Newsgroups: rec.audio.tech Subject: Re: Machinations on ideal PC<-->Stereo dorm setup References: <[email protected]> Jim G <[email protected]> writes: > Hi ppl. First timer here... I've been nosing around for a good > computer/music setup for my daughter's dorm room for this coming > September (she made it into the freekin Ivy League-- first person in 4 > American generations to even come close (snob-by-proxy time for me?)). > > It's been tough settling on a setup. My budget for it is about $2200, > no more than $2400 (this includes the puter). At first I was > determined to put together a whole networked extravaganza anchored by > a modest component stereo system. Her MP3s and other digital music on > the PC would get to the stereo via Ethernet, and she would use the > stereo directly for CDs (standard and data), DVD-Audio and AM/FM > radio. Then I said "Hold on-- this is a dorm room. The stereo will be > so close to the PC, might as well scrap the Ethernet and run direct > audio wires from the soundcard (Audigy) to the stereo". This would be > done using either the mini-stereo-plug->rca plugs->aux jacks trick or > some sort of mini-plug->coax->digital input scheme. Sounds reasonable. > Then I started worrying the room space would be so cramped that > magnetic fallout from normal stereo speakers would mess with her PC > monitor (19" flat panel) Stereo speakers can mess with the traditional CRT monitors quite baddly. The modern flat panel monitors are diffent story. Flat panel monitors (LCD technology) are not sensitive magnetic fields so should not be worry about magenti field causing problems to monitor. Anyway there are magneticlly shielded speakers avilable nowadays. > and even her hard drive. So I started looking > into the best available PC audio setups and was on the verge of > ordering Klipsch ProMedia 5.1 (apparently only $200 through Dell). > > But I soured on that. Kept reading bout Klipsch and other pricey > puterAudio systems crapping out as if on cue at the end of > warranty. And I didn't like the idea she would miss out on everything > a proper receiver gives-- nice balanced output even for symphonic > music, AM/FM tuner, carousel disks, etc.,. > > So I read a lot about PC->stereo system hookups. Discovered there's a > fair availabilty of shielded speakers. Decided my budget couldn't > accomodate both a decent PC and a full component system and that a > real rack system was overkill for a dorm room anyway. So I started > looking into best-of-class mini stereos (sometimes called "bookshelf" > or "executive" or "tabletop") from Philips, Onkyo, Panasonic, JVC, > etc,. > > The mini-plug->rca plugs->aux inputs idea was looking good until I > read something on a web forum about a voltage mismatch between the > Audigy lineout and the typical aux in. A lot of people were getting > away with it, but it seemed a fair threat to eventually fry the > receiver. I am just wondering why people are reporting on voltage mismatch between soundcard line out and normal stereo aux in. I have connected quite many PCs to a quite wide variety of audio equipment, and things generally have worked very well. Sometimes when sound level is too low, the reason for that have been that soundcard setting have been wrong (all output mixer settings set to minumum etc..). A properly done connection should not fry the receiver no matter how volumes are set. The accidents where receivers and/or soundcards have been fried have been related to connection and disconnection of audio cables. If PC has not been connected to grounded outlet, the case if it is not grounded, but it is bloating at potential of tens of volts AC above ground... enough to fry some sensitive equipment when you connect/disconnect audio cables... when cables are connected/disconnected there is typically time when there is just the center pin in RCA connector making connection but ground is not making connection -> potential difference between equipmen gets injected into signal input connector :-( When connectors are fully inserted, also the ground makes connection, so there will be no potential differences between equipment and nothing ha would fry things as logn as signal grounds are connected! The 3.5 mm jack and RCA are both stupid connector designs, because in those the signal wire gets connected before reliable gound connection. This increases the possibility of frying your equipment when making interconnections greatly compared to connectors that guarantee that gound makes connection first (XLR, BNC, special professional RCA connectors etc..). The PC should be well grounded always for your safety and to avoid equipment damage! Grounding can sometimes cause another problem, called ground loop that causes humming noise to your system. But that's another story told at http://www.epanorama.net/documents/groundloop/index.html There are audio signal isolation transformes, that can make your analogue interconnection between PC soundcard and stereo system free of dangers of frying your equipment and ground loop noise. Some links: http://www.epanorama.net/documents/groundloop/audio_isolators.html http://www.epanorama.net/documents/groundloop/audio_isolator_building.html http://www.pcmag.com/article2/0,1759,1768471,00.asp http://www.vego.nl/xitel/05/05.htm http://www.maplin.co.uk/Module.aspx?ModuleNo=33172&TabID=1&source=14&doy=25m2 http://www.biltema.fi/osteri/osteri.cgi?sivu=skriptisivut/index_kauppa.htm&linkki=31441.htm&tuote=31441&ryhmaid=30 > That's when I came upon the Philips MCM530, a mini stereo > using a USB connection to the PC. I have not used those USB interfaces to make audio connection to stereo equipment. I don't know well how they work.. I would like to know some more technical details on them, for example are those implemented in such way that they can cause ground loop problems and cause equipment to fry when making connections... > But I soured on that too. It just > seemed that a self-powered connection like USB would _have to_ > introduce noise or irregularities into an audio stream, and I've been > less than thrilled with a few other USB gadgets. I want my daughter to > throw music to the stereo system from the PC with as much ease as with > a normal computer speaker setup and I was sure this > USB-with-special-drivers deal would have her messing with software > settings each session and/or endlessly plugging/unplugging the USB > cable as the PC tried to get straight on what it was outputting to at > the moment: mini stereo or soundcard. > > It was back to the Audigy lineout->rca->aux deal, but the voltage > mismatch still bothered me. Can you give more details on this voltage mismatch issued. Where have you seen this mentioned? Please post the details to this discussion group or links to the pages talking on those. > I looked into all-digital connections but > was discouraged by the Audigy's use of a mini-plug output for digital > (forcing at least two possibly signal degrading adapters) and the > scarcity of bonafide digital inputs on mini stereo systems. That's > when I came upon the "Xitel Analog HiFi Link" > (http://www.xitel.com/product_hfl.htm) for about $50. > > Xitel says "By taking digital information from your computer's USB > port, the HiFi-Link also avoids relying on the typically inferior > audio characteristics of installed soundcards." They go on to gush > about their massaging the signal into just the right form for the aux > jacks. Is this believable? At least lost of sales talk there... Basicly thsi device just looks to be just another USB to analogue output gadget. They claims that it better than the "cheap crap" similar adapters... I have not tired this myself so I can't say if they speak truth or not. And the technical description on the page at was not too complete so I could say if using this would be in any way better than interconnection made with analogue cable from any decent quality PC soundcard line output. There was not technical data on that page that would say that plugging the computer through this soudl be in any way safer for the stereo aquipment than plugging it directly from sound card line output. My quess that with this kind of adapter the possibility of frying something or getting other kind of problems would be similar to using normal sound cards! If you have made something specifically better with this product, they did not succeed in giving this information on their web page. > Are the "audio characteristics" from an > Audigy lineout actually "inferior" in any way? I don't know. I have not tested that soundcard myself. > Am I mistaken about the > wattage mismatch (if so, my problem is solved with an $18 piece from > Radio Shack and no intervening gadget)? > > Ok, I've spewed enough. The "HiFi Link" (and similar devices I've seen > since, particularly the M-Audio "Transit") does look interesting, but > I'd like to hear what some of you mavens think of it. I'm not keen on > its use of USB, but it doesn't look as bad as the Philips arrangement > (special drivers under XP, ugh)... What do you say? And, if you were > me, what would you put together? > > -- > JG -- Tomi Engdahl (http://www.iki.fi/then/) Take a look at my electronics web links and documents at http://www.epanorama.net/
