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Need help in combining balanced and unbalanced gear

Discussion in 'Amps and Cabs [BG]' started by l0calh05t, Dec 22, 2002.


  1. Please help me, I have this new rack unit and it only has balanced low impedance (600 Ohm) +4dBu inputs and outputs, and my other gear has unbalanced high impedance -10dBu inputs and outputs. I need something which can convert in both directions. ( I found this article about how to build such a thing but the pictures of the circuit layouts are missing :mad: ) , whatever you suggest it should be as cheap as possible (hey i ain't rich!)
     
  2. I guess I'll just use simple passive transformers for the time being, but if anyone has the schematics for that level converter please give them to me if possible
     
  3. Munjibunga

    Munjibunga Total Hyper-Elite Member Gold Supporting Member

    May 6, 2000
    San Diego (when not at Groom Lake)
    Independent Contractor to Bass San Diego
    As a general rule, you can just use unbalanced connections (tip-sleeve) between balanced and unbalanced gear. It doesn't care. If you're connecting quarter-inch plugs to XLR, you will need a converter. Get one with a transformer only for impedance matching, if you need it.
     
  4. Are you sure that works? I checked the internet and it seemed that just using normal mono cables between balanced and unbalanced inputs would cause grounding problems :confused:

    Oh, btw. the unbalanced output has <200 Ohm impedance according to the manual , so I guess impedance matching isn't required
     
  5. another question: if mono cables work do they work in both directions (balanced out to unbalanced in and unbalanced out to balanced in)?
     
  6. Lord Valve

    Lord Valve

    Dec 13, 2002
    Denver, CO.
    The impedance isn't nearly as big a problem as the difference in operating level. What you need is called a bump/dump box, which can convert between output levels. One such device which can solve all of your problems is the Ebtech Level Shifter, which can convert from -10 to +4 (or from +4 to -10) and also balance or unbalance a line in either direction. As an added bonus, it also transformer-isolates grounds, thereby breaking any ground loops which may occur between the connected equipment. It's a passive box, so no batteries or wall-warts are required. Last time I checked, it retailed for around $90, which isn't bad for two channels of high-quality transformer isolated bump/dump.

    Lord Valve
    *******
     
  7. problem is, I can't find the EBTECH in germany, i found one on the website of a swiss music shop , but they don't have an online shop :(
     
  8. I was now finally able to try my rack compressor, and it worked well with the unbalanced jacks (no noticable noise), the only problem is that I can't use the full range of all knobs because of the lower input level, so now it isn't so urgent that I get this EBTECH thing, maybe I'll wait until I get other rack gear