Need help OOW Monoprice Cavalli LP

Hello everyone, first timer here!

So I bought Alex Cavalli's Liquid Platinum second hand (warranty is still going strong but Monoprice doesn't do service on these anymore, I'll get something back if I send the amplifier back to the seller, he sends it to the Monoprice, I get store credits, order something from Monoprice which could sell as a new product and then I'd have something in my hand after national and international shippings.

Let's then go to the problem which started all this: I bought PC88 tubes from my local retailer thinking I'm buying PCC88s (texts were wiped pretty much) and had slapped those in. Started the amp and before I could do anything just a hiss and just a hint of smoke I think, barely visible. Next panic hits and I put stock ones in and try the amp, it starts to power up like normal but stays on the red light.

Of course local tube retailer won't take any of this for himself, I should know what I'm putting into the amp, like I thought I did and by being new in this hoppy, didn't see from the tube wiring that "Hey! This is PC88, not PCC88 what I ordered, let's stop here!". Monoprice won't share circuit schematics of course, Cavalli having the ownership to those (so if you're listening, please share these with me for personal use only, I have only one local electric engineer who could check out this amp and he would do it by reading the schematics which are unavailable for me) and neither they will service it, just shop credits on the table (how much - don't know after a lots of shipping payments nationally and internationally).

I've sent a lot of emails for TV- and radio service shops but they a) tell me to send it to the place I ordered it b) are willing to check out it for pretty nice amount of money but no guarantees for service c) won't answer.

So, I'm pretty much circled by people who's 'hands are tied'. Only thing at the moment that could save me (what I can think of) is those schematics that I will not be seeing I would presume.

Here's link to some photos of the MOSFETs which are the only components I think that seem different than the counterparts. No smoke trails, nothing. But, here we go (there's some text on my language to my local electric engineer): https://imgur.com/a/nJf0iWG

Thank you for your answers already!

 

Wish that i could help but someone here may be able to.

Good luck

 

If you really want to fix it.
Avenson Audio are the official repairer for Cavalli amplifiers.

Your best bet is to ask them if they can help.
It will cost you in international shipping as they are located in the USA.

@dBel84 might be able to offer further advice.
I'd take anything he says as a hard truth.

 

What Marv said.

The Monoprice LP is a microprocessor controlled tube hybrid. I suspect you have blown the high voltage section of the power supply which is not as simple as just repairing the switch mode elements that make it up. Avenson may be able to repair and reprogram.

Good luck.. dB

 

Listen to @dBel84 and @purr1n

 

Thank you for your answers and the information you shared with me. The thing is that Monoprice is offering me (after international and national shippings) shop credits IF they think that warranty covers it. No service available. Also I payed about 300e for the amp. What I've heard, the warrant probably will be denied and I'd have to pay the shipments back too. I'm listening to @dBel84 and @purr1n about this case, also my local amp designer could probably help out since he has been involved with the same amp back in the day, doesn't hurt to show it to him because he won't take any payment just for check it out. Thank you everyone, this was the first forum I got seriously helped out!

 

Yeah, nah yeah...

It's almost one year later now and no one has touched it in local repair shops (living in the capital and trust me, I chose the best ones out there) and I'm still a little bit pissed off while moving on from this piece of a nice sound but very short lifetime of a brick.

Took it to a few places which already took few bucks here and there just to check it out but nothing seems to be out of order and since Alex has the schematics in his pocket and like everyone rightfully tried to help me out here, there is something that they cannot see which seems to be the microprocessor controller chip thingy. It's been a long shitty journey from door to door asking for help and since they're not manufactured anymore, I will in no way buy a new one used since the lifetime probably is three years when bought new (yes, I'm calculating this way under but the percentage of mishappenings is huge), so used ones probably won't last long.

What got me interested to come back here and write up it's that since there is now way more people like me (even without dysflexia and putting in PC88 tubes which I thought were PCC88s) that have had the same symptoms even with the EH 6922's that came with it? Same channel gone, same wiff of a sound and now they're stuck in the red lights. What gives? I guess it's the end of Monoprice but why would there be a need for a microcontroller (which probably should be the safety here, not the hazard) since so many well reviewed hybrids are pretty straight forward? One can only tell.

I'm not that guy but because of my neurological disorders, this have become a really effective tool to discharge my own impulses, not just AC/DC but slam that thing everytime I get mad and it really helps! So maybe Alex should start making these yet again, with even lower price point though and start marketing them to prisons and other places where people really need tools for their anger management. Jokes aside, Alex is probably a good guy, nothing personal here, it was just so personal gift from my wife at the time that I took it so bad it actually makes me laugh these days. Bitterly, but still.

But while at it and this is my last cry about the brick that seems like it landed from space, gave me once more that 'wow' effect and flew away, is there a way to modify this thing (jumping over that 'safety' circuit) since I've seen someone wondering why there was some jumpers soldered to his/hers amplifier when bought used, scavenge something off it to make some DIY project or anything useful? Not going to pay one more euro for trying to keep my hopes up but trying to find a way to maybe get something useful off it?

Best regards, Me

 

Hard to imagine that trying to modify a broken amp with a microprocessor in it to bypass a 'safety' circuit is a good idea. It's definitely possible to do minor modifications and some people have, but a complicated design (with unknown schematic) that's broken but you're not sure exactly what part broke is... at best, going to be more trouble than it's worth to do anything to. At worst, let's not think too much about that.

I'd be sad if mine broke (it's my most-used amp by far, I'm listening through it right now), but there's similar-sounding stuff out there. Maybe even better stuff. Best to move on if you can't get another one.

 

Yes, that's true. Should've staid at my lane and just ask about scavenging components out of the amplifier. I know that was a silly question I added there but was just curious what was those jumpers about in someone's amplifier who acquired the amplifier used, hehe! So, maybe I should just add that I'm not suicidal enough to do some bypasses that could be dangerous for me or for the whole flat's electricity if everything goes haywire! So, if anyone has any ideas about scavenging components from this for some DIY project, hit me up, otherwise, this topic can be closed.

Oh, and I could get another one but I won't get another one for sure. There's always going to be this cloud of uncertainty hovering over my head from now on about Cavalli amplifiers since they clearly cannot be serviced locally by the best professionals around here.

Thanks for your replies everyone who has written to this topic, you're great!

EDIT: What would be your recommendations for good tube amplifiers? I'm open for OTLs and hybrids as well. I've been eyeing on Schiit Vali 3 for used as a pre-amp, xDuoo TA-10/TA-20 used as a straight up headphone amplifier but I'm sad to see that Loxjie P20 is not in production anymore. There is of course more expensive amplifiers too but if I could find Feniks Audio Echo MKII for good price, that could be one option too. Also there's a few DIY amps (Bottlehead Crack /w Speedball as my main option on these).

 

If you want something in the same sonic universe, Lyr 3 was around at the same time and is similar. I don't think they sound identical, but I would struggle to articulate the differences in a way that I think would help you right now (I like both of them).

Lyr+ is the new and improved version with a lot of neat features (fancy relay volume control, usable without a tube, etc), so you might look into that (although my understanding is that dealing with their European distributor isn't always ideal). People seem to think it sounds a bit better than Lyr 3 did.

If you mean in general, there are dozens of different tube amps that people here think are good, but may or may not recommend depending on what headphones and DAC you're using. Probably should look around, maybe ask in the advice thread with some specifics about your budget, preferred headphones, etc.

 

Will do, thank you ser! I actually first got the amplifer strictly for it's power and wanted to look into it's 'optimized' or 'preferred' balanced topology and struggled to to find any sonic differences compared to my SS amplifiers but since I got pair of some older Siemens D-getter PCC88s, they were the first pair of tubes that revealed me what those clichés about tube amplifiers ment really about the holographic nature and the great synergy it provided listening music with ATH-R70x headphones, so yeah, I will look into some advice threads, thanks again and I think this is now ready to be archived!