Re: STX-II *tonal characteristics*?

On Fri, 19 Nov 2021 15:59:34 -0500, bad sector
<forgetski@postit_INVALID_.gov> wrote:

>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!
>
>
I was helping another tech move a telephone system. The customer had
time tones go off in the factory and the system couldn't do it without
help. Went to Radio Shack and got some parts to build something. The
tech could not stop talking about it for months. Score ten for Ham
Radio and computers.


KenW