[wilsonjm]

I noticed that the left channel of my HD600s was making a slight buzz on some frequencies.

If anyone has the Radiohead song "No Surprises", turn up your amp loud and listen to the intro. Is there an annoying buzz in either channel?

For this song specifically I noticed the left channel to have a loud buzz instead of the bass notes.

I downloaded a bass test that goes through the lower frequencies. Near the end of this test (20-60Hz?) the left channel would start to buzz. Turn the volume up a little more, and both left and right buzz. Worried that I had damaged my HD600s at some point, I took out my EL2001s from my META42. This improved the situation a bit - the left channel no longer buzzes at lower volumes than the right. Then I swapped out my AD8610s for a AD823. This improved the problem a little more, now the buzzing starts at a slightly higher volume. HOPING that voltage is the issue, i checked my voltage and found +/- 5.5V (damn batteries go fast).

Is this likely the problem? +/- 5.5V for AD8610/AD823 not enough for low frequencies?

 

[eric343]

Hmm...

Have you tried replacing the batteries?

 

[wilsonjm]

Nope. Don't have any more batteries. These aren't rechargable either - just wanted to see how long batteries would last. I think I am definitely going to just get a wall wart

 

[thomas]

I have noticed that buzz on "No Surprises" on many low end systems, esp my parents Bose lifestyle crap...There must be some very deep bass on that track...

That said, my headphones/amps (apheared 42, szekeres) have no problems with it...


Check batteries, first, AD823 should work well at 5.5V

then check the layout- if the amp is oscillating at high frequencies, it can greatly reduce the power available for audiable frequencies.... Keep wires at short as possible, use bypass caps around opamps, check for poor soldering joints, etc... Also, you can increase the local gain around the opamp to help keep it stable...

 

[wilsonjm]

Ok,

I let the batteries rest up overnight, this morning they were back up to +/- 6V. I tried with just the AD823 as this requires less voltage than the AD8610 or the EL2001s. There is no no buzz in either channel on the bass test track at max volume. It's still in No Surprises though, but not as bad. I'll have my Elpac PS in a few days so I'll find out for sure if it's voltage

My gain is set around 10-11, the default META42 values (as provided by tangent). I think the original META42 values work better for a gain of 15. The gain of 10-11 certainly produces loud listening levels, but you have to have the pot all the way up on some tracks and that could be a problem with the amp crapping out on the bass