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Soldering a Cable (Cable Design)

Discussion in 'Accessories / Connections' started by Doublehelix, Oct 2, 2002.

  1. Doublehelix

    Doublehelix Well-Known Member

    OK...as I am going through this "wonder" that I call re-wiring my studio using a patch bay, I have found one cable that I would like to have made that I am a bit unclear about how to design.

    It is the cable that goes from my mixer's headphone output (1/4" stereo) to my headphone amp. Currently, I am just using a single TRS cable to a TRS jack on the *front* of my headphone amp. Now that I have added the patch bay, I would love to get rid of that ugly wire sticking through the last 1 space opening in my rack, and into the front of the headphone amp. Plus, I am planning on filling that last remaining 1 space hole with a pair of RNC compressors. Now on the back of the headphone amp, there are some other "main ins", but they are separate Left and Right inputs (either TRS *or* XLR).

    So now to my questions:

    How can I go from a stereo TRS jack to a pair of left and right TRS or XLR ins? How do I wire this so that I can still get true stereo separation?

    I guess I could get/make a Y-cable that goes from TRS Stereo to mono 1/4" jacks, that would be fairly easy, but not balanced (which I guess would be OK...). This would be by far the easiest solution, and I know how to do this...but if I wanted the cables to be balanced, or if I wanted to go into the XLR jacks...how would this work to still get stereo?

    Thanks!
     
  2. Blutone

    Blutone Guest

    If the Y-adaptor splits the stereo signal into separate channels, just buy a couple XLR adaptors to go on the ends(assuming you have more than one XLR-in to spare). As far as actual cable splicing, I wouldn't want to say without seeing the way it's set-up. So, I'll be over, oh let's say, around 2:00pm.

    ::snikers and points at DH standing there with that look on his face::
     
  3. Doublehelix

    Doublehelix Well-Known Member

    OK Blutone, but let's make it 2:30, I'm a bit tied up at 2:00!! :)

    I understand your repsonse, and that solution would work fine, but the cable would still not be balanced. Wouldn't this solution give the same results as just using the Y-cable "as-is", and plugging the mono ends into the TRS 1/4" input jacks? (just cheaper!)

    Maybe I am just being obsessed with balanced cables here. In this particular setup, I only need to run the cable a few feet.
     
  4. Blutone

    Blutone Guest

    DH, you're absolutely right. Please accept my appologies for my haste in rendering a solution. I should've thought it through more thoroughly. Because the Y adaptor splits into 2 'mono' 1/4" jacks, the cable would be unbalanced.

    Lemme run this by ya. Seeing as how you're wanting to go from an unbalanced to a balanced connection, can you get a Y adaptor that splits to 2 TRS males?

    I'm sure you already understand this, DH, but for the sake of educating the masses, here's why.

    The TRS(Tip, Ring and Sleve) connetors have 3 wires(2 leads and 1 ground). The tip and ring are the leads and the sleve is the ground.

    The XLR connectors also have 3 wires(2 leads and 1 ground). Only, the signal from one of the leads will be inverted to make the signal balanced.

    Having said that, back to the task at hand. If you split the stereo signal into separate channels with the Y adaptor, make sure that it splits to 2 TRS ends. Get the XLR adaptors and use them like I said before. The difference being that the Y is TRS instead of the mono TS. The XLR adaptor will take the signal from the tip and ring and invert one of them, making the signal balanced. I think that's how it'll work. I know those XLR adaptors aren't cheap, but I'm not sure how to split the stereo channels and make them balanced any other way. I hope this helps.
     
  5. Blutone

    Blutone Guest

    DH, if you come up with a better/cheaper solution, let us know.
     
  6. Kurt Foster

    Kurt Foster Distinguished Member

    DH,
    The headphone output isn't balanced. You're not going to be able to send a true balanced signal unless you run it through transformers or an amp. I would run it unbalanced using a trs 1/4" insert cable. Now if you want to go to the hassle of custom configuring a cable I think what you would do is; using 2 balanced cables, at the headphone send connect the cold sides to the ground (along with the ground shields) and the hot sides to the tip (R) and ring (L). Connect the other ends of the 2 cables to balanced connectors in the normal fashion. This is a psudeo balanced line now, the receiving side doing the balancing. You will not benefit from increased gain as you would with a true balanced line but any noise induced into the line will still be canceled out. I hope this is correct, I'm pretty sure it is.....if not the alternative is completely lifting the cold sides on the headphone send end and letting them "float". The rest would be the same. Sorry if this is confusing. By the way, the adapters Bluetone was mentioning would do this also............Fats
    ______________________________________________________________________
    Aaa Ha Ha Ha Ha I finally found out how to use spell check here! :D
     
  7. Kurt Foster

    Kurt Foster Distinguished Member

    DH,
    I was wrong about this. Over in "Tech Talk" I saw this comment,
    So there you go, just tie the cold sides to the shield at the balanced end and let them float at the unbalanced end. Sorry for the confusion.....Fats
     
  8. Doublehelix

    Doublehelix Well-Known Member

    Thanks for the advice guys. I think I have pretty much decided to just split the signal using an insert Y-cable. As mentioned, it looks like the headphone output is not balanced anyway. In addition, I am not going to be recording anything out of this jack, just monitoring, so I guess if I get some hum, it will just add to my ear fatigue, but not get saved to tape.

    Cheers!
     
  9. Blutone

    Blutone Guest

    WHAT!!! All that fuss, and you're not even gonna record off of it? You mean to tell me I wasted all that breath...oh wait, I typed that up there didn't I?...LOL. Anyway, it's good to hear you got it worked out. That should just about do it for the new studio re-vamp huh? How 'bout some pics?
     
  10. knightfly

    knightfly Active Member

    James, short runs at either line or speaker/phone level shouldn't need to be balanced. If your mixer has a spare set of "control room" outs, just run a pair of cables from those into the headphone amp.

    If you run the output of your mixer headphone amp into yet another headphone amp, you are taking the output of a "power amp" of sorts, and feeding it into another "power amp", which could result in more distortion than just taking a signal off your mixer which is earlier in the signal path, and feeding THAT line level signal into the separate headphone amp with two proper cables.

    The other advantage of that method is that you now have the option of a separately adjustable headphone output from the main mixer if you need "just one more phone output" - by feeding the headphone amp with the control room outs, anything you can call up from your mixer's control room switching matrix can be fed to the cans, like 2-track playback for the talent, etc.

    Just another way... Steve
     
  11. Doublehelix

    Doublehelix Well-Known Member

    Steve: Unfortunately, I have no control room outs on my board, and I am using the main outs to feed my monitors. I have worried about using that headphone send, but didn't see any other option. I am also feeding 2 prefader aux sends into the headphone amp's aux inputs to be able to give the talent a "bit more of me in the cans", but this only allows for 2 headphone mixes (well, I guess that is really *three* if you count the "plain" mix). All of the other Aux outs on the board are postfader, and I am actually using one of those thru an outboard reverb unit for *just* the headphone mix, not to be recorded.

    Without getting into *too* much detail, nothing that goes through my board is getting recorded to tape, it is only used for monitoring. Here's how I have it set up:

    Here is the recording pathway:
    I have a PreSonus Digimax outboard mic pre setup with 8 mic pres. I take the ADAT lightpipe output from the DigiMax into the digital ADAT inputs of an Echo Layla/24 that sends the signal directly to tape. The Layla also has an *additional* set of 8 analog inputs (no mic pres however) that I feed line signals into (keys, DI boxes, guitar preamp outputs, etc.). This setup allows me to record up to 16 channels at once. (I also have a couple of ART Tube MPs to feed the Layla if I absolutely *have* to...last resort however).

    Here is the monitoring pathway:
    Main outs from the Layla go into channels 1 & 2 of the mixer. I also take the 8 *analog* outs from the PreSonus into channels 3 - 10 on the board (line ins). Remember that this is my main mic pre piece, and I am taking the digital outs from here to be recorded, so the analog outs that are going to the board are used for monitoring *only*. I also have the rest of the Layla's analog outs routed to channels 11 - 16 so i can monitor anything that is being recorded through the Layla. Now, the Main Outs from the board are being sent directly to my monitors, which during mixdown and mastering is just the feeds from channels 1 & 2 (I mute all the other channels). Then, as mentioned above, I route my 2 prefader aux sends to two of the aux ins on the headphone amp, and the headphone output from the board into the main ins on the headphone amp. Finally, I have a reverb unit patched into one of the Postfader aux sends.

    I know that is a long story, but you can see that this setup gives me a lot of monitoring flexibility, with the ability to provide a couple of different headphone mixes, along with some reverb in the headphones if requested, but *nothing* that goes through the board gets recorded. The mix that I provide on the board via the faders will be heard by anyone that has a set of cans on, or through the monitors if I have them on, but this has no effect on what is going to tape. I can then augment this mix by using the 2 aux sends to the headphone amp to add "more of me in the headphones, please."

    I hope that all made sense, and I would love to hear of any other suggestions you might have to improve this setup...I really don't like using the headphone sends either...I guess I could use one of the other postfader aux sends...Hmmmm....on this board, that would be mono however. I could route 2 aux sends to 2 of the board channels, although I am out of free channels, I never use them all at once, and now everything is wired up through the patch bay, it might be do-able that way...any other suggestions?

    (sorry for the long post)
     
  12. Doublehelix

    Doublehelix Well-Known Member

    Wow...I just noticed that my last post was number 365 for me (of course, now I am up to "366), and that I registered here in October of 2001...that makes "365 posts in one year"...or about "one post a day"!!! :D
     
  13. BrockStapper

    BrockStapper Guest

    what mixer are you using? Do you have any group outputs that could be routed to the headphone amp?
     
  14. knightfly

    knightfly Active Member

    James, looks like you're doing about all you can with what you have - if it matters, you might try sending the output from a really squeaky clean CD, such as Kamakiriad from Donald Fagen, or similar, thru your setup and try gain staging til it sounds best in your best quality cans - try turning the board phone level to about midway, getting a good signal in the cans with in and out levels on the phone amp, then turn the board output up/amp output down, and vice versa, listening for any noticeable change in distortion - If it doesn't seem to make much difference, then you're probably as good as it gets.

    If you ran your board outputs thru the PB on the way to amplification/powered speakers, and also the in's to the phone amp, you could mult the board outputs into the phone amp and I doubt you'd hear any level change at the speakers. The output of the board should be low Z enough to drive two sets of inputs.

    Sounds like you've pretty much optimised your monitoring already... Steve
     
  15. Doublehelix

    Doublehelix Well-Known Member

    I thought about that too, but didn't want to compromise my sound at the monitors. I know many would argue with me on this, but the sound quality going to the monitors is *much* more important imho than to the headphones. When tracking, I have never had any complaints on the quality of the sound in the cans, so I guess that I am probably making a big deal over nothing. I took the advice of using an insert Y-cable, from the headphone output to the L & R inputs on the back of the headphone amp, and it is working just great!

    I have another problem that I need to solve now, but that should be an easy fix (I think). The Aux Outs are mono, and since wiring up the patch bay, I am only getting the aux mix in one ear of the cans! Grrrr...I do have a mono switch on the headphone amp that I have been using until I can make *another* cable (it never ends) that has a mono 1/4" on one end, and a stereo 1/4" on the other end. I will just solder both the tip and ring leads from the stereo end to the tip of the mono end, and that should just give me a mono aux send in both ears...better than having to mono the entire mix when tracking!

    Brock...the mixer is an old POS live board (Peavy) that I am using to route the monitor sends. There are no groups sends. It used to be the mixer that we kept on stage for our on-stage monitor mixes... I never send anything through the board that gets recorded. I have another mixer on my wish list, but right now it is about #3 or #4, so it is going to have to wait a while!!! That is unless you would like to make a small contribution to the "Doublehelix Fund"??? :) Hehe...
     
  16. BrockStapper

    BrockStapper Guest

    well, for me money is no object... and hasn't been for quite some time...
     
  17. Kurt Foster

    Kurt Foster Distinguished Member

    Brock,
    That's nice...good for you. :D
     
  18. BrockStapper

    BrockStapper Guest

    well, actually what I meant was that money is no object for me, at least no object I currently have in my pocket or bank account...

    soooo, I started considering myself a non-profit organization. Don't know if the IRS will buy it or not...
     
  19. Doublehelix

    Doublehelix Well-Known Member

    Fats:

    I am using the PreSonus Digimax...I did list it in my long post above...you must have missed it. I use the 8 mic pres there, then I still have the 8 line ins on the Layla free. This is where I plug in the line signals, or if I need more than 8 mic pres, I have a couple of ART Tube MPs that I can plug into a couple of those line inputs...

    I have a couple of the ART Tube MPs, not the Dual MP Pro...not sure if they are similar or not... I paid less than US$100 for each one, and I always felt that they were ok for the price...I can tell you that the Digimax is 5 billion times better however!!! (Better clarity, tone, etc.) It is hard to describe the difference, but it is like night and day! I honestly used to get some pretty good results with the ART units, so I don't mean to sound like I am slamming them too much.

    Brock:

    Hehe...I'm with ya here buddy! I keep telling my wife that I'm gonna win the lottery some day...but until that time...<sigh>
     
  20. Kurt Foster

    Kurt Foster Distinguished Member

    DH,
    Ok I see it now... I venture a guess and say that the difference you're hearing between the pres is the difference of solid state and tube stages. I was under the impression the MP Pro was the same topology as the Dual MP's but with more features... meters, clip lights . I could be mistaken, wouldn't be the first time. I have asked on Forum about these before but I received no reply..... Thanks, Fats
     

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