Monoprice Monolith Liquid Platinum Headphone Amplifier by Alex Cavalli

I've had LP since launch and I still say tube rolling is sort of a waste of time on this amp. I've tried a few and just sold them cuz they were worth more in currency than in sound improvement. I've found the EH, JJ and Gold lion obtained as cheap as possible is all you need. I've settled on JJ, Gold lion were great in Valhalla 2 though. All my opinion of course.

 

^ agreed. Even with Telefunken and a few other $$$ tubes it wasn't worth it to me. I would probably settle on the JJ or "mid priced" vintage 6922 at most.

Granted, part of this may depend on how much you're willing to spend on audio gear and how much you got the tubes for.

 

Still my favorite pair of tubes I have run in the LP were via an adapter to go to 12a-7 and they were the Raytheon 7730 12au7, long plate, square getter tubes that I bought on Ebay two years ago almost. TheyLP was also modded which increases the effectiveness of tube rolling. The soundstage is very tall and wide, and just overall more open sounding. Great texture on the bass as well.

Not so many of them around right now, but every once and a while a sellers shows up with a handful of the 7730 variants on the bay.

I now use them in my quicksilver HPA

 

You still modding the LP ? I was considering this after being bored and now owning a Bifrost 2.

 

It’s something I would do for you anytime (and others around here), but I am low on time lately and am not really taking on orders until after the holidays for the most part.

I think the mod improves the LP by reducing some of what i perceived as muddiness and giving it some more air to breathe. It’s a good amp, but I have moved on from owning one.

 

Yeah next year sounds good. I heard the mod as you were nice enough to lend. I think it would blend excellent with Bifrost 2 I think I had a modius then. I haven't moved on from it because it's excellent with both my headphones I own and I am a cheap bastard.

 

This for sure. Getting 12A*7 adapters and some cheap NOS 12AU7's is the way to go if you want to roll quality tubes in the LP without breaking the bank. The last time I owned this amp I used some 50's Hammond organ branded blackplate 12AU7's made by GE and Raytheon, which sounded really nice in this amp. These can be had for $40 a pair or less.

 

Ugh, tube woes. This is the first time in about a decade that I've been tempted to go solid state.

I absolutely LOVE the Gold Lions on the LP, but one of my tubes has been developing some noise issues. It used to only be a hum in one channel on startup that would go away once the amp was warmed up, but now I'm getting very slight background hiss that never leaves. Sadly, the price on these things has nearly doubled...I paid $80 for a matched pair a couple years ago and now they are going for $160+.

I have a pair of Amperex that are decent, but the stage is smaller and the dynamics take a hit.

The stage on the stock tubes is fine, but they're flat and boring.

There's no real point to this post...just whining, haha.

Has anyone tried the JJ gold pins? They seem to be about the only affordable new production option out there these days other than the EH tubes that came stock with the amp.

*EDIT* Just saw @HotRatSalad above say the JJs are decent. Maybe that's my next move...

 

Currently on sale for $339.99, try SAVE25 at checkout for an extra $25 off.

https://www.monoprice.com/product?p_id=33305

 

On sale for $288.99 at Target, online only since they ship directly from Monoprice.

Monolith Liquid Platinum Headphone Amplifier - Designed By Alex Cavalli | 3.6 Watts Per Channel, Fully Ballanced Amp : Target

 

these are crazy prices for what you are getting

 

I could not resist and bought one today. Does this amp use a regular male XLR on the headphone cable? I put in for a quote on a Hart balanced cable.

 

Yes, regular XLR but do note LP has high gain and there is no gain switch to control the gain and hence will need some preamp if you want to go full balanced

 

Thanks for the advice. I have M1070 headphones which are difficult to drive which will help. Moreover, I had trouble with channel imbalances with my Sunrise 3 and Ember 2 tube gain stages and this solved the problem completely ....

https://www.superbestaudiofriends.org/index.php?threads/need-a-good-balance-control.13035/

 

It is a 4pin XLR not a standard 3pin that is used for balanced interconnects

 

I think he means a Hart hp cable.

 

This has always been out there as a thing with the LP and perhaps it is with certain headphones.

But, I've used the LP fully balanced since it was released with the HD600/650 and planar headphones alike. A preamp is not necessary in my opinion. The volume knob is sensitive to small changes, but is perfectly usable.

A pre-amp won't hurt, but no point in spending the extra money in my experience.

*edit* Balanced DACs used without issue have been the Modius and BF2, for reference.

 

I don't own the LP, but I own the somewhat comparable Liquid Gold X: comparable in that the gain is quite high (LGX' gain is switchable, unlike LP's, but it's no help since "Low" gain is so high to begin with). This leaves the user entirely at the mercy of the output voltage of the DAC.

If that is relatively low, ~2V single-ended, maybe it will be OK, depending on the sensitivity of the headphones used--with "OK" meaning the user has sufficient play on the volume pot to actually control HP volume. But if the DAC's output is hotter than that (my single-ended DAC outputs 3.0 volts), then the LP will start having the classic excess gain issue of too little usable play on the volume pot before volume is intolerably loud.

If the DAC is balanced and its balanced output is used for the LP, that's a prescription for real excess gain trouble, because balanced DACs usually output twice or more the voltage of single ended DACs (ie, 4 to 6 volts out).

Thus the utility of a preamp, PVC, TVC, anything w/a volume pot between the DAC & LP.

 

It's just a bad design (the ridiculously high gain). By using a preamp to reduce the gain (lower the signal from the DAC) all you're doing is raising the system noise floor. Some may not care about this.

 

I will be using my LP with a SE input from a MMB2 so that helps. I have a passive volume control if needed. I also have a balance control if I am at the point where there is a channel imbalance but the overall volume is OK. I will be using this amp with my modded M1070 which is much more difficult to drive than any other headphone I have. Thanks for the input everyone.