Page 1 of 2 1 2 LastLast
Results 1 to 10 of 17

Thread: Reel to Reel to Mixing desk - unbalanced to balanced

  1. #1
    Join Date
    Oct 2007
    Location
    Toronto
    Posts
    125
    Thanks
    3
    Thanked 6 Times in 5 Posts
    Rep Power
    39552

    Reel to Reel to Mixing desk - unbalanced to balanced

    Sign in to disable this ad
    I figured I'm not the only one who is in this situation and I thought I would run it by you guys.

    I have a Soundcraft series II mixing desk that operates at +4. My Teac 80-8 operates at -10. Ths is my signal chain:

    Mics -> Soundcraft -> 80-8 -> Soundcraft -> computer

    I have been fighting some hiss issues that I usually just do some high cut to accomodate but I got to thinking about the signals. The signal is leaving my board at +4 (0db VU on the soundcraft is 0db VU on the Teac), but out of the Teac is a -10v signal which i run into the line in of a channel on my mixing desk and trim the level up to where is appropriate. I do this so I can use the EQ on my board - I don't record w/ any EQ.

    To me it seems like an invitation for noise to have to reamp the level like this to use EQ... while it hasn't been too bad, I do notice it.

    I assume I should be using some sort of balancing interface between the 80-8 and my board... but basically I'm just increasing the levels through a different device.

    Am I being crazy? Should this balanced -> unbalanced - > balanced be a cause of noise? Is there a better way to approach this?

    For reference when signal is coming back from the 80-8 to the board I have to turn the channel gain up 1/2 way at least (sometimes more). There is at most a 5'-8' run between the 2 units.

    Any thoughts on how to get the hiss down as far as signal flow changes?

  2. #2
    Join Date
    May 2008
    Posts
    792
    Thanks
    12
    Thanked 13 Times in 12 Posts
    Rep Power
    741177
    someone with more experience (plenty on this board!) should chime in but my understanding is you should be able to change your soundcraft board internally to operate at -10.

  3. #3
    Join Date
    Sep 2008
    Location
    NW USA
    Posts
    1,568
    Thanks
    10
    Thanked 6 Times in 6 Posts
    Rep Power
    1686109
    There is a 12dB difference between 0 VU on the Teac and 0 VU on the board if one is operating at -10dBm nominal and the other +4dBu nominal. I'd guess it is a level matching issue, not a balanced unbalanced issue, as the board expects a hotter signal coming in, so you are getting the noise by having the ramp up the gain more than you should coming from the 80-8. Also, you didn't indicate what type of interface you are using on the computer. That should be set (and most can via software) for the +4 input.

    I'm assuming that the board has XLR's or TRS inputs and that you have the proper wiring from the XLR's/TRS's to the RCA's. If not, Jensen and Rane websites, both have good articles on that. I'll post a link if you need.

    If you can jumper the Soundcraft that's great, you have a manual?

    The next easiest thing would be to get a Fostex 5030 or a pair of Tascam LA-40 to put between the 80-8 and the board to match the +4 levels. You could also get the passive shifters from Ebtech, but going from -10 to +4 via transformer might get you some impedance matching issues.

  4. #4
    Join Date
    Jul 2006
    Location
    92W 39N
    Posts
    1,391
    Thanks
    0
    Thanked 0 Times in 0 Posts
    Rep Power
    211779
    Having to amplify by 12 dB or so should not be a problem. The limiting factor, by far, will be the S/N of the tape playback signal, not the input noise of your console channels. That is, the signal level of the tape hiss will be much larger than the input noise level of the console channel or the electronic noise level in the tape output signal. 12 dB of gain won't change the relative levels of those noise components. Relax.

    BTW, if you plan to use HF EQ boost, you might want to consider recording that to tape, rather than waiting to apply that HF boost at mix time and simultaneously boost the tape hiss.

    Cheers,

    Otto

  5. #5
    Join Date
    Oct 2007
    Location
    Toronto
    Posts
    125
    Thanks
    3
    Thanked 6 Times in 5 Posts
    Rep Power
    39552
    Heyo - I guess I worded it wrong... I am more concerned with the levels (but it is a matter of the outputs of the 80-8 being unbalanced and operating at -10, if it had balanced outs it would likely operate at +4).

    I have an Audiotrak Maya1010 on the computer (which is +4) but there is no issue there as I have that side all set up (board -> computer w/ Reaper running about -12dbFS when the board is 0dbVU... i know that is a bit hot!).

    I guess what is most distressing is that I am losing that level only at the 80-8 (+4 in and -10 out, yikes!)... I realize now that I should have something like a Tascam LA-80 inbetween the two to match levels.

    What I am most concerned with is how much noise an LA-80 would impart on the signal as opposed to pushing the line ins on my board.

    No option to operate the Soundcraft at -10, which is fine... I think I know my answer here! I need some type converter inbetween the 2 to get the levels up... needs to be clean though!

  6. #6
    Join Date
    Jul 2006
    Location
    92W 39N
    Posts
    1,391
    Thanks
    0
    Thanked 0 Times in 0 Posts
    Rep Power
    211779
    Quote Originally Posted by man-bot View Post
    No option to operate the Soundcraft at -10, which is fine... I think I know my answer here! I need some type converter inbetween the 2 to get the levels up... needs to be clean though!
    You can use one, but it's not needed and won't really improve things. Just use the console input gains. Again, 12 dB of gain (-10 dBV to +4dBu) is not going to make a difference in the relative levels of the noise components. The noise level will still be dictated by the tape hiss, and you will determine the signal to noise level by where you set the recorder gain, that is, how "hot" you record onto the tape.

    Cheers,

    Otto

  7. #7
    Join Date
    Oct 2007
    Location
    Toronto
    Posts
    125
    Thanks
    3
    Thanked 6 Times in 5 Posts
    Rep Power
    39552
    Thanks Otto... that answers that, line in on the Soundcraft it is! Its too bad 12db of gain is lost with the 80-8.

    As far as recording levels, I usually keep them aroung 0VU on Teac... of course when recording drums there are some peaks at +3 or more but no distortion...

    I really can't figure out my tape hiss issue then, I may have to make some new cables that are 1/4" mono (I modded my 80-8 to have 1/4" jacks not RCA) to XLR and used the transformer based mic ins on the board ot see if the noise levels are better...

    I guess its all gain staging...

  8. #8
    Join Date
    Sep 2010
    Location
    Oshkosh, WI USA
    Age
    38
    Posts
    643
    Thanks
    0
    Thanked 0 Times in 0 Posts
    Rep Power
    929185
    If you're wanting to boost -10 up to +4 I'd suggest the Ebtech Line Level Shifers. They made two-channel boxes and 8-channel reackmounts for a better value than the Tascam LA kits. Some models are 1/4" jack only; others have XLRs too. I use a couple Ebtech boxes for patching -10 aux outs from my console to our outboard gear, pretty much all of which is +4 balanced. They're quiet and they do the job. They pop up on eBay for good prices periodically.

  9. #9
    Join Date
    Sep 2008
    Location
    NW USA
    Posts
    1,568
    Thanks
    10
    Thanked 6 Times in 6 Posts
    Rep Power
    1686109
    Quote Originally Posted by man-bot View Post
    Heyo - I guess I worded it wrong... I am more concerned with the levels (but it is a matter of the outputs of the 80-8 being unbalanced and operating at -10, if it had balanced outs it would likely operate at +4).

    I have an Audiotrak Maya1010 on the computer (which is +4) but there is no issue there as I have that side all set up (board -> computer w/ Reaper running about -12dbFS when the board is 0dbVU... i know that is a bit hot!).

    I guess what is most distressing is that I am losing that level only at the 80-8 (+4 in and -10 out, yikes!)... I realize now that I should have something like a Tascam LA-80 inbetween the two to match levels.

    What I am most concerned with is how much noise an LA-80 would impart on the signal as opposed to pushing the line ins on my board.

    No option to operate the Soundcraft at -10, which is fine... I think I know my answer here! I need some type converter inbetween the 2 to get the levels up... needs to be clean though!
    Hard to say on the noise the LA-80 would impart. Note that there was a thread here a while back re I think a MS-16 or 85-16 (can't remember) and the deck itself operated at -10 with amps up and down converting the signal to +4 on the XLR inputs.

    You could just get a 48 or 58 with balanced i/o.....

    Also, any kind of amp between the 80-8 and the board is going to have its sonic impact. You could build your own using discrete opamps or something.

    You could also use the Ebtech's (the trafo might ad some color) also, depending on teh output impedance of the 80-8 and the input impedance of the board, you're using a 1:4 ratio transformer so that *could* be an issue, if the impedance on the board is rather low. Try it out and see what sounds the best.

  10. #10
    Join Date
    Jan 2007
    Location
    A Complete Unknown
    Posts
    1,576
    Thanks
    4
    Thanked 1 Time in 1 Post
    Rep Power
    18063234
    Quote Originally Posted by ofajen View Post
    You can use one, but it's not needed and won't really improve things. Just use the console input gains. Again, 12 dB of gain (-10 dBV to +4dBu) is not going to make a difference in the relative levels of the noise components. The noise level will still be dictated by the tape hiss, and you will determine the signal to noise level by where you set the recorder gain, that is, how "hot" you record onto the tape.

    Cheers,

    Otto
    So you don't think it's necessary? What about going from a +4 to a -10 mixer? I'm using an LA40 now on mine like that. If I didn't have to maybe I wouldn't. But what do you recommend for the balanced to unbalanced conversion?
    "He has erected a multitude of New Offices, and sent hither swarms of Officers to harass our people, and eat out their substance."

    _________________________
    ^^^^^^^^^^^^^^^^^^^^^^

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Can I hook up my soundcraft 328xd digital desk to my Reel to Reel? mixer suggestions?
    By fisheric in forum Analog Recording & Mixing - Tape & Gear
    Replies: 6
    Last Post: 06-19-2009, 12:17
  2. Replies: 1
    Last Post: 07-17-2006, 16:35
  3. Reel to reel desk placement
    By gororbs in forum Analog Recording & Mixing - Tape & Gear
    Replies: 5
    Last Post: 06-04-2006, 13:05
  4. logic with delta 66, vlz1604 desk and a r8 reel to reel
    By daliscar in forum Digital Recording & Computers
    Replies: 0
    Last Post: 01-04-2006, 15:36
  5. Replies: 4
    Last Post: 07-07-2002, 10:43

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •