Audio-Technica AT-LP120 Preamp Removal (Detailed Instructions Video)

Discussion in 'Audio Hardware' started by FrankieP, May 20, 2013.

  1. JimSpark

    JimSpark Forum Resident

    To Ben Adams, Dr. Metal MD, and Budsyr: What counterweight are you all talking about? I'd be interested in checking it out for my AT-LP120.

    Thanks!
     
  2. Dr. Metal MD

    Dr. Metal MD Forum Resident

    Location:
    Coruscant, Ohio
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  3. mattanderson

    mattanderson New Member

    Here's my completed handiwork.

    I de-soldered the wires connected to the tone arm board, and then directly soldered the RCA's to the board. I also just cut the ground wire going to the pre-amp board, and soldered a new wire to it for my ground.

    Unfortunately, I am getting a bit of hum, as well as a faint "helicopter" sound, so it seems like the ground is bad or I failed somewhere. Has anyone else experienced similar symptoms?

    Guess I should have used wire nuts. :hide:

    [​IMG]
     
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  4. Budysr

    Budysr Well-Known Member

    Location:
    Pensacola, FL.
    Did you not remove the preamp while you were in there?
     
  5. mattanderson

    mattanderson New Member

    Oh it's gone. It normally mounts to the plastic posts you see in the top right of my pic.
     
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  6. Ben Adams

    Ben Adams Forum Resident

    Location:
    Phoenix, AZ, USA
    No matter what, with this table you're going to have some motor noise which may account for the "helicopter" sound. It's just a fact of life for an inexpensive direct drive table. The humming, on the other hand, is something else. There shouldn't be humming. Could be something in the wiring, could be your cartridge, could be something in the tonearm. I would double check your cartridge lead wires first.
     
  7. Poison_Flour

    Poison_Flour Well-Known Member

    This turntable does have noticeable motor noise in my needledrops

    I have started to notice a hum recently as well which I put down to bad grounding on my behalf need to get around to updating the rca cables and ground on this soon
     
  8. mattanderson

    mattanderson New Member

    Thanks for the responses.

    I got the hum to mostly go away by fiddling with the ground and making sure the ground was secure.

    I also figured out the "helicopter" sound -- it was EMI from my wireless router! Even just having the router within 6 feet or so of the TT causes pretty noticeable interference.

    So, for now, I've relocated my wireless router, and everything sounds great.

    Now I'm thinking about rewiring the tonearm and bypassing the first PCB, as well, though, and swapping in some shorter and higher quality RCA's.

    A couple guys over here seem to have done that with success: http://www.vinylaudio.net/index.php?topic=15.0
     
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  9. mattanderson

    mattanderson New Member

    Welp, last night I listened to the noise floor with the turntable turned off, and then on, and the TT added no noise floor whatsoever. So I think rewiring the tonearm would be extreme overkill at this point.

    I'm just going to install my heavier rubber slipmat + heavier counterweight and enjoy listening to records for a while.
     
  10. parisisburning

    parisisburning Well-Known Member

    Location:
    Paris
    Mattanderson,

    i imagine you probably made a cold solder joint on the ground. And soldering should be better than wire nuts
     
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  11. kyleboedeker

    kyleboedeker New Member

    After reading and obsessing over this for a few days I just removed my pre-amp last night. Sounds great! Unfortunately the smallest wire nuts at the home depot were still too big, so I just taped the wires :/.... Now my only issue is that it seems more sensitive to dust than before. I'm getting pops and cracks on some vinyl that seems relatively clean. I guess I need to buy one of those spin cleaner things.
     
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  12. G Bo

    G Bo New Member

    Location:
    Denver
    Hello Everyone,

    I've been following this thread and am ready to take the plunge and get rid of this pesky built in pre. However, like Deangersmith I have the older model (without the USB connection) that contains the bypass switch below the platter. The video is extremely helpful but I'm looking for further clarification on where to cut the wires. Looking at my picture below, I'm assuming the yellow board is the pre and the small rectangular board next to the grounding spring is the bypass switch board. I don't believe there is a way to remove the bypass switch board. What is the best way to bypass that? There are also two red wires soldered to the main board that look like the power supply for the pre - can I simply unplug that or do I need to cut those as well?

    Any help is greatly appreciated. Thank you!

    [​IMG]
     
  13. vlds8

    vlds8 Active Member

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  14. Dr. Metal MD

    Dr. Metal MD Forum Resident

    Location:
    Coruscant, Ohio
    I'm not sure. It doesn't feel THAT much heavier to be honest. However, it is closer to the tonearm with the same tracking force as the stock weight, so it certainly is heavier. I think I've noticed improved sound quality and tracking with it. It's not night and day difference, but it's a cheap upgrade that seems to help.

    Speaking of cheap upgrades, I have been eyeing record clamps or weights to help stabilize my records on my AT LP 120. I read about using a hockey puck as a weight, and since that is a great deal cheaper than a dedicated TT weight/clamp, I tried that out. I drilled a hole in the center, not completely through the puck, using a 15/64" drill bit. With this bit, the puck fits tight enough against the spindle that I can screw it down and use it as a clamp AND a weight. So, for $3, I get a new record clamp and weight. Just thought I'd share. I have noticed a widened soundstage and better bass performance. It helps tame some warps, but on others, I would need outer clamps. Very, very easy and cheap upgrade for those wondering about disc stabilizers. It makes a noticeable difference.
     
  15. kyleboedeker

    kyleboedeker New Member

    Just an update. Been enjoying the TT for a couple weeks now sans preamp. Picked up one of those corkstone cork mats off ebay and am really digging that. For $30 it's hard to beat! I also just bit the bullet and ordered an AT440MLA cartridge. That comes in tomorrow. I'm hooked up to a Pioneer SX-727 with Kef C-40 speakers. The speakers may be my next upgrade, but I'll see how they sound with the new cartridge.
     
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  16. Dr. Metal MD

    Dr. Metal MD Forum Resident

    Location:
    Coruscant, Ohio
    Nice buy with that corkstone mat. I have the same one, and I loved it. I noticed an immediate improvement in sound quality after replacing the stock Audio Technica mat with that one. Plus, the corkstone mat looks awesome on the turntable.
     
  17. rst72

    rst72 New Member

    So, does this mod make sense if only running pre-amp directly through powered speakers vs using a typical receiver/speaker set up?
     
  18. Ben Adams

    Ben Adams Forum Resident

    Location:
    Phoenix, AZ, USA
    I think I may be unclear as to what you mean. In essence, by removing the built-in pre-amp, you're turning this into a regular turntable. It will need a phone stage, either an external pre-amp or a receiver with phono inputs.
     
  19. rst72

    rst72 New Member

    Sorry...yes, was curious if anyone did this mod to run through an external pre-amp, powered speakers and saw positive results.

    Anyhow...I just did it. Sounds great through tcc tc750lc preamp and jbl lsr305 speakers.

    So worth it!
     
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  20. Ben Adams

    Ben Adams Forum Resident

    Location:
    Phoenix, AZ, USA
    Glad to hear it!!! :)
     
  21. parkmebike

    parkmebike Well-Known Member

    Location:
    Wisconsin, USA
    Another happy person here now with a preamp-less AT LP120! Man, what a difference in sound - I was hesitant at first but am so glad I did this. I couldn't have done it without the video and all the great information here so big thanks to you guys. Only trouble I had was the ground wire, I had first connected it to the ground wires on the audio cable and got a terrible hum. Once I read through the info again, I found that I needed to attach it at the spring screw, now sounds great.

    Has anyone got a response from Audio Technica in regards to this preamp? I'm going to send them an email to let them know what I did and how great it sounds without it. They've been pretty responsive to emails I've sent in the past.

    Thanks again!
     
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  22. Ben Adams

    Ben Adams Forum Resident

    Location:
    Phoenix, AZ, USA
    Glad to hear you love the mod!

    I've never considered writing AT about this. I guess I think they'd probably send a "That's great, but you just voided your warranty" letter back. :D
     
  23. Tokamak

    Tokamak New Member

    If you don't mind my asking, what analog-to-digital converter are you using and where did you get it. I've been looking for something better than my Sound Blaster X-FI HD (SB1240).

    Thanks!
     
  24. Ben Adams

    Ben Adams Forum Resident

    Location:
    Phoenix, AZ, USA
    Just my old MiniDisc deck, which provides on-the-fly ADC at 20 bits.
     
  25. Arvid Audio

    Arvid Audio New Member

    Location:
    Issaquah, WA
    Just something to consider: Back in 1987, I used a fender washer spray painted black and a little string of black speaker putty (don't remember the official name) to attach it to the rear of my TT counterweight to put more weight on it and get it as close to the gimbal as possible. And it's still there.
     

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