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

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

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?

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).

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..