[voodoochile]

Look what landed on my desk a couple days ago!

Impressions to follow after it's had a chance to burn in, but my initial impression is that it's outstanding sounding right out of the box. 

[Berndt]

That's a beautiful thing, I've been eyeing one myself.
Look forward to your impressions.

[accentstryping]

Is that a Paravinci unit?
                                      MMM

[londonbarn]

no , i think you are mistaking it with a design by Tim deParavicini.....  THIS amp product is designed by Lloyd de Peppardavicini..... 

[londonbarn]

we have 2 weeks left to order! Bring on the impressions/reviews.... aa

[urlawyer]

When will you have your impressions ready for us to read?
I have ordered one and I am interested in what you have to say.
R.

[voodoochile]

PART ONE (10,000 character limit exceeded)

Finally feeling well- my head cleared at last, I was able to spend some time with the new HD150 amp from M.A.D. Sorry for the delay, but what the hell, I ordered mine without hearing any reviews! It’s a nice amplifier, and while one shoe will never fit all people, I think many people will find this one comfortable. I will preface this short review by saying that I really wished to have put this off further, as I have a lot more listening, testing, and comparison that I would like to do, but I realize that many want to see something before the end of the month. Having been pretty ill, laid up with a lot of head and chest congestion, then followed by the holiday and it’s associated travel, I have not had much opportunity to get on this earlier. I hope to follow it up after the new year with more extensive findings and comparisons.

Peripheral Equipment:
Headphones: Grado HF-1 with senn pads; Senn 650 with Equinox cable
Source: Marantz DV7600 feeding an Electrocompaniet ECD-1 DAC
Tubes: Sylvania 5751 blackplate (input), JJ ECC99 (output)
Cables: Canare L5-CFB with crimped Canare terminations, transport to DAC, and DAC to amp
Power: balanced power on a dedicated circuit provided for all 3 pieces
I stuck with as close a setup as I typically use, trying to minimize the extraneous differences. I even used the same input tube for much of my testing that I typically use in my custom Ear+HD, which is a Sylvania 5751 blackplate piece.

Physical Impressions:
Overall, the amp is nice looking. It’s so different looking than the typical Mapletree offerings that it’s hard to believe that it’s another variant of this line, aside from the familiar transformer covers, which in this case are canted 45 degrees and cut into each other. I am not sold on the look, having grown accustomed to the “Wellborne” look of my main amp, but it’s attractive for sure, and the eggshell white gloss finish on the chassis works well with the wrinkle-finished satin black of the transformer covers and the soft purpleheart wood trim. I am thankful that the good Dr opted for a thicker set of sideslabs, particularly since the chassis is so thin in height. There are two knobs, one for volume and one for crossfeed, the knobs themselves being what has become a Mapletree characteristic- the fluted communications style knob, remniniscent of the bakelite knobs used on early military equipment. There are two jacks, one for high impedance cans, the other for low impedance cans. On the back it’s basic business, with an IEC inlet and a single pair of inputs. The RCA inputs are the nice Cardas GRFA jacks, which is a welcome touch. There is a power switch on the left rear of the deck, and a heater switch for the output tube on the right rear deck, labelled for the two provided output tubes.

While there are four sockets on the chassis, the left pair are unwired, serving to accommodate the alternate input and output tubes. At first, I found this to be a bit odd, having the right two sockets powered and the left two serving essentially as storage for a spare or alternate set of tubes. But the layout, electrically speaking, works very well, and it is nice to have a place to ‘hold’ an alternate tube if you are doing a lot of a/b testing between a given pair. The other thing is that while the ECC99 glows well enough, the input tube has such a faint glow that you can barely tell it’s running… so the fact that only one set of tubes is powered is not readily apparent to the casual glance. Everyone here will notice it immediately, though.

Listening Impressions:
The HD150 has perhaps 160 hours on it now, about 20-25 of which I have been listening to it. My initial impressions posted here(http://www6.head-fi.org/forums/showpost.php?p=2482851&postcount=93) are holding largely true, but there have been some further developments and observations.

Starting with the Grado HF-1, I find that the amp drives them with ease, and plugged into the low-Z jack, the volume sweep is very useful, allowing comfortable listening up to the 12 o’clock position. In the high impedance jack, you get a similar output level with the volume midway between the 9 and 10 o’clock position. The highs are typically clear and accurate, but never harsh. I have found that many amps sound somewhat ragged with Grados in this region, to my ears. On some material, I found there to be a slight bit of sibilance, but this was not common, and when I noted this, it was not particularly offensive. Very slight. On the whole, the clarity of the presentation is excellent; slightly better with the HD150 than with my regular amp. The bass performace seemed thin in my early impressions, but this had indeed loosened up a bit and is fuller than before. Again, it comes across as accurate and realistic, not mushy at all, and it is not sluggish. It was not all good news for me with the HF-1/HD150 combo, however. I noticed a slight hum in the amp while wearing the Grados, only to find that I had them plugged into the high impedance jack. When I switched to the low impedance jack, I did not note the hum. In the low impedance jack, I have to turn the volume to the 2 o’clock position before I notice the hum, which would be truly loud if a source was playing. In the high impedance socket, I can hear the hum in any position, including all the way down. The occasional note of sibilance, while not offensive to me, I do not note happening in my regular amp. Were it not for that, it probably would not bother me at all- it only bothers me because the other amp does not demonstrate this effect. Finally, the bass, while deep and realistic, is not have the same impact and speed that I am used to with my own amp. Don’t get me wrong, it’s good, and is not anemic. It’s just a bit more laid back than what I am used to. My normal rig is pretty darn fast; many people remark that it does not ‘sound like a tube amp’.  All you Grado fans can start groaning now, but relax, and remember that I am a Sennheiser guy at heart, still. I like these cans plenty, and with some material, moreso than the Senns. The HD150 does them good justice, with a smooth and accurate presentation. It is airy and articulate, not harsh or boomy. And while the bass is not as impactful as I am used to with the Grados and my main amp, it is certainly not weak, nor mushy. I am not sure why this is at this time, but I want to find out.

Moving on to the Senn 650s, I find that the HD150 handles them with ease as well. In the high impedance jack, I can use the volume sweep up to about 1 o’clock. I cannot perceive any hum, even at maximum volume. There is a slight hum when you first power up, which Dr P notes in his literature, but it is faint, and passes within 20 seconds or so. Listening to the 650/equinox combo, the highs come through very clean and clear. It’s very accurate to my ears, and I found no instance of sibilance on tracks where I had noted it with the Grados. Again, the upper registers come through with a smooth and airy delicacy, excellent resolution. I do not find that the 650/equinox has any veil in a well-rounded setup, and certainly it does not in my normal rig. The HD150, while a bit diminutive in appearance, is giving my regular amp a run for the money in the treble detail region. In comparison to it, sometimes it seems slightly lacking, other times it’s slightly better. I have struggled with this aspect, and want to spend some further time with both amps. At some time, I also want to experiment with the coupling in my amp. Mine has Blackgates bypassed with Auricaps; the HD150 has Solens on their own. I’d like to hear mine with Solens alone, and also with the Blackgates on their own. I have heard that in many applications the Blackgates perform bettter unbypassed, when used in signal-coupling applications. Should be interesting. In the bass department, my impressions are similar to those with the HF-1. The Senns seem to offer a more authorative presentation, articulate and clean, with good extention. It is better than my out-of-the-box findings, and I would call it accurate and realistic. It is tight and responsive, but again, it slightly slower than I am used to. I’m not trying to discourage anyone from giving it a shot, it is only slightly slower. The amp presents very nicely, with good pace, and very flat response from bottom to top. The HD150 has plenty of power and authority to drive either of these headphones with ease, and the listening is really a treat. My foot was indeed tapping. If I had to write a one-line review, I would characterize the HD150 as having an airy and articulate presentation, with the power to drive to more than ample levels without breaking apart.

I have reserved commentary on the “blend” control for last, as it’s effect is common to either pair of headphones. The crossfeed in the HD150 is a welcome addition, and the variable dial offers a sliding seat from the back of the auditorium to the center stage. While I am not generally a fan of crossfeed, I really like this implementation! Most of the crossfeeds I have tried have either an exaggerated effect, or little effect at all. Being able to dial this forward and back a bit, until it’s just right, is a real treat, especially with some recordings. While I find crossfeed unneccessary on my favorite recordings, there are a lot of others that really do benefit from some crossfeed. I found myself using it quite a bit… more than I had expected.

[voodoochile]

PART TWO (10,000 character limit exceeded)
...continued from previous post

Early Conclusions:
Overall, it is a startlingly good performer in a compact package, and for relativelty short outlay. In that regard, I am pretty impressed with it’s performance. I must admit that I was worried that after having spend so much time and effort on my own rendition of the Ear+HD that the HD150 would eclipse it. While I don’t think that has happened, the HD150 has come pretty close, which is rather remarkable given it’s scant size. While my amp has a beefier and quieter power supply and switched inputs, the HD150 has crossfeed and a much (!) smaller size. The HD150 does indeed outperform the normal Ear+HD in my recollection, having owned that amp for quite a while, and while it is not outperforming my present Ear+HD concoction, that amp’s performace came at a fairly high price, and resulted in a much larger and heavier chassis. The performance of the HD150 intrigues me, the output tube and coupling caps in particular. It has inspired me to do some experimentation with these elements in an larger environment that could accommodate a heavier power supply configuration. Specifically, I’d like to more directly compare the performace of the 12B4A to the ECC99; and  also directly compare Solens against Blackgate/Auricap against Blackgate against poly in oil coupling caps- in the same amplifier. I have been struggling comparing apples to oranges (okay, perhaps comparing two very different varieties of apples), and would love to experience a more direct comparison. I think Dr. Peppard has really outdone himself here, delivering an amp that is both a polished performer, and attractive and unusual looking. I feel that it’s an excellent value for such a combination.

[londonbarn]

wow, thanks voodoochile...... good review 

[voodoochile]

Way-late update at last.
I've been pretty much offline for a while now due to some extenuating circumstances, but realized that I never followed up on the HD-150.

At last conversation with Dr P in late December, he suggested that I move the low-z output to the 4-ohm tap on the OPT, and also replace the 39 ohm dropping resistor with a larger one (50-some odd ohms, I can't recall).

First, I tried just moving the existing resitors to the 4-ohm tap. This alone made the hum nearly inaudible, but I still could just make out the slightest bit. So I ended up installing some 46.5 ohm 1 watt film resistors, not sure if they would provide enough additional impedance to be effective. Well, they were more than ample. The amp is now truly silent with my Grados. Now, the hum was not very noticible in the first place, and I prefer to listen to Senn 650s, which exhibited no hum whatsoever in the first place. But knowing it was there with Grados just irked me, so I had to try and fix it. I believe that shortly after discussing this with Dr. P, he began wiring the subsequent amps this way. So, if any of you have an early serial number, you can drop the bottom plate and have a peek to see if your dropper resistors are wired between the two jacks, or with seperate leads to the 4-ohm OPT taps.

The amp has several hundred hours on it now (maybe 500??), and is quite smooth. Although it has been some time since I wrote the initial review, the amp does seem to have settled down and burned in nicely. I will say that my original findings, while refined now, seem to hold true still. The bass is very clean and authorative, but not quite as intense as on my other Ear amp (may be a good thing, technically, or may be my preference). The upper midrange and treble regions are damn sweet, still. I have not torn into my other amp to try swapping the coupling caps, nor do I dislike the performance of the other amp. In fact, I like it a lot! But the HD-150 is just a little sweeter, more fluid-like. It's very difficult for me to express. They are both really nice, but are different from each other, too.

[R_burke]

Are these still available, I didn't see them on the site?
 
If so $$$, if not   

[Berndt]

Are these still available, I didn't see them on the site?
 
If so $$$, if not   

Limited edition, The good Dr only made so many.
Perhaps post a wtb on headfi and here as well....

[jrebman]

I'm having a little trouble sorting out the various models, what chassis sizes are, which amps have multiple ins and pre-out jacks, etc.

I'm looking for a headphone amp that will do well with Sennheiser 650s, allow for two inputs, and allow for an output to go to some powered monitors on my desktop, and I'd prefer to build it myself.  If the combination of multiple inputs, the pre out, larger chassis, 12B4 family tubes exists in kit form, that is what I'd be looking for.

Thanks for any help in sorting all this out.

-- Jim

[saisunil]

Call Dr. LLoyd - he can do custom stuff. I have custom Mapletree headphone amp on order and he was able to give me everything on my wish list with a modest extra charge.

Cheers

[jrebman]

Thanks.  I actually did talk to him today and now have it all sorted out.

-- Jim

[Berndt]

Thanks.  I actually did talk to him today and now have it all sorted out.

-- Jim

let us know what you decided!