Preamp section

[audiow99]

Hi guys,

Just got my Wiim Ultra today and hooked it up. Testing the preamp section not ended up well. Feeding the analogue into Line In, output goes to ACA amp (2 x 8W class A).

In this config, am I bypassing DAC?

I need to turn the volume all the way to 100 to get decent volume level out, around 78 dB measured with iphone from the listening position. Low band is very flat, no kick. Highs are too bright. I know there is an EQ that can help but my main concern is where is all the power I was getting before using different preamps?

Thanks!

 

[hgo58]

Hi guys,

Just got my Wiim Ultra today and hooked it up. Testing the preamp section not ended up well. Feeding the analogue into Line In, output goes to ACA amp (2 x 8W class A).

In this config, am I bypassing DAC?

I need to turn the volume all the way to 100 to get decent volume level out, around 78 dB measured with iphone from the listening position. Low band is very flat, no kick. Highs are too bright. I know there is an EQ that can help but my main concern is where is all the power I was getting before using different preamps?

Thanks!

If you use analog output (RCA) it will use the ADC and DAC. All pre-amp functionality is in the digital domain.

What input voltage is defined for the power amplifier and what have you configured for the line out for the Ultra?
It may look like the settings are too low.

 

[audiow99]

Thanks for the quick reply!

Line Out Level = 2 Vrms
Volume Limit = 100%

The amp needs around 2.2 Vrms for full delivery. Am I missing something?

 

[hgo58]

Thanks for the quick reply!

Line Out Level = 2 Vrms
Volume Limit = 100%

The amp needs around 2.2 Vrms for full delivery. Am I missing something?

Do you have XLR input on amplifier and ise a converter cable? That could explain it.

Or it is it could be the line input that is too low? What about streaming services? Do they work ok?

PS: Set the line in sample rate to 24/96 for optimal use of the ADC.

 

[audiow99]

Changing to 96 made it even more quieter but not much. 16 to 24 bits no audible difference.

Bumping up Pre-Gain does help a lot but the question is how much additional distortion will it bring in?

Everything is RCA. Streaming sounds ok.

P.S. Definitely stealing your signature!

 

[slartibartfast]

Changing to 96 made it even more quieter but not much. 16 to 24 bits no audible difference.

Bumping up Pre-Gain does help a lot but the question is how much additional distortion will it bring in?

Everything is RCA. Streaming sounds ok.

P.S. Definitely stealing your signature!

This review says the amp is very quiet

Pass ACA Class A Power Amplifier Review

This is a review and detailed measurements of the Pass ACA Class A stereo power amplifier. It is a DIY design by the famous designer, Nelson Pass, meant to be starter amplifier for people new to audio electronics to build. There are many kits available. The one loaned to me from a long time...

www.audiosciencereview.com

 

[hgo58]

Streaming sounds ok.

So the issue is with the line in. What have you connected?

If it's a turntable, does it have a proper RIAA pre-amp?

 

[audiow99]

@hgo58

Please see post #1.

 

[audiow99]

@slartibartfast

Yes, meaning it doesn't produce any buzzing or humming sound/noise.

 

[hgo58]

@hgo58

Please see post #1.

Sorry, I cannot see what the analog input source is, from your comments. I suspect the issue is there.

 

[Valentino]

If you’re happy with digital sources but analog is too quiet it’s not a problem to boost the analog. Those 10 dB are free to use as long as you don’t get audible distortion.
Any distortion in the from the Ultra will be masked by the power amp, ref the ASR measurements.

What is your analog source?
(And curiously: what speakers do you use?)

 

[slartibartfast]

@slartibartfast

Yes, meaning it doesn't produce any buzzing or humming sound/noise.

The review said the volume was low since the gain was only 9-10 dB.

"Listening Tests
Is this thing on? That is the expression that immediately came to mind after I hooked up the ACA amp to my Sonus Faber Concertino bookshelf speaker. Granted, the Concertino is spec'ed at 86 dB efficiency but come on, I could barely hear it. There was no bass naturally. But not much above that either. And this was with my Topping DX3 Pro at full volume".

 

[Valentino]

Yes, but a sensitivity of 2,2 V is fine for the Ultra’s max 2,0 V output. Max is 0,8 dB below the clipping point of the amp.
The Pass is NOT an amp for the Sonus faber Concerto speakers used in the ASR listening test. I had those 20 years ago. A 150 W Tandberg TPA 3026A was adequate.

 

[slartibartfast]

Yes, but a sensitivity of 2,2 V is fine for the Ultra’s max 2,0 V output. Max is 0,8 dB below the clipping point of the amp.
The Pass is NOT an amp for the Sonus faber Concerto speakers used in the ASR listening test. I had those 20 years ago. A 150 W Tandberg TPA 3026A was adequate.

True but nevertheless the gain is only 9-10dB.

 

[Valentino]

Indeed, but the gain structure Ultra-amp is as shown and as told by OP not the problem here.

 

[slartibartfast]

Indeed, but the gain structure Ultra-amp is as shown and as told by OP not the problem here.

So the analog output of whatever is feeding the Ultra line in must be low.

 

[audiow99]

The analog output that is feeding the Ultra is HDMI output of the PS5 (using the HDMI splitter).

Other two preamps I have at home are doing just fine with that feed.

The idea of not bypassing the DAC when feeding in the analog but rather double converting is funky.

Thanks for all the input and help guys. Ultra is packed up and ready to be returned as I don't like the product (besides the line in issue, the display feels and looks cheap, volume knob feels like grinder, can't fully turn off the device and so on...).

Thanks everyone! Cheers!