DC issues: Batteries were extremely low, much lower than the regulation threshold, so DC appeared.
Having left the preamp hooked on AC enough time has restored batteries so now you don't have DC issue when in battery mode (except that you still must turn the volume down when changing input source).
When you talk about "switching in battery mode", I suppose that you remove either the AC cord (edit; yes i do exactly that) or the umbilical, since there is no real switch to do that.
When the preamp has enough charge (after several days, or even a week), the power led will eventually goes off when the preamp is off. As long as the power led is illuminated when the preamp is off, charging is not completed and the preamp doe not run in battery mode until unplugging AC cord.
When not using the preamp it is very important to plug it on the AC again, or batteries will be drawn out again. In case of non use (unplugged) for more than 1 day (or for shipping) it is strongly recommended opening it and unplugging the battery connectors inside, located at the middle of the preamp, on the bottom of the main PCB.
When the machine is in battery mode, you can still hear slight difference when the umbilical in plugged or not, even if the external power circuit is fully switched off. This is due to some residual coupling with AC mains, but the difference is marginal. (edit; this means it gets even better).
The preamp you have is also suffering from all software bugs, so the use is not the most convenient one you could expect... My own sample behaves as yours, but with full software fixes. Battery behavior remains the same, but after some days they were charged, and provided I do not listen for more than 6-8 hours a day, they are always charged for the next day... I mean that a "standard" user can perfectly live with a pre-serial - debugged - sample... :-)"
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Herve also sent me info on how the production (commercial) units will work that i thought would be of interest.
**************
"All the following for the coming commercial release:
The new release will NOT drain current when off, and the charging process will be much smarter: always battery mode when switched ON, always charging when switched OFF. If batteries will go low during playback it will switch to AC mode, but if you will switch it off, you won't need to wait for the full charge before benefiting for battery mode: if you leave it for 1-2 hours off, you will have 2-3 hours on battery mode at power on, and of course more if you leave it off longer. No memory effect on batteries guaranteed, whatever the charge state. When leaving the preamp always on you will cycle the batteries continuously (about 8 hours charging, 12 hours discharging) and the total span life will be around 3 years. When using the preamp "normally", say, with quite intensive listening 4 hours a day and 5/7, you can expect a life span of 5-10 years (the figure is no more precise at the moment since we have to complete our tests; we think it is closer to 10 years than 5).
As most parts of the preamp will NOT be energized when the preamp will be off, it will take about 20-30 minutes to sound good. There is little difference, since small devices are much faster at right temperature than power devices.
This time, there will be NO DIFFERENCE AT ALL in battery mode with AC/umbilical plug removed or not. We will add AC relays in the external power supply, so in battery mode these relays will be activated, opening the AC circuit, EXACTLY as if you would unplug the cord: doing so would not improve things further, as you cannot better switch off a bulb you already removed from the lamp... :-)
______________________________________________________________
As for the sound, both machines are completely identical, and there is not a single component or layout change about the signal path in both versions. Differences will be mainly addressing the battery behavior, removing some remaining small caveats in the volume control command, and also a - hopefully - less directional, more sensitive IR receiver."
************
i contemplated trying to explain the above myself but figured it would be better to just quote Herve's e-mail to me. however you describe it; the sound is miraculous.
**************
Herve's message;
"this is ONLY for the pre-serial machine you have:
The preamp is always drawing battery current, even when the preamp is switched off. So when you received it, maybe that the batteries were severely drawn out due to no AC connections for a while. Restoring the full charge would take several DAYS to recover, so the problem you had with DC issues: Batteries were extremely low, much lower than the regulation threshold, so DC appeared.
Having left the preamp hooked on AC enough time has restored batteries so now you don't have DC issue when in battery mode (except that you still must turn the volume down when changing input source).
When you talk about "switching in battery mode", I suppose that you remove either the AC cord (edit; yes i do exactly that) or the umbilical, since there is no real switch to do that.
When the preamp has enough charge (after several days, or even a week), the power led will eventually goes off when the preamp is off. As long as the power led is illuminated when the preamp is off, charging is not completed and the preamp doe not run in battery mode until unplugging AC cord.
When not using the preamp it is very important to plug it on the AC again, or batteries will be drawn out again. In case of non use (unplugged) for more than 1 day (or for shipping) it is strongly recommended opening it and unplugging the battery connectors inside, located at the middle of the preamp, on the bottom of the main PCB.
When the machine is in battery mode, you can still hear slight difference when the umbilical in plugged or not, even if the external power circuit is fully switched off. This is due to some residual coupling with AC mains, but the difference is marginal. (edit; this means it gets even better).
The preamp you have is also suffering from all software bugs, so the use is not the most convenient one you could expect... My own sample behaves as yours, but with full software fixes. Battery behavior remains the same, but after some days they were charged, and provided I do not listen for more than 6-8 hours a day, they are always charged for the next day... I mean that a "standard" user can perfectly live with a pre-serial - debugged - sample... :-)"
**************
Herve also sent me info on how the production (commercial) units will work that i thought would be of interest.
**************
"All the following for the coming commercial release:
The new release will NOT drain current when off, and the charging process will be much smarter: always battery mode when switched ON, always charging when switched OFF. If batteries will go low during playback it will switch to AC mode, but if you will switch it off, you won't need to wait for the full charge before benefiting for battery mode: if you leave it for 1-2 hours off, you will have 2-3 hours on battery mode at power on, and of course more if you leave it off longer. No memory effect on batteries guaranteed, whatever the charge state. When leaving the preamp always on you will cycle the batteries continuously (about 8 hours charging, 12 hours discharging) and the total span life will be around 3 years. When using the preamp "normally", say, with quite intensive listening 4 hours a day and 5/7, you can expect a life span of 5-10 years (the figure is no more precise at the moment since we have to complete our tests; we think it is closer to 10 years than 5).
As most parts of the preamp will NOT be energized when the preamp will be off, it will take about 20-30 minutes to sound good. There is little difference, since small devices are much faster at right temperature than power devices.
This time, there will be NO DIFFERENCE AT ALL in battery mode with AC/umbilical plug removed or not. We will add AC relays in the external power supply, so in battery mode these relays will be activated, opening the AC circuit, EXACTLY as if you would unplug the cord: doing so would not improve things further, as you cannot better switch off a bulb you already removed from the lamp... :-)
______________________________________________________________
As for the sound, both machines are completely identical, and there is not a single component or layout change about the signal path in both versions. Differences will be mainly addressing the battery behavior, removing some remaining small caveats in the volume control command, and also a - hopefully - less directional, more sensitive IR receiver."
************
i contemplated trying to explain the above myself but figured it would be better to just quote Herve's e-mail to me. however you describe it; the sound is miraculous.