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adriel~2

modded soundcard for better sound

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Hello. I've figured that as long as I use a computer for games and movies, I might as well bring its analog sound output quality closer to that of the cd player that is my music reference and A/B switching comparator.

The soundcard modded today was the M-audio Audiophile 2496. Although it has some useful features such as S/PDIF i/o and ASIO for synths, its analog output quality has faults.* A good external DAC would help, but I decided to go cheap for now and just mod the soundcard directly.

I installed the Burr-Brown OPA2604 as a compatible drop-in replacement for the JRC 5532 output buffer opamp. The other stock opamps are 5532s for input and low pass filters.

The other mod I did involved switching out some caps for Black Gate N and PK types. I'm currently looking into OS-CON SPs for power filtering caps, and possibly bypassing the caps before the analog RCA output.

The OPA2604 largely addressed the main sonic deficiencies, and although the soundcard is still not up to par with the cd player in terms of detail and some other sonic characteristics, I'm not complaining. I can recommend the OPA2604 as a replacement for the 5532 on this soundcard.

*-smeared rather than focused sound; very apparent on centered vocals. Rather than being able to almost see the artist performing due to realistic sound, it was only apparent that the artist was singing, not performing. This smearing flattens the depth and detail of vocals.

-almost no bass output; very easy to tell with bookshelf sized speakers

-thin sounding, incorrect frequency balance

The OPA2604 removed a majority of the smearing and fixed the thin frequency balance.

cd player used as A/B switching comparator: modified Sony CE775 cd/sacd player

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Yes, because modding an external D/A would be a lot easier than this small soundcard crap. However, as I said, "A good external DAC would help, but I decided to go cheap for now and just mod the soundcard directly". An external DAC would be $150 and up, and full mods for the DAC would be $100-$200. I'm not sure if it is worth that much for mere soundcard audio, but I am considering it.

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Interesting.

It's stereo, so I'd imagine it comes in an 8-pin DIP package, right?

...Ah, indeed it does. Just checked Burr-Brown's site. Should be easy enough to solder.

What's the cost per piece?

I wonder if my Delta1010 could benefit from a similar upgrade. I'm ashamed to admit that I've never cracked it open to see what lurks within, but knowing how companies like buying components en masse, I wouldn'tbe surprised if the two cards used the same OpAmp.

Thanks for the tip!

Piyono

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Piyono, they were $3.56 per piece from Digi-Key.

What's the rest of Your gear?

The listening gear accompanying the SCD-CE775 and PC are:

Omega TS2R speakers

NAD 312 integrated amp

Pure Silver Sound Integre' jumper cables

some cheap Monster cables (Z100i and Z1)

some cheap cd case shelves for stands

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Hmm... is it reasonable to expect the same quality of sound from a PC soundcard than from an audio CD player? I don't think so. Consider, for example, the EMI... there is no cost-effective way I can think of to completely shield the card from the high-frequency interference prevalent inside a PC.

Another factor is that cheap PC PSUs and ultra-clean analog signals generally don't mix very well...

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Hmm... is it reasonable to expect the same quality of sound from a PC soundcard than from an audio CD player? I don't think so. Consider, for example, the EMI... there is no cost-effective way I can think of to completely shield the card from the high-frequency interference prevalent inside a PC.

Another factor is that cheap PC PSUs and ultra-clean analog signals generally don't mix very well...

Well, there are some semi/pro cards (with onboard AD/DA) that are held in very high regard by many a reviewer; the Lynx Two for example. I've never used this card so for all I know the hype may just be marketing bunk, but I like to give folks the benefit of the doubt.

Piyono

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I've had 4.7k ohm resistors between the opamp's negative power rail and its outputs for some time now, biasing it into class A operation. This was a significant sonic change, a change that I like so far. However, I'm looking into replacing the resistors with a JFET cascode configuration.

I'm not sure if replacing the lowpass opamps with 2604s brought any sonic improvement. They looked like they were only applicable to the ADC section anyhow.

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I really wish I knew what you guys were talking about.

I've recently been upgrading my "stuff", including audio gear. Going from Altec-Lansing speakers on an AC'97 soundcard to Bose 201s on a SB Live. I know this is chump-change compared to what you are talking about, but I need to ask the guys who (obviously) know.

What's a good pair of speakers with (either integrated or seperate) amp for $300-$500? A grand? I know Bose is considered a supermarket band, 90% marketing, but I used to work there and got a deal. Who are the good guys?

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ddrueding1,

A decent 2.1 speaker system for around $150 is the Klipsch ProMedia 2.1, which sounds fine (though it lacks a solid midrange punch) when paired with a great soundcard like the Turtle Beach Santa Cruz ($50). An even better choice is the Cambridge SoundWorks MegaWorks 213, but it costs around $400. If you have more cash and better hearing (or want to create an amateur home studio), then the $900 VideoLogic Sirroco Pro speakers are among the best multimedia speakers/monitors within the $1500 price range. Combine the Sirroco Pro with a great semi-pro card like the Terratec DMX 6fire2496 ($250) or the audiophile/sound engineer level Lynx Two ($900) for the ultimate in amateur home studio recording. If you are looking for a great 5.1 channel solution, the Cambridge SoundWorks 550 surpasses its Logitech and Klipsch competitors for around $275 (the older 510D is also quite good, but the Logitech Z-680 is better and cheaper than this older model). To sum up, the Klipsch ProMedia 2.1/Cambridge Soundworks 550 combined with either a Turtle Beach Santa Cruz or Audigy 2 (though I personally stay away from Creative soundcards due to poor drivers and deceptive specs on their hardware) is a great combination. Purchasing audio products is a very personal endeavor; if you can’t hear the difference between a $50 set of speakers or a $1000 set of speakers than don’t waste your money. 8)

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I've had 4.7k ohm resistors between the opamp's negative power rail and its outputs for some time now, biasing it into class A operation. This was a significant sonic change, a change that I like so far. However, I'm looking into replacing the resistors with a JFET cascode configuration.

Assuming the original topology was balanced (which the negative rail would suggest it is), wouldn't you also have had to add a blocking capacitor on the output, reducing the damping factor?

I would thing biasing a class AB amp into class A without specificly being designed around it in the first place would cause more harm then good. Though it might work a bit differently on preamplifiers rather then current gain stages.

-Chris

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Sorry to throw another (couple) basic questions in here. I have many situations where an audio signal needs to travel 50'+ to the speakers/amplifier. Should I put a smaller amplifier at the source? What cables would you reccomend? Am I going to lose quality no matter what? What about a digital (SPDIF?) connection? Would it require a toslink cable to get decent quality?

Thanks in advance. :wink:

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that depends what type of amplifier you mean....voltage or current and what magnitude. A bit of voltage amplification at the start of a long cable will reduce the amount of noise, because the amoutn of noise will decrease in relation to the now much larger signal. Care must be taken however that the amplfiication doesn't oversaturate the inputs of the amplifier at the other end, otherwise it's distortion time.

Toslink and coax are preferable over long runs because they're far more resistant to noise then analog. As with analog systems, make sure that everything is grounded well as digital inputs have a tendancy to "pop and crackle" if a ground is floating and noise is on the line.

-Chris

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Adriel,

I have to ask - what do you think of the new M-Audio Revolution 7.1 card? Have you had a chance to hear it?

Future Shock

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...there is no cost-effective way I can think of to completely shield the card from the high-frequency interference prevalent inside a PC.

Another factor is that cheap PC PSUs and ultra-clean analog signals generally don't mix very well...

I've always wondered about this... With digital audio extraction being common place these days, as well as digital output, what effect would EMI really have?

I always thought it would be cool (and probably expensive) to have a digital signals sent to each speaker and on each speaker a separate ADC and amplifier. Is there any setup like this on the market? That would seem to totally eliminate the effects of interference.

If it was made in a modular fashion, you could use any normal speakers attached to the ADC/amps.

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I always thought it would be cool (and probably expensive) to have a digital signals sent to each speaker and on each speaker a separate ADC and amplifier. Is there any setup like this on the market? That would seem to totally eliminate the effects of interference.

Well if you think about it, then each speaker would have to have a built-in power amplifer to provide enough current to drive a speaker. This also means each speaker would have to have a transformer, and power cord. Also simply sticking an amp of any power inside a speaker would pose a cooling nightmare, so you've have to come up with some way to cool them.

Of course this is all moot because speaker level signals are pretty much immune to EMI and RFI due to their magnitude. An induced signal of 25mv doesn't make much of a difference on 30V speaker input, but on a 200mv line-level input it certainly would.

-Chris

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Of course this is all moot because speaker level signals are pretty much immune to EMI and RFI due to their magnitude. An induced signal of 25mv doesn't make much of a difference on 30V speaker input, but on a 200mv line-level input it certainly would.

Taking this information into account for my situation: I'd have better quality if I left all the amplification at the sound source, and ran individual speaker cables 50'+ to my workstation?

Explination: My solution of the "quiet PC" is a Belkin KVM extender, keeping my PC in the garage ;)

http://catalog.belkin.com/IWCatProductPage...ers%2Fct_Id>

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In theory...yes. However high quality signal cables and proper grounding can close the gap significantly.

-Chris

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Well if you think about it, then each speaker would have to have a built-in power amplifer to provide enough current to drive a speaker.

Those active speakers already exist... but mainly in professional audio applications, not so much in HiFi. I've seen many active studio or stage monitors... in fact the monitors I use for my keyboard are active:

http://www.event1.com/Products/20_20/20_20bas.html

I haven't noticed any cooling problems, even though the speakers are sometimes (ab)used far beyond their intended studio usage...

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