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

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

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  1. Octavian

    Octavian Forum Resident

    Location:
    Louisiana
    Yup. No reason to buy this table in my opinion. The Technics that I bought is far superior
     
    Cyclone Ranger likes this.
  2. Dr. Metal MD

    Dr. Metal MD Forum Resident

    Location:
    USA
    I would say that if you are worried about having to take out the preamp and you have a slightly higher budget, find a lightly used Technics 1200, preferably one that has never been used by a DJ.
     
  3. Jam757

    Jam757 Forum Resident

    Location:
    Seattle
    My LP120's are absolutely work horses, love both of them immensely which produce absolutely amazing and stunning sound quality. Incredible machines for the great price of around $250. They both track great, barely any inner groove distortion and/or skipping. I paid to have my pre-amps removed as I certainly didn't trust myself to do it. Overall investment around $300-325 and you're in business. I loved them before removing the preamps but it just takes the sound quality to that "next" level.
     
  4. TheGratefulDane

    TheGratefulDane Member

    Location:
    Indiana
    So I'm looking to perform this mod myself, though, I do have some questions before I get started.

    This question may have been answered time and time again, but I really want to make sure I understand this properly: Is it acceptable for me to use spare speaker wire as the new ground wire?

    On that note, I should take a moment to explain my setup as the new ground wire spade hook is an interesting concept. From the LP120, I currently have the integrated RCA cables plugged into an RCA-to-3.5mm converter cable (I think this shipped with the TT). From there, the 3.5mm male end is plugged into my Schitt Fulla 2 pre-amp front audio-in. From the back, a 3.5mm-to-RCA cable feeds from the Fulla 2 into the "VIDEO-2 AUX" input of a JVC R-X350V receiver. From the receiver, speaker wires feed into my towers.
    Given this setup, is it absolutely necessary for the new ground wire to be attached to the pre-amp (the Fulla 2 does not have a receptacle for a ground wire), or can I attach the ground to the receiver while still keeping my connections the same as they currently are?

    I appreciate any and all suggestions.
     
    vince2398 likes this.
  5. urbanj

    urbanj New Member

    Location:
    Earlysville, VA
    I need help with (HUM) after removing the pre-amp.
    I am using a Pro-Ject Phono Box MM.

    I removed the solder points and need someone to tell me if I have a continuity problem.
    Are all red, white and black on the same plate?
    Red, white and black all have continuity when checked.
    The speakers are working fine, but I can't seem to get rid of the buzz.

    I un-soldered everything
    [​IMG]
    I checked continuity (There is continuity between A - B / A - C / B - C (Is that correct?))
    [​IMG]
    I re-soldered using new cables
    [​IMG]
    I connected a new ground
    [​IMG]
     
  6. Richard--W

    Richard--W Forum Resident

    I'm the last person to know, but first, your images are not visible in the post. Check the images.

    Second, do you get a buzz when you play the radio or CD's?
     
  7. Davey

    Davey NP: Portishead ~ Portishead (1997)

    Location:
    SF Bay Area, USA
    You have to be signed in to see images attached to most sites like vinylmeplease, so you would need to host them someplace like imgur and then post the links here for us to see them, or people can see the thumbnails in your thread there ... Removing The Pre-amp From An At-lp120
     
  8. Zatoichi

    Zatoichi Forum Resident

    Location:
    Wisconsin
    Hum.. suggests Ground issue. Make sure your using a thick enough wire.
     
  9. urbanj

    urbanj New Member

    Location:
    Earlysville, VA
    Let's try these photos.
    I hope they work.
    (this is un-soldered) You can see they are all attached to one plate which, when checked, are show continuity.
    [​IMG]
    This is my ground wire which should be plenty big.
    [​IMG]
    This is everything re-soldered.
    [​IMG]
     
  10. Davey

    Davey NP: Portishead ~ Portishead (1997)

    Location:
    SF Bay Area, USA
    Looks like you forgot to connect the left ground from the tonearm wires to anything. The red (R+) and white (L+) are connected correctly to the center conductors on the phono cables, but for some reason you tied the two phono cable returns together and connected them both to the right return on the tonearm wires from the cartridge...

    [​IMG]


    I've never been inside one of these AT tables, and I guess there's probably more than one way to do the mod, but this image below looks like the way I would do it, and is more like a normal turntable would be wired ... I guess that is a small resistor that some people leave and some remove to connect the left ground, think I'd remove it like below and take the returns separate to the phono preamp to avoid the possibility of ground loop hum. Wires of course don't have to be in the same order shown below, but looks like it lays out a little easier on the phono cable side with his order as opposed to yours.

    [​IMG]
     
    Last edited: Sep 3, 2018
    Ben Adams likes this.
  11. urbanj

    urbanj New Member

    Location:
    Earlysville, VA
    I watched a few different videos and people were tying the two returns together.
    The original board didn't have a wire attached to the end return and I saw someone else shorted out the jumper and split the return.

    Is there a "correct way" to do this?
     
  12. Davey

    Davey NP: Portishead ~ Portishead (1997)

    Location:
    SF Bay Area, USA
    The correct way in my mind is to let the phono preamp designer decide how to properly handle the returns, so they should be separately routed to the preamp and not tied to chassis ground at the turntable, which is how most turntables are wired. Like I said above, I don't know much about this mod so you shouldn't put too much weight on my advice, but I personally wouldn't do it the way you showed.
     
    Last edited: Sep 4, 2018
  13. Dexter_prog

    Dexter_prog Active Member

    Location:
    Argentina
    For someone that doesn't want to rip off the preamp (TT is under warranty) and owns an ART DJ Pre II, should I bypass (switch) the preamp and use the ART or just stay with the built in preampt and save the ART for another TT? I read that bypassing worsens sound by some way I didn't understand (as mentioned here: the_multiformous: AT-LP120 Pre-Amp Removal Mod - Test Recordings )
     
  14. draden1

    draden1 Forum Resident

    Location:
    Des Moines, IA
    I found that I enjoyed the sound more when I used the bypass switch and ran the signal into a standalone phono pre. Try it and trust your ears....enjoy!
     
  15. I
    I don't own an AT-LP120-USB, but I have an USB turntable and I can tell you: The ART DJ PRE II is a real improvement over the built-in preamp. Actually, I consider the DJ PRE II a product with an unbeatable price / quality relationship.
     
    bru87tr likes this.
  16. Dexter_prog

    Dexter_prog Active Member

    Location:
    Argentina
  17. "A" sounds more detailed ("prettier") because of the higher treble content, but "B" sounds "ballsier" to me because of the more present mids. The overall EQ curve is flatter, more even on "B", while "A" has more of a "smiley" EQ curve in comparison. I think both samples have their own merits, but I'm almost sure that "A" would win in a poll because there seems to be a direct correlation between the amount of treble and "fidelity" in a sound wave for many people.
     
    Clonesteak likes this.
  18. Dexter_prog

    Dexter_prog Active Member

    Location:
    Argentina
    I kind of concur, even though I though B sounds like the highs were cut off a bit, like there was some high cut filter going on (haven't analyzed the spectrum to be honest).
     
  19. bru87tr

    bru87tr 80’s rule

    Location:
    MA
  20. JRingo

    JRingo New Member

    Location:
    Hialeah, Florida
    Reagrding the ATLP 120, I am in the process of upgrading it. I already removed the preamp, which I was very hesitant to do. I thought about it a lot before I finally did it and I am very happy now. Do not be afraid. It is easy to do. However, if you have no experience soldering, I recommend taking the TT to an electronics repair shop to solder the RCA and ground wires. You do not want any humming. These wires are very thin and not so easy to make good connections. The sound improvement was huge. I am receiving a heavier counterweight that I ordered two days ago at www.lpgear.com. Next, I am going to replace the felt mat and try a rubber/cork mat. Any recommendations about mats?
     
  21. hlennarz

    hlennarz Forum Resident

    Location:
    Germany
    Get an "AVSKILD" from ikea. It's 5$ for a pack of 4. So even if you are the most clumsy person out there, you can mess up multiple times, lol
    Cut out a platter sized circle and you are done with a perfectly fine cork matt minus the upcharge of any vinyl-gear branding.

    AVSKILD Place mat - IKEA

    Been running with it for a few months now and I never want to go back. I especially enjoy that it's not atracting any dust unlike my former technics rubber-matt, wich was basically a magnet for dust.
     
    vince2398 likes this.
  22. ibanez_ax

    ibanez_ax Forum Resident

    I have this one.

    https://www.amazon.com/gp/product/B003DQILKO/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
     
  23. Octavian

    Octavian Forum Resident

    Location:
    Louisiana
    I personally didn’t find soldering very difficult. I didn’t do this exact procedure but I took apart my Technics SL-1200 because I had to add some grease to the spindal and also install a brand new tone arm, meaning I had to solder a bunch of small wires to a little circuit board. It takes some patience but as long as you don’t rush it it’s quite simple.
     
  24. Richard--W

    Richard--W Forum Resident

    which counterweight did you choose?
     
  25. Zatoichi

    Zatoichi Forum Resident

    Location:
    Wisconsin
    I recently did a lot of testing with different alignments, I found this one is the best, uses the most accurate measurements for the table. Make sure you use A4 for paper size when printing.
    Box
     
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