tpg Posted March 30, 2003 Share Posted March 30, 2003 I have been wanting to connect my soundcard to my receiver for some time... and I have decided to do it now over spring break, since I am really bored. (I have no one to talk to... so I NEED to build something ) I had the idea to use a single cable out, convert it to balanced output for each channel, run this balanced cable to my receiver behind all my electronics, then use an amp converter to make it a single output again. This uses Burr Brown DRV134's, an OPA2132, and CAT5 (8-conductor, unshielded, 24 guage) cable. I have drawn out the circuit, it is easy to build, but over my target price of $20 for this project. The budget really doesn't matter, though, so you know. The other option is to buy a 1/8" plug and two RCA plugs, and 20 or so feet of 24 guage 4-conductor shielded wire. Hook up both ends accordingly, plug it up and go. Which would be better for this approx. 15-foot run? Which will have best sound and pick up the least RFI? Advatages on both sides prevent me from deciding... I leave it to you. Quote Link to comment Share on other sites More sharing options...
prodj101 Posted March 30, 2003 Share Posted March 30, 2003 when I want to connect my comp to my receiver/stereo system, I just go 1/8 inch to stereo RCA. Quote Link to comment Share on other sites More sharing options...
tpg Posted March 30, 2003 Author Share Posted March 30, 2003 I know, I wanted to get fancy with it... Quote Link to comment Share on other sites More sharing options...
Invidiosulus Posted March 31, 2003 Share Posted March 31, 2003 My soundcaard has a digital output which I run to the input on my yamaha receiver. This sounds pretty good and to my ears sounds a little cleaner then using an analog 1/8" cable. Peace, Josh Quote Link to comment Share on other sites More sharing options...
Stephen328 Posted April 1, 2003 Share Posted April 1, 2003 hmmmmmmmmm. That balanced plan sounds pretty spiffy. probably overkill, but theres nothing wrong with that. Quote Link to comment Share on other sites More sharing options...
m00n Posted April 1, 2003 Share Posted April 1, 2003 Here you go... This might be what your looking for Harman Kardon Computer To Home Audio Link Quote Link to comment Share on other sites More sharing options...
tpg Posted April 1, 2003 Author Share Posted April 1, 2003 Oooh that's kinda pretty... but if its an HK, its probably too expensive for me. The balanced output converter is overkill for my setup, but if you had your computer downstairs and your home theatre upstairs and wanted to connect them (distance of around 50-100 feet) then this would be the best way to do it. In theory, the signal would stay strong and not pick up as much RFI as an analog connection. But, if you did this through digital coax, you still wouldn't have to worry about RFI, would you? Well... when I get in a building mood, I just may make this converter so I can have another elecronic gadget hanging around. Quote Link to comment Share on other sites More sharing options...
cyclonecj Posted April 1, 2003 Share Posted April 1, 2003 I found the Harmon priced at $149. Here is one from Sound Pro It is only $35. Since this only transfers digital data to the receiver, I would guess it is up the the receiver as to what it sounds like. Quote Link to comment Share on other sites More sharing options...
m00n Posted April 1, 2003 Share Posted April 1, 2003 Here is something that looks kinda cool... Audiotron ------------------------------------------------------------- Listen to your PC digital music library and Internet radio from anywhere in your home. AudioTron is a 'smart stereo component' that takes full advantage of the power of home networking, yet fits right in with the rest of your home entertainment system. AudioTron uses your home network to play Internet radio from a networked Internet connection and digital music files from a PCs hard drive, so you dont have to be in front of your PC to enjoy the benefits of digital music. ------------------------------------------------------------- Quote Link to comment Share on other sites More sharing options...
cyclonecj Posted April 1, 2003 Share Posted April 1, 2003 HP also is building one. The difference is that the HP does not have a display, so your TV has to be on. HP EN5000 I have seen at least 5 reviews of this unit, but not one has said anything about the sound quality. Quote Link to comment Share on other sites More sharing options...
tpg Posted April 2, 2003 Author Share Posted April 2, 2003 Although there are easier and cheaper methods to doing this... I have opted to build the balanced converter for my connection option. It is mainly to give me something to do- I am on spring break, and have no one to talk to and nothing to do, so I shall build. This project cost me quite a bit, since I had to buy a power adapter, but, ahh, oh well. I shall go clean off my electronics workbench now, and hopefully start building by noon. Quote Link to comment Share on other sites More sharing options...
Marvel Posted April 2, 2003 Share Posted April 2, 2003 The spec for spdif really is for short distances, it just keeps the signal digital. Optical would work better but most of the toslink cables are plastic fiber, and won't go the distance either. If you can get someone to terminate the connectors onto glass fiber, it can work for pretty long distances (and no interference). M-audio makes an spdif to optical convertor (bi directional) that sells for about $60. Marvel Quote Link to comment Share on other sites More sharing options...
m00n Posted April 2, 2003 Share Posted April 2, 2003 Marvel, like the new avitar. Quote Link to comment Share on other sites More sharing options...
cyclonecj Posted April 2, 2003 Share Posted April 2, 2003 I just looked up the USB to Optical adapter that came with my Sony MD recorder. It is from Xitel. They now have a pro version: Xitel.com I might have to try mine out & see how it sounds. I have not been happy with my current computer link. Quote Link to comment Share on other sites More sharing options...
tpg Posted April 2, 2003 Author Share Posted April 2, 2003 Well, as of now, the unbalanced to balanced converter is built, not tested, but built. Power rails check out ok... will have to see if it functions tomorrow. The balanced to unbalanced converter is still not made... I miscalculated how many resistors I needed and am short one. I have everything... just need one freakin resistor. I hope it all works... I will be supremely dissapointed if it does not. Wait a sec... of course it will. Quote Link to comment Share on other sites More sharing options...
cyclonecj Posted April 2, 2003 Share Posted April 2, 2003 ---------------- On 4/2/2003 9:40:28 PM trespasser_guy wrote: Wait a sec... of course it will. ---------------- I like your confidence! Quote Link to comment Share on other sites More sharing options...
Marvel Posted April 3, 2003 Share Posted April 3, 2003 Moon, Thanks. Even though I am behind the guitar, the Taylor is a lot nicer to look at. Trespasser_Guy, You must have a schematic for the line drivers, etc. Could you post a copy? The only thing I've not liked about my M-Audio AP 2496 is the unbalanced i/o on it. My mixer has balanced I/o and would make it easier for me to located my pc in another room (and get rid of the fan noise). Marvel Quote Link to comment Share on other sites More sharing options...
tpg Posted April 3, 2003 Author Share Posted April 3, 2003 Another TPG creation. The schem is attached. Notes on schem: I always put a coupling cap on the input because I don't trust my sources, and I REALLY don't trust my computer as a source. So, it is there. You can leave it out, but my Audigy has a short... so it is in. I value my receiver more than my soundcard. This is one channel. I used one DRV134 per channel as IC1, and an OPA2132P (dual channel opamp) as IC2. If you use single channel opamps, not that the positive rail supply goes to pin 7, not pin 8 as on duals. R2/R4/R6 set the gain, which is 2. Gain across the DRV134 is 1. To make up for this gain, if it is not wanted, tack a resistor on the output of IC2, don't really know which value, maybe 1k? I think I will leave it stock gain for a try first off. You can also include a 10uF electrolytic cap from pin 2 to 1 and from pin 7 to 8 to reduce common-mode offset errors... but I didn't do this and don't really plan to. Why do it you ask? I honestly don't know, thus I didn't do it. I am not expecting pro-level sound from this thing, though that would be nice. Anyway, those are my notes... if you need an example power supply, let me know. I have one, and can draw up several depending on what you want. Values: C1- at least .1uf (I used .33uF- the larger the better, but keep it a film type, preferably polypropylene or metallized polypropylene, but mylar is ok...) C2,C3- 680pF film cap if you can find them... I have run this thing on breadboard with .1uF's there and it was fine. Final amp is using .0022uF IC1- Burr-Brown DRV134 IC2- Burr-Brown OPA2132-- any opamp will do. Two single opamps will probably sound better, less cross-talk between channels because they are not connected... R1- 10k ohms R2,R3- 1k ohms R4,R5- 1.2k ohms R6,R7- 2.2k ohms You can use any resistor values for R2-R7, just make sure R2+R4=R6 and R3+R5=R7. But wait... you said you had a balanced input... so you really only need the driver section. Darn that is ieasy to build. lol Quote Link to comment Share on other sites More sharing options...
Marvel Posted April 3, 2003 Share Posted April 3, 2003 TPG, Thanks. I've got good dual supplies laying around. I could use the balanced in to unbalanced out, but can figure it out. I've got a couple other schematics somewhere, and WOULD like it to be pretty good. I do multitrack audio work, blah, blah blah... As many other projects as I have going on right now, it may never get built. What schematic program did you use? I have been using the free version of Cadsoft's Eagle layout and editor. I used to work with a guv'mint contractor, and we had the pricey stuff, but my wallet is much thinner and my needs a bit less. Marvel Quote Link to comment Share on other sites More sharing options...
tpg Posted April 3, 2003 Author Share Posted April 3, 2003 That schem is pieced together using bitmap images. Takes a while. Normally, I draw by hand, but when I use my computer for a quick schem drawing thing, I use ExpressSCH, and ExpressPCB for boards. It is free and easy to use, and I don't really use it all the time anyway. It should sound quite good... For what you would use it for, you may want to add the 10uF caps. Other than that, there really isn't much to add to the driver as far as I know... the receiver end is what's going to kill me. I just started it... and I just ended it. I am extremely angry right now. How many times can I screw up? I'd like to know. That should have taken me 15 minutes to sodler everything. BUT here I am about 2 hours later and the whole thing is screwed up. My hands shake like crazy, my soldering iron tip is melted flat, I can't see... can't conentrate, make stupid errors... WTF is wrong with me?! Well... what was already way too expensive of a project for me is going to get worse... I get to replace ALL of my resistors and caps and have to buy a new board. I am so very irritated... Quote Link to comment Share on other sites More sharing options...
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