More line level output settings please

[Orcker]

Hi I love my Ultra. It's the best all in one front end I have ever owned and I so pleased that WiiM keeps it updated regularly.

As someone who owns multiple amplifiers, both tube and solid state, the variable line level out is super useful for better line level matching to suit each amplifier.

The current options are: 2000, 1000, 800, 500 and 200mV.

Many tube amplifiers require generally lower line level inputs. 300, 150 and even 100mV are common.

E.g., my Audio Note OTO SE needs 300mV, but the 200mV on the Ultra is too low and 500mV completely overloads the circuit - losing separation, clarity and dynamics. My very sensitive Audion 300B amp needs 100-150mV so the 200mV setting is already too much, causing system overload and less than ideal sound

So can we please have additional line level voltage settings please if it's possible to implement?

Suggested add ons: 100mV, 150mV, 300mV, 400mV

Many many thanks in advance!

Warmest regards
O

 

[Orcker]

Just out of curiosity - have you tried the combination of 200mV while increasing Pre-Gain (for particular source) in Audio Input section? I am not saying it is ideal, but maybe it could temporarily help?

Yes I have and it definitely helps. But from a simplicity viewpoint, it'll be great to have more granularity at the lower line level output settings for tube amps. It makes using various amps and speaker combinations that much easier if you just have to set the line level for what each amp is spec'd for.

 

[harkpabst]

The thing is, at 200mV, with the volume pot maxed out on the OTO using the WiiM to control the volume, most non DSD rips are fine with the Ultra's volume between 60-75%, with some softer recordings requiring higher. With the majority of DSD files, I am at nearly 100% and often require more.

Don't shy back from setting the WiiM Ultra volume control to 100%, if it solves the loudness problem. There are absolutely no downsides to doing so. Some are afraid of not having some kind of extra margin, but that's a really a big misunderstanding. Setting the volume to 100% is the only way to get its maximum output voltage from the Ultra.

If that's still too low then maybe just because the recording is very low level, as you already mentioned.

At 500mV with the OTO, you'd think that tinkering with the volume pot on the amp to tune it down suitably might work but the sound at most listenable volumes is just poor. Vocals are swamped by instruments for instance and the sound lacks the finesse you hear at 200mV. Is it the quality of the volume pot of the OTO - a fairly standard ALPS Blue, that's not good at that particular less than max setting? Is it something else on the Ultra side? Who knows?

It's absolutely safe to assume that the pot is not at fault. A blue ALPS is pretty much good enough for everything. It's most likely the amp's input circuitry causing the issue.

The 300mV value specified by OTO is not based on magically best sound. It's very simply and very technically the input voltage (RMS, sinusoidal input signal) that will result in the full output wattage of 10 W (RMS) into 4 ohm or 8 ohm with the volume pot full open. That's it. The equivalent peak voltage of a sinusoidal signal is √2 * 300 mV = 424 mV.

• If the input voltage (loudest possible digital signal) is any lower than that, you're not getting the full power from your amp.
• If the input voltage (loudest possible digital signal) is any higher than that, you'll be getting clipping distortion from your power amp section (setting in rather softly with valve amps).

But things could be much worse. The input section of the amp could also be overdriven by a higher input signal. This already disturbed signal would then be amplified by a high distortion power stage. I have no idea if the OTO even has any form of input amplifier (or if the pot is just employed as a "passive" preamp). I hope it does.

With my various amps and speaker combinations, it'll just make it that much easier to easily get the right sound if there are just those additional 100, 150 and 300mV settings. And if it can be implemented in firmware, why not? It'll give us tube amp owners a lot more flexibility of control over sound quality.

If WiiM decide to do so I won't mind. I don't want to talk about a niche requirement again, but just to put things into perspective: The "non-valve digital audiophile nerds" (e.g. those tinkering with the original Playstation SCPH-1002) give an arm and a leg for each additional millivolt they can squeeze out of the DAC output. The higher above 2 V the better. And yes, technically, a higher output voltage means potentially better SNR.

Just out of curiosity - have you tried the combination of 200mV while increasing Pre-Gain (for particular source) in Audio Input section? I am not saying it is ideal, but maybe it could temporarily help?

Or the other way around: 500 mV setting and negative pre-gain to avoid potential digital clipping.

Or, while we're at it (and if it's not a matter of different sources from the Ultra's point of view), just set a volume limit of 92 or 93% in Audio Settings.

 

[Orcker]

Don't shy back from setting the WiiM Ultra volume control to 100%, if it solves the loudness problem. There are absolutely no downsides to doing so. Some are afraid of not having some kind of extra margin, but that's a really a big misunderstanding. Setting the volume to 100% us the only way to get its maximum output voltage from the Ultra.

If that's still too low then maybe just because the recording is very low level, as you already mentioned.


It's absolutely safe to assume that the pot is not at fault. A blue ALPS is pretty much good enough for everything. It's most likely the amp's input circuitry causing the issue.

The 300mV value specified by OTO is not based on magically best sound. It's very simply and very technically technically the input voltage (RMS, sinusoidal input signall that will result in the full output wattage of 10 W (RMS) into 4 ohm or 8 ohm with the volume pot full open. That's it. The equivalent peak voltage of a sinusoidal signal is √2 * 300 mV = 424 mV.

• If the input voltage (loudest possible digital signal) is any lower than that, you're not getting the full power from your amp.
• If the input voltage (loudest possible digital signal) is any higher than that, you'll be getting clipping distortion from your power amp section (setting in rather softly with valve amps).

But things could be much worse. The input section of the amp could also be overdriven by a higher input signal. This already disturbed signal would then be amplified by a high distortion power stage. I have no idea if the OTO even has any form of input amplifier (or if the pot is just employed as a "passive" preamp). I hope it does.

Thanks for your thoughts. The OTO has a pre-amp section. In mine (and there have been many versions), it's driven by a single 12AU7. And yes, the sound performance is pretty much determined by this front end. If it gets overloaded, the sound gets really bad. If it's under, say at 200mV, it becomes too thin. Ever since I upgraded the old ERO polyester input and coupling caps to better caps, the sound differences are more obvious at the input levels