Alright I'll give that a try. When eventually transitioning to an amp with much lower output (e.g., the Seductor or Stereomour) will this present a problem? That is, will I still need the attenuators to reduce the hum, and will this in turn affect the ability of the amp to drive the speakers at adequate volume?
Hum, buzz, and microphonics. [resolved]
- Thread starter Rublyow
- Start date
Rublyow said:
What you're really after is an amplifier with lower gain. To get hundreds of Watts out of an amplifier with only a volt or so of signal at the input requires much less gain than getting four Watts out of the same volt at the input.
This is a function of mostly the sensitivity of the loudspeakers in conjunction with the available power from your amplifier.Rublyow said:
Just an update -- I borrowed a Quicksand from a friend to see if there way any benefit of having the power amplifier be totally out of the ground loop situations. It didn't really help things, there's still a hum (though sounds a bit more buzzy through the Quicksand). Interestingly, when I listen through the headphones with the speaker wires plugged in, there is no hum in the heapdhones, but when I unplug the speaker wires from the Quicksand, the hum becomes very loud through the headphones. Maybe it's just an issue of the heaphones and speakers "splitting" some of the signal, but still a bit weird.
Anyway, still working on tracking things down. Are there any good ways to isolate if it's an issue with the Smash wiring versus an issue with the wiring in my house (i.e., a light dimmer). Any other thoughts would be appreciated. I'm starting to run out of ideas. Maybe it's time for a full rewire....
Anyway, still working on tracking things down. Are there any good ways to isolate if it's an issue with the Smash wiring versus an issue with the wiring in my house (i.e., a light dimmer). Any other thoughts would be appreciated. I'm starting to run out of ideas. Maybe it's time for a full rewire....
Try a pair of these and let us know what happens:
http://www.parts-express.com/harrison-labs-12-db-rca-line-level-audio-attenuator-pair--266-244
http://www.parts-express.com/harrison-labs-12-db-rca-line-level-audio-attenuator-pair--266-244
Ok, some progress. I was able to try the Quicksand with the -12 db attenuators and that basically fixed the problem. There is a tiny bit of hum when you're right next to the speakers, but nothing beyond what I'd expect from a DHT amp.
But using the attenuators did drop the max volume from the speaker by a huge mount, basically such that even at max volume it's well below "comfortably loud". I know the Quicksand isn't really meant for large speakers, even if they are efficient (98 db sensitivity), but how might I go about avoiding this issue in the future? (Sorry if this is a really uniformed question!) Should I be cautious about adding more gain to the preamp section of my rig? For example, would doing the Smash-up upgrade be ill-advised since it's going to increase gain even more? Or are there ways around this, like adding a passive attenuator between the Smash and my amp? Or, lastly, is it just an issue with what power amp I use? I was thinking about trying the Seductor next, but now I'm a bit concerned that this isn't a good match since the Seductor has no gain control.
Thanks!
But using the attenuators did drop the max volume from the speaker by a huge mount, basically such that even at max volume it's well below "comfortably loud". I know the Quicksand isn't really meant for large speakers, even if they are efficient (98 db sensitivity), but how might I go about avoiding this issue in the future? (Sorry if this is a really uniformed question!) Should I be cautious about adding more gain to the preamp section of my rig? For example, would doing the Smash-up upgrade be ill-advised since it's going to increase gain even more? Or are there ways around this, like adding a passive attenuator between the Smash and my amp? Or, lastly, is it just an issue with what power amp I use? I was thinking about trying the Seductor next, but now I'm a bit concerned that this isn't a good match since the Seductor has no gain control.
Thanks!
That makes sense, but still seems like a temporary patch to me. If I add more gain to the preamp stage, again, for example, with the Smash-up upgrade, or by upgrading my phono stage with more gain, then I would expect the issue to get even worse, correct? Is there a better way to deal with this issue besides jerry-rigging in-line attenuators? And what would I look for in a power amp to to determine if its likely to exacerbate the problem or make it better?
Smash-up may improve your situation.
Try clip leading A6 and C6 to ground, then listen for noise. (Grounds are terminal 6 and 7)
Try clip leading A6 and C6 to ground, then listen for noise. (Grounds are terminal 6 and 7)
Hi Paul, I finally had a chance to try clipping A6 and C6 to ground, but no change at all to the hum. One odd thing that was a bit noticeable before but is fairly striking now, when I turn the volume knob all the way up (with no source connected) the hum totally disappears, and is loudest when the volume know is all the way down. Anyway, just one last ditch effort to diagnose things. I'm going to give it one more solder touch-up job this weekend as well.
I should also so that overall things sounds great when music is playing. It's light years ahead of my old solid state... just a bit annoying during the quiet passages and between tracks.
I should also so that overall things sounds great when music is playing. It's light years ahead of my old solid state... just a bit annoying during the quiet passages and between tracks.
Just an update. I installed the Smash-up upgrade and that definitely helped things. The hum is probably about 30% of what it was before, and is totally gone with -12 db attenuators. The extra gain also gives me a bit more headroom, so even with the attenuate I can reach decent volumes with low-level input sources. Definitely an improvement.
Those attenuators sure are handy under the right circumstances. I'm glad you're all up and running!
-PP
-PP
