Mccormack DNA-1 power amp

[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.

Thanks,
Gary

 

[Netlist]

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]

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]

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]

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]

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