Line-in quality issues with turntable

[wilxuk]

Hi everyone! I’m new to Wiim and new to the forum and wondered if anyone had any experience with this particular issue I’m having…

I bought the Wiim Pro Plus recently as a dedicated solution for expanding my turntable across my network. I went with Wiim based on the great reviews and the Pro Plus specifically because of the high-spec ADC.

I have a mid-high-end Roksan Attessa turntable with a built in phono pre-amp. I've tried a few different configurations, but the resulting sound quality when paired with the Wiimis unexpectedly poor. There is very little clarity, particularly in the mid and low frequencies, and there's an overbearing crackle/static that takes over when certain frequencies play, resulting in an unlistenable experience.

I’ve been in touch with Wiim about this and with nothing showing in the log, they suspected a faulty ADC (which I also suspected). However, the replacement unit is doing the exact same thing. Here‘a a few details for wider context:

1. The turntable works perfectly – when wired directly into my speakers, the sound quality is perfect, so there’s no obvious issue here.
2. The cables are in good working order. I've tried 3 different line-in connects between the turntable and the Wiim – all brand new. The same cables work fine when I bi-pass the Wiim as well.
3. I have a high-speed home network
4. My networked/bluetooth speakers work perfectly, and also work perfectly with the Wiim when playing Spotify over Airplay or Bluetooth. The issue seems to occur when the source is line-in and the ADC comes into play.
5. I experience the poor sound issue in multiple scenarios when using the Wiim and line-in is the source:
   1. When airplaying to high-quality Naim speakers
   2. When using my Naim speakers as Bluetooth receiver
   3. Even when hardwiring into my speakers via line-out on the Wiim
   4. These scenarios suggest that issue might lie with the signal processing
6. In addition, I've tried adjusting the line-in sample rates from low to high, which didn't make a difference.

My primary use-case is to play my turntable over Airplay (which the Wiim is absolutely ideal for on paper), so I'd be massively grateful to hear if anyone has experienced this issue, has a solve for it or any suggestions that I haven’t thought of.

Thanks I’m advance Wiim community

 

[AlPo]

Hi! I play my Pro-Ject E1 Phono line output into WiiMPro Plus with no issues and more than acceptable quality. However, I remember from tests posted by @onlyoneme and/or @VintageFlanker that Pro Plus (and even more so the regular Plus) have limited headroom as to line-input voltage. My table’s built-in phono preamp has a rather modest gain of 34db, hence it’s output voltage is also on the lowish side . Could it be a highish output voltage problem in your case? Do you have an idea what is your Roksan’s phono gain is? Do you have any other line-level source to connect to your WiiM line-in to check?

 

[wilxuk]

Hi! I play my Pro-Ject E1 Phono line output into WiiMPro Plus with no issues and more than acceptable quality. However, I remember from tests posted by @onlyoneme and/or @VintageFlanker that Pro Plus (and even more so the regular Plus) have limited headroom as to line-input voltage. My table’s built-in phono preamp has a rather modest gain of 34db, hence it’s output voltage is also on the lowish side . Could it be a highish output voltage problem in your case? Do you have an idea what is your Roksan’s phono gain is? Do you have any other line-level source to connect to your WiiM line-in to check?

Great to hear your insight, thank you! And really interesting to hear you’ve had good success with the unit.

The gain is 42db according to specs - do you think this might be contributing towards the issue?

Testing other analogue inputs is a great suggestion and something I’d like to do asap. I don’t have anything to hand but I’ll try and get hold of something to test it with. I’ll provide updates as I uncover more.

Another thought I had was to test it with an external phono pre-amp, but everything I’ve read about wiim is that it has zero compatibility issues so this could be an unnecessary expense (and you’d expect Roksan to have a pretty tight pre-amp, even for a built in).

 

[AlPo]

Best to do a test with any line-out source, especially one with a volume control. Even a phone with a basic minijack to RCA cable or adapter would do. Test at different volume settings and see how it goes)

 

[wilxuk]

I have a mini jack to RCA cable so will try this and report back, thanks for the suggestion. Would the wiim receive a phone’s output as an analogue signal this way tho (comparable test) or do you think it would already be digital (and hence not require the ADC in the wiim)? Im determined to get to the bottom of this

 

[AlPo]

if a phone has a mini-jack out it is analogue by definition (modern iPhones don’t have it). BUT! First of all, make sure to set the phone volume to the LOWEST level before connecting it to WiiM Line-in, as a phone mini-jack socket is not strictly line-level (rather it’s headphone out) , and can amplify the signal beyond the standard line level voltage. Then increase it in small increments. Do you hear music through your chain? Are the same artifacts there or not? Proceed to increase the volume carefully. Stop once you hear any hint of distortion.

 

[wilxuk]

Cheers. I’ve got a few old bricks lying around so I’ll test over the weekend and let you know the results. Really appreciate the support, thank you!

 

[megabigeye]

Hi,
I'm wondering what the outcome of this was for you? Did you ever get it figured out?

I've got the exact same problem with my Pro Plus using it with my turntable setup. I haven't tested with any outputs other than line out into my amp, though (it doesn't recognize my Raspberry Pis running Volumio).

 

[megabigeye]

In case anybody is reading this, I think the issue is between my phono preamp (Parasound ZPhono USB) and the Pro Plus. I plugged an old Blu-Ray player into it via line in and there is no distortion on line out. I used an online gain calculator and it says my preamp has a gain of 47dB. I don't really feel like spending the money on a new preamp, but maybe that's what's needed in order to make it work.

 

[toomuchstuff]

Hi all.

I've just hit the buy button on a WiiM Pro Plus and a Pro-Ject Tube Box S2 premap (replacing my Fosi Audio Box X3 preamp), which I'll connect to my Pro-Ject Debut Carbon EVO turntable.

I'll share with you all in a week or so if I had any problems with how the X3 and S2 sounded through the line-in of the WiiM, and how the sound compared when to going direct to the power amp.

 

[toomuchstuff]

Hi all.

I've just hit the buy button on a WiiM Pro Plus and a Pro-Ject Tube Box S2 premap (replacing my Fosi Audio Box X3 preamp), which I'll connect to my Pro-Ject Debut Carbon EVO turntable.

I'll share with you all in a week or so if I had any problems with how the X3 and S2 sounded through the line-in of the WiiM, and how the sound compared when to going direct to the power amp.

I didn't intend to write an essay, but here we are. If you want to skip the detail, the conclusion is at the bottom.

Disclaimer: I'm very new to audio, and still learning and building up my system as and when I find good deals on components. If I made any attempt to explain any of the science in this or made accidental assumptions, please disregard .

Setup:

• Turntable: Pro-Ject Debut Carbon Evo
• Stylus: Ortofon Stylus 2M Blue
• Phono Preamp 1: Fosi Audio Box X3
• Phono Preamp 2: Pro-Ject Tube Box S2
• Amp: Fosi Audio V3 with 48V Power Supply
• Streamer: WiiM Pro Plus
• Album: Radiohead - In Rainbows - Jigsaw Falling Into Place

Notes:

• The X3 has treble, bass and volume control but no gain, whereas the S2 has only gain control where you can select from the following (in dB): 40, 43, 50, 53, 60 and 63.
• The Ortofon is a MM cartridge, and I expect a gain setting on the S2 of 40 or 43 to be adequate.
• WiiM volume set to max and EQ off.
• WiiM settings all on default, so line-in input resolution set to bit depth of 16 bits, and sample rate 48 kHz. I'll tinker with these settings later.
• X3 treble and bass set to the midpoint.

Tests:

# Test 1 - Fosi Audio Box X3 straight into V3

1. X3 vol 25%, V3 vol 50% - Too faint
2. X3 vol 50%, V3 vol 50% - Comfortable level, no distortion
3. X3 vol 75%, V3 vol 50% - Loud enough, no distortion
4. X3 vol 100%, V3 vol 33% - Turned the V3 down as likely to annoy the neighbours. Treble slightly jarring at this point.

# Test 2 - Pro-Ject Tube Box S2 straight into V3

1. S2 gain 40dB, V3 vol 33% - Comfortable level for me.
2. S2 gain 43dB, V3 vol 33% - Louder.
3. S2 gain 50dB...63dB, V3 vol 5% - Progressively louder. Music still audible but V3 volume needs to be set low. No distortion heard at any level.

# Test 3 - Fosi Audio Box X3 via WiiM line-in

Same results as Test 1. Perhaps a little louder than when input straight to V3. I need an RCA switch to be conclusive.

# Test 4 - Pro-Ject Tube Box S2 via WiiM line-in

1. S2 gain 40dB, V3 vol 33% - Sounds good, lower volume than equivalent song playing through Spotify.
2. S2 gain 43dB, V3 vol 33% - Louder, almost the same volume when I switched over to the same song playing on Spotify. The first half of song was clear with some crackling noise developing into the second half.
3. S2 gain 50dB, V3 vol 33% - Inaudible. The sound was like radio static, very distorted, crackly and loud.
4. 53dB...63dB - Nope, not going there.
5. S2 gain 50dB, V3 vol 33%, WiiM bit depth increased to 24 bits. - Increasing the bit depth cleaned up the sound significantly. Still, some 'static' present.
6. S2 gain 50dB, V3 vol 33%, WiiM bit depth 24 bits, WiiM sample rate increased to 192 kHz. - No change. Increasing the sample rate has no impact.

To conclude:

It's clear that gain influences the quality of the audio through the WiiM line-in, from audible to completely inaudible.

It appears the WiiM line-in, on default settings, cannot handle gain above 40dB.

Increasing the WiiM line-in bit depth to 24 bits yields a significant improvement in cleaning up that 'static' noise. This is good news for me, as 43dB (which at 16 bits revealed some slight distortion), feels like the optimum setting for my turntable in terms of my perception of volume, allowing it to be almost equivalent to other inputs such as from streaming services or ethernet. I've just played the entire album at 43dB and it sounds perfect now.

The Fosi Audio Box X3 had no issues, albeit it was not as loud and detailed as the Pro-Ject Tube Box S2. The X3 is designed for MM cartridges only, so I assume it has a fixed gain at the lower end and uses volume to compensate.

Therefore…

• Increase the line-in bit depth (WiiM app -> Devices -> Settings icon (the cog) -> Audio input -> Line-In Input Resolution -> Bit depth: 24 bits). I think 24 bits is only available on the WiiM Pro Plus and is determined by the onboard ADC, though I’m just speculating here.
• Consider one of those cheap phono preamps that use volume, like the X3. I see the X4 is discounted on Amazon UK right now @£73

Hope this helps.

 

[megabigeye]

Wow, thanks for testing so thoroughly!
For some reason I thought about changing the bit depth but thought, "nah, it's probably not that." Derp!

I've been thinking of getting a cheap preamp with level control, but I'll try changing bit depth first. I'm away on vacation this week, so I'll try it when I get home.

 

[megabigeye]

Sorry to report that switching the 24 bit depth (nor changing sample rates) did not change anything for me. Still lots of the static noise. I'm nearing the end of my return window for the Pro Plus, so I may have to return and then re-purchase when I have a new preamp. Boo.

 

[Schmidlapper]

I am pretty sure that tests conducted and presented by onlyoneme, a member here showed that the analog input of the pro + began clipping at anything much over one volt PP in. I use the lower output of my tuner because of this resul.

 

[megabigeye]

I am pretty sure that tests conducted and presented by onlyoneme, a member here showed that the analog input of the pro + began clipping at anything much over one volt PP in. I use the lower output of my tuner because of this resul.

Yes, I noticed that in the manual it states 1V on the analog input. I think I also read the same thing on AudioScienceReview, but then I couldn't remember if it was the Mini or Pro Plus.
It seems like a strange design decision since most consumer sources have ~2V line out. Anyway, I was hopeful because of @toomuchstuff's experience.

 

[Schmidlapper]

I believe I also read WiiM claimed a fix was coming with a v2 circuit board, but I never read where anyone ever saw one In the wild before either. I too find a one volt limit to be rather annoying, limiting and unnecessary.

 

[canard]

seems that the ADC is well designed for 2v rms on the "plus" (it was a little more limited on the "pro").. so this seems surprising regarding possible clipping (if your phono outputs less than 2v rms max)..
i speak only clipping not quality" etc , another thing...
(it seems to me that these entries are more taken as additional troubleshooting given the measurements etc.)

 

[d6jg]

I don't have a use case for trying a turntable through the line in on a WiiM but I do have the ability to stream my turntable into LMS and I can advise from experience that you get much better results if the input to an ADC if the source is true line level i.e. off the Tape Out circuit of an amplifier.

My set up goes like this

Source (whatever I choose on Amp1 eg Turntable, CD etc ) -> Tape Out - > USB ADC -> then splits

USB Out - > Raspberry Pi running Liquidsoap and Icecast2 -> presents as a playable Ogg Flac stream. Some latency - can be synced across multiple players which can include WiiM Pro running Squeezelite.
RCA Out -> Amp2 (only used if LMS is not be involved, for synced streaming Amp2 is set to a different input)

 

[canard]

for my personal culture..
who remembers the input impedance value to the ADC of the "plus"?
thanks...
;-)

 

[megabigeye]

Happy to report that the New WPP and phono pre (Technolink TC-750LC) both arrived, are hooked up and sound great together, even with the trim pot on the Technolink all the way open. If I have time (a.k.a, patience) tomorrow maybe I'll see if this Wiim also works with my old preamp (Parasound ZPhono USB).