FileFixer
Well-Known Member
Hello again...
Before I did one useful guide about your AT-LP120 USB turntable to be more dead on vibration.This guide you can find into this DIY section on AK or just simple click on this direct link...
http://audiokarma.org/forums/index....lp120-usb-turntable-and-all-other-too.799039/
Now I want to show you how to improve sound on AT-LP120 USB... This is not simple to do but if you have any experience with soldering and you have time and good nerve then you can to improve this turntable to be very nice and decent with pleasure sound then "plastic junk" as many people say.
My statement about AT-LP120 USB is then this turntable have many manufacturer's mistakes but this turntable have huge space to be great turntable...
So, how to do this, I will to explain... with many pictures.
For this modification I try to found some preamplifier what have similar dimensions to fit inside turntable on same place where is located old internal preamplifier but with relative good sound and I found that Audiowind A-300 satisfies my criteria for dimension, sound and future modifications on it. It`s based on OPA2134 Burr-Brown Op-Amps.
Basic schematics for complete connections looks like this...
First you must to remove headshell, counterweight, platter and 78RPM adapter from turntable. After that you must to secure tonearm and all upper parts on the turntable.
I`m pinned dust cover and turntable together with scotch tape around dust cover and edge of the turntable.
Pictures show how to use scotch tape to do this (not AT-LP120 on this pictures)...
Prepare some soft cloth as a base because it will turn turntable upside down on its dust cover.
When you prepare your turntable and workspace then you can to remove back cover from it. Unscrew eight screws, labeled with arrows on back cover plastic and easy remove back cover.
Be careful of the small rollers that are inside of the screws holes !!!
After you remove back cover, you can to start to modify your AT-LP120 USB turntable...
Lets begin...
First unplug any connectors from internal preamp then cut ground wire what come from GND spring. Also you must to desolder three wires on controller board where is connected GND shim from tonearm. These three wires is connected on 2,3,4 pins from left side shown on picture. On the right side from shim is wires which comes from headshel and tonearm and that wires dont need to desolder from board, only wires on left side what goes to internal preamplifier..
Then place new preamplifier when it has been him future place to see how can fit and how can be attached. I am attached preamp on that place with scotch tape but you can find any other way to fix it on that place.
Remove new preamp and back to another task... power source...
For that purpose I`m use +/- 18V 500mA transformer and Velleman K8042 power supply kit.
My idea was that this power supply must be on power when put power switch to ON and power off when power switch put to OFF position, so we must to find points where curren comes after power switch and this is point where we must to connect transformer. This place is located on little electronic board near existing transformer.
This picture shows where is placed that two poins where current goes to transformer (DANGER high voltage 110/220V !!!)
Before I did one useful guide about your AT-LP120 USB turntable to be more dead on vibration.This guide you can find into this DIY section on AK or just simple click on this direct link...
http://audiokarma.org/forums/index....lp120-usb-turntable-and-all-other-too.799039/
Now I want to show you how to improve sound on AT-LP120 USB... This is not simple to do but if you have any experience with soldering and you have time and good nerve then you can to improve this turntable to be very nice and decent with pleasure sound then "plastic junk" as many people say.
My statement about AT-LP120 USB is then this turntable have many manufacturer's mistakes but this turntable have huge space to be great turntable...
So, how to do this, I will to explain... with many pictures.
For this modification I try to found some preamplifier what have similar dimensions to fit inside turntable on same place where is located old internal preamplifier but with relative good sound and I found that Audiowind A-300 satisfies my criteria for dimension, sound and future modifications on it. It`s based on OPA2134 Burr-Brown Op-Amps.
Basic schematics for complete connections looks like this...
First you must to remove headshell, counterweight, platter and 78RPM adapter from turntable. After that you must to secure tonearm and all upper parts on the turntable.
I`m pinned dust cover and turntable together with scotch tape around dust cover and edge of the turntable.
Pictures show how to use scotch tape to do this (not AT-LP120 on this pictures)...
Prepare some soft cloth as a base because it will turn turntable upside down on its dust cover.
When you prepare your turntable and workspace then you can to remove back cover from it. Unscrew eight screws, labeled with arrows on back cover plastic and easy remove back cover.
Be careful of the small rollers that are inside of the screws holes !!!
After you remove back cover, you can to start to modify your AT-LP120 USB turntable...
Lets begin...
First unplug any connectors from internal preamp then cut ground wire what come from GND spring. Also you must to desolder three wires on controller board where is connected GND shim from tonearm. These three wires is connected on 2,3,4 pins from left side shown on picture. On the right side from shim is wires which comes from headshel and tonearm and that wires dont need to desolder from board, only wires on left side what goes to internal preamplifier..
Then place new preamplifier when it has been him future place to see how can fit and how can be attached. I am attached preamp on that place with scotch tape but you can find any other way to fix it on that place.
Remove new preamp and back to another task... power source...
For that purpose I`m use +/- 18V 500mA transformer and Velleman K8042 power supply kit.
My idea was that this power supply must be on power when put power switch to ON and power off when power switch put to OFF position, so we must to find points where curren comes after power switch and this is point where we must to connect transformer. This place is located on little electronic board near existing transformer.
This picture shows where is placed that two poins where current goes to transformer (DANGER high voltage 110/220V !!!)
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