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NP-100v12 - 12AU7 / IRF510 HeadAmp Support Thread
http://diyaudioprojects.com/Forum/viewtopic.php?f=10&t=1799
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Author:  mcmillant [ 16 Apr 2019, 00:18 ]
Post subject:  Re: NP-100v12 - 12AU7 / IRF510 HeadAmp Support Thread

ILoveHiFi wrote:
You need to use coax cables for input wires, not twisted pairs as offers very litte or zero proetion against noise pick up.

viewtopic.php?f=9&t=6392&start=70
Theres also quite a few plorbems which you also may be doing which I disscussed with another dude in this thread.


Thnk you for reply, last weekend i tried something and here is results
- Replaced coax cable in input signal wire like you said - nothing change, i notice when i touch to the cable or input caps the noise go heavier.
- Then i replaced input jack cable with a coax calbe too, the noise reduce abit.
- This buzz noise complete disapear when i touch to the volume pot (which shorted to pot gnd), but in my country there have no any ground system in house, and my department on 4th floor ...
- I thought about volume pot, then i remove volume pot (left input signal with 100 ohm resistors) and yea, buzz noise gone. The only noise i can notice is small hum (maybe from my power which i reduted it by diode bridge). Buzz noise still apear when i touch to input wire or input caps. So is it all about my volume pot have bad quality ????
- Larger power caps i put to power, the hum go smaller but still noticed when source silent, the problem is i feel with about 4700uf, the sound quality gone so heavy and not clear , after few calculator i found on internet, i plan make a lc filter (3mh coil inductance and 1000uf caps) hope it will go well.
Srry for my bad english

Author:  romapryst [ 24 Apr 2019, 08:03 ]
Post subject:  Re: NP-100v12 - 12AU7 / IRF510 HeadAmp Support Thread

Recently completed this scheme, adding a 12V lithium battery, orange LED under the lamp for more drama and turning the lamp in parallel with the board for portability. Passing capacitors put 6.8mF. The result is very pleasing, the input signal does not distort, but makes it natural for listening. Now I cant find a power supply that does not add noise, so I only use the battery and the power supply to charge.

Author:  oloppolo [ 16 Jun 2019, 10:12 ]
Post subject:  Re: NP-100v12 - 12AU7 / IRF510 HeadAmp Support Thread

Hi! I have build with ecc81 (I have a lot in the drawer). It is a good project. :up:
Bye.

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