Sonos Connect->"Gaterised" Caiman -> B&W MM-1 Line Out vs Variable?

[Kendalbeefcake]

Hello everyone, I relise there are more than a few places I could post this, but I guess my question is mostly related to the Caiman, so I thought I'd try here first.

I work from home these days and find that I actually listen to most music sitting at my desk, so this has become my focus rather than my "main" hi-fi.

I'm very limited for space, so I have I use a pair of Bowers and Wilikins MM-1 desktop speakers, which had been fed directly (via a QED Phono to 3.5mm jack) by a Sonos:Connect/ZP90. Whilst I'm generally very happy, certain tracks at higher-volumes produce distinct crackle/clipping that are not there on the original recording. As an example, Comptine d'un autre ete (L' apres midi) from the Amelie OST is just a "simple" piano track, but the MM-1 can't cope.

As I understand it, this is most likely to be caused by the limitations of the (tiny) 18w Amp, and there isn't a lot that can be done about it within the package.. I have a "Booster" on the SMPSU, which seemed to help a bit, but not significantly so.

I've just moved my Caiman and it's a Linear PSU into the system, and whilst it sounds even better, I'm still getting the clipping at the high-end (I didn't expect the DAC to solve this). However, IIRC the variable output line on the upgraded Caiman is quite powerful. I know that in some circumstances AMPs can be linked in series, and I was wondering if using the variable output on the DAC would give the MM-1s a higher input voltage. My theory being that a larger input voltage means better output voltage, and able to drive the speakers better..

So my questions are:

1) Have I correctly diagnosed the cause of my clipping/crackling?
2) Would hooking up my speakers to the variable output make a difference (I know some equipment max-variable output is the same as the fixed output) and also, importantly, not damage anything.


Thanks in advance

Glen

[StanleyB]

I would try the variable output on the Caiman. But the problem could also be with the amp inside those powered B&W. Are there any gain controls on the B&W?

[Kendalbeefcake]

Thanks Stan,

It's just a simple volume/up down.. There are also controls for the USB interface (one of the reasons I chose the MM-1s), and Windows will me fiddle with the equalisation etc, but that has no effect on the analogue line-in.

Ok, I'm feeling brave, lets give it a go!

(If you don't hear from me in the next hour, assume that I've burnt my house down).

[Kendalbeefcake]

Ok, no housefire. Whilst the variable output produced more volume with the pot all the way around, it didn't help with the crackle at all..

Crackle Doesn't Appear:
- If I plug headphones into the Caiman Headphone AMP
- If I play the same track through the MM-1 USB Line-in direct to the speakers
- If I play the same track through the MM-1 USB Line-in and out via the headphone AMP

Crackle Does appear:
- If I play the track via the Sonos Internal DAC->MM-1 Analogue Line-in
- If I play the track via the Sonos->Caiman Fixed->MM-1 Analogue Line-in
- If I play the track via the Sonos->Caiman Variable->MM-1 Analogue Line-in
- If I play the track via the Sonos->Caiman Variable->MM-1 Analogue Line-in -> MM-1 Headphone Amp


I have tried this with a couple of tracks that are reliably unreliable, and found the same thing..

So this suggests it's not an output problem after all, but something in analogue line-in stage; the power required to drive the cans is tiny, so it can't be that.

The annoying things is apart from the crackle, the Sonos->Caiman->MM-1 sounds Terrific

Having lived with this for a while, I'm fairly sure my speakers are now out of warranty, so that's not really an option open to me.

I'm going to replace the Phono->3.5mm cable to rule it out, but I wouldn't have expected it to be the problem.?? (Edit: Not the cable!)

Otherwise back to the drawing board for me..