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OPA Moon HDAM revelations Pt 1-first impressions, plus updates

post #1 of 48
Thread Starter 
A brief prologue, if I may: KHA is my main headphone amplifier, it's built from a kit available from Jaycar Electronics in both Australia and New Zealand. KHA is a name I applied myself and stands for the first letters of Kit Headphone Amplifier, I did this so that I didn't have to write the whole thing out everytime. It's a pretty easy kit to build, even for noobies at this game and there is a separate +-15 Volt power supply available for it. I have built two already and will have a Mk II version of it soon with highly upgraded parts, known as KHA II. When the damn parts eventually get here! If anyone is interested, I will post a link for the kit at the end of this review.

For those of you who might be new to this thread and the whole Moon/Earth/Sun business, these are all what are known as HDAMs, a term pioneered by Phillips/Marantz, Hyper Dynamic Amplifier Module. An HDAM is an all discrete - ie separate transistors, resistors and capacitors - module that plugs into the same socket that is used by the ubiquitous and much cheaper op-amps we are all mostly familiar with. Consequently, using discrete components makes the HDAM unit much larger and sometimes a set of extension cables are used to lie the HDAM down flat, as opposed to it standing upright in the op-amp socket. Numerous example of this are available to be seen in the Zero's thread.
Briefly, HDAMs are noted for their greater headroom with dynamic signals, expansive soundstage and greater detail in the musical picture. The website to purchase these HDAMs from will be with the KHA link below.

OK, now down to the review itself.

First off, I need to say that if I don't take my Senn 650s off my head while I'm writing this it will take an awful long time to write! With OPA Moon in my amp -KHA- I am constantly drawn into the music, so hard as it is ....... ok, I had to wait until Sara K had finished.

Some time ago in my distant past, maybe some twenty seven/eight years ago, I had the first real shock in my musical evolution. I had just co-created the Hawkes Bay Audio Club with a couple of friends, wanting to expand our musical universe. The head salesman for Perreax Audio at the time brought along an Aura turntable, a magnificent and weighty gold beast, topped with a Dynavector 505 arm and a Koetsu Onyx moving coil cartridge, the sound was so stunning it was a revelation that has stuck with me ever since. Even on the Sex Pistols' God Save the Queen, the sheer physical presence of that sound opened me up to a whole new world of audio.
Some years later I was to have that arm and cartridge living in my lounge mounted on an Oracle turntable for a month or two.
There have been other quantum leaps in my audio evolution like that and another one came my way yesterday in the form of OPA Moon.
It's come as such a surprise that I will guard a tendency to gush over it, which would not be hard!
Firstly, I need to put it into some form of context, because I am using the OPA Moon in my amp, KHA, and not in the Zero's DAC, which has OPA Earth installed. The two are intimately related because what I am now hearing through the Sennheiser 650s is telling me I wasn't previously getting the best from the DAC with OPA Earth.
Somehow there is a far greater synergy in KHA with the Moon module installed, than there was with OPA Earth in there. I am putting it down to the single ended circuit of Moon being rather different than that of the more complex circuit of Earth as a distinct possibility. So far.
Although the Moon could hardly be described as run-in, of all the three HDAM modules, it has taken by far the shortest time to warm to the task. After a couple of hours warm up, I moved it from my Yamaha CD player to the Mac iBook and it has done nothing but sing it's heart out since. I basically listened to music for hours until 1:30 AM and even then it was a tough call to switch off the kit.
There is a mellifulous and effortless flow to the music that just pours into the Senns, with all styles of music that I have played so far. Classical, jazz, rock and pop and Loreena McKennitt, who has a style all of her own.
The word that really comes to mind for me is LYRICAL. No CD is untouched by it's presence. Actually, I'm not sure audio-gd do it any great favours in describing the way they have; as 'tube like and sentimental'. If you think of that description as soft and warm, it's not accurate. In my system at present, it's that very lyrical nature that is so tube-like. What has surprised me in that are the dynamics! From drums to cymbals there is a realism that just sounds so right that I'm having some difficulty finding the language to describe it. Some of the midrange dynamics just awed me, not in the hi-fi sense of great speed and pushing the emphasis forward, far from it, more in the lines of changing from a 50W amp to 200W, it becomes effortless. Rhythmically it's superb, wonderful timing, yes that's true. In saying that though, it's the small details, dynamic accents, subtle inflections in the way an instrument is played that abound here in a way that Earth didn't do in KHA, as great as it sounded there. It's now as if I can actually here the Zero properly, which shows how terrific the Earth HDAM is in the DAC's output.
I don't see it at all as the Moon colouring the sound of the DAC, quite the opposite. For those in the Zero Owners Club who like their midrange pushed forward, you may find the Moon not to your liking, it's a little more laid back here, though please do NOT claim that to mean it's warm and lacking in detail. You would be missing out big time. Conversely, those of you with slightly bright and/or forward headphones that might like some midrange solidity and dimension in their music may come to really appreciate what the Moon has to offer.
I'm going to go out on a bit of a limb here and say OPA Moon is tube-like in the best sense, open, clean, flowing, lyrical, integrated from top to bottom. I like this better than with my own Trevor Lees tube pre-amp in circuit, though it shares many attributes. OPA Moon in KHA connects me emotionally to the music, it communicates in ways that are truly exciting. There is a greater sense of humanity, easily heard in songs that are duets. With most CDs it's as if I've never really heard them before.
All I can say is, go try it, see if it works for you. I'm buying more next week!
Kingwa, you're a legend!
S-Man

Equipment used in this review is as follows:
Apple G4 iBook; USB lead to PCLink that came with my Zero and thence to the standard optical cable that came with the Zero; Zero DAC with OPA Earth in the DAC and LT1364s in the amp (unused for this review); Neotech interconnects to KHA with OPA Moon; Sennheiser HD 650's with standard cable.

NB: OPA Moon had around 8 hours at the time of these impressions and as of 40 hours plus at present, has only become even more expressive and communicative and utterly addictive. A revelation in the world of music for me. It is still a huge task to switch the gear off at night!

New notes added, 19/10/08 or for those in the US 10/19/08!

KHA's power supply has since undergone a major revision, in that all the standard caps have been replaced with Nichicon FG (Fine Gold) by four and Elna Silmic caps by two, plus all diodes had been changed to Shottkey UF 4001 previously. It's possible their addition may have been nullified by the el cheapo caps at the time, if that's true, they sure as heck aren't now!
However, the enormous changes wrought to the sound of KHA's main board, including HDAM Moon has been dramatic, to say the least.
The overall wonders of OPA Moon have been expanded upon, taking on a new level of transparency that had to be heard to be believed! Gone is the slight thickness in the vocals that PP and I noted, while the slight laid back nature is basically still there, yet is clearer at the same time. Treble has extended and gained speed and openness and while the bass took some time off for a few hours, it has returned with renewed speed, transparency and depth.
Dynamics on a King Crimson Live concert nearly had me changing the underwear several times! Such speed and clarity, even the distortion used on the guitars was so clean I could listen at higher volume levels without cringing. Awesome!
What I am saying here is that OPA Moon has risen to new heights in my admiration for it's music making abilities, because I can hear much more clearly what is is doing in the system. Simply stunning! S-Man


Links are as follows: KHA
Jaycar Electronics

KHA power supply (basic though works well, quiet!)
Jaycar Electronics

HDAMs
н¨ÍøÒ³ 1
post #2 of 48
Nice writeup. You might want to edit your post and rename it to "Moon HDAM First Impressions" so that it's easy to find in the future. It also might be worth explaining that the Earth and Moon are HDAM units, that replace opamps with discrete circuits.

I hope soon to be posting the results of putting a pair in my Little Dot MKV in place of the opamps in it. HDAMs are definitely a great find, for which I believe we have to thank Pricklely Peete for.
post #3 of 48
Hi sennsay!

I have not really understood what the KHA amp is that you have. Is it a amplifier that you have exchanged the amp in the Zero with or is it a stand-alone amp?

Thanks for the write up,

Cheers!
post #4 of 48
Thread Starter 
Quote:
Originally Posted by Currawong View Post
Nice writeup. You might want to edit your post and rename it to "Moon HDAM First Impressions" so that it's easy to find in the future. It also might be worth explaining that the Earth and Moon are HDAM units, that replace opamps with discrete circuits.

I hope soon to be posting the results of putting a pair in my Little Dot MKV in place of the opamps in it. HDAMs are definitely a great find, for which I believe we have to thank Pricklely Peete for.
Thanks Currawong and your point on the HDAMs is well taken. I didn't consider those who may have only recently arrived on the Zero and HDAM scene, thanks for the reminder!
And I certainly have thanked PP for spotting those gems!
As for OPA Moon, it has only improved further! Awesome creation and has been singing it's heart out this morning on the end of a turntable system, to hear what an analogue signal may be like through it. Emotive, expressive, dynamic, delicate, all describe what I heard through KHA and OPA Moon.
Happy sigh.
post #5 of 48
Thread Starter 
Quote:
Originally Posted by Deftoned View Post
Hi sennsay!

I have not really understood what the KHA amp is that you have. Is it a amplifier that you have exchanged the amp in the Zero with or is it a stand-alone amp?

Thanks for the write up,

Cheers!
My apologies, Deftoned, once again I assumed most would have read through the Zero's thread and it really is far too big to absorb all the info. KHA stands for Kit Headphone Amplifier and is a high quality unit designed by one Peter Smith at or through Silicon Chip Magazine, based in Australia. It has no official name so I gave it one so that I didn't have to write the full title out each time. KHA is about to much upgraded on a brand new board to become KHA II and it too will most certainly have an OPA Moon on board! As standard, KHA has a slightly mid forward nature and the Moon HDAM balances it out to perfection, whilst adding a little warmth to go with the fast and clean nature of the circuit. It's a match made in heaven, as Prickley Pete is finding out in his own system (though not with KHA) and as I'm sure you'll get to hear about it, I won't say a word further about it.
KHA originally came with a Burr Brown OPA2134 op-amp, a goodie in it's own right and is used with some quite upmarket DACs from time to time.
I use my Zero with an OPA Earth HDAM in the DAC and LT1364s in the headamp which gets little use these days. So yes, KHA is a stand alone amplifier and sounds every bit as deliciously fine whether the signal comes from my Apple iBook or from the turntable and a phono stage. S-Man
post #6 of 48
Any pics in situ?
post #7 of 48
Thread Starter 
Quote:
Originally Posted by 1UP View Post
Any pics in situ?
Ok. At present, since it has been undergoing reconstruction, KHA is caseless, since both it and the power supply (PS) have been modified with bypass caps. The PS has since been stripped of the unnecessary 5 volt parts for use with some switching in the pre-amp that it was designed to go with. I don't have pics of that particular mod, as it too will undergo quite a transformation soon, and is in fact most likely is being replaced altogether for a much beefier unit from Kingwa at audio-gd. Hence an entirely new case will need to be designed to cope.
Pics below show the basic stock unit from the Jaycar website, then KHA as it sometimes is in my system, though it usually resides beside the iBook elsewhere.
Then a pic as I built it a while ago with OPA Earth HDAM installed.
Lastly, KHA is atop the Trevor Lees tube pre-amp, itself sited upon the big Yamaha AX-900 amplifier. Next door is the Zero atop the Yamaha CDX 1110 CDP.

PS: Also, I have recently soldered the earth cable from the HDAM to a hole I drilled in the PCB centrally between the inputs. Sonically, it has made no difference, but Kingwa says it's superior technically so who am I to argue with the genius who designed OPA Moon!
LL
LL
LL
post #8 of 48

Nice job on the write up

Hi S-Man

Your enthusiasm is infectious As I get to know this latest audi-gd creation it helps to have others input of that same experience be so well explained it really leaves nothing else to cover on it.....the more you speak of the KHA the more I want to build one (since I have no SS can amp ...yet).

It's interesting to note the synergy you've noted with the Zero (Earth) combo feeding the (mid forward) KHA. I wonder if the II's changes address this minor complaint ? In this case it isn't a drawback as you note with the Moon module.

As this module evolves and settles in (in another DAC at the moment since Frank is due for some minor upgrades- proper coax in CMC jack and silver wiring, swap the older rhodium plated jacks for CMC's once again) it has matched very very well with that DAC ( a Cirrus Logic based DAC using CS4397 DAC/CS8416 receiver ). It's an engaging thoroughly enjoyable module of the same family of attributes of the Earth module but voiced decidedly on the warm side of things. It certainly is analog from start to finish.

Some drawbacks compared to the Earth is the rolled off highs and slightly recessed mids (upper mid region) slightly thickened mid bass range with a lower end region that doesn't quite have the speed and control of the Earth module. Sound stage I find is a little narrower than the Earth although very good in it's own right.

Some of these factors may change while the module settles in further ( I only have 25-30 hours on it so far and counting).

Let me say when I mention differences the actual amount of mid recess is subtle as is the high end roll off. Part of those drawbacks were mitigated today (in the SuperDAC ) when it was treated to a full Frankenization of sorts that was in the works from day one of purchase. What that tells me is the Moon modules signature although a general impression is highly mission specific. As the fully modified and completed (finally ) SuperDAC settles (250 hours or so) I can bet I'll enjoy the process from start to finish using the Moon HDAMs in it.....

I may try mixing the modules in that DAC and see if I can replicate the chain you have going.....Earth module in the I/V stage and the Moon in the amping "analog" stage....might be the perfect combination.

Thanks for the throughly enjoyable and informative mini evaluation, great job !!

Peete.
post #9 of 48
Thread Starter 
Quote:
Originally Posted by Pricklely Peete View Post
Hi S-Man

Your enthusiasm is infectious As I get to know this latest audi-gd creation it helps to have others input of that same experience be so well explained it really leaves nothing else to cover on it.....the more you speak of the KHA the more I want to build one (since I have no SS can amp ...yet).

It's interesting to note the synergy you've noted with the Zero (Earth) combo feeding the (mid forward) KHA. I wonder if the II's changes address this minor complaint ? In this case it isn't a drawback as you note with the Moon module.

As this module evolves and settles in (in another DAC at the moment since Frank is due for some minor upgrades- proper coax in CMC jack and silver wiring, swap the older rhodium plated jacks for CMC's once again) it has matched very very well with that DAC ( a Cirrus Logic based DAC using CS4397 DAC/CS8416 receiver ). It's an engaging thoroughly enjoyable module of the same family of attributes of the Earth module but voiced decidedly on the warm side of things. It certainly is analog from start to finish.

Some drawbacks compared to the Earth is the rolled off highs and slightly recessed mids (upper mid region) slightly thickened mid bass range with a lower end region that doesn't quite have the speed and control of the Earth module. Sound stage I find is a little narrower than the Earth although very good in it's own right.

Some of these factors may change while the module settles in further ( I only have 25-30 hours on it so far and counting).

Let me say when I mention differences the actual amount of mid recess is subtle as is the high end roll off. Part of those drawbacks were mitigated today (in the SuperDAC ) when it was treated to a full Frankenization of sorts that was in the works from day one of purchase. What that tells me is the Moon modules signature although a general impression is highly mission specific. As the fully modified and completed (finally ) SuperDAC settles (250 hours or so) I can bet I'll enjoy the process from start to finish using the Moon HDAMs in it.....

I may try mixing the modules in that DAC and see if I can replicate the chain you have going.....Earth module in the I/V stage and the Moon in the amping "analog" stage....might be the perfect combination.

Thanks for the throughly enjoyable and informative mini evaluation, great job !!

Peete.
Aaaawww shucks, PP, You've noted a couple of points I haven't yet, though I am aware of them, namely the slight mid bass warmth and yes indeedilydoodily there is less sheer transparency in the lower bass at this time in the burn-in - almost 50 hours. That truly is something I adore in the Earth HDAM, such clarity! What gets to me with the Moon Unit () is the unadulterated joy of communication and for that I can forgive any of the gentle veering away from absolute accuracy. The beauty of having these HDAMs is that we can swap between them at any time! Just plug and play.
In saying that, the Moon in that place in KHA does things the Earth never has in there, prime example last night was the Rain Tree Crow album, utterly sublime! I never 'got' more than a couple of tracks before and now it's as if the whole album has transformed into something else again, where every track is a masterpiece. I can listen right into the music and it makes real sense. Man, does that make my heart sing or what! As they say down here, "You beudy!" And do you think that's happened with just one album? Not on your nelly!
Cheers buddy, thanks for the comments one and all. S-Man
post #10 of 48
Thank you sennsay for your explanation!
post #11 of 48
Thread Starter 
Quote:
Originally Posted by Deftoned View Post
Thank you sennsay for your explanation!
Thanks Deftoned for helping me clarify a few things.

Moon has undergone further changes in the last couple of days, with a power supply upgrade to KHA and if you think that hasn't floored me, you'd have another think coming!
Will post updates when things have run-in some more, but the levels of increase in transparency and speed have utterly gobsmacked me, while retaining that delicious joie de vivre that is so much of the OPA Moon experience. So much so that I'm too stunned to write much here at the moment, scribbling notes and I need a fine brew (not the malted variety).
Let's say for now that with the new caps in the power supply, KHA with Moon on board has gone from a well made homemade go cart into a racing version, use your own analogies. Simply stunning!
post #12 of 48
I've just received another lot of HDAMs. My first impression of the Moon is that it has a different EQ to the Earth HDAM. I'll check again though after it has been burned in.
post #13 of 48
Ok, an update: I thought initially that the Moon and Sun V2 had a different EQ, but couldn't nail it down. What was really going on is, the Moon (in my Zero) has a wider soundstage, where the Sun V2 feels more closed-in.
post #14 of 48
I have the Jaycar Headphone Amp w/ matching power supply. My unit was built for me as a gift from an Aussie DIYer who highly modified the unit inclusive of a JLH additional board for the power supply.

It is a superb unit, does who wish to follow over 6 months of tweaks and improvements to the Jaycar Headphone Amp send me a PM. I will provide a link to the forum w/ the mods/improvements.
post #15 of 48
i'll order 2 opa.
Could you help me to make a choice ?
I need one (2 singles) to put it in my XP 7 RSA amp and the other in my dac witch drive an tube preamp.
I was thinking about the Moon for the XP7 and about the Hearth for the dac.
Is it a good choice ?
moon 'll be instead of my 797 in the XP7 and Hearth instead of the 637 AP in the dac.

Thank you.
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