Monoprice Monolith Electostatic Headphones

[spritzer]

Well...these arrived this week via the Gilmore express and to make it easier for anybody looking for info on them, a new thread it is.    As Kevin documented before, the amplifier is a dinky little thing and a direct clone of the Stax SRM-001.  The amp is pretty much useless though as it doesn't have any volume control and you can't use it from a portable device as it needs a full 2Vrms input signal to reach usable volume levels.  Here is a picture of the entire system plus what Kevin Posted:

Opamp feeding a quad of fet's and into the output transistors.  All AC coupled... 

Yet again another clone of older Stax stuff but onto the headphones.  The build quality from the outside is pretty mediocre, flimsy plastic everywhere and the creek and rattle like a 50$ set of headphones.  The earpads are actually leather on the important parts so that is nice.  The cable is rather nice though, a bit stiff and microphonic but a far cry better than what Hifiman and Mr. Speakers include with their sets. 

I was first a bit puzzled as to how the phones were put together as nothing came loose with minimal force.  I stated by removing the back of the drivers which just popped off:

That revealed this very minimal damping foam:

Now that got me to the back of the drivers but nothing budged.  Then I go medieval on it and the earpads do pull off... there is just a lot of adhesive holding them on. 

I did take the pics afterwards which is why the pads are there in the previous pics.    The adhesive is nice though as the pads are securely fastened and can be put back as the adhesive doesn't fall apart.  

Now we are onto the baffle and this is after I removed the first dust cover stuck to the front there.  I'm rather impressed with the build quality and the attention to detail.  The drivers are on the small side but that does mean there is room to raise the baffle and get away with flat earpads, Audio-Techica style. 

Now the money shot, the back of the drivers.  Now, when I opened it first up it didn't look like that as there is custom cut, black tape covering all the connections and around the perimeter of the drivers as well.  Really impressed by the attention to detail here. 

Now I did open up the drivers but the angle was really awkward so I couldn't take any good pics.  The stators are PCB though and this was a well thought out design.  I first though King Sound might have a hand in this design but this is leagues ahead of their crappy drivers. 

Now some notes, there are only woven dust covers here, two on the front and one on the back (plus the foam) so dust will be an issue.  Both drivers on this set have started to squeal though that is at Pro bias levels.  More on that later...  On the whole though I just don't get this package, the cable on the headphones is too short so are they supposed to be portable?  Sure but no normal DAP can drive them properly so it kinda doesn't work...  The sound with the stock amp is pretty bad too, no bass to speak of  and it is all compressed to hell.  I fed it with a preamp to help with the silly low input impedance but it doesn't really help. 

Now the specs for the headphones are close enough to Stax (well...they use a Stax amp after all) so it is adapter time.    The headphones use a bog standard 5-pin DIN plug (nowhere near to be rated fort the voltages involved though) so a quick trip to the local parts store and 2$ later I had a socket in hand.  10 minutes later I had an adapter and off the Carbon CC...well these are quite good.  The 50mm drivers will not produce any meaningful bass output compared to larger units but over all, yeah their sins are of omission rather than adding something that shouldn't be there.  To me these remind me of Stax SR-X Mk3 Pro's in some ways and what I've been doing with those drivers converted to Pro bias in different shells. 

The imaging is nice and tight with a solid sound stage, nice midrange presence and a nice neutral sound signature.  The bass doesn't go deep but it's tuneful and fun and the treble is nice and extended without ever being bright.  The lack of bass depth and bloom does make them a tad thin sounding at times but that is rare.  Feed them well and these are very fun headphones to listen to. 

Bottom line is that the amp is crap and there are issues but there is also a lot to like here.  The Massdrop Koss ESP950 setup is probably a better deal at 500$ but these are fun to play with. 

[Timb5881]

Very interesting.  I was almost sure that these were made by KingSound.

[Timb5881]

Spritzer, you made a Stax adapter for this headphone.  Is there any way I could purchase one of these from you?  If not could you share the Monoprice pin out so I could make my own?    These are a decent set of cans, but I think a Stax amp would improve them a lot.

[spritzer]

I can make an adapter no problem.  I'd just have to dig mine out from storage and look at the pinout.  I know I bought some extra sockets for these when I made my adapter. 

[Timb5881]

For those who might be interested in these headphones Monoprice has them on sale for $294.  At this price they are a steal.

[spritzer]

That's a hell of a deal and makes me mad knowing how much I paid for my set... 

[Pars]

Curious... I’m building a Carbon for a European user and don’t have any Stax to test it with. If I can’t find a pair I can borrow, which one of these would you buy: the Monoprice, or the Kaldas Resaech RR1s?


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[spritzer]

If you just want to have a simple test rig, the price here is hard to beat unless you can find a used Lambda for a similar amount.  You would need to reterminate though or use an adapter. 

The RR1 sounds a lot better though. 

[jose]

A Lambda pro may be a good option... if the price is acceptable.

[Timb5881]

I have been using the Monoprice Electrostatic headphones with the adapter I purchased from Spritzer.  I am using it with my SRD-7, which is being fed by my trusty old Golden Tube SE40 and sounds very good this way.  Very smooth and more bass than with the little amp it came with.

[spritzer]

I just put a new cable on my second set (beause reasons) and I do like them a lot.  I also ripped apart one set to examine the drivers and a lot of effort went into these.  Bunch of custom molded parts though the stators themselves are PCB. 

[Timb5881]

Bad news, Monoprice raised the price back up to $629.  To much in my mind.

[spritzer]

I agree, with the Massdrop Koss at 450$ it makes little sense. 

[Timb5881]

Just dropped to best price yet, $249.99. Well worth that price

[dh]

With the Spritzer plug adapter, I auditioned my Monolith electrostatic with both of my Stax amps (SRM1-MK2 Pro recapped & SRM-353X). Using very familiar true hi-res music from AIX through my Oppo UDP-205, I could not even tell that there was a bass player in the mix, and the high-frequency hand percussion was nearly inaudible. My Koss ESP/950 with plug adapter on the same amplifiers clearly reproduces those two frequency extremes. (My Stax SR-007MK2 and Sennheiser HE 60 with adapter sound even better, but it is not a fair comparison in terms of price.) The Monolith M1060 planar headset reproduces the full frequency spectrum much better than the Monolith ES. And for dynamic driver models, my AKG K1000 also reproduces the missing bass and percussion (again, not a fair comparison pricewise) and the Sennheiser HD 600 and 650 (and 58X Jubilee at $170) have a more satisfying overall frequency balance than the Monolith ES. So I returned them to Monoprice because, for me, a midrange-centric headset is not worth $250. 

[gruiz3]

Pardon, spritzer do you still have the original amp for the monoprice electrostats? I bought a pair on ebay. But they are as is. Seller says that they have static while listening to them. Any thoughts? I'm assuming it's the amp. But I get them next week. At 80 dollars I took the risk. Any feedback from anyone would be appreciated, thank you. 

[spritzer]

No, none of the amps are left here but it is a very noisy thing.  Plenty of high frequency noise in that thing. 

[gruiz3]

Cool, thank you for the response. I'm looking forward to getting them. 

[JJN]

Spritzer, thanks for your review, it was very helpful.  I'm also interested in the adapter for the monoprice electrostats.  How can I purchase one from you?  I'm a newbie in this, so what setup do you recommend to get the best of those cans.

[spritzer]

I'm not sure where I wrote down the pinout for the Monoprice headphones so I'll have to dig through my archives to see if I can find it.  If I find it then I can make adapters as soon as the local store opens up after the long holiday here. 

As for getting the most out of these, an amp upgrade would be the first port of call. 

[JJN]

Perfect.. thanks.  Any desktop amp that you recommend?

 

[spritzer]

Stax SRM-1 Mk2 and upwards. 

[JJN]

Perfect..

[solaral]

Question for Spritzer,

How can I buy one of your Monoprice/Stax adapters, and how $ much?

Also, do you sell the Koss/Stax adapters as well, how $ much?

Thanks, -AL

[Sherwood]

3 hours ago, solaral said:

Question for Spritzer,

How can I buy one of your Monoprice/Stax adapters, and how $ much?

Also, do you sell the Koss/Stax adapters as well, how $ much?

Thanks, -AL

You can find all of Spritzer’s products on his site:  https://mjolnir-audio.com/