Upgrading an Audio-Technica AT-LP120-USB turntable

Here's a few pictures of the inside of my nephew's AT-LP120-USB turntable. After looking it over, we decided to remove the built-in preamp / USB PC board and route the tonearm cable directly to a pair of RCA jacks out the back.

This mod is only recommended if you already have a phono preamp, and don't plan on using the built-in preamp or USB output. My nephew uses a Cambridge 640P, so the built-in electronics were not needed.

I removed the PC board, cut out the stock black RCA cable and routed the grey tonearm cable to two Neutrik gold plated RCA's ($7 for the set from Mouser Electronics). Both RCA grounds were soldered together with the grounding wire in the grey cable. Next, Holes were drilled through the back of the top cover. You can mount the RCA's through holes on either half of the case, I choose the top half for convenience. Just make sure it doesn't interfere with anything else inside or out (cover) when locating a spot for the RCA connectors.

I used a banana plug from an old speaker binding post as the ground. I just soldered it to a wire leading to the 'grounding star' already there from the factory.

I used WBT silver solder for all of the connections, but that's only because I bought a 1lb. spool of it years ago when silver solder was cheap. Now, the same spool costs an arm and a leg. I do recommend using good solder since the signal level that will be flowing through it is very low, but any decent brand of solder should do.

The end result was dramatic. Everything sounds more open, with better extension in the bass, smoother mid-range, and cleaner highs. From what I seen on the PC board, the tonearm wire goes through a few solder connections, possibly a few resistors, then through a switch before exiting through the hard wired RCA cable. Not the cleanest path for such a low signal to take.

The next mod will be to replace the tonearm wire with a couple feet of bulk Cardas 4x33 gauge tonearm wire. Buying it by the foot, it usually goes for ~ $8 a foot, so it's not to costly. Two foot should be plenty. I'll post a short how-to article when we decide to tackle that upgrade.

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Nice upgrade. My first choice when I was going to buy a TT was the Technics SL 1200 Mk 2, and later upgrading it with better tone arm, external power supply, etc. What  I was interested in was the direct drive, which allow an extremely low wow and flutter amount: less than 0.01%, a value that only higher end belt TTs have. Unfortunately, when I decided myself to buy it, I discovered that Panasonic had already dropped all the Technics line
I didn't want an used one, and since all the cheaper direct drive clones, like the Audio Technica (which is the best among all) have a typical wow and flutter value of 0.1% - ten times higher! - I decided for a good belt drive, the Pro-Ject RPM 5.1, which doesn't need dramatic upgrades, and has 0.08% wow and flutter value.

it was definitely a great improvement, i'm interested in hearing what it will sound like with the upgraded cable, and i was thinking about going with a denon dl103R, the 160 sounds great but it seems like there is much more musical information to extract from a record as i've heard what a ZYX sounds like and nearly crapped my pants, makes me really wonder what the mega bucks cartridges, turn tables, and audio processing equipment sound like...

the nephew, lol

How does the Cambridge Audio preamp sound like?

The Denon 103r may not be suitable to the standard Audio Technica tonearm, since it has a stiff stylus and thus needs heavier tonearms to have a full, deep sound. The Audio Technica and Technics tonearms are more suitable to cartridges like the Denon 160, which have a less stiff stylus, and require lower tracking force and lighter tonearms.

the cambridge sounds good for an entry level solid-state preamp, however; I've listened to my uncles tube pre-amps and they have a sweeter sound, smoother all around, the lows are deeper, the highs are sweeter, and the midrange is usually right where it should be. the Denon 160 is what i have now, if i would try the 103r i can add a weight to the head shell to help with the mass of the arm.

Nick

Hey Ncik - if you want, you could borrow my DL-103R and see how it sounds. I have a headshell that has screw on weights for up to 4 grams of added weight. Ishin80 is right though - the 103 may not be the best match for an arm like yours due to the compliance of the 103 being so stiff.

I did experiment with 103R on my Technics turntable and it wasn't half bad, but the 103R is capable of better performance with a higher mass arm.

I think today I'll mount the 103R on the heavier headshell and see how it sounds.

We could also replace some of the parts (caps, op-amps) inside the 640p and improve the SQ a bit, if you feel adventurous. 

Here's a few samples of the DL-103R with a 2g weight (VTF set to 2.5g) on a really beat up Technics SL-235 turntable:

Gary Numan - Cars (Extended Remix - 45RPM)


Earl Klugh - Jolanta (from the LP 'Finger Paintings' on MFSL)


I used a Musical Fidelity X-LP phono preamp using the MC setting. No step up transformer was used. The recordings are in 320K .mp3 format for streaming purposes.

As you can hear, the bass is severely limited and begins to roll off after 50hz or so. The mid-range is nice and clear - as are the highs. There was some oscillation in the tonearm at a few points in the song so the tonearm was resonating at a much higher frequency then is optimal. Overall, the DL-103R wouldn't be a good match for a light Technics style tonearm.

thos clips sounded pretty good but i hear what you are saying about the roll off

hmm, i wonder what would match this tt that isn't crazy expensive but would be a decent upgrade? i guess the thing i should actually upgrade first is the pre-amp to maybe a tube preamp?

Nick

i guess the thing i should actually upgrade first is the pre-amp to maybe a tube preamp?

Nick

I agree. Upgrading the preamp will better show off the Denon 160.

Here's a quick peek inside the 640p.

We can replace the power supply caps, maybe the input caps too. I have some spare 8pin DIP sockets and a few Burr Brown 2134's, LM4562's, and maybe a couple AD823 op-amps we could try in it.

i basically joined the forum to see the pics for this mod . . . noicee . .

i basically joined the forum to see the pics for this mod . . . noicee . .

Let me be the first to say: Welcome Aboard! 

I plan on continuing the upgrades on the AT-LP120 turntable in the next few weeks. The next upgrade will be replacing the tonearm wire with Cardas 4x33g, going from the connecter in the tonearm straight to the RCA outputs.

i basically joined the forum to see the pics for this mod . . . noicee . .

Let me be the first to say: Welcome Aboard! 

I plan on continuing the upgrades on the AT-LP120 turntable in the next few weeks. The next upgrade will be replacing the tonearm wire with Cardas 4x33g, going from the connecter in the tonearm straight to the RCA outputs.

appreciate it

Originally i bought the AT lp120 usb for a friend abroad . . . cause of the voltage selector and built in preamp, but somehow i got stuck with it  . . and now im in love with it. I do want to remove the onboard preamp just like you and purchase a Cambridge 540 preamp. Also want to buy a decent cartridge to go along with the preamp.

Well after a lengthy hiatus I finally got the cables in, possibly tomorrow we'll upgrade the tone-arm cables and align it, then possibly post some samples!

Nick52284