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Cheap to Audiophile with Simple Hacks
petertrog writes "The IEEE has a story showing how you can turn a cheap DVD player into something that sounds a whole lot more exotic. All you need is a small budget, a soldering iron and a desire to void your warranty."
I'd like to see him put this stuff on the scope before and after each of these changes. That way we could get an idea of what he means by a 'dramatic improvement'. I can see the op-amp changes and the power supply upgrades helping a lot... However I have a hard time believing that he would be able to demonstrate a difference in the analog output with some reference tones by, say, buffering the crystal from vibration on a standard scope. I'm sceptical he can hear the jitter too. Even cheap clocks these days are pretty damned good once everything warms up.
I grabbed one of those $35 "5.1 surround sound" speaker systems from Wal-Mart. They only accept a stereo input, and just kind of mix in the surrounds, center, and sub. So I popped it open and ran the numbers on the chips inside, locating the 6-channel volume control IC. I discovered that if I ran an audio signal directly to the inputs on the chip, it bypassed the stereo upmix. A few wires and drilled holes later, I had actual surround sound for my computer. Not gonna say it's the greatest sounding setup ever, but it was cheap.
...now I know the purpose of my EE degree.
It seems simple enough. Basically you're replacing components with ones that are better with no major rewiring of the circuitry. Diodes with faster switching times, add noise reducing capacitors, gold terminals instead of nickel or tin, replace the op-amps to get better slew rates and less distortion... etc. All this is pretty much what the more expensive models would have done anyway.
This is a good general reference for those who aren't afraid of electronics. But, I strongly warn against it for anyone who really doesn't know what they're doing (especially the ones who can't solder). These components are simple enough, and swapping identical devices shouldn't be too hard, but going from schematic to PCB is very challenging if you're not used to it.
On a side note... Favorite quote: "Plug it in and turn it on. No sparks or smoke? Terrific!"
High end audiophiles will squak. Meridian's G98 costs $6k (review), the Lexicon RT20 is $5k, an Ayre costs $6k, and the Arcam FMJ 29 (highly rated starting end of high end) will set you back $3k. The top reference player, Meridan 808, will set you back $20k.
The Denon 2910 (about $600) (review) is the beginning of better quality players. The article being discussed does exactly what a lot of the higher end players do -- swap out cheap parts for better ones. For those who don't think it makes a difference, you've never had the pleasure of good quality sound. A wide, three dimensional sound stage with clear separation of instruments and fine detail puts a smile on your face. Being able to get that for much less than above (and have the second pleasure of do it yourself) is well worth it.
the power supply mods I can make sense of... but personally, I'd ignore the analogue side and just hook the digital sound output straight into the digital input of my system pre-amp... and I'd make sure I'd gotten a DVD player with a DVI output and not a crummy scart one...
Donald 'Duck' Dunn: We had a band powerful enough to turn goat piss into gasoline.
Don't most people hook their DVD players up to their receivers using either an optical or a coaxial digital cable? Why would changing anything in the dvd player make any kind of difference in the sound quality if all the player is doing is passing along a digital bitstream to the receiver?
What kit did you use, btw? I'm going to put together a pair of Ellis 1801s this summer and am looking forward to listening to them.
A deep unwavering belief is a sure sign you're missing something...
In the end, get another brand-new player and someone to help you double-blind test it. And please, broadcast it live on the net.
Don't you just need to stick a patch like this on the unit?
AT&ROFLMAO
I wouldn't think their use were limited to DVDs. I've assumed and often been abandoned dead or old CD-ROM drives whereof the previous owners have wanted DVD capability upgrades. It's a great episode of salvage rights! I took an old servo from a CD-ROM drive and made a centrifuge out of it. With another servo from a CD-ROM drive, I've been trying to build a turn-table so I can use a diamond blade on a submerses pane of glass to grind it to a convex lens for a telescope project, with poor success thus far. In many other projects, I used the CD-ROM drive housing for breadboard enclosures. Also, I don't need to buy variable potentiometers and LEDs anymore, but that's about all you can pull from them. I save plastic inside them to melt it down with a injection moulder i am slowly learning to build.
without prejudice
This is not an engineering hack, this is the same trap all the tweako audio magazines fall into. Sure it sounds better after he spend a hundred bucks and a few hours of his time... show me the measurements and I'll believe it wasn't an emotionally influenced subjective improvement.
The starting premise, that manufacturers use the least expensive components they can get away with is no big news. This has been considered good engineering just about forever: use those parts that are good enough technically and least costly. The key is "good enough", though for what? The subsequent discussion on audio and video quality just indicates that the player is working as it should. As to distortion, there is only the subjective opinion that the cymbals don't sound as clear as they should, but there is no further indication of whether this comes from the player or the amplifier chain following.
Then the discussion proceeds to take apart and redo the power supply... Not components in the signal path, but the power supply. A switching power supply that is powered direct from the mains, with X and/or Y-rated capacitors and inductors in the power entrance, and a somewhat carefully orchestrated feedback loop that causes its components to oscillate and generate the correct DC voltages for the electronics. Apparently, (and fortunately) most of the really important components are surface-mount and thus not amenable to this kind of tinkering. The argument goes on that this more "stiff" power is needed for more accurate bass-response. Hello? this isn't a 30 Watt tube-amplifier we are talking about here, where such an argument might hold, but something that puts out a few tens of milliwatts of power into maybe 600 Ohms at the most. Unless the power supply is pathologically feeble, this is really just -- marketing-speak, to use a polite term.
However, even if putting in larger filter electrolytic capacitors might be harmless, the replacement of the X-rated capacitor with an "Auricap" which is evidently NOT X-rated, sounds dodgy, as in potential fire hazard. The Auricaps seem to be marketed as non-electrolytic replacements for electrolytic capacitors in the signal path, and might do a fine job here, but we're not expecting any of our precious signal to enter the mains are we?
The fact that there is an X-rated capacitor there at all and not just a cheaper one, is that this is sitting across the mains voltage, and has to conform to specific requirements from the UL, CSA, TUV and so on, lest they refuse to List or certify the equipment for sale. And probably more important, that the component fails safe and does not start a fire.
Googling for "aurocaps" shows several sites catering to the same merry lot who depends on "oxygen-free" cables, and praise the virtues of the gold-plated RCA connectors... There is a reason why professional kit uses XLR or BNC connectors, or even 1/4inch jacks by the way, and it has to do with mechanical and electrical stability and shielding, not any magic properties of gold or nickel that makes one good and the other bad.
It goes on about replacing more of the bypass capacitors in the digital processing section, and mentions the possibility of clock jitter. Technically correct. But no quantitative information, no measurements done on a distortion analyzer or even a picture of the signal on an oscilloscope. Just all this non-scientific hand-waving that if we put in more expensive capacitors the sound will be better.
Finally, op-amps and possible replacements. Again, the observation is that the amplifiers are low cost, and obviously we could put in better and more expensive ones. Low cost is not the same as crummy; had the manufacturer put in really bad ones, everyone would have heard. Again, it is a matter of good enough, though the only parameter that might make a difference would be the noise of the amplifier. Unless they are really atrocious (with obvious effects on sales), gain and slew-rate would not matter, except for marketing purposes.
My guess for what might constitute the perceived "improvement" in this case, is that the frequency response of the audio chain has changed, boosting the higher frequencies, and thus made the modified unit appear to sound better.
SIGBUS @ NO-07.308
Screwing around with the power supply is just stupid, a decent Tripp-lite conditioner or a UPS would handle line noise much better, simpler, and more safely..
Replacing the op-amps with better ones is probably the best tip in the whole article, and the only thing that is likely to have a serious impact on the sound. Replacing caps and other components in the signal path will have some effect.
The jacks have to be the dumbest thing I have ever heard.
All this 'gold-plated, super oxy-free' stuff is pure hokum. Sure, the cables might conceivably make a difference when you're using an Apogee converter to run audio from your RME Hammerfall through your $50K amp to your $250K mastering monitors.
But on a consumer-level system with unbalanced jacks? Please.
Unbalanced cable can only be run for 3 feet without serious risk of RFI and EMI corrupting the signal. You can run balanced cable 1000 feet before you face similar risks.
Pro recording and audio environments use almost entirely balnced gear, because it provides the signal quality necessary for major recording projects. For cable, it's plain old Mogami or Belkin. We break out the fancy-looking gold-braided super cable when we get a cranky performer who insists that our gear is simply not capturing his muse, because he always delivers perfect performances. Slap those into the mic chain, and watch them listen to the playbacks, nod knowingly, and say "Yeah...it sounds right now"
Nothing has acutally changed, but it sure makes some people feel better, and the same thing is at work in the audiophile arena.
Sure, different compositions of metals have different abilities to conduct signal, but once you get to a certain level of qaulity (which all basic cables meet), it doesn't matter too much.
"Why don't you interface with my ass...by biting it!" -Bender B. Rodriguez
There is one more reason to record at a 96k sampling rate, eliminating the need for a "brick wall" input filter and the resulting phase distortion.
A 44.1k sampling rate does give a flat audio frequence response, that's not the problem. The problem is the music doesn't all come out at the same time. the high frequency stuff is a hair off the beat. Sampling theory, filter theory, in general, weird shit.
At 44.1k sampling, you really, really don't want any input over 22k. You can't hear it going in, but it wraps around coming out. That is to say, 23k input comes out as 23k-44k/2= 1k output. That, 1000 Hz, you can hear.
So filter out every thing over 22k, let every thing under 18k come through. A sharp, brick, wall. OK, now you have the frequency response correct, no dog whistles in the background,
Real world is, your input filter also changes the phase of the sound signal depending on frequency, The low frequency signals don't come out in phase, at the same time as, the high frequency signals. A sharp click isn't so sharp any more, it's "muddy" (Think, Fourier transforms of a unit impulse). And sound location by way of L/R timing of output sound to the ear also gets confusing, less "presence".
A low pass sharp cut of filter centered at 20k will have significant phase distortion down towards 15k. It's not the sort of thing you will pick up on a single tone and it doesn't show up on a simple sweep signal / o-scope check. But you can tell the difference with a good rig between digital sampled at 44.1k and a good LP. Both are pretty much flat 20 to 20k, but the vinyl sounds a bit better.
To beat this, sample at 96k. Now you only have to kill anything over 43k, pass all under 20k. With a slow roll off centered around 44k, there is hardly any phase distortion at audio frequencies. Got lottsa hard drive space and a good DSP chip, sample at 192k, save on the filter. Go to 24 or 32 bits, less jitter, shot noise.
In short, higher sampling rates are not about hearing (or not hearing) higher frequencies. It's about recording, storing, hearing the usual, same old up to 20k audio, analog frequencies RIGHT by way of more digital bits.
By the way, vinyl can't touch digital at the extreemly low frequency end. And no RIAA curve nonsense either. CD's are pretty good, but 44.1 sampling goes back to tech limits (and a surfing bet) twenty odd years ago. IMHO, it will not be still around twenty years from now.
Rip EVERY single last wire out and replace with silver wire (or, if you can't find that, then use silver coated oxygen free wire), replace all of the capacitors with polypropylene, silver mica, or paper caps (use only 10% or lower tolerance caps). Replace all resistors with 1% tolerance, zero capacitance mil-spec pieces (they cost a dime each at most electronic surplus stores).
What you just bought for $125 or so on E-Bay, along with $30-$40 in parts, with a few hours of soldering work will give a MacIntosh amp a run for the money.
See if you can find the pentode-triode modification online or in a VERY old "Glass-Tube Audio" magazine and convert the first stage tubes to triode operation instead of Pentode, and it will DEFINATELY keep pace with amps selling for up to $2,500 or so. (my modded amp's power output is essentially flat from 15hz -> 80Khz with only a 3db rolloff at 100Khz)
If you are a dyed in the wool audiophile who likes the "vintage" look, then you might want to consider a project like this.
It's a lot of fun for only a couple of hundred bucks, and it will sound like it's worth thousands.