WiiM Amp discussion

[vurt]

It's the rca cord out from the sub out to the rca in on the sub. You can Google a demonstration or message me tomorrow and I can look up the back of your sub.

Thank you so much for your help!

You need to connect Left/Mono RCA in on the back of the sub to the Wiim Amp Sub Out RCA.

OH! So it's an RCA cable with single termination on both ends? Because I kept thinking I need an RCA Y-splitter to plug into both "Left/Mono" and "Right".

 

[Inertiaman]

Not helpful.

Actually, to be fair, @ninetylol's response did provide the answer/solution

Thank you so much for your help!



OH! So it's an RCA cable with single termination on both ends? Because I kept thinking I need an RCA Y-splitter to plug into both "Left/Mono" and "Right".

The Wiim Amp has already summed the L & R channel low-frequency into the single subout signal. The VX-7 (assuming you have the the mkII version since it has one RCA noted Left/mono) therefore doesn't need to do any mixing/summing. It only needs the mono signal from Wiim. The VX-7 provided a L and R for a scenario where you don't have a subout, but may have a stereo pre-out signal. In that case you would connect both L and R, and the VX-7 would do the mixing/summing.

 

[Inertiaman]

Yes. I personally see the WiiM Home app as only one of several control points for playback to WiiM devices: for example, I tend to use LMS with its Material Skin for playback of my local files, Qobuz, BBC Sounds and Radio Paradise as it’s much better than the WiiM app in those areas. Also, BubbleUPNP is the pre-eminent UPnP app, so others use that in preference too. Horses for courses really…


I only mentioned it as an extension of the device’s current output capabilities, nothing to do with ChromeCast specifically, which I didn’t realise was UPnP based too. So who knows maybe WiiM’s planned UPNP casting might be a door to ChromeCast casting.

Circling back to some of my earlier questions about the USB drive, Chromecast "transmit" and UpNP, I've learned a few things since getting the amp in hand.

The Wiim Amp essentially sets up the USB drive as a UpNP server. It is discoverable by other non-Wiim service/devices, some of which can then "send" to Chromecast endpoints. For example, using VLC, I could go to View/Playlist and see the Wiim USB content under the Local Network / UpNP, select that and browse thru artists and albums, and send music hosted on the Wiim to a Chromecast audio endpoint. So although the Wiim App isn't configured to directly support that use-case, the hardware supports it. I expect that in addition to VLC, other apps such as BubbleUPNP will also support this case. I'm sort of curious why Wiim hasn't implemented this, since it is presumably desirable, and clearly achievable within app SW.

I was even able to use the Wiim App to play internet radio over the Wiim Amp's locally connected speakers, while simultaneously using VLC to play files from the Wiim USB via Chromecast to a CCA attached to a different amp.

I do have one ongoing frustration w/ the USB / UPNP setup on the Wiim. Its pretty unpredictable when the USB drive will actually show up on the network. Sometimes its there a few seconds after opening the Wiim Amp, sometimes it takes 5 to 10 minutes. Sometimes I can see it on the network even when the Wiim Amp is in standby (or at least appears to be, based on the LED state) and other times I need to intentionally power on the Wiim Amp. This may have something to do with my router behavior, I'm not sure. But its pretty annoying when you think "oh, I'd like to listen to album XYZ" so you open the app, and stare at it for 5 minutes and still can't see the USB content to browse. I'll submit a ticket to Wiim once I have a more definitive sense of what is/isn't happening.

 

[Brantome]

Maybe the second bug fix in today‘s firmware (see above) will help your USB discovery issue

 

[Yoku-San]

Thank you. It says "PCB_version": "4". So mine's another version 4 that seems to be working fine.

My replacement unit from Audiotrade seems to be the same build week (2350) as the unit I sent back. But the replacement unit does not make any noise, it is PCB4.

 

[wilkman]

My replacement unit from Audiotrade seems to be the same build week (2350) as the unit I sent back. But the replacement unit does not make any noise, it is PCB4.

Where exactly can I see the build week? And second question - did you ask for replacement at audio trade directly or via wiim support? Thanks

 

[Inertiaman]

Maybe the second bug fix in today‘s firmware (see above) will help your USB discovery issue

It does indeed. In fact it seems to have totally resolved it. The USB drive is there anytime I look, either from Wiim app or other apps. Hoping that this continues thru different network states, router actions and other devices involved over the next couple days. So far so good.

 

[xSDMx]

Buddy just got a PCB version 2 that sounds totally fine, so I think the PCB version theory isn't 100%.

 

[Yoku-San]

Where exactly can I see the build week? And second question - did you ask for replacement at audio trade directly or via wiim support? Thanks

I asked Audiotrade for a replacement as they are the seller/distributor.

The serial number starts with PTF and that number. People have stated these represent year an week of production.

 

[Inertiaman]

Buddy just got a PCB version 2 that sounds totally fine, so I think the PCB version theory isn't 100%.

I've never put any faith in the idea that a particular PCB rev was directly correlated with the coil whine. Having spent some of my career involved in supplying components to high volume consumer electronics brands and their partner manufacturing companies, I feel some of the default "explanations" offered by some folks on this forum to reflect an ignorance of how a typical product build cycle happens.

I'll give an example that, to me, seems far more conceivable than a PCB rev having a problem. A designer/brand like Wiim in this case would typically have a qualified component list. Some of those components -- the TPA3255 for example -- are unique, single-source products and there is no confusion on the source (TI in my example). But many other components are far more generic: resistors, capacitors, and coils among others. Those generic components may have multiple vendors qualified by Wiim to supply the manufacturing partner. Or even NO qualified vendors: just a spec that any source would need to meet.

So I can imagine some subset of the coils being out-of-spec and contributing to the whine issue. Or perhaps there were multiple vendors qualified, and one vendor was out-of-spec, or even was in-spec but had some novel, unanticipated attribute that the spec didn't comprehend. Or perhaps Wiim didn't even spec the coil, maybe it was spec'd by a power supply sub-system supplied by a secondary vendor. Whatever the cause, Wiim was likely able to identify it and track with some accuracy which batches of product may have the problem. That cause, and those batches, may or may not correlate with a PCB rev, depending on the how the supply chain flowed and the nature of the problem. While I would expect Wiim to know exactly what the origin was, I would not expect them to share it publicly with any granularity. It wouldn't serve much purpose and may even conflict with contractual or NDA obligations with their vendors.

Short version: there are wide variety of possible causes behind this, none of us here have any informed idea of how/why/when the coil whine issue happened, and there is little or no benefit to ongoing speculation or assumptions about it. Personally, I'm just happy to see Wiim act responsibly, acknowledge the issue, replace units when requested, and have the experience/process (and integrity) to intersect with a solution and (apparently) eliminate the problem from the product. That puts them in rarified air in the consumer electronics industry, IMHO.

 

[vurt]

Actually, to be fair, @ninetylol's response did provide the answer/solution

The Wiim Amp has already summed the L & R channel low-frequency into the single subout signal. The VX-7 (assuming you have the the mkII version since it has one RCA noted Left/mono) therefore doesn't need to do any mixing/summing. It only needs the mono signal from Wiim. The VX-7 provided a L and R for a scenario where you don't have a subout, but may have a stereo pre-out signal. In that case you would connect both L and R, and the VX-7 would do the mixing/summing.

Thank you so much. I google and read but there are different terminologies and connection options: LFE, 3.5mm to RCA split, the labeling on the VX7 with "Left/Mono", inputs from amp as well (which looks like different plugs or bare wires); and things like banana plugs are new to me. I couldn't match what I saw on the VX-7 with something I'd read about.

 

[Inertiaman]

It does indeed. In fact it seems to have totally resolved it. The USB drive is there anytime I look, either from Wiim app or other apps. Hoping that this continues thru different network states, router actions and other devices involved over the next couple days. So far so good.

Well my joy was short lived. A couple hours after posting the comment above, the USB drive disappeared from the Wiim app and the UPnP server disappeared on the network. 12 hours later, still no visibility, despite several actions to close/reopen the app, change sources on the amp, put amp in/out of standby, open/close my VLC app, etc.

Haven't tried removing/reinserting the USB stick, or power cycling my router. Will do so just for debug purposes, but my tolerance for those types of actions is more like once every few months, not 2X/day. I think its reasonable to expect the USB source to be just as accessible as any other source, ie immediate and deterministic. Given that Linkplay's core competency is WiFi modules and associated network stack firmware, I'm surprised this is in such a poor state currently, especially after the last update claimed a fix.

 

[Malis]

Here is a video for those who do not want to take their amp apart.
I really like to see my purchase on the inside before I pay my money, hope that it helps for some to decide.

 

[Brantome]

New firmware with individual audio input volume control - I’d expect an app update to follow soon to use them.

Thread 'New firmware v.5.0.605563'
https://forum.wiimhome.com/threads/new-firmware-v-5-0-605563.2536/

WiiM have confirmed a new app version should be available next week to partner this firmware change

https://forum.wiimhome.com/threads/new-firmware-v-5-0-605563.2536/post-37396

 

[bcfc]

Here is a video for those who do not want to take their amp apart.
I really like to see my purchase on the inside before I pay my money, hope that it helps for some to decide.

Hello. Were you able to find out what operational amplifiers are installed on the board?

 

[Malis]

Hello. Were you able to find out what operational amplifiers are installed on the board?

Here are some photos of the PCB, maybe you can see on the board.

 

[morillon]

pcm5112 like wiim "pro"....

 

[onlyoneme]

5121 but this is weird anyway. Might be for sub out?

 

[Inertiaman]

5121 but this is weird anyway. Might be for sub out?

What's weird about it? Same DAC used in Pro streamer. If the Amp is conceptually a Wiim Pro + ARC + amp + USB, wouldn't it be logical to use the same/similar DAC if Wiim has experience with it and is happy with it?

 

[onlyoneme]

It's not and it's advertised to have ESS chip from 9018 family.