Wadia S7i direct to amp

i'll say this again: don't take my word for it, READ THE WADIA WHITEPAPERS and draw your own conclusions. wadia has several whitepapers posted on their website that anyone can download and read.

OK, I see that I am right & you are also right - after upsampling (marketing verbage used by Wadia is "resolution enhancement") the word length is 24 bits (which is what I wrote) & then, after processing by DigiMaster algo, they chuck the least 2 significant bits & reduce the rez to 21/22 bits (which is what you wrote).

On a side note - I think all of us would be better of if you dropped your high-handedness altogether. You might have a good reason to attain your attitude but realize that you are on a PUBLIC forum where all sorts come to visit & discuss. If you feel compelled to share your knowledge & uplift the "ignorant" masses here do it with an attitude of a school teacher - you'll be appreciated much more. Just my suggestion to you being a long-term member here.

however, where it can make a difference is that you can lose resolution through the process or digital attenuation. the source material from a redbook cd has 16 bits of digital resolution. the wadia operates with 21 bits of digital resolution.

Paperw8, I'm pretty sure that the Wadia resolution is 24 bits (& not 21 bits) after it upsamples.

that's why you don't start losing significant bits (from the 16-bit input stream recovered from the cd) until you hit a digital output level of about 65 (out of 100). each step in the digital output level knocks off about 0.5dB, so by the time you get to 65, you are down about 18dB, which effectively reduces the signal by a factor of about 64; i.e. the signal is about 64 times weaker in comparison to the unattenuated digital signal....

yes, Paperw8, thanks for taking the time to explain this to me but I already understand the concepts of DSP.
I agree that (100-65)*0.5 = 17.5dB, which you are rounding up to 18dB. I seem to have 1 issue in your calculations - how did you arrive at 18dB being an attenuation factor of 64??
it's a voltage attenuation of 18dB i.e. 20log10(x)=18dB. So, what should x be to get 18dB?

the digital preamplifier is operating on voltage (and not power), so 3dB is a halving of voltage level.

wrong! every 6dB (i.e. every 12 steps) is halving of the voltage amplitude. You correctly wrote that the digital amp works in the voltage domain & not the power domain but you did not understand that concept fully.
Did you do a sanity check to see if every 6 counts starting from 100 down to 0 would yield exactly 50dB of amplitude control before you wrote you prev post?

We have 100 steps with each step giving us 0.5dB => 50dB of voltage control.
What is 50dB in linear/numeric? 316.22.
So, we can attenuate the digital music signal by a factor of 316.22 using the DSP.
setting 100 = full scale signal amplitude
setting 88 = 1/2 full scale
setting 76 = 1/4 FS
setting 64 = 1/8 FS
setting 52 = 1/16 FS
setting 40 = 1/32 FS
setting 28 = 1/64 FS
setting 16 = 1/128 FS
setting 04 = 1/256 FS
setting 00 = 1/307.175 FS

& 20log10(1/307.175) = -49.75dB, which I'll round off to -50dB, which is exactly the amplitude control range of the digital preamp.

so, a 3dB reduction in voltage corresponds to a 6dB reduction in power.

wrong! a 3dB reduction in POWER corresponds to a 6dB reduction in VOLTAGE.

i took a look at the wadia manual, and i think that there is an error in the manual.

I had a good laugh at this one!!! :-)

it appears that there is actually a 1dB change in volume for each step in the digital volume control.

Oh, is it??
so, now we have 100 steps & 100dB of volume control??
You better call up Wadia & tell them that they actually have 100dB of volume control & not 50dB.....

A 3db reduction in power corresponds to a 3db reduction in voltage, for a given impedance. A 6db reduction in power corresponds to a 6db reduction in voltage, for a given impedance.

Almarg, you are correct. Guys, I stand corrected on this.

P1 = V1^2/R1 & P2 = V2^2/R2
P2 = 0.5*P1 & R1 = R2 = R because we are looking at the power reduction at the same location hence impedance at that point remains unchanged.
So, if we take the ratios: P2/P1 = 0.5 = (V2^2/R)/(V2^2/R)
or V2^2/V1^2 = 0.5
or V2/V1 = sqrt(0.5) = 0.707

I should have done this calc before I wrote my post - my bad. ;-O
Yeah, so if we want half the amplitude, we will find it at 6dB lower power where we'll have 6dB reduction in ampl as well. So, my earlier post on 12/04/10 is correct where I showed the digital volume versus full-scale amplitude - you will get 1/2 the voltage amplitude at setting 88 & at setting 65, you will get approx 1/8 full-scale meaning that you will lose 3 bits. If you start from 21-bits, you'll be down to 18-bits at digital volume setting 65. You will lose 6 bits at digital volume setting 28.

Dennis_the_menace, I apologize for hijacking your thread. If it is any solace to you, I think, that you already got your answer to your question (which is depends on the quality of your preamp & on your personal preferences -> cannot remember right now which members wrote these 2 apt replies).