Autoranger for soundcards

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Chamberman

Member
Joined 2001
jan.didden said:
I have modified the switching logic so that now the maximum attenuation is -48dB. There will be two software-controlled settings for the nominal output levels to the soundcard input: 1V (0dBV) and -8dBV (which is around 400mV).

That means that with the maximum input level of 100VRMS, the output to the sound card will be either 1VRMS or 0.4VRMS.

Jan
Click to expand...

I'm happy to hear this, my QA400 seems to give its optimal noise measurements in the range of 350mv - 450mv input.
 
jan.didden

jan.didden

AX tech editor
Joined 2002
linearaudio.net
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soongsc said:
Looks interesting, I would love a more flexible output level instead of being fixed to 1Vrms. Is the output the same for balanced and single ended?


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Click to expand...

The final version will have switchable output levels of either 1V or 0.4V. Software switchable from the front panel.
Bal and SE outputs are the same.

Jan
 
M

MarkS

Member
Joined 2004
I use one of these stereo microscopes running with x10 eye pieces and a x1 base lens for smd work. Gives a nice wide field of view with a good distance between base lens and pcb.

I deliberately chose the goose neck led light as its adjustment helps avoid glare off the solder resist. Additionally, the light psu in the base makes it possible to swing the beam backwards, so to speak, without any danger of toppling over to give reach over very large boards...

BM1 longarm

Hth.
 
E

ergo

Member
Joined 2001
It's hard to be a DIY nut. The RTX6001 GB that JensH is running gives a real itch to apply for one too.... but then I keep telling myself that Jan's Autoranger with the RME UCX that I bought some 6 months ago will also take me a long way there and I do not need another thing on top of those.
I just hope the RTX6001 success will not take too many Autoranger customers away to put that project at risk.
 
jan.didden

jan.didden

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Joined 2002
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trobbins said:
Jan, what would need to be repaired for an over-voltaged input, and could that mean a PCB replacement?
Would there be a different outcome for AC versus DC over-voltaged?
Ta, Tim
Click to expand...

Not much actually; just a resistor and possibly some clamp diodes. Which I thoughtfully implemented as through-hole ;)
But overvoltage would not be an issue up to several 100 volts AC or DC, so unless you would hang the AR directly on a tube anode, chances of problems are pretty small. Even then, 300 or 400V would cause no damage.

Jan
 
L

Lbud4

Member
Joined 2013
vacuphile said:
Ergo,

I think the combination of the Autoranger together with the RTX6001 would be perfect. They are not at all mutually exclusive; both products imo reinforce each other.

Vac
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The RTX6001 has ranging built in. It is not auto ranging at this point but could be made to be through access to its uC over its USB interface. Putting an autoranger in front of the RTX6001 will degrade the performance of the device by how much is the question.
 
jan.didden

jan.didden

AX tech editor
Joined 2002
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Not wanting to brag, but degradation is unlikely. My dScope series III measures the same, with or without the autoranger.
I think there is space for both. I did sign up for an RTX myself. If you have a good soundcard, an autoranger gives you a low cost upgrade to similar performance. We don´t all drive the same car either :cool:

Jan
 
soongsc

soongsc

Member
Joined 2005
1audio said:
Can you be a little more clear what you mean by "full range"? The AR has a wider response range than any sound card i know of.
Click to expand...

I think I should use the term "full scale". Babyface Pro takes 10Vrms full scale, if I just give it 1V, seems to me I am only using a very small portion of the input unnecessarily. Other single ended sound cards I have are closer to 1V. It seems quite small for balanced Interface. I am wondering what voltage levels other cards use though.


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anatech

anatech

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Joined 2004
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Hi Jan,
Ahhh, wrong kind of toys my friend! :eek:

I do think that both could co-exist on the bench, but I doubt the would be connected together. Yours suits sound cards very, very well. They would make the perfect front end for a couple sound cards I bought a few years ago for this purpose.

-Chris
 
1

1audio

Member
Joined 2004
Paid Member
We were looking at that. I have several pro cards that take +4 levels and can handle 6V typically. What I have discovered and others have verified is that you get better performance at -15 to -20 dBFS in. The converters work better at those levels. Using high res FFT's make seeing into the noise easy. Remember you aren't recording through this interface, just measuring. And its easier to fix than a fried input on the babyface.


What ADC is in the Babyface? I couldn't find info online.
 
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