where is my turntable distortion coming from?

I’ve got a technics 1200 MD3 turntable. I run it into a little RIAA-certified (or whatever) phono amp - that is, one that simply brings it up to “line level” and doesn’t have any sort of gain control on it. It has RCA outputs, and I use RCA–> 1/4" cables to run it into the inputs of my mixer (a mackie desktop mixer). I do this (rather than just using rca->rca cables and running it into the tape-in) so that I can use the aux send to send its feed to my sampler (which I can’t do if I run it into the tape-in, as it bypasses the aux bus).

The problem is that I get a very fuzzy, poor-quality sound. It’s subtle; I didn’t even realize it until I listened to a recent record on a friend’s cheap belt-driven turntable. It sounded 10 times better on his bobo setup than it sounded on my 1200 w/ ortofon cartridge!

So, what’s the deal - why am I getting crappy sound quality? Is it that I’m going from RCA to 1/4"? Is it some sort of impedance issue (i’m pretty ignorant when it comes to that stuff). I don’t think I’m overloading the mixer’s input, because the signal is actually pretty weak (i have to put it into +4 rather than -10 just to get a decent level).

I could fix this for you if I was there; however, instead I’ll have to make a bunch of suggestions to try to troubleshoot the problem. I can’t see there being a distortion problem unless you have the channels your TT is plugged into on the Mackie on Mic instead of Line. There ought to be a pushbutton for it. Another place to look is in the gain controls for the two channel strips. They may be turned up too high. Is it a mixer that has, i.e. 4 mono channels (or more) and one or two stereo channels (one fader for two channels of input)? Have you tried plugging the preamp into the stereo channel? If an inadvertently wrong mixer setting is not the cause, can you plug the preamp output directly into an amplifier’s line in and see if it still sounds bad? If it’s not the mixer, it’s the preamp. Is your cartridge MM (moving magnet) or MC (moving coil)? Those have different impedances and output voltages; you can’t listen to one on the other’s settings. Your preamp most likely does not have a MC input.

Try those, and see if anything changes. Hope that helps. If not, maybe come back with a description of how your system is wired up.

Fishbicycle has hit most of the key factors, but I’ll throw in my two cents as well.

What mackie model is it - some of the lower end models have some iffy preamps, especially when dealing with unbalanced signal. My order of troubleshooting this would be:

  1. check input signal gain via PFL switch.

  2. try a different channel on the board.

  3. check the signal from your headphone jack and/or an aux send, to eliminate an internal mixer issue.

  4. balance the signal, by going RCA to 1/4 into a decent DI box, from there XLR to board pre.

  5. swap out all cabling, one piece at a time from the TT to the main out.

  6. swap in a different signal source and/or plug TT into a different preamp/console.

  7. check post mixer issues - power amp, crossover, snake etc. Very unlikely but possible in certain circumstances.

Just my thoughts.

Ok, I’ll try to break it down like this. It’s a Mackie 1202VLZ mixer. This is the preamp. The turntable is a standard Techincs 1200 MD3.

The output of the preamp runs into one of the stereo channels on the mixer. I also have synthesizers and mics running into the mixer, as well as a CD player running into the tape-in. The “control room out” on the back of the mixer runs into a breakout box, which goes to an audio cards in my computer. The output of this breakout box feeds the powered monitor speakers.

I should specify that everything else sounds great - I’ve had this setup working this way for a few years now with no complaints. Mics, any other line-in sources like synths or rack units, etc. always sound great.

I’ve checked the cabling, different mixer setups, etc. and nothing seems to work. It just has that oh-so-slightly overdriven sound - too much sibilance and “shh” type sounds on trebly parts. I thought it was just that my records had needle burn, since I have 95% old, used records. I was shocked when I put one of these “worn out” records on a friend’s cheap hi-fi and it sounded magnificent.

Sounds like a signal noise issue. i would say try a nice direct box - as I mentioned above, it will convert an unbalanced 1/4" into a balanced XLR. The sturdiest, cheapest one that I would recommend (and I in fact have about 10 of these for my generic, knockaround boxes) would be the Whirlwind Imp.

It also has a ground lift switch (useful, particularly if you’re spinning in rooms with less than steller wiring to eliminate 60 cycle hum).

The biggest advantage is that you’ll be able to use the XLR inputs on the 1202, which are, IMO, far superior to the 1/4 inserts. The balanced signal will also provide a better signal-to-noise ratio than an unbalanced one.

Um, that would be stellar.

It’s drunk and I’m late… :smack:

I never considered using a DI. I’d rather not lose two of the XLR inputs, though - I have four Sm-57’s running into it right now. I still can’t imagine that it’s just the use of the 1/4 inputs that would be making it sound so bad - it would be more obvious. To me, it sounds like a very subtle overloading at some point - I just can’t figure out where.

Thanks for the input.

See the “SOUNDS LIKE CRAP” switch on the side of the turntable? Flick that to the “OFF” setting.

Is it possible that your records really are worn, and that your friend’s cheap stereo doesn’t have enough high end to reproduce the distortion?

Have you inspected and cleaned your stylus? One speck of lint can make a record sound fuzzy.

Yeah–what picker said. In addition…

Your Rolls pre-amp appears to be MM only. Are you sure that you do not have an MC cartridge? Without the proper pre-amp boost, an MC cartridge will sound weak and muddled.

Here’s another suggestion: do you have a stereo receiver or integrated amp with phono inputs? Connect the TT to that, take a line out from the Tape Out into the mixer’s stereo channel and see if that improves your lot.

Going over your second post, I just came up with another idea: what’s the tracking force on the tonearm in grams? Too low of a weight will make a record sound really strange, with pronounced sibilance. Do you know how to adjust it to zero grams and work up from there? How is the sound of the TT overall, besides this distortion? Do you have an otherwise normal sound, with proper sounding bass and midrange?

I have a Rolls GCI-404 Audio Interface for my computer. While it is the handiest thing since sliced bread for getting multiple sources into my sound card, it is real noisy once you turn the inupts up. I haven’t tried its phono section yet, but the instrument input has a grody noise in it that gets worse as you turn it up. This introduces the possibility that it may be the quality of their cheap little boxes… just a thought.

This is probably a waste of pixels, but the first thing I thought of was, “is the grounding wire making connection?”

"Course, when it isn’t making a connection on my turntable, there’s nothing subtle about it; I get a 60Hz hum that’s unmistakable for anything else.

The ground is most definitely connected. That one’s a rather obvious OOOOHMMMMMMMMMMMMMMMMMMMMMMMM if you forget. :wink:

I actually have the tracking force set pretty high, becuase I’m using some really thin records at times.