Mccormack DNA-1 power amp

gmak · 15th April 2009, 05:01 PM

Hi, my Mccormack DNA-1 power amp has hiss noise coming out from both channels if I put my ear very close the speaker.
Any suggestions to correct this problem.

Thanks,
Gary

Netlist · 15th April 2009, 05:13 PM

Hard to tell.
How close is your ear?
Are your inputs shorted?
How sensitive are your speakers?

Probably it is normal. Few amps are absolutely silent and if no hiss can be heard at the listening position and with silent music playing, why bother?

A good RMS DMM meter or a scope could tell you what the residual noise exactly is. If it meets the specs, enjoy your amp.

/Hugo

ekaerin · 15th April 2009, 08:17 PM

Hi,

Didn´t you hear the noise before. If it appeared suddenly then what could be wrong ? If itworks OK otherwise.

I listened to this amp a few times long ago. It's one of the best amps
I ever heard.

I think it is J-FET input, MOS-FET gain/drive and bipolar output.
And was it CFB....

I hope someone with the schematic will put it up some day.
I would just love to build me one.

Regards / Mattias

vinnysj · 16th April 2009, 01:42 PM

Quote:

Originally posted by gmak
Hi, my Mccormack DNA-1 power amp has hiss noise coming out from both channels if I put my ear very close the speaker.
Any suggestions to correct this problem.

Check all ground points. Tighten screws, you might need to clean the contacts. Also, check the power supply capacitors.

gmak · 20th April 2009, 05:01 PM

I have disconnected the source input and just power up the amp. I can still hear the hiss noise within a foot from my speaker. Few months ago the fuses on the left channel blew up when I switched speakers and accidentaly short the wire. After I changed the fuses, I notice that. I hope I can obtain a copy the schematic too, or at least the input amplification portion.

Thanks,
Gary

BobM · 20th April 2009, 05:40 PM

Steve McCormack is very open, approachable and available and will probably send you a schematic upon request.

He can be reached through his mod site:

http://www.smcaudio.com/

Enjoy,
Bob

15th April 2009, 05:01 PM	#1
gmak diyAudio Member Join Date: Mar 2005 Location: toronto	Mccormack DNA-1 power amp Hi, my Mccormack DNA-1 power amp has hiss noise coming out from both channels if I put my ear very close the speaker. Any suggestions to correct this problem. Thanks, Gary

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Functional of opamps in McCormack amp	100db	Solid State	17	17th October 2008 07:26 PM
McCormack DNA-500 one channel out	kaboom	Solid State	12	20th June 2006 01:41 PM
For Sale: McCormack Micro Phono Drive component case/ chassis	Joseph0	Swap Meet	2	6th March 2006 10:24 PM
McCormack DNA 2 power amp	Tony	Solid State	1	26th November 2005 04:10 AM
McCormack DNA125 & Quad 909	Al Raj	Solid State	3	8th August 2005 09:51 AM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

15th April 2009, 05:13 PM	#2
Netlist diyAudio Moderator Join Date: Jan 2003	Hard to tell. How close is your ear? Are your inputs shorted? How sensitive are your speakers? Probably it is normal. Few amps are absolutely silent and if no hiss can be heard at the listening position and with silent music playing, why bother? A good RMS DMM meter or a scope could tell you what the residual noise exactly is. If it meets the specs, enjoy your amp. /Hugo

15th April 2009, 08:17 PM	#3
ekaerin diyAudio Member Join Date: Jun 2004 Location: Stockholm	Hi, Didn´t you hear the noise before. If it appeared suddenly then what could be wrong ? If itworks OK otherwise. I listened to this amp a few times long ago. It's one of the best amps I ever heard. I think it is J-FET input, MOS-FET gain/drive and bipolar output. And was it CFB.... I hope someone with the schematic will put it up some day. I would just love to build me one. Regards / Mattias

20th April 2009, 05:01 PM	#5
gmak diyAudio Member Join Date: Mar 2005 Location: toronto	I have disconnected the source input and just power up the amp. I can still hear the hiss noise within a foot from my speaker. Few months ago the fuses on the left channel blew up when I switched speakers and accidentaly short the wire. After I changed the fuses, I notice that. I hope I can obtain a copy the schematic too, or at least the input amplification portion. Thanks, Gary

20th April 2009, 05:40 PM	#6
BobM diyAudio Member Join Date: Apr 2003 Location: Long Island, New York	Steve McCormack is very open, approachable and available and will probably send you a schematic upon request. He can be reached through his mod site: http://www.smcaudio.com/ Enjoy, Bob

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)