Audio-technica AT-LP120-USB preamp Mod Brainstorming.

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ajazatvengine
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Audio-technica AT-LP120-USB preamp Mod Brainstorming.

Post by ajazatvengine » 20 Jun 2017 21:47

Looking about the internal pre-amp mod I have found a couple of interesting videos in my search, but I am still not completely satisfied with what I have found so far like for example the youtube video attached bellow. I would prefer to find some way without mutilating the actual internal preamp board nor sacrificing its USB capability, neither the outside aesthetic of the turntable. I am thinking in something like to get 2 separated independent lines out from the stylus board main audio connection with rca male plugs on it like the one rca connectors that originally comes into the turntable, just two identical cables with right (red) & left (white) RCAs male connectors out and connected to an external audio switcher like this one I already have:

http://www.ebay.com/itm/RS-Video-Audio- ... 1535295808 ,

then out from the external audio switcher to the Phono pre-amp...

My Issue is that I don't know how to effectively get both cables independently soldered to just one actual stylus board main possible connection avoiding any possible interference between each other... Any ideas???


https://youtu.be/0LGEuWc3POs

JeffS7444
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Re: Audio-technica AT-LP120-USB preamp Mod Brainstorming.

Post by JeffS7444 » 21 Jun 2017 05:17

Out of the box, I wasn't very impressed by the LP120, either by the apparent build quality or the sonics. But now that I've taken some time to tune it up, I'm liking it!

Wish I had used the USB output more from the very start, to record the output from the unit as it was the day I set it up, and after each modification so I could ABX at leisure and have an even better sense of the things which made the biggest audible differences! But I did not even think of this until I had already performed a number of mods, ah well.

I suspect this is the #1 thing you can do to improve sonics of the built in preamp:

(Option A) Be patient, and allow for a longish burn-in period.

Or

(Option B) Locate the (4) 2.2 uF, 16V electrolytic capacitors. Two of these are used for signal coupling at the input of your phono preamp. If you're not sure which two, just replace all 4 with the smallest 2.2 uF film capacitors that you can find.

I think what's happening is that you're "forming" those electrolytic capacitors, but your cartridge only exposes them to a few millivolts, so it's slow going. On the other hand, film capacitors pretty much just work right from the start.

#2 may be cartridge alignment! As delivered, it doesn't seem to conform to any standard. And the alignment which seemed to deliver the lowest audible distortion for me was Stevenson, which results in the cart being skewed inwards by a couple of millimeters.

And yes, as some of the Youtube videos show, there's a couple of surface mount inductors and ceramic capacitors acting as filters (not sure why?) I replaced the former with jumpers, and simply removed the latter.

For most folks, I'd probably suggest Option A combined with cartridge alignment because it doesn't affect your warranty.

ajazatvengine
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Re: Audio-technica AT-LP120-USB preamp Mod Brainstorming.

Post by ajazatvengine » 22 Jun 2017 16:00

JeffS7444 wrote:Out of the box, I wasn't very impressed by the LP120, either by the apparent build quality or the sonics. But now that I've taken some time to tune it up, I'm liking it!

Wish I had used the USB output more from the very start, to record the output from the unit as it was the day I set it up, and after each modification so I could ABX at leisure and have an even better sense of the things which made the biggest audible differences! But I did not even think of this until I had already performed a number of mods, ah well.

I suspect this is the #1 thing you can do to improve sonics of the built in preamp:

(Option A) Be patient, and allow for a longish burn-in period.

Or

(Option B) Locate the (4) 2.2 uF, 16V electrolytic capacitors. Two of these are used for signal coupling at the input of your phono preamp. If you're not sure which two, just replace all 4 with the smallest 2.2 uF film capacitors that you can find.

I think what's happening is that you're "forming" those electrolytic capacitors, but your cartridge only exposes them to a few millivolts, so it's slow going. On the other hand, film capacitors pretty much just work right from the start.

#2 may be cartridge alignment! As delivered, it doesn't seem to conform to any standard. And the alignment which seemed to deliver the lowest audible distortion for me was Stevenson, which results in the cart being skewed inwards by a couple of millimeters.

And yes, as some of the Youtube videos show, there's a couple of surface mount inductors and ceramic capacitors acting as filters (not sure why?) I replaced the former with jumpers, and simply removed the latter.

For most folks, I'd probably suggest Option A combined with cartridge alignment because it doesn't affect your warranty.

Thanks not only for your valuable tips, but also and mainly for reminding me about the warranty because mine is just Brand new, and I hadn't even thought about it, so I have actually not other choice than looking forward Option A for a while... Very Appreciate it buddy... (y) :-)

yarvelling
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Re: Audio-technica AT-LP120-USB preamp Mod Brainstorming.

Post by yarvelling » 16 Sep 2019 15:05

JeffS7444 wrote:
21 Jun 2017 05:17
Out of the box, I wasn't very impressed by the LP120, either by the apparent build quality or the sonics. But now that I've taken some time to tune it up, I'm liking it!

Wish I had used the USB output more from the very start, to record the output from the unit as it was the day I set it up, and after each modification so I could ABX at leisure and have an even better sense of the things which made the biggest audible differences! But I did not even think of this until I had already performed a number of mods, ah well.

I suspect this is the #1 thing you can do to improve sonics of the built in preamp:

(Option A) Be patient, and allow for a longish burn-in period.

Or

(Option B) Locate the (4) 2.2 uF, 16V electrolytic capacitors. Two of these are used for signal coupling at the input of your phono preamp. If you're not sure which two, just replace all 4 with the smallest 2.2 uF film capacitors that you can find.

I think what's happening is that you're "forming" those electrolytic capacitors, but your cartridge only exposes them to a few millivolts, so it's slow going. On the other hand, film capacitors pretty much just work right from the start.

#2 may be cartridge alignment! As delivered, it doesn't seem to conform to any standard. And the alignment which seemed to deliver the lowest audible distortion for me was Stevenson, which results in the cart being skewed inwards by a couple of millimeters.

And yes, as some of the Youtube videos show, there's a couple of surface mount inductors and ceramic capacitors acting as filters (not sure why?) I replaced the former with jumpers, and simply removed the latter.

For most folks, I'd probably suggest Option A combined with cartridge alignment because it doesn't affect your warranty.

Great post! It confirmed what I'd thought may be a 'cleaner and neater' solution: remove the inductors and ceramic capacitors..... Not being that smart when it comes to electronics, I wasn't sure whether this may not work!
Anyway...after reading your post, I tried it.
My word....what a difference!!
I've been using a Rega Carbon in place of the AT95E as I prefer it's tone, and love it in the Rega RP1. Well, now that those idiot caps and inductors are out of the way, the sound has 'opened-up' in the mids and highs, and the soundstage has widened considerably; A massive improvement...many thanks for your original posting here... :D

BMRR
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Re: Audio-technica AT-LP120-USB preamp Mod Brainstorming.

Post by BMRR » 16 Sep 2019 16:43

For those of us who are visual learners, can you post some photos or diagrams to explain how this is done?

yarvelling
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Re: Audio-technica AT-LP120-USB preamp Mod Brainstorming.

Post by yarvelling » 16 Sep 2019 22:33

BMRR wrote:
16 Sep 2019 16:43
For those of us who are visual learners, can you post some photos or diagrams to explain how this is done?
As for my mod, it's done! I didn't take any footage or photo's...sorry..... However, the video that was mentioned earlier as pointing out the offending parts is here on Youtube....
https://www.youtube.com/watch?v=4NT67ii04uQ

Go to about 10:58, where L606 and L607 are shown....these are the two inductors that need removing and then very small pieces of wire used to bridge across the gap left behind...... also shown at this point are the two capacitors: C631, and C632.
These two can just be removed. (Lay the point of the iron along the side of each small component to heat each one evenly, then it'll lift off nicely with fine pointed tweezers)
Use a small soldering iron tip to remove the components, and solder jumpers across the gaps left by L606 & L607.... and then to clean-up the very small gaps left behind by the two capacitors.

If the job is nice and clean, and neat, then the difference in sound quality should be noticable instantly a record is played: no more 'auto-mute' delay, and possibly more volume - cartridge dependant. For the rest...see my earlier post!

BMRR
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Re: Audio-technica AT-LP120-USB preamp Mod Brainstorming.

Post by BMRR » 16 Sep 2019 23:11

Thank you!

PioneerFan
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Re: Audio-technica AT-LP120-USB preamp Mod Brainstorming.

Post by PioneerFan » 12 Nov 2019 15:20

For all the efforts people go through in removing the preamp from this turntable, amazed folks don't venture out to build their own machines, or, just choose to purchase a different one, if its presence really bothers them so much. Personally, I have one, and in A/B comparison with my PL-516, and the AT-95E, I hear little to no difference.

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