Cavalli Audio Liquid Lightning

[spritzer]

I've been the proud owner of a Cavalli Audio Liquid Lightning for over a month now.  Now as most will know, this hasn't been exactly a dream of mine but the owner practically begged me to take it and the price was low enough to waste money on it.  The normal market price on the Mk1 model has dropped well below half of retail (2400$) at this point and this one was even cheaper.  What finally made me buy it is the very unhealthy discussion about this piece and the clear attempts of the manufacturer to kill any negative discussion about it.  My views will be questioned because of my history with Cavalli but that's exactly what should be done to any impression that is read.  Nothing should be taken as gospel but I've put my money where my mouth is and that's not something you can say about the people who rave about the LL. 

 

 

The main goal of this thread though will be to document just how badly built and designed this amp is but also to document ways of improving is and indeed, making it safe for the user.  The circuit has been fully drawn up and analyzed and it will be posted in full later on.  Any issues of copyright are blown aside as this is very similar to the Exstata which in it self was a Stax design lifted off the web.  Cavalli has admitted to that in the past and the "improvements" make it even more similar to the SRM-323/727.   We'll get to that later though when I start the ordeal of making something useful out of this box. 

 

Perhaps we should start with some impressions of the sound.  First impressions were just how small it is and very light.  It's about double the size of the SRM-727/007t but doesn't weigh all that much more.  The casework is flimsy but well made.  Some plainly odd bits such as the volume knob is painted, not powder coated as one would expect and there is no primer used.  Very odd...  The switch on the front is neat but the circuit driving it could use a lot of work. 

 

As for the sound, well the output capacitance of this amp is about 300pf so it sounds very odd.  It's utterly unusable with the SR-003 as they are just 44pf with the cable.  Same with the SR-007 and SR-Omega, way, way too much bass, no life at all and the treble is just gone.  The midrange which makes these so special has no depth, no height so voices just sit flat on the front of your face.  Let's break this down a bit:

 

The bass is by far the worst part about this amp.  There is no sub bass output and the rest is both anemic and overblown at the same time.  The bass has no power, no heft until it hits a certain frequency range and then it turns into a overblown mess that consumes everything.  This is worthy of cheap closed dynamics and is very annoying.  The SR-007 when driven well rivals any transducer when it comes to bass impact but here it is just a weak muddling mess. 

 

The midrange doesn't have any presence or bite to it, it just sits there.  The soundstage has no depth and is pretty much stuck directly in front of the face.  Remember those bell graphs... that's how it sounds.  Some output low down on each side but almost everything in the center.  The HE90/Stax hybrid I have rivals even the Sigma's when it comes to casting a vast soundstage but here it is just dead.  The lovely out of head experience of the SR-Omega... completely gone.  Voices are separate and not really joined in with the rest of the stage, almost like a bubble directly in front of the eyes.  Truly weird and it's there no matter the recording. 

 

The top end is highly rolled off, there are no shimmering cymbals here or guitars piercing as they are driven into overload.  Nope, just lifeless and inoffensive.  I can see people liking the SR-009 with this but it's like taking a sledgehammer to the sound.  Instead of gently molding the top end it's just cut off entirely. 

 

Now this is the Liquid Lightning Mk1 I have here so how different is it to the Mk2?  Well until I posted my findings it was supposed to be identical on the inside, all the same parts used and just some slight tweaking plus the new case.  Now suddenly it is massively different and a gigantic improvement.  Nothing backs this up, no pictures, no clearly defined part changes and only the testimony of people to who I wouldn't take at their word.  Until something comes along that actually backs up these stories of major improvements then I have to assume that they are exactly the same.  Same output devices which have a combined output capacitance of 270pf per transducer and the same fucked CCS that kills the top end and fucks up the phasing on the low end. 

 

Finally the first steps in improving this pile of fail.  I naturally needed to change it to 230V so I was greeted by this:

 

 

That is not a very professional job to be honest.  Two wires are the primary windings of the small standby transformer and the two green wires are the pass through to the large HV transformer. 

 

 

Here is how I did it.  Fun fact, there is actually no locknut on that grounding post.  There are two lock washers but they are both right next to the eyelet, there is none on the nut which secures the whole assembly.  You can see where this is going, fucking amateur hour... 

 

To cap this off I decided the blue knob had to go.  This is what I had "in stock":

 

 

Much better and since that is a Headamp knob I hoped that the amp would sound a bit better.  It didn't... 

Edited September 21, 2013 by spritzer

[Jon L]

Umm, even with the heroic mod attempt surely under way, how much improvement do you expect to squeeze out of this basic circuitry, and Oh  why?

[kevin gilmore]

You have seen the singlepower esx rebuilds we have done right?

 

remember this?

http://gilmore.chem.northwestern.edu/liquidlightning.pdf

well we built it just for fun and it sounded fucking awful.

remember what alex said about it... it was a SLOW amplifier

 

well the real thing is virtually identical to this.

and its still fucking awful.

but we have ways to fix it.

 

at least we think we do.

 

It is kind of a shame, the chassis is actually very nicely done

and the power supply is pretty decent. The stax jacks are still

way to tight and for no reason. Transformers are very nice.

Now all alex needs is a decent amplifier to go inside the

box.

Edited September 22, 2013 by kevin gilmore

[tin ear]

Very shoddy for a premium priced head amp. Look forward to seeing how you pimp it.

[DefQon]

I still can't get the fact that thing retailed at $4800. Not $480, $4800. You know there were some rumors back then after the LF was praised and some internal shots of a prototype LL was posted, naysayers justified that the thing was just plainly not worth the asking price, well I'm glad it's confirmed now subjective or not. Even if you count in labor costs and shit, I've seen bog standard DIY'd KGSSHV's sold for less than $4.8k and still look more polished with crimped connectors to the AEC outlet than this amp. 

[spritzer]

I'm a glutton for punishment, that's why I'm modifying it.  It was also about time somebody spoke up about this amp once and for all as it isn't normal that something is sold after just one days ownership, by three people.  One of the amps out there is fast approaching the tenth owner in a year. 

 

Before I begin, here is a picture of the amp in full D800 glory:

 

http://gilmore.chem.northwestern.edu/ll-1.jpg

 

Easy see here that this is just an Exstata with a CCS.  Same basic layout except the output devices have their own sinks rotated 90° (there were two on each sink in the Exstata) and the CCS is on those small sinks towards the front. 

 

 

The resistors between the main sinks are now the CCS. 

 

Another thing of interest is the bias supply.  Just below the transformers in that pic, next to the white caps you can see two CMF55 4.7M resistors.  Those are the ballast resistors for the bias and an important safety feature.  The CMF55 is how ever rated for max 250V but here it is sitting at 600V.  Should be fine when the bias is an open circuit but if it shorts to ground then those resistors are useless.  Also notice the small jumper next to them, that selects between high and low bias.  Not the best idea to run these at high voltage... 

 

What I have to do is to add loopouts to the back of the amp, do something about those Stax sockets and replace almost all of the transistors used in the amp with new BJT's to decrease the distortion by 15-20dB -  ditto the output capacitance down to ca. 20pf.  I'm also thinking about scrapping the main CCS as it is just fucked.  My options would be to go with a BHSE style design or what Stax are already using in the SRM-323S.  The latter should be more stable in this circuit and just needs one 2.5" heatsink per phase. 

Edited September 22, 2013 by spritzer

[RudeWolf]

Has someone done spectral readings on this thing? Would be nice to see the objective improvements by doing the active device swap. If it is as bad as you say a dummy load + voltage divider should do the trick together with a simple mic inlet.

 

Maybe even compare it to a KGSS/HV?

[DefQon]

The quality of that PCB looks so cheaply made. I bet a few quick desolders and the trace will be ripped off.

[kevin gilmore]

Well its a bright and sunny sunday morning and the don of the stax mafia says its

ok for me to publish the schematic, so here it is.

http://gilmore.chem.northwestern.edu/llmk1.pdf

 

 

 

that triple current source at the top of the gain stage with the feedback from the output

stage is what alex (knowingly or not) traded 1db of 2nd harmonic for 7db of 3rd harmonic.

all the spice models are available, stuff them into ltspice and see for yourself.

 

output transistor pics

http://gilmore.chem.northwestern.edu/ll-2.jpg

the tough one to take a picture of

http://gilmore.chem.northwestern.edu/ll-3.jpg

how about that quality way to jumper out a zener

http://gilmore.chem.northwestern.edu/ll-4.jpg

and a cold solder joint or 3

http://gilmore.chem.northwestern.edu/ll-5.jpg

 

and here are some simple fixes that make the thing sound bunches better with just removing

parts and only 2 jumpers

http://gilmore.chem.northwestern.edu/llmk1fix.pdf

 

at least alex did learn something from the exstata disaster.

The power supply is no longer a shunt regulator.

Its actually fairly quiet, and has a temperature stability of

about 2% strictly due to the zener reference.

Edited September 23, 2013 by kevin gilmore

[s_r]

So I take it that figure of 0.0009% THD+N isn't exactly accurate?

[kevin gilmore]

Do a quick calculation noticing that the j176 is 10 times as noisy as the j74

With an amplifier with a voltage gain of 500 and see if you can get the

Signal to noise ratio shown in that picture.

[guzziguy]

Hint: Use "new" math.

[spritzer]

Yes, same math they used in 2006 for the housing market in the US.  Moar+moar=MOAR!!!!!  Works great...

 

That graph makes me wonder though, does Cavalli not understand it or does he think his potential customers are braindead idiots? 

 

I'll start work on ripping this POS apart tomorrow and a new CCS using 2SA1968 it is.  New Fairchild output devices as they are in current production and lower the output capacitance more than 10 fold.  See if I don't have some J74's of the right IDSS too.  Are the LSJ74's shipping yet? 

[shellylh]

Fuzzy math?

 

Edited September 22, 2013 by shellylh

[HiWire]

For pure entertainment value, this thread delivers. I am curious whether a decent amp can be made in this enclosure.

Their product names remind me of diarrhea, unfortunately.

Edited September 23, 2013 by HiWire

[Audiojunkie]

Their product names remind me of diarrhea, unfortunately.

 

[kevin gilmore]

For pure entertainment value, this thread delivers. I am curious whether a decent amp can be made in this enclosure.

Their product names remind me of diarrhea, unfortunately.

 

definitely.

 

Alex should go into the custom chassis business.

 

I have 3 chassis I need right now, and don't have the time to do myself.

[spritzer]

I'm a bit worried that the PSU may pose some problems but I can make something useful out of this pile of parts.  Moar pics later as I start stripping it down. 

[wink]

Would you say the LL is better than the King Sound amps? The King Sounds have SMD......

[kevin gilmore]

http://gilmore.chem.northwestern.edu/m10.pdf

http://gilmore.chem.northwestern.edu/m20.pdf

 

I think its safe to say that even an exstata is better than the kingsound amps.

[spritzer]

Ohh yes, the Exstata is better than the M-10.  My Exstata has been on loan for the last few years but I tried it recently just as a refresher and it wasn't nearly as bad.  It runs at +/-350V and uses a BHSE PSU though... 

[eggil]

The pundits at headfi have been admitting how poorly the Mk1 sounds but I remember when they said it was better than anything else. It is amazing how things change when they release a new version.

The comment that the KGSSHV has loud hisses and clicks was an utter lie.

Edited September 23, 2013 by eggil

[Knuckledragger]

I don't knowm my ass from a hole in the chassis when it comes to stat amps, but I always enjoy these Stax Mafia Excoriations.

[morphsci]

...

The comment that the KGSSHV has loud hisses and clicks was an utter lie.

Unless it was a hennyo built KGSSHV.

[spritzer]

There was just one Hennyo built amp in circulation and it blew up... as soon as it arrived. 

 

Stay tuned for some pics...