Interesting: P-amp Headphone amp from Grey Rollins

promitheus · 3rd July 2009, 04:05 PM

I just found this article:
http://www.enjoythemusic.com/diy/0709/p_amp_v1.htm

Has anybody built it?
What is your opinion?

the parts are relatively cheap but I don´t know the J271 Jfets.

Question for Grey Rollins if he is reading this.
is it possible to build the amp without matched parts for testing?

chrismercurio · 21st July 2009, 03:50 AM

bump...read the article

h_a · 21st July 2009, 07:36 AM

Thanks for the link!

For a quick test you can completely ignore jfet matching, it's anyway way overrated. If you're happy with your amp and want to get the most out of it, you can match the differential.

If you feel bored, match the rest.

Have fun, Hannes

chrismercurio · 21st July 2009, 03:19 PM

ALERT: Dumb question below:

Since the power dissapation is so low, is any heatsinking required? Or can this all be done point to point on a breadboard with no heat sink and simple wall wart supply?

Chris

jcx · 21st July 2009, 04:44 PM

I don't see the point unless you're acutually helping Grey use up his excess stock - if you're going to buy parts why not something like:

http://headwize.com/projects/showfil...lmore3_prj.htm

TO-92 plastic transistors are usually rated 600mW free air pwr dissipation - good engineering practice would be to only use ~1/2 that

chrismercurio · 21st July 2009, 05:04 PM

Quote:

Originally posted by jcx
if you're going to buy parts why not something like:
http://headwize.com/projects/showfil...lmore3_prj.htm

What headphones do you use? with what amplifier? Are there other amplifiers that you like more than the above?

jcx · 21st July 2009, 05:47 PM

I have a range of headphones including HD600, K701, SA5000 and most recently Koss ESP950 electrostatic

I've built my own unusual high feedback composite op amp based amps for the dynamics:

http://www.diyaudio.com/forums/showt...58#post1392458

more pics:

http://www.head-fi.org/forums/f6/ad8...8/#post2263321

some composite circuits (conceptualy related to what I used in my amp)

http://www.diyaudio.com/forums/showt...806#post512806

I hope to design/build a high gain composite SS amp for the electrostatics as well - looking at optocouplers cascoded with IXTP01N100 running Class A for the high V

chrismercurio · 21st July 2009, 06:07 PM

I like your heatsink. Reminds me of the DIY section of a PC store.

3rd July 2009, 04:05 PM	#1
promitheus diyAudio Member Join Date: Jan 2001 Location: Germany	Interesting: P-amp Headphone amp from Grey Rollins I just found this article: http://www.enjoythemusic.com/diy/0709/p_amp_v1.htm Has anybody built it? What is your opinion? the parts are relatively cheap but I don´t know the J271 Jfets. Question for Grey Rollins if he is reading this. is it possible to build the amp without matched parts for testing?

21st July 2009, 07:36 AM	#3
h_a diyAudio Member Join Date: Sep 2006 Location: Graz, Austria	Thanks for the link! For a quick test you can completely ignore jfet matching, it's anyway way overrated. If you're happy with your amp and want to get the most out of it, you can match the differential. If you feel bored, match the rest. Have fun, Hannes __________________ fresh matched IRFP240/IRFP9240 fets \|\| AlephJ/JX-kits F5 transistor kits \|\| Burning Amp BA-1/2/3 transistor kits

21st July 2009, 05:47 PM	#7
jcx diyAudio Member Join Date: Feb 2003 Location: ..	Op Amps not discrete I have a range of headphones including HD600, K701, SA5000 and most recently Koss ESP950 electrostatic I've built my own unusual high feedback composite op amp based amps for the dynamics: http://www.diyaudio.com/forums/showt...58#post1392458 more pics: http://www.head-fi.org/forums/f6/ad8...8/#post2263321 some composite circuits (conceptualy related to what I used in my amp) http://www.diyaudio.com/forums/showt...806#post512806 I hope to design/build a high gain composite SS amp for the electrostatics as well - looking at optocouplers cascoded with IXTP01N100 running Class A for the high V

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21st July 2009, 03:50 AM	#2
chrismercurio diyAudio Member Join Date: Aug 2006 Location: Silicon Valley	bump...read the article

21st July 2009, 03:19 PM	#4
chrismercurio diyAudio Member Join Date: Aug 2006 Location: Silicon Valley	ALERT: Dumb question below: Since the power dissapation is so low, is any heatsinking required? Or can this all be done point to point on a breadboard with no heat sink and simple wall wart supply? Chris

21st July 2009, 04:44 PM	#5
jcx diyAudio Member Join Date: Feb 2003 Location: ..	I don't see the point unless you're acutually helping Grey use up his excess stock - if you're going to buy parts why not something like: http://headwize.com/projects/showfil...lmore3_prj.htm TO-92 plastic transistors are usually rated 600mW free air pwr dissipation - good engineering practice would be to only use ~1/2 that

21st July 2009, 06:07 PM	#8
chrismercurio diyAudio Member Join Date: Aug 2006 Location: Silicon Valley	I like your heatsink. Reminds me of the DIY section of a PC store.

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