[95bcwh]

I received this amp on Tuesday, 1st impression was that there're little to choose between it and Bryston 4B-SST. So I left it played continuously for two days. Now the "burn-in" effect is very evident, the D200 now sounds much warmer and sweeter than before, it sounds like "tube" . The overall presentation is now more musical and natural. When I put back the Bryston 4B-SST, it sounds relatively lean and mechanical.

I'm using a fully modified Tact 2.0S DAC/preamp, the funny thing is, I have been using the correction curve "optimized" for my Bryston 4B-SST.

Just now I followed Zybar's advice, re-did the measurement using the D200, re-calculate the correction using the same target curve I used for Bryston 4B-SST. And the reason was very surprising: The D200 now sounds just like the Bryston - lean and mechanical!

Hence the best sound I got so far is by using the "correction curve for Bryston" on D200, which to my ear sounded better than using the same curve on Bryston, and better than using the "D200 curve" on D200. Granted, now I know I have more work to do...

I noticed that when I plug in the power cord on the D200, it generate a little "buzz", one of the monoblock is slightly louder than the other. In absolute term, it's not loud, but it's audible when I get close to it and when no music is being played. I wonder if this is normal?

Best regards
barry

[CIAudio]

It sounds like you don't like the "target curve". I'm not too familiar with the Tact, but it sounds like you will have to experiment with it's settings/adjustments.

It's normal to have a surge hum as you plug them in, but once settled should not be heard unless you put your ear up to the amp chassis. If it's louder than this you either have some DC on your AC lines or something distorting the AC waveform.

[95bcwh]

Dusty,
  Thanks for the fast response.. I am getting the best sound out of my system so far with your D200 with the "wrong correction curve"..so I'm not complaining  
 
  The hum is really not that loud, hence I wouldn't worry too much about it for the time being, the two monoblock is sharing the same dedicated 20A circuit line, is this going to be a problem.

  best regards
  barry

It sounds like you don't like the "target curve". I'm not too familiar with the Tact, but it sounds like you will have to experiment with it's settings/adjustments.

It;s normal to have a surge hum as you plug them in, but once settled should not be heard unless you put your ear up the amp chassis. If it's louder than this you either have some DC on your AC lines or something distorting the AC waveform.

[CIAudio]

Glad you're enjoying your D•200's.
No problem running them on a 20A circuit, each amp draws 3A maximum.

[zybar]

Barry,

Are you using the auto-curve function or are you manually creating your curve?

There is no right or wrong curve, simply what works best to your ears.

George

[Nick B]

Barry
My D200's have a very slight hum that is barely detectable. Great sound and great value. Glad you are enjoying them as I am 
Nick

[denjo]

Nick B

The hum is definitely not from the D200. Through my Bent Audio TAP preamp, the D200 is DEAD quiet. You will need look to your preamp, cables, equipment, etc and by a process of elimination determine what is causing the hum.

Denjo

[Nick B]

Hi Dennis
The hum I have is very, very minimal. I will do a quick check and see if I can improve things a bit. I just have a modded Aberdeen SB2 and deluxe PS going into the amp. I kept your PM of many months ago about the D200's and you were absolutely right!!
Regards
Nick

[mfsoa]

I agree w/ Dusty that the turn-on surge noise goes away, down to barely audible. Disconcerting at first power-up though!

I had one lamp in my room, though, that would make my D200s hum like mad (amps themselves - Not the stereo). Any idea on why this would be? Maybe the amps double as noise-sniffers!

I have no dedicated outlets or AC filtration at the moment.

[CIAudio]

I agree w/ Dusty that the turn-on surge noise goes away, down to barely audible. Disconcerting at first power-up though!

I had one lamp in my room, though, that would make my D200s hum like mad (amps themselves - Not the stereo). Any idea on why this would be? Maybe the amps double as noise-sniffers!

I have no dedicated outlets or AC filtration at the moment.

Some electronic devices/appliances can severely distort your AC waveform, this tends to make transformers hum, especially toroidal types.

[95bcwh]

I noticed something interesting - "warm up"!

In my previous posts, I mentioned that after running the D200 for 2 days non-stop, the sound of the D200 become warmer, and smoother, I liked this sound better than my Bryston 4B-SST.

Last night there was a thunder storm in my area so I turned off the D200. Today as I switched it back again, I noticed that the sound is no longer as warm as it was yesterday, in fact, it sounded cold and lean, just like the first day. I left the D200 play on for 12 hours, let the temperature warm up, went back to listen again, the sound is back to warm and smooth..

So perhaps what I noticed is not so much of a "burn-in" effect, it's "warm up"..

[CIAudio]

Last night there was a thunder storm in my area so I turned off the D200. Today as I switched it back again, I noticed that the sound is no longer as warm as it was yesterday, in fact, it sounded cold and lean, just like the first day. I left the D200 play on for 12 hours, let the temperature warm up, went back to listen again, the sound is back to warm and smooth..

So perhaps what I noticed is not so much of a "burn-in" effect, it's "warm up"..

They do sound best once they've reach normal operating temperature, which takes an hour or two from turn on (play mode). Being that they draw very little current at idle, we suggest leaving them on all the time other than things like you mention (thunder storms, etc.). The mute switch comes in handy for component/cable changes, or if you won't be using them for a week or more.