Agreed but when is there 5Hz in the signal or even 10Hz. Perhaps rumble from a wobbly LP gives these ultra-low frequencies on a turntable but with digital sources?

Besides that, the level compared to higher frequencies is always a lot less in dB's and also highly reduced by most  speakers themselves (mechanically restricted by suspension or air load).

I do not see a problem with that theoretical 5Hz signal simply because it is not there or very low in gain; it will hurt less than using a capacitor trying to reduce these ultra-low frequencies (phase shifts already kicking in 4 octaves higher and ringing with very steep filters which should then be used anyway to be somewhat effective...).

Bert

Simply because it will displace the coil out of its center alignment and that will give extra non-linear distortion on its own and it will also limit its max linear excursion.

Think about a 6mm high coil in a 9mm thick magnet gap...move it 1,5mm with DC (not that much DC is needed to do that!) and the driver will not be linear as soon as it starts to move when playing music.

Just my 2 cts.

Bert

With all respect, I did not bring up the 5Hz response, I guess you have to ask this to yourself? I only tried to explain that your 5Hz is still AC and has nothing to do with DC.

Bert

What has this to do with protecting the woofer from DC?

5Hz is still AC (5 times per second) and not just leaning in one direction (DC) making no movement at all...

If your speakers can't handle 5Hz is something for a complete other topic and therefore not on topic in this topic...or even at this forum.



Bert

Yes, true DC which will misalign the cone in one direction and even burning the coils (depending on the output power and DC Voltage) if its on there too long (getting overheated while not moving!) but that is the least of the problem...

A capacitor in series with the DC/AC signal blocks DC and passes AC (this AC is making your diagramps vibrate and accepted as making music or "wanted" noise).

Edit: Best spot for this protecting capacitor is at the input. The value can then be a lot lower due to the higher impedance as seen by the capacitor. This position also prevents the amp to become instable when a source outputting DC (should not be allowed if you ask me) is connected to the amp.

Bert

There is NO DC-offset at the outputs. A servo regulation makes it 0.


Duelunds 

Bert

No problems with noise whatsoever but after trying Qx I couldn't recreate the situation as before. Rebooting, turning off the PC completely, nothing helped for the better.

The noise started after I thought the setting was the same as before (Qx 1) but apparently it was set to 0!

Should that be even possible?

Firecrackers was the result which only could be more or less silenced after changing the USB buffer to 4ms (was set to 8ms before).

Unplugging the DAC, restoring old settings and restarting the PC after that cured things again...

Bert

PS, no more tweaking for me for a while. Everything I do now (so did Qx) makes the sound flatter, makes things more digital and sounds less refined and less real. Its very organic now and draws you into the music instead of pushing me away...

This is fun...

No idea how my old little LaCie USB2.0 30GB HDD 3.600RPM compares to a normal external HDD but this tiny disc (USB powered) sounds wonderful!

I have a spare one too! 

It’s a similar HDD as used in the older iPods and not the flash drives commonly used these days.

It is not the fastest in the world so I should not load 3 CD's at once but fast enough for one CD.

At first I partitioned my OS disc to create a dedicated partition as Playback Drive but that sounds flattish... worse than copy to XX (same drive!).

I will also test a normal older drive for use inside the PC and one externally to compare but not this evening...

...it’s time for some music first and relax.

Bert

....and forced to use only my PC to check the forum because I can't change the look on my tablet to something I like and the same as on my PC.

Then better use what I was used to see...

Life just become more easy this way.

Bert

Ah, okay. I wasn't aware that it is a known situation... 

Any idea how to get that aligned in the middle of the screen?

Bert

Yep, always wanting to see things improve until it is good enough... 

After that the nagging in my head stops and so does expressing it to the outside world.

If nobody is complaining then why bother to change things eh? 

Bert

It would be more fulfilling if all buttons could be edited, skinning options are now too limited so it will then always looks unfinished to me...

Bert

Attenuation will not help. Better would be to use a battery with a > 47kohm potentiometer in series with the input of your amp/speaker to create your own DC Voltage.

The battery will then be your "NOS1" for a while.

This way you can just give it just a little DC and see how the woofer reacts (or if the amps safety circuit - if present - helps you out).

Another advantage is that this test can be very short making things burn less obvious if DC is to become a problem. Just disconnect the battery and the DC is gone again...and that works a lot faster than trying to stop XX playing!

Do measure the manually created DC first before you connect to check though and keep it low at first. 50mV should not give a problem to any amplifier and then check what is the Voltage at the output of the amplifier.

If you're not sure how to do this or when you have no idea what I am talking about then DO NOT APPLY or simply use PA and cross your fingers...or ask the manufacturer of your speakers if the amps are DC protected or have somebody come over with knowledge and check it for you.

If DC is a problem then you will NOT have time to cross your fingers...

BTW, People with tube amplifiers should not be worried to try the above, those amps always (99% sure) have a capacitor on their inputs. Not to protect the amp from external DC but to protect eveything else connected to the amp itself for its own DC (300V-1200V!).

Bert

Nope, bought a new one. First time install of this new version and I was told to get a new activation code which I did and all worked flawlessly...this time at least! 

I didn't participated with the previous test versions of this release.

Bert

PS Can't wait much longer for the BT-drivers and communicate at a distance to play music...