[stingfan]

Excellent point.  So in my estimation, a key factory update for the P-9 would be, via software:  Resetting the digital-to-ALPS volume interface as follows:  100 steps of **equal** gain all the way around the ALPS dial should do the trick, with 0 being silent and 100 = 100% gain.   Agree?

[nuforce-casey]

The Alps port only comes with Log-scale Audio steps only.  Alps does not make a linear pot (useful in adjusting voltage) with a motor control.

The following chart shows the various difference scales used in potentiometer:



With Audio-taper potentiometer, 50% half-way point actually is 1/10 of the full wiper range (i.e. total resistance), i.e. for a 10k pot, 50% is 1k.
 
Supply Voltage= 1.0 Volts
Pot's Total Resistance = 10kOhms
Position (0-100%)=50%
Wiper Voltage (Linear)=0.5Volts
Wiper Voltage (Logarithmic)=0.11Volts

Further reading:  http://tangentsoft.net/audio/atten.html

[stingfan]

Yes, thanks for your chart etc.  But you have misunderstood me. The Alps POT is NOT in question here.  Using the Alps dial manually works great, and I'm fine with its log based steps.   Lets be clear there are two "steps" we are talking about here:  Alps steps and your digital volume controller display steps.  Two very different things.

The problem is in the P-9's electronic volume controller that interfaces with, and controls the Alps pot motor for motorized (not manual, hand turned) volume adjustment.  When # clicks = 1 and display = 1, you send a signal to the Alps motor to rotate the POT certain distance around the dial.  Let's say for display volume step 1 it rotates the POT roughly 12 degrees on the dial.  You can easily tell the motor not to travel such a long distance for display = 1.  This has nothing to do with the Alps.  Because I can manual dial/adjust the Alps dial in much smaller increments than your controller is moving it, and get much more precise volume adjustments, which means the solution to this resides in tuning your digital volume controller.  For example:  reprogram the digital volume controller display=1 to equate to moving the Alps motor only say 6 degrees around the dial instead of 12.  This very different from the actual Alps steps which are fine when manual dialing volume with the Alps.  The problem is not the Alps, nor its own steps itself.  Does everyone understand this now? 

[beachbum]

sorry to hear your volume control problems stingfan, and knowing the nuforce gang i am sure they will work it out, are you getting much music time. whats your thoughts on the audio secton of the p-9?

[stingfan]

Oh for sure.  I think part of the frustration simply stems from trying to explain a complex problem in email or a forum.   This one is particularly hard, given both the price and the top billing for the P-9.  Mostly because I am getting the impression that these 'artifacts' ma As there are a zillion Alps-based pre-amps out there, and they all let the remote control directly control the Alps, making fluid, limitless volume control. Why would someone pay $3k to have such imprecise control over volume?

Hardly any air time with the P-9, other than when I switched back to the P-8 (with zero problems with my XLRs) did I hear a noticeable downgrade in resolution, clarity, and detail...I was not even formally paying attention to the music when this difference practically hit me over the head.  I decided it would be harder to judge it fairly until my 4 other issues are addressed.  Its deliciately placed back in the box, and going to Milpitas tomorrow. Hopefully it doesn't get scratched in the repair shop. I'm very particular about this.  My old Ref 9's probably look better than they did when I bought them. 

[beachbum]

stingfan call nuforce by phone, they have always been able to answer my questions,

[rustydoglim]

We lowered the gain on P-9 for Stinfan.  The noise that he reported is always there in his system. I beleive Casey worked with him to get rid of the noise (not related to Nuforce equipment).
As the alps motor turns, there is a very small (I have to put my ear to the tweeter to hear the very faint sound) noise but it becomes dead quiet when it stops.
Anyway, the P-9 is back to Stinfan and we'll hear from him next week.  We did not find any fault with his P-9.

Using the digital volume to control the Alps motor is tough to make it perfect (ie as smooth as manually turning the Alps pot). We understand Stinfan's point.  I guess we're asking customer to get use to it as a compromise to the superior sound of P-9.

[stingfan]

My interactions, test sessions, and discussions with Casey were long, thorough, and quite enjoyable.  Definitely upholding the Nuforce reputation of their commitment to quality, performance, and service.  We learned many things through our exchange.  Yes, some minor things that I will have to live with as Jason points out, in exchange for the best sound. I have 101db sensitive speakers, far more efficient that the S-9's used to test my P-9 back at Nuforce.  So indeed my speakers will be far more revealing of any residual noise or other artifacts.   
 
Indeed together with Nuforce, we found some removable noise coming from the HDMI of a couple of my sources, but it was only with the P-8 in the system thus far, while P-9 at their lab. We have not yet concluded the noise was/is solely from the sources, but we sure hope this is indeed the case!   

Jason left out one very fascinating fact I learned from Casey regarding the non-uniformity of the *motorized* movement of the Alps pot.  The reason the motorized dial travels so far for the first 1-10 steps displayed on the P-9's digital controller display and then much less so for say, steps 30-50 has to do with the resistance on the Alps.  The best sound, as Casey explains, comes when there is minimal resistance on the signal.  The resistance on the Alps goes down as you turn up the dial, or when the dial is 'opened' up all the way.  So apparently the ideal minimal resistance position, or "sweet spot" for the dial is between 12-3pm (closer to 3pm) To achieve this,  the *digital* steps are set to manage the motorized alps movement scale in such a way as to get the "ideal" listening volumes to align with the dial in the 12-3pm.  By universally lowering my gain in some special way (different than described earlier in this thread)  we enable my system to get to 3pm on the dial without shattering the windows in my loft.  Should be quite interesting to see the results.  Unfortunately, I have to fly to east coast for mtgs all next week, so I won't be able to test until Sunday of next week.  Stay tuned!!

Final Disclaimer:

I am a product designer by profession, as such, my design-related and usability issues with the system stem from my ruthless attention to detail that often goes well beyond most prosumers, and even audiophiles in this department.  This explains why you'll often see quite a bit of colorful feedback in this regard, in my postings here.

I really appreciate Nuforce's approachability and time commitment to one small customer such as myself.  It is what makes the different between really good companies and really great companies.  More on this story to follow!