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I'm saturating the input of my UTC transformer direct box

Discussion in 'Pro Audio Equipment' started by thebassboy, Jan 2, 2009.

  1. thebassboy

    thebassboy Guest

    Hi, Being the electronics novice that I am, I actually put together a really great sounding direct box for my recording basses (passive and active) using a UTC transformer 30hz-20k response, +8db, 50k secondary, 150/250/600 primary. I prefer the UTC's 150ohm output into my LA610 mic input. My only problem is that when I play my bass harder (dynamically/not out of control) towards the ends of recorded tunes, I hear the UTC transformer input farting out a bit sometimes--the UTC output IS NOT hitting the LA610 input too hard. On the Jensen site they have a 6.8k resistor between the 1/4 inch input tip and the transformer input of their DI schematic. I tried this and it works. But.. it doesn't seem to sound quite as good/rich as it does without the resistor. -----------My question: Does a typical high quality resistor only affect the level, not the tone into the transformer, and what would be the lowest resistor workable rating to use to invisibly keep the transformer from saturating but working hard and getting close to the good tone it has without resistor?
    Thanks,
    Keith
    http://
     
  2. Space

    Space Well-Known Member

    It's always you, you, you isn't it?
     
  3. thebassboy

    thebassboy Guest

    I don't know, Spaced. What does you, you, you have to do with my question. If you're not interested in my post, or don't like my question, actually, why don't you get "your kind of creative" on another post.
     
  4. Space

    Space Well-Known Member

    I prefer this one. We can both wait for someone..maybe JP to the 22nd power will show up.
     
  5. thebassboy

    thebassboy Guest

    Honestly, Spaced... Dude... go away
     
  6. RemyRAD

    RemyRAD Well-Known Member

    Yup. It sounds as though you are using a UTC A-10? One of my favorites.

    I wouldn't bother with the 6800 ohm resistor. I certainly never have and have not had the problems you are describing. If you have an active output bass? You may be in fact overloading the transformer? If you have a passive output pickup, you will never overload that transformer. Remember you have a 50,000 ohm input. The Jensen is 220,000 ohm. That's a little different. And I'm really not sure why one would need an extra 6800 ohms in addition to 220,000 ohms? But Dean is dead so we can't ask him. I would imagine it is there for current limiting purposes? But you really shouldn't need that. You are indicating that it's not hitting the LA 610 too hard. But have you tried engaging the pad & increasing gain? That's how you're going to get your best & most open sound. What you don't want to do is load down those passive pickups. And while I have used the A-10 D. I. since the mid-1970s & still do, I frequently love the bass, with passive pickups, into a higher input impedance. Such as the direct music instrument input on your LA 610. Consider the possibility you are hitting the input of the transformer too hard. That problem, I have experienced before from other bass players. Remember, you're actually running the transformer backwards. And in that respect, it's actually dropping the level of the bass by about 10 DB. Have you tried another microphone preamp input other than the 610? This really sounds like some kind of gain staging issue to me?

    I like my bass like I like my men. Lots of balls!
    Ms. Remy Ann David
     
  7. thebassboy

    thebassboy Guest

    Hi RemyRad,

    First off, thanks for actually trying to help with my post question. It's a UTC 0-16. It was saturating with my passive basses when played strongly. The Jensen Di transformer that everyone uses, and that the Jensen site schematic with the 6.8k resistor is for, has a 10k input/600ohm output--the same one in the in Radial JDI, but maybe Radial uses a different wiring design? When I turned down the volume control a little bit on my bass the saturation went away, but for me a passive bass sounds less punchy with its volume control set below full. The 6.8k resistor completely alleviated the saturation. The LA610 mic input meter reading is on the low to moderate side in any instance using this UTC, so it's not hitting the '610 too hard? Does the resistor the affect tone, too, and level, or is it used just for level/pad control?
     
  8. thebassboy

    thebassboy Guest

    RemyRad,

    I soloed the first bass track I did with the UTC 0-16 without the 6.8k resistor. I noticed that the DAW was getting quite a bit of signal from the LA610 with this track. I'm going to remove the resistor and turn down the output of the '610 into the DAW. If that doesn't work I'll post again. Thanks for your time.
     
  9. thebassboy

    thebassboy Guest

    RemyRad,

    The problem was a gain stage issue: the LA610 output gain was set too hot into the DAW. You were also right about it being near impossible for a passive bass to distort the UTC 0-16 input --With the LA610 set correctly in my system I couldn't get the UTC to distort no matter how hard I played my basses. Lastly, you mentioned how my setup of the UTC was actually lowering/padding the gain a bit...I think this "padding" of the bass' output before it hits the LA610 input is doing what you described about padding and boosting the '610 input gain. I boost the input gain of the '610 +6 when using the UTC, while properly setting the level into the DAW and it's sounding great. I really appreciate your help and time.
    Best,
    Keith
     
  10. Space

    Space Well-Known Member

    Gain staging is always a problem. I prefer to think of it as a loose nut on the keyboard...ironic?

    http://www.mememe.com
     

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