HPA-2 headphone amplifiers - Page 4

GLooP · 29th November 2011, 06:46 AM

Dear Kawo,

Please accept my high regards for your finest craftmanship!

Are you planning on selling DIY kits or PCBs only?

kawo · 29th November 2011, 04:02 PM

Dear GLoop,
Is there any good recommendations?Thankyou

kawo · 2nd December 2011, 03:10 AM

Dear Gloop,
I think both DIY kits and PCBs inappropriate, because the manufacturing of this HPA-2 to use equipment help, so now is the product on ebay to sell better,Thankyou

GLooP · 2nd December 2011, 06:38 AM

Dear Kawo,

Since we are an DIY forum, I think people around would be more interested in doing things on their own than having them already assembled.

One again - congratulations for you fine design!

techbiker · 7th December 2011, 03:42 AM

Kawo,

Your design looks very professional. I'm also very pleased that you are using a Neutrik connector.

I do have one suggestion though... Have you considered using National Semiconductor LME49720 opamps? These might not be great for the application, however they have gotten excellent reviews.

LME49720 - Dual High Performance, High Fidelity Audio Operational Amplifier

kawo · 7th December 2011, 01:45 PM

Thank you for your appreciation, in the HPA-2 can only be used on a single op amp, dual op amp can not be used with I being tested there ... OP07, OP37, PM1008, NE5534, AD844/883, A843BH, OPA627AP, OPA637SM . the best op-amp is OPA637SM, but with not enough on the HPA-2 stable, so the OPA627 is the preferred.

kawo · 16th December 2011, 02:58 PM

OPA637SM sound very good, but unfortunately unstable in the HPA-2.

bart_dood · 26th December 2012, 07:11 PM

I have looked on ebay and simply can't find this product for sale, do you have links?

Thanks

kawo · 28th December 2012, 12:41 AM

Hi: bart_dood
This product is sold out,sorry. I will launch a very strong front instead.

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29th November 2011, 06:46 AM	#31
GLooP diyAudio Member Join Date: May 2011	Dear Kawo, Please accept my high regards for your finest craftmanship! Are you planning on selling DIY kits or PCBs only?

29th November 2011, 04:02 PM	#32
kawo diyAudio Member Join Date: Mar 2010 Location: Hong Kong	Dear GLoop, Is there any good recommendations?Thankyou

2nd December 2011, 03:10 AM	#33
kawo diyAudio Member Join Date: Mar 2010 Location: Hong Kong	Dear Gloop, I think both DIY kits and PCBs inappropriate, because the manufacturing of this HPA-2 to use equipment help, so now is the product on ebay to sell better,Thankyou

2nd December 2011, 06:38 AM	#34
GLooP diyAudio Member Join Date: May 2011	Dear Kawo, Since we are an DIY forum, I think people around would be more interested in doing things on their own than having them already assembled. One again - congratulations for you fine design!

7th December 2011, 03:42 AM	#35
techbiker diyAudio Member Join Date: Sep 2011 Location: Texas	Kawo, Your design looks very professional. I'm also very pleased that you are using a Neutrik connector. I do have one suggestion though... Have you considered using National Semiconductor LME49720 opamps? These might not be great for the application, however they have gotten excellent reviews. LME49720 - Dual High Performance, High Fidelity Audio Operational Amplifier

7th December 2011, 01:45 PM	#36
kawo diyAudio Member Join Date: Mar 2010 Location: Hong Kong	Thank you for your appreciation, in the HPA-2 can only be used on a single op amp, dual op amp can not be used with I being tested there ... OP07, OP37, PM1008, NE5534, AD844/883, A843BH, OPA627AP, OPA637SM . the best op-amp is OPA637SM, but with not enough on the HPA-2 stable, so the OPA627 is the preferred.

26th December 2012, 07:11 PM	#38
bart_dood diyAudio Member Join Date: Dec 2003 Location: Massachusetts	I have looked on ebay and simply can't find this product for sale, do you have links? Thanks

28th December 2012, 12:41 AM	#39
kawo diyAudio Member Join Date: Mar 2010 Location: Hong Kong	Hi: bart_dood This product is sold out,sorry. I will launch a very strong front instead.