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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:  katip [ 10 Jun 2010, 05:22 ]
Post subject:  Re: NP-100v12 - 12AU7 / IRF510 HeadAmp Support Thread

if i use 12ax7 replace 12au7.
the value of component will change.
please tell me about value of component to use for 12ax7
katip

Author:  roggom [ 10 Jun 2010, 07:48 ]
Post subject:  Re: NP-100v12 - 12AU7 / IRF510 HeadAmp Support Thread

katip wrote:
if i use 12ax7 replace 12au7.
the value of component will change.
please tell me about value of component to use for 12ax7

Katip,
To use a 12AX7, P1 must be in the 50K ohm range. I do not have the exact value. Remember that the mu for a 12AU7 is 17 and the mu for the 12AX7 is 100. If you are using a line level input, you may experience a lot of distortion. The only other tube that I have success with is the 12AT7, as a 10k pot will allow you to adjust for half the B+.

Author:  katip [ 10 Jun 2010, 12:41 ]
Post subject:  Re: NP-100v12 - 12AU7 / IRF510 HeadAmp Support Thread

thank roggom :)

Author:  J&B [ 14 Jun 2010, 01:53 ]
Post subject:  Re: NP-100v12 - 12AU7 / IRF510 HeadAmp Support Thread

Hi y'all

We finally got around to putting the amp together and I must say it rocks! After listening to it at work for about a day the sound quality is really nice. I just want to thank the designer dor designing such a great amp and sharing it here on the web.

Cheers
/Jonas

Author:  roggom [ 14 Jun 2010, 22:54 ]
Post subject:  Re: NP-100v12 - 12AU7 / IRF510 HeadAmp Support Thread

Thank you for the kind words, I am glad you like it and I am happy that I could help out.

Rogers

Author:  jaume [ 18 Jun 2010, 15:16 ]
Post subject:  Re: NP-100v12 - 12AU7 / IRF510 HeadAmp Support Thread

Hello, apologies for my poor English, I just mount the amplifier, and it works perfectly :headphones:

Image

, thanks for the schematics and the article, I have also put an LED below the valve. :D 8-)

Image

WAAAAAAAAARRMMMMMMMMM!!!!!!!!!!!!!!!!!!!!!!!!!!

I'm just a fan of electronics, has any idea for the power supply?
All sources I've tested, producing AC noise :mad:
How I can filter properly?

Thankyou very much!

greetings!

Author:  roggom [ 18 Jun 2010, 23:38 ]
Post subject:  Re: NP-100v12 - 12AU7 / IRF510 HeadAmp Support Thread

Jaume,

Looks great,

As many have found, it may take a while to find the perfect wal wart. I use a Canon AD360U, it is from a compact portable printer and is 13v 1.8A and works very well. I am not sure where you are located, but thrift stores and second hand shops are a great place to find power supplies.

Thanks

Rogers

Author:  jaume [ 19 Jun 2010, 07:03 ]
Post subject:  Re: NP-100v12 - 12AU7 / IRF510 HeadAmp Support Thread

thanks Rogers, I'm from Spain, I'll try some power supplies, i find some on ebay and Cash Converters ...

Furthermore
pc power supply, it seemed a good candidate, but the two I have, add fan noise,
are powerfull and stable, but the fan noise is unbearable. :shock: :mad:

I will continue testing...

Regards!

Author:  roggom [ 19 Jun 2010, 09:49 ]
Post subject:  Re: NP-100v12 - 12AU7 / IRF510 HeadAmp Support Thread

Just a thought, since you are experimenting. Since you are only loading the pc power supply about 300mA, try disconnecting the fan. Check if the heat stays within a reasonable temp. If anything you can run the pc supply without the top for passive airflow.

Rogers

Author:  Gio [ 19 Jun 2010, 19:53 ]
Post subject:  Re: NP-100v12 - 12AU7 / IRF510 HeadAmp Support Thread

Nice work jaume.

If you have a 15VDC (or greater) supply, you can run it through a LM317 voltage regulator to make a 12V regulated supply which will be very clean. All the info you need is on that page, but if you have questions or need help, feel free to ask.

Welcome to the forum.
Cheers

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