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

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

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  1. Zatoichi

    Zatoichi Forum Resident

    Location:
    Wisconsin
    After jumping through all the hoops.. (Removing Pre-Amp, Fixing the Anti-Skate, upgrading the Cart) the AT LP120 sounds really good with a Budgie PreAmp. I recently swapped out a cork mat for a hudson hi-fi acrylic mat and its noticeably better.

    But.. if I could do it over. I would get a Music Hall 2.2 instead. Same price. No hoops to jump through.
     
  2. thesituationist

    thesituationist New Member

    Location:
    USA
    This is a fair point. For my specific case, though, I think buying was a mistake. I have a tiny collection of around a dozen LPs, and while I'm open to buying them a bit more regularly going forward, I don't see myself becoming a huge enthusiast anytime soon (I have several other expensive hobbies that take precedence).

    Plus, I'm of the belief that lossless digital played through a good DAC will always be a more accurate representation of the original recording than any vinyl setup I'll ever be able to afford. Vinyl is more just a fun thing to collect from my favorite artists, and there are some cases where a different master is pressed to vinyl than CD. I was looking forward to having a colored sound from vinyl (at the slight expense of fidelity/accuracy), but only if it was to my taste... and that's where the LP120 is failing me. I didn't appreciate how big a deal this internal pre-amp rolloff really is, apparently, and if I'd known the hoops I'd be jumping through and that the final bill would be closer to $500 than $250 (with a voided warranty), I probably would've just held off on vinyl altogether for awhile longer.

    Now that I'm here, though, I'll definitely be ripping that demonic pre-amp out soon.

    I'm also feeling like there surely must've been a better option in the $300 range for my purposes. However, I really wanted direct drive, and it looks like the Music Hall has a straight tonearm. It seems like the LP120 has a few crucial features that are hard to find in its price range, yet those features might be worth sacrificing them for a buyer who's really averse to the risk of doing the pre-amp removal (both immediate and for warranty purposes throughout the first year of ownership).
     
  3. thesituationist

    thesituationist New Member

    Location:
    USA
    I've watched the meat of this a couple times now, and I'm feeling better about this approach. A few questions for those who followed this procedure:

    1. Was unsoldering the stock RCA cable and then soldering in the new RCA cable to the main board as painless as he makes it look? I've done *zero* soldering in my life, even though I do own a very cheap soldering iron. Watching this, you'd think you just kind of poke at the leads to disconnect, then poke around on the board's connectors for a few seconds in order to attach the new cable. This is definitely the part I'm most concerned about, as a mistake at this stage seems like it would surely be fatal. Also, he mentions something about checking for shorts, which isn't helping assuage my concerns...

    2. What kind of RCA cable should I buy if I take this approach? I assume any old male-to-male cable will work when stripping off one end, and will contain the black/ground wire that must be attached to the mainboard? It looks like the shielding shouldn't be too thick to fit through the harness, but also I'd think you want a decent quality cable since it's what you're stuck with for good once you close the table up.
     
  4. thesituationist

    thesituationist New Member

    Location:
    USA
    My LP120 is out of surgery. For now, anyway.

    TLDR: For me, this mod wasn't exactly a painless 30-minute process. However, the sound difference is beyond night and day. My main conclusion is that I wouldn't recommend the LP120 to anyone, knowing what I do now. But if you have it already, this procedure may be worth doing when you have a good chunk of time.

    I used the VinylTV guide which involves soldering on a new RCA cable, rather than cutting and re-splicing the old one with twist caps.

    Cautions based on complications I encountered:

    1. Removing the bottom panel (after the 8 screws are out) should be done with care and patience. Someone earlier in the thread reported breaking the circuit board during this process, and I can believe it. Just make sure you've already worked on each corner carefully before applying tons of force to yank it off.

    2. When you strip your new RCA cable, you'll find each channel has its own separate ground wire. In my case, I found the main L and R signal wires wrapped in white and red, and then there was some bare wire immediately outside the shielded signal wire on each channel. As far as I can tell, the correct procedure is to combine the ground wire from each channel by twisting them together to form a single "joint ground" wire (which connects to the leftmost solder joint on the circuit board). However, I'm still having some minor hum issues, so this is subject to revision when/if I figure out how to fix that.

    3. When unsoldering the original RCA leads from the circuit board, it's best to poke the very tip of the iron right at the point where the lead connects for about 2 sec, then pull the cable out firmly. If you do this inefficiently at first and engage in too much trial and error, you're going to spread molten solder around and make a mess -- there's so much of it that I came close to accidentally joining one joint with the adjacent joint, which would've resulted in a short.

    4. If you've never soldered before, it's critical to understand that Craig (in the YouTube video) is leaving out a major step for connecting the new RCA leads to the circuit board: tinning the wire. I followed his guide too literally at first, thinking I could just poke at the solder joints on the circuit board and force the new RCA cable leads in. This made a further mess on top of what I warn about in #3, since the new leads just wouldn't "stick." In reality, you must buy solder (should be $2-3, or even come with lots of soldering irons) and spread some of it on the exposed wires/leads before attempting to connect it to the circuit board. Afterwards, when connecting the leads to the circuit board, it's best to sandwich the lead between the soldering iron (top) and circuit board joint (bottom) for 2-4 sec. The solder you applied to the wire earlier will melt again and quickly complete the joining process. Good video explaining the tinning process:

    5. Re-attaching the bottom panel is the sole area step that I found most of the existing guides overcomplicate things, rather than the opposite. Forget taping the spacers down and all that noise. All you need to do is place the panel back on (without screws or spacers), make sure it's aligned properly with the screw holes (a flashlight can help with this), then drop the screws into the holes one-by-one with the spacers "on" the screws (pull the spacer up to the top of the screw, so it's snug against the screw head). This essentially forces the spacers to fall into the correct position, as long as you're reasonably careful about placing the screws straight down into the holes.

    Remaining issues:

    I used 18-20 AWG wire I had lying around for the new ground wire. I even crimped on a ring terminal for the end that gets screwed on (under the spring), and a spade terminal for the other end that attaches to the pre-amp. Unfortunately, I'm still getting some hum. I'm using a DJ Pre II, and the ground wire is snugly connected to its ground port. When I disconnect the ground wire, the hum is severe. When I connect the ground wire, it decreases by maybe 60-75%, but enough remains to be annoying between songs at moderate listening levels. I'm fairly confident I did everything correctly, so I'm a bit stumped on this. Each channel seems to have a similar level of hum. Also, I did a continuity test with a multimeter to ensure there were no shorts on the board before I closed everything up. Therefore, I'm just not sure what the next step is.

    Changes in sound:

    As promised, the sound is infinitely brighter than it was using the same pre-amp with the bypass circuit. Using an AT100e cart, the sound went from being far darker than my DAC to noticeably brighter than my DAC. I can easily see where this mod would backfire for someone who hates bright treble or finds it fatiguing, so keep that in mind. Make no mistake - the change in sound here is overwhelming, not audiophile mumbo jumbo. If the sound through the bypass circuit is 0 and with the pre-amp removed is 100, the effect of changing carts from the 95 to 100e is probably a 10 or 15, if that.

    There are lots more pops and clicks with the first couple LPs I've played, to the point of annoyance. This is very likely why the low-pass filter was included in the bypass circuitry in the first place. I'm playing fairly new LPs, but they haven't been cleaned thoroughly to remove dust and debris from the paper sleeves, so I'm hopeful that could alleviate the issue.

    And as I mentioned above, there's now a moderate hum that wasn't an issue before. I'll definitely give an update if I figure out what's going on there or how to fix it.
     
    Bluzuner, Michael Rose and nosliw like this.
  5. thesituationist

    thesituationist New Member

    Location:
    USA
    Update on fixing hum

    The reason I was still getting moderate hum even with a properly attached ground wire ended up being the crappy RCA cable I originally soldered onto the turntable. If you're doing this mod and realize you need to buy a cable, it's apparently a bad idea to rush to Wal Mart and get the $6.99 one they sell there. I found an ancient composite video cable stashed away in a drawer, so I got that out, ripped off the video side, and stripped the RCA side. What I found was that there were about twice as many strands for each channel's ground wire, compared to the Wal Mart garbage. After a second lovely soldering session, the hum is completely gone and everything sounds great.

    So to add to my list of caveats above: use a high quality RCA cable! It's not always easy to judge these by their appearance. The telltale sign of a problem will only be found when you strip them: on a good cable, the ground wire for each channel will be just as thick as the signal wire (i.e., the wire wrapped in white or red). On the cable that gave me trouble, the exposed ground wire on each channel consisted of like 8 strands total, and I think this proved to be its downfall.
     
    nosliw likes this.
  6. Dale Murray

    Dale Murray Well-Known Member

    Location:
    Illinois
    I'll add my name to the list of skeptics in regard to amp removal. I recently purchased a pair of Goden Ear Triton Fives and figured, with these speakers, I should see if there really is something to gain from the amp removal.

    I am gobsmacked. Later this week I will tackle the anti skate issue now that I am verified setting it to 7 still doesn't do the job.
     
  7. Arvid Audio

    Arvid Audio Well-Known Member

    Location:
    Issaquah, WA
    Rather than solder new RCA cables on, I drilled the case and installed gold-plated RCA jacks, so I can swap cables at will. I used a headphone extension cable that went bad to get the thin wire to connect the tonearm leads to the jacks. I cut some heat shrink tubing to pull over the arm and shrunk that into place (tonearm damping) and glued a 5/8-inch Fender washer to the rear of the counterweight to let the CW rest closer to the pivot point which improves tracking and gives more detail and less inner groove distortion. When I can get to it, I'm to put Mortite (2 layers) on the inside walls of the lower half of the case to add weight and to damp the case. I've already damped the platter, all I can think of....
     
  8. Richard--W

    Richard--W Forum Resident

    I haven't read all the posts in this thread, but I read most of them and watched the video twice.

    May I ask, when you all bought the Audio-Technica AT-LP 120 didn't you buy it because of the preamp | usb advantage?
    If it you didn't want that, wouldn't it have been easier to buy a different turntable?

    Wish I'd seen this thread before I bought mine. Jeez.
     
  9. guidedbyvoices

    guidedbyvoices Old Dan's Records

    Location:
    Alpine, TX
    Yes, that was an advantage when I bought it. I had a very limited budget, but wanted to start with a table that I could upgrade over time as my budget could handle. The USB was a nice thing to have, but I never used it honestly. So over time, I upgraded my speakers, cart, and then the pre-amp, just bypassing it. I eventually ripped it out as a cheap DIY upgrade. Some people feel its a huge improvement. I hear a more modest improvement. But for $15 of tools it was worth doing.
     
    Richard--W likes this.
  10. draden1

    draden1 Forum Resident

    Location:
    Des Moines, IA
    For me (I'm also assuming most others) the table outperforms other entry level tables after the preamp mod. Most here feel it competes with or outperforms many tables in the $500-$1,000 range.
     
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  11. Richard--W

    Richard--W Forum Resident

    But the USB port doesn't function without the preamp, right?
     
  12. guidedbyvoices

    guidedbyvoices Old Dan's Records

    Location:
    Alpine, TX
    Correct. It’s attached to the same thing. If usb is important you can get a preamp with a usb like the djpreii or whatever. It wasnt important to me so I got a Schiit mani I’m happy with.
     
    Richard--W likes this.
  13. JimSpark

    JimSpark I haven't got a title

    I bought mine without caring about either the built-in preamp or the USB. I wanted to easily change out headshells with different carts, and adjust platter speed any way I like, after my previous TT (belt drive) would have speeds anywhere between 33.0 and 35.2 RPM, depending on how it was feeling that day :p I wanted a new TT, and the similar Pioneer model was more than twice the cost of the AT.

    Before buying it, I had read many reviews of the AT-LP120 which overwhelmingly told me that the built-in preamp was garbage. I bought it knowing I wouldn't ever use that built-in preamp, because I'd rather keep using my own external phono preamp which I already had from my previous TT.

    I didn't care about it having a USB jack and hadn't planned to ever use it. I removed the internal preamp/USB 6 months after purchase, after reading the reviews in this very thread which recommended removing it :righton: I still love my AT-LP120, I have 5 headshells w/carts so I can swap them whenever, and I use the heavier counterweight, too. No complaints or regrets, and no plans to buy a different TT.
     
    Last edited: Mar 23, 2018
    Richard--W likes this.
  14. Richard--W

    Richard--W Forum Resident

    If I remove the preamp | USB, how do I feed the turntable into the computer?
    What's the simplest cleanest most direct way of replacing this disconnected function?
    and will that dampen the sound again?
     
    Last edited: Mar 23, 2018
  15. Richard--W

    Richard--W Forum Resident

    Where does one order the heavier counterweight?

    Tell me about your different headshells / styluses. Which and what for?
     
    Last edited: Mar 23, 2018
  16. JimSpark and Richard--W like this.
  17. JimSpark

    JimSpark I haven't got a title

    Well, I have the following carts on 5 separate headshells:

    - AT95e that came preinstalled with the TT. Rarely use it, but it's OK.
    - AT311EP p-mount cartridge mounted onto a 1/2" adapter. Rarely use that cart, but it has slightly more detail than the AT95e.
    - AT CN5625AL conical. The cart I want when I plan to play some 45s. Great on LPs too. Costs just $25, but I prefer its sound to the AT95e and AT311EP.
    - Grado Prestige Silver1. Less bright than the ATs, great fat midrange, probably the most enjoyable cart I own. I hope to add an 8MZ stylus to it one day :agree:
    - AT 440mlB. Sharp, crisp, definitely the most detailed cart I own, I probably run this 50% of the time.

    4 of the 5 headshells are the stock AT headshells, the AT-HS1. The Grado is mounted to a black Turntable Lab headshell that I got in an Amazon sale.
     
    Richard--W likes this.
  18. Richard--W

    Richard--W Forum Resident

  19. Claude Benshaul

    Claude Benshaul Forum Resident

    I bought mine knowing about the built-in pre-amp and the possibility that I will have to remove it. The reason I bought it was due my dissatisfaction from the RP1 and the Debut II that I previously owned. Both were inferior in about every metric that matter, except for anti-skating where all three are pretty bad, IMHO. Being able to change cartridges, steady pitch, ditching the belts were a big advantage as well as the fact that it cost half the price of an RP1. The pre-amp was replaced with an Emotiva XPS-1 and that also was a good thing because the one I have in the receiver is also very basic.

    I don't miss the USB because digitizing my record collection isn't a priority and there are better solutions or alternatives to the one included with the LP120.
     
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  20. Richard--W

    Richard--W Forum Resident

    ... but the Emotiva XPS-1 doesn't have a USB port.
    Thanks for your good reply.
     
    Claude Benshaul likes this.
  21. Claude Benshaul

    Claude Benshaul Forum Resident

    I'm sorry that I may have made the impression that it included one. It doesn't and the reasons I bought it had nothing to do with a USB interface, which I neither need nor want.
     
  22. Octavian

    Octavian Forum Resident

    Location:
    Louisiana
    So I only just recently got into vinyl and got an LP120. I'm planning on doing this mod in the next week, just have to gather supplies and get the courage to perform it.

    I see some users mentioning in the post of fixing the antiskate. I found this album with info on how to fix it. Is this the best way to go about this? I'm planning on doing this at the same time as removing the preamp since everything will be apart already.
     
  23. Clonesteak

    Clonesteak Forum Resident

    Location:
    Kalamazoo, MI
    I wish that I did the anti skate mod when I had this apart last month. Feeling lazy about opening this turntable up so soon. Smart move Beatmaniac to do this at the same time. Good luck and hope all goes smooth sailing.
     
    Octavian likes this.
  24. Octavian

    Octavian Forum Resident

    Location:
    Louisiana
    I actually decided to go a different route. I bought a used Technics 1200 instead for $400. I figured the labor + the cost to fix the LP120 was at least equal to that, so why not go with the better option?

    Now I just have to sell my LP120...
     
  25. hlennarz

    hlennarz Forum Resident

    Location:
    Germany
    Buy a Hanpin Table without a Pre-Amp -> Problem solved.

    Like the Reloop RP-4000. Pretty much the exact same TT minus the bad Pre-Amp.

    Bigger problem is the joke of a (pretty much non-functioning) Anti-Skate these tables have.
     
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