[Rob Watts]

@Rob Watts

Woow, super confused at the moment. Why would 0L and 0H be matched in terms of SPL?.Isn't high gain meant to be 9dB greater (volt. gain) than low gain?? Wouldn't 0H be matched to -9L? And 0L be the eq. of 9H?

But the thing is, if this is the case, if 0H was eq. to -9L wouldn't that mean a 0dBFS signal at 0L be louder than at 0H? So it does make sense to me - its like saying there is more energy in a 0L signal than a 0H signal, in which it should be the other way around.

And another confusion... if I was at 0L and put TT2 into high gain, that would bring me to 9H - what is the difference between going from 0L to 9H as opposed to 0L to 9L? Why is it I get more body to the sound in high gain that in low? Placebo?

I am confused for real. I may just not understand how the TT2 gain modes work.

Please clarify because I'm pulling my hair out. Thanks.

So imagine you have the volume control set to +6H - high gain, + 6 dB, so the output is 8.45V RMS with 0dBFS digital input (the largest input signal possible).

Now throw the gain control, without touching volume, then you would expect the OP to fall by 9dB (9dB is the gain change)? Correct, that exactly what it does - the volume control now says -3L. That means now you have 3V RMS with 0dBFS digital input.

So the gain will change the volume control setting directly - it's just that it always displays the absolute OP value in dB. -3 is 3V RMS and -3H is the same actual level as -3L. Note above -3L (say -2L) you will clip the OP with a 0dBFS input. For high gain setting it is +7H when clipping will occur with 0dBFS.

 

[RustyGates]

So imagine you have the volume control set to +6H - high gain, + 6 dB, so the output is 8.45V RMS with 0dBFS digital input (the largest input signal possible).

Now throw the gain control, without touching volume, then you would expect the OP to fall by 9dB (9dB is the gain change)? Correct, that exactly what it does - the volume control now says -3L. That means now you have 3V RMS with 0dBFS digital input.

So the gain will change the volume control setting directly - it's just that it always displays the absolute OP value in dB. -3 is 3V RMS and -3H is the same actual level as -3L. Note above -3L (say -2L) you will clip the OP with a 0dBFS input. For high gain setting it is +7H when clipping will occur with 0dBFS.

Hi Rob, thanks for that.

So let me get this straight - the way I understand it now is a drop in gain (say dropping from +6H to low gain resulting in -3L as per your example) is the same as if I was running at +6H and I reduced the VOLUME to -3H, I would attenuate a 0dBFS signal at 8.45V RMS down to 3V RMS? So basically, @0dBFS, -3L = -3H = 3V RMS at that point, and @0dBFS, 0L = 0H = 4.25V RMS, which is basically what you said initially.

Therefore, because the voltage levels are all equivalent at the OP regardless of high or low gain setting i.e. @0dBFS: +7L = +7H 8.45Vrms, 0L = 0H = 4.25Vrms, -3L = -3H = 3Vrms etc.; am I right in saying the gain function simply limits current supply? Because you just said the TT2 OP clips at -2L, that means when the RMS voltage for a 0dBFS signal has increase by 1dB beyond 3V RMS (@-3L), current supply is cut, whereas if I was at -3H, I can increase the volume until I get to +7H before current supply cuts out and the signal clips?

 

[Rob Watts]

No it actually changes the gain of the OP amplifier. So with the pulse array at max output, you will get just over 3v RMS in low gain, and 9.3v RMS in high gain, both with max output from the pulse array. It's just I have calibrated the volume control to tell you what the actual output is.

 

[JTbbb]

Hello all, I have a query which I think can be applicable within this thread.

I have been researching usb cables and find much effort is made to shield the signal cable from the power cable. Now if I’ve got this right that is something you certainly want to do when you’re music server is pc based, as there will be a dc current flowing to charge your pc battery?

My query is, if you’re music server is an Innuos, or something similar, there is no current flow as there is no battery to charge? Therefore this power cable could be dispensed with?

Have I got this all wrong?

 

[Whazzzup]

Everything needs a power chord of some sort

 

[jarnopp]

So imagine you have the volume control set to +6H - high gain, + 6 dB, so the output is 8.45V RMS with 0dBFS digital input (the largest input signal possible).

Now throw the gain control, without touching volume, then you would expect the OP to fall by 9dB (9dB is the gain change)? Correct, that exactly what it does - the volume control now says -3L. That means now you have 3V RMS with 0dBFS digital input.

So the gain will change the volume control setting directly - it's just that it always displays the absolute OP value in dB. -3 is 3V RMS and -3H is the same actual level as -3L. Note above -3L (say -2L) you will clip the OP with a 0dBFS input. For high gain setting it is +7H when clipping will occur with 0dBFS.

Rob, have you done the same between balanced output (XLR) and RCA? So is -3H 3V out of both outputs, or if not, what would the difference be? Thanks!

 

[dawktah2]

Hello all, I have a query which I think can be applicable within this thread.

I have been researching usb cables and find much effort is made to shield the signal cable from the power cable. Now if I’ve got this right that is something you certainly want to do when you’re music server is pc based, as there will be a dc current flowing to charge your pc battery?

My query is, if you’re music server is an Innuos, or something similar, there is no current flow as there is no battery to charge? Therefore this power cable could be dispensed with?

Have I got this all wrong?

In this vein, is anyone using the Curious USB cable with their TT 2? I am using the Chord C-series for the moment.

 

[RustyGates]

No it actually changes the gain of the OP amplifier. So with the pulse array at max output, you will get just over 3v RMS in low gain, and 9.3v RMS in high gain, both with max output from the pulse array. It's just I have calibrated the volume control to tell you what the actual output is.

Thanks Rob, I get it now. The volume matching had me confused.

 

[RustyGates]

In this vein, is anyone using the Curious USB cable with their TT 2? I am using the Chord C-series for the moment.

Just get a Supra USB 2.0 CERTIFIED cable. Its perfect.

 

[JTbbb]

Just get a Supra USB 2.0 CERTIFIED cable. Its perfect.

This is indeed the cable I have ordered. I’m hoping to compare it to more expensive cables in the future.

 

[Rob Watts]

Rob, have you done the same between balanced output (XLR) and RCA? So is -3H 3V out of both outputs, or if not, what would the difference be? Thanks!

Balanced is the same - but of course double the OP voltage, so 3v RMS (-3H) is 6v balanced, and 8.46v (+6H) is 16.92v RMS balanced.

 

[Mediahound]

My TT 2 occasionally makes a click/pop sound from inside the case. Maybe like once every couple of hours. Anyone know what that might be? Performance does not seem to be affected. Or I suppose it could be the M Scaler, I cannot tell as they are both on when it happens.

 

[Foxman50]

In this vein, is anyone using the Curious USB cable with their TT 2? I am using the Chord C-series for the moment.

I use a curious USB on my MScaler. I have a number of USB cables with a headphone and a speaker system. The curious is on the speaker system but is too bright on the headphone system. As you can imagine the USB cable i use on the headphone system is too dull on the speaker system. Both USB cables are great in their respective systems. As with everything hifi you need to try in your system.

 

[flyte3333]

Hi @Rob Watts

If you had the option of RCA or XLR analogue cables between TT2 and powered/active analogue speakers which can accept either RCA/XLR, which would you use?

Cables need to each be 3m from DAC to speakers.

I know balanced output has higher distortion than single ended but for 3m length, can balanced cables be of benefit (CM ground currents, RF pickup etc)?

Or for 3m lengths, you would stick with well shielded RCA cables?

Cheers

 

[andrewd01]

I use a curious USB on my MScaler. I have a number of USB cables with a headphone and a speaker system. The curious is on the speaker system but is too bright on the headphone system. As you can imagine the USB cable i use on the headphone system is too dull on the speaker system. Both USB cables are great in their respective systems. As with everything hifi you need to try in your system.

Thanks for sharing. Which USB cable are you using for the headphone system? Also what server are you using for each system, and what headphones?