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Old 21st May 2007, 03:09 PM   #1
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Default Lt115 Based Phono Amp (With Pics!!!)


Just completed my very first MC based phono amp. Am very new at this thus just "copied" the design as shown in the Linear Technology datasheet. I am using the Denon DL-103 with the phono amp

To my surprise, it sounds pretty decent! The guitars and mids on the records just sounds so much better!

I have attached some pictures for all your comments, please. Any suggestions to further improved the design would be greatly appreciated.


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Old 19th October 2008, 02:36 PM   #2
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Thought I post an update on what I have been doing since the very 1st post...way overdue man...

Basically, I decide to power the design from lithium batteries and thus built a custom lithium battery charger system. Some general information as follows:

1. I use 2 x 4 cell pack lithium battery pack to provide +/- 15Volts
2. A customise battery charger system with micro chip controller to controll the charging process.

Listening conclusion is that the amp is very quiet and clean. Sometimes too clean for the LPs...hearing too much "unwanted" elements on very old records!

Her are some pictures. Enjoy!

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Old 20th October 2008, 02:18 AM   #3
iko is offline iko  Canada
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Looks very nice, well done. I was going to build this phono stage but then decided to try the elcheapo and ended up doing both the old and the new version. I found the given schematic sort of cold, clinical, and the highs a bit too edgy so I added a mosfet buffer. What's your impression about the tonal quality of your preamp?

BTW, did you have the pcb professionally made? They look nice.

I'm torn now between designing a balanced input phono stage based on the ina630 or a tube based one.
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Old 20th October 2008, 02:54 PM   #4
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Thanks. It was really fun building the amp.

"Clean, Quiet and Fast" would be how I would describe the tonal quality. It would bring out the worst if your LP or turn table are not up to scratch. You can heard literally "everything". It is that "clean".

The imaging is also very good. Using decent components, the left right response and phase are literally identical, as far as measurement are concern, as validated by listening test.

So I guess the sound depends very much on the entire setup and the individual. My uncle did not like it because it was just too "clean" for his liking. He reckon that the tone would be much better (to his liking), if it was matched to tube amplifiers.

The PCBs are indeed professionally made.

Go for balanced tube based design. It would be a blast to design and built.
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