Re: STX-II *tonal characteristics*?

On 11/19/21 1:37 PM, Paul wrote:
> On 11/19/2021 12:22 PM, bad sector wrote:
>> http://dlcdnet.asus.com/pub/ASUS/Audio_Card/Essence_STX_II/E9122_Essence_STX_II_User_Manual.pdf
>>
>>
>>
>> 
I bought
>> this card like in another life because the Crosshair mobo
>> 
>> (also bought in another life) onboard 1/8" audio connectors aren't 
>> worth a shit (continuous crackling and things) making music work 
>> IMPOSSIBLE. This card has the 1/4" jacks as well!!! Going through 
>> my things I just found the bundled pair of small pliers and these
>> 3 chips. Very nice idea for the pliers, maybe other makers could 
>> start bundling other computer-handy tools, bits-&-pieces, cpu-paste
>> and stuff :-))
>> 
>> BUT...
>> 
>> p-11 says the (supplied) 3 chips will "change the tonal 
>> characteristics"
>> 
>> without so much as giving a hint as to in what way, something one
>> 
>> would want to know BEFOREHAND! Are all manufacturers this freakin'
>> 
>> stupid?
> 
> Some commercial DAC chips, have high impedance outputs. Like one
> megohm to ten megohms. This means for the next circuit in
> 
> line in the chain, they have no "driving power". An opamp with
> 
> FET inputs and 10^12 input impedance, helps quell any audio rolloff.
> 
> ---- 1 megohm ---+-----> instrumentation amp ---> and so on
> 
> | unity gain follower
> 
> Cin
> 
> |
> 
> GND
> 
> When you substitute a 741 in the circuit, it sounds like a phone 
> booth on the output. All the high frequencies disappear.
> 
> 
> At a guess, the "tonal characteristic" is "low pass filter".

that one I don't need, actually this card is more than what I do
need except for the reliable 1/4" jacks which are a must 
until the minis get totally redesigned with many sprung 
contacts that cnnot fatigue.


> As a result of this, at least a bit of care is required in vetting 
> amps to shove in the hole :-) Don't be shoving
> the one volt item in there, or there will be magic smoke. The 
> sockets presented, will have no armament to protect
> from catastrophe. You have to know what you're doing, and the damn 
> documentation should explain stuff like this if the intent is for
> the user to be running off to Radio Shack for Opamps.
> 
> When I was in school, one afternoon I had a lab, and it had to do 
> with high frequency rolloff. And we were given
> a 741 each, to play with. So what I did, is left the lab and ran 
> across the street to the Radio Shack, and got a CMOS amp with 6MHz 
> gain bandwidth, and I did my lab with that :-) That's why I tell 
> these little jokes about Radio Shack, because I've actually done
> that in a real world situation (play the part of an opamp snob :-)
> ).

:-)

Thank you, I'm very happy to just leave as was, keeping the nice little pliers!