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Class A Headphone Amplifier with IRF610 and LM317 CCS
http://diyaudioprojects.com/Forum/viewtopic.php?f=10&t=55
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Author:  Gio [ 05 Jun 2016, 09:58 ]
Post subject:  Re: Class A Headphone Amplifier with IRF610 and LM317 CCS

HI Ashkan,

A resistor can also be used. For this project I was interested in trying regulator IC as a CCS. I like how they perform. You can use separate power supplies for each channel, but I don't think that will add much.

There may be more info on the design here: http://web.archive.org/web/201503142336 ... page_id=31
as the original link does not seem to be working.

Author:  saheb11123 [ 19 Jul 2016, 08:04 ]
Post subject:  Re: Class A Headphone Amplifier with IRF610 and LM317 CCS

Hi I am new to the forum.
I stumbled upon this forum when I was searching for a headphone amp because I bought a new headphone ( Beyerdynamic dtx 910).
So I have a few questions before I begin to build this , have anyone tried using BJT instead of a MOSFET as the output device. Also what is the proper procedure to attach a gain stage before the class a part.
if Vishay 240 is used as the output device would it work given the biasing current is the same.
Thanks and regards.

Author:  saheb11123 [ 01 Aug 2016, 05:23 ]
Post subject:  Re: Class A Headphone Amplifier with IRF610 and LM317 CCS

Guess nobody is interested in this project anymore?

Author:  Gio [ 01 Aug 2016, 08:50 ]
Post subject:  Re: Class A Headphone Amplifier with IRF610 and LM317 CCS

saheb11123 wrote:
have anyone tried using BJT instead of a MOSFET as the output device.


Hello, I have not tried BJT, However, I've had success with IRF510, IRF610, IRF611, IRF612 and IRF710. You will want to stay away from IRFx30 or IRFx40 types

Cheers

Author:  saheb11123 [ 19 Aug 2016, 02:20 ]
Post subject:  Re: Class A Headphone Amplifier with IRF610 and LM317 CCS

Gio wrote:
saheb11123 wrote:
have anyone tried using BJT instead of a MOSFET as the output device.


Hello, I have not tried BJT, However, I've had success with IRF510, IRF610, IRF611, IRF612 and IRF710. You will want to stay away from IRFx30 or IRFx40 types

Cheers


Thank you gio.

Author:  acomeau [ 27 Aug 2016, 07:59 ]
Post subject:  Re: Class A Headphone Amplifier with IRF610 and LM317 CCS

psyactive wrote:
I finally found a way to eliminate the hiss by adding 2* 4700uf capacitor to the power supply, .


You could have used a capacitance multiplier ..............http://sound.westhost.com/project15.htm

You might also try using a PI filter http://www.daenotes.com/electronics/dev ... r-circuits

Author:  acomeau [ 27 Aug 2016, 08:04 ]
Post subject:  Re: Class A Headphone Amplifier with IRF610 and LM317 CCS

saheb11123 wrote:
Guess nobody is interested in this project anymore?


Asking about using a BJT is entirely misplaced. Like asking if you could use a tube instead.

The circuit was designed for a MOSFET...........................NOT a BJT


Look at the LJH for a BJT design

Author:  acomeau [ 27 Aug 2016, 19:54 ]
Post subject:  Re: Class A Headphone Amplifier with IRF610 and LM317 CCS

thinkbrown wrote:
I have an old PSU from a computer somewhere. I believe it supplies 85ish watts at 12volt. Would that do it?


A power supply is not a power supply..........that is just because the rating is the same does NOT mean its performance is the same.

SPSU [switching power supplies] are notorious for noise and IMHO should be avoided entirely for audio circuits. Would be experts claim SPSUs are more efficient - and that is usually but Not always true - but they fail to understand that SPSUs are noisy and can be less stable [in some conditions] and have other problems.

I Never use a SPSU in development work, nor in audio circuits.

In addition, SPSUs can fail with terrible results - destroying what the circuit they supply. I had that happen twice.

In summary then never use an old SPSU for a circuit you care about, and never use for audio circuits.

Author:  acomeau [ 27 Aug 2016, 20:02 ]
Post subject:  Re: Class A Headphone Amplifier with IRF610 and LM317 CCS

The LM317 is not noted for being quiet..........http://tech.juaneda.com/en/articles/lm317noise.html http://www.tnt-audio.com/clinica/regula ... se2_e.html in its normal role as a voltage regulator.

Any comments, observations, ideas?

Author:  Gio [ 29 Aug 2016, 22:13 ]
Post subject:  Re: Class A Headphone Amplifier with IRF610 and LM317 CCS

Hello, good links.

I never found the noise to be audible but for higher performance I've been using newer regulators like IXYS and LT1085. But the LM317 works well in this role and they are abundant and low cost.

Cheers

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