Upgrading your AT-LP120 turntable

Here's an excellent explanation of the preamp circuitry, which also includes a preamp removal and a pre- and post-removal comparison.

I'll take his word for the sound improvement - after all, he's right there - but I cannot detect it (and I don't see how those commenting can hear the clear difference they seem to). But maybe it's my ears or my computer (though I used good headphones).

 

1. I removed it but wouldn't do it over again. It's a very small difference IMO.
2. Very hard to say, records now are cut at a much lower volume than older records. You will want more power for newer records and many times the pre-amp in a receiver may be lacking but ymmv depending on receiver. If you only listen to records pressed in the '80s or before, this probably won't affect you. The built-in amp on the AT-120 is garbage and very noticeably lacking when playing new records. Even if you don't remove the pre-amp, you should bypass it and replace it with something else.

 

Someone at this forum had the opposite view and, perhaps with the aid of the power of suggestion, I tended to agree. I've been using the pre-amp for awhile, but I'm going to give the by-pass another go. Frankly, whether it's aging ears or otherwise, I don't hear much difference with any of these upgrades. I'm in the market for a vacation house (I currently live in an apartment), and I suspect I will do some audio retooling when I get to that point. Right now I don't have much of an opportunity to air out my music, so to speak.

 

The built-in pre-amp is fine as long as you use it. If you wish to use an external pre-amp (or the phono input of a receiver), flipping the switch on the back from Line to Phono does not bypass the built-in pre-amp completely, and leaves in the signal path some filtering components (designed to prevent the nearby USB circuitry from interfering with the audio) that can and often do negatively impact the sound quality, usually causing a loss of treble response. I noticed this right away when comparing the LP120's built-in pre-amp with using an external one with the switch on the back set to Phono.

For me, the biggest advantage to removing the built-in pre-amp was giving me the ability to use any kind of phono cartridge I want, from ceramic to moving coil, without needing to worry about whether or not it will be compatible with the built-in pre-amp and how the filtering in the signal path will mess with the capacitance and resistance loading of the cartridge when using an external pre-amp.

As for the new AT-LP120X model, Audio-Technica claims that they improved the built-in pre-amp -- and so far users seem to give it good reviews in terms of audio quality, even when using an external pre-amp with the built-in one switched off but not removed -- but an Audio-Technica engineer stated that it still has the aforementioned filtering in the signal path because it was required to meet FCC certification; nonetheless, he insisted that it should have no negative impact on the sound quality, unlike with the original LP120. Audio-Technica also now offers the AT-LP140XP "professional" model, which is very similar to the LP120(X) but does not have a built-in pre-amp.

 

Do you have a preference - line + built-in vs phono + external? Sounds like you prefer the built-in (assuming no removal, of course)? I'm going to try a comparison again, but I don't think I'll notice a difference. Last time I tried, I thought the built-in sounded better, but I don't think I could take the Pepsi challenge on it.

 

Here were the comparisons I recorded:

Using the built-in pre-amp (at 7:25 in the video):


Built-in pre-amp removed, now using the phono input of a Technics receiver (at 4:25 in the video):
Audio-Technica AT-LP120 turntable modifications

 

This seems to be the most simple method of preamp removal. It's solderless, which appeals to me. I don't want to unsolder and resolder the wires to the circuit board. The connections are so close together I'm afraid I'd link two together. I might solder the two wires together, though this guy just used small screw caps.

 

Removing these crappy built in preamps was a significant sound upgrade and the smartest decision I’ve made with 2 AT-LP120 turntables. It’s a major sound improvement and not some subtle difference. Highly recommended! Either do it yourself or bring to a shop. I think I paid around $150 to have 2 turntables done.

 

I removed the internal preamp using the solderless method and it was much easier than expected. I realize everyone has differing levels of diy-ness so “easier” is relative. One trip to the hardware store for wire caps and a ground wire that ran from the table to the new preamp was all that was needed.

I remember the sound got brighter, there’s a post a couple of years ago where I spoke about this.

 

Yeah. The hardest part looks like fashioning a solid styrofoam base to safely invert the TT.

 

I’d say the sound doesn’t just get brighter but much, much better. I typically listen with high quality headphones 90% of the time. Maybe similar in some respects to a major cartridge upgrade, at least for myself.

 

What about the preamp? The Pro-Ject Tube Box S seems to be an affordable option, but every time I switch out my cart/stulus I have to turn the premap over and change the settings? Seems like a pain. The Pro-Ject Tube Box DS2 is much more expensive. I don't need two TT inputs, but it appears as though it's easier to change the settings.

 

Just ran this test - TT preamp + "line" vs external (receiver/amp) + "phono" - and my conclusion was the same as yours. On the latter, I at the very least noticed a treble loss on the high notes (I used Bach organ works as my test record, given their often extreme treble-bass variances in short periods of time).

 

Not an LP upgrade per se, but I get better sound with my speaker grilles off (though I wouldn't leave them off). I heard about that some time ago, but I decided for some reason to leave them on at all times.

 

It seems to me that the improvement from removing the preamp is in the higher frequencies. My 65 yo ears don't go up there any longer. There is a thread on Audiokarma showing how to bypass the low pass filter w/o removing the preamp. This is where the problem is. I am fine with mine as is as it's still under warranty.

 

Tube box S2 works really well for me with this turntable, along with an Ortofon Blue cart. Most MM carts will work fine on the same settings so I don’t mess with it on the rare occasions I switch carts. The gain is easy to change on the front without having to adjust the dip switches on the bottom if needed.

 

Hi all,

Getting up to date with this thread I realized I never came back with the Bellari issue. Long story short it sounded horrible and I was really frustrated with it. Got in touch with ROLLS and received prompt feedback.

It turns out one of the switches was faulty and had to be replaced. I was able to detect the issue because half-pressing the switch the sound was as it should’ve been or that’s what I thought. In the end I was right. I bought a few of them (just in case) from an Amazon Marketplace seller for like 3 USD each and got it fixed by a technician here.

The result is it sound great. It sounds great I must say and gives a nice warmth sound. I have a few different tubes (some new and some NOS) so I can test different flavors. To the dismay of those supporting the removal of the crappy internal amp I have not touched it because I plan to sell the table at some point due to a potential move to Australia when things open up after the pandemic hopefully ends.

Best to all!

 

This is completely unnecessary, simply remove the headshell, secure/tie the tonearm down, remove the included round metal 45rpm adapter (important!), and flip the deck over onto a towel. Just make sure to grip the dust cover and base together when you turn it over so the cover doesn't fall off. The dust cover is a rigid square- it evenly distributes the weight of the table when placed on a flat surface.

 

Hey everyone, I've been reading this thread for a few years and finally decided to go ahead and pull the preamp out of my turntable. Well, one-half of my turntable now sounds incredible. However, my left channel provides a loud hum at all times and I'm not really getting hardly any sound out of the left-side speaker. I get some treble sounds from the LP on the left side, but the mids and lows seem to be taken up fully with the hum. I am wondering if anyone has had a similar experience or if anyone knows how I could go about fixing this. I have the ground wire connected to the back of my receiver, but I do get a much louder hum if I put my hand near the cartridge, or if I touch the left RCA cable where it is plugged into the receiver.

I will say that when I was in my turntable, working on the removal, I had the ground wire connection that is next to the left and right channel origin come loose. Poor soldering from the factory, I guess. Anyway, I had to scrape away some solder resist on the circuit board, put down a small piece of copper tape and re-solder the ground connection to the circuit board and I feel like this can't be the cause of my hum, because it's not both sides that are giving me a problem.

Final piece of the puzzle is that I have a three-year old Ortofan 2M Red that has always worked just fine, so I feel like it would not be an issue with the cartridge itself because why would it suddenly just show up right after I pulled the preamp out? I'm confident that it has something to do with the RCA wiring, but I have no idea what I could have done wrong. I am open to literally any suggestion as to what the issue could be.

 

Did you check the connection from the headshell to the tonearm? Maybe the four pin contacts are clean and the locking collar is screwed on tightly.

 

I have not pulled the pre-amp out of mine yet but have certainly considered it. It makes me nervous messing around with the internal circuitry even though I used to be in the business of electronic board repair. What you describe sounds like a loose connection. Let us know if you're able to track down the problem.

 

Pull the preamp, it's worth it. When bypassing the preamp with the switch it's still rolling off the high frequencies.

 

Well, I ended up having to take it in to get repaired. Guy who fixed it said I did everything right, he said I just didn’t finish the job. I’m not sure what he meant by that and I was in a hurry, or the wife was anyway, so I couldn’t ask for specifics. I think maybe I didn’t solder properly? It was an easy job to do, up until I couldn’t locate the source of the hum so maybe just make sure when you do it, you have a friend who can check your work or something of that nature. Anyway, it definitely sounds much better now with the preamp pulled out. Ultimately, though, I think I will be upgrading to a new table within the next year or so. I’m looking at a Fluance RT85. The solid wood plinth really has me interested.

 

This is why I’m hesitant to pull the preamp out of mine. I just don’t trust myself with a soldering iron.

 

What would be the next step up from that turntable, and would it have been more cost-effective purchasing the next step up or the AT-LP120 (and performing the updates/upgrades)?