Saturday, May 21, 2016

Furman PL-PLUS DMC Power Conditioner - Dead Eye Mod

The Furman PL-PLUS DMC is a power conditioner featuring Furman's serial, non-sacrificial power conditioning technology. It's a very nifty unit I'd recommend to anyone.

One issue that may drive some to modifications however is the voltage meter. It's easily off by about 2-4%. due to the use of a low-tolerance part.  This may sound pretty good, but consider if you are in an environment with slightly elevated voltages, around 125VAC.  You'll see 130 which is a cause for real concern.  This is exactly why I hacked this unit to be within 1%. Though less frequent in residential areas it's quite common in commercial locations (auditoriums, office buildings, parks).

Of course, any time that you work in a device like this you take your fate and that of your unborn children into your own hands, so this is not for the inexperienced stupid, or squeamish. If you don't know that you must disconnect the unit from the wall before working on it, just stop, stop right here.

Open up the unit and look at the meter board.   You will see resistor R10 that is nominally 2.2k. The voltage reading is proportional to the resistor value here, so if, hypothetically, the meter was reading high by two percentage points, adding a high value resistor (around 180k) in parallel would correct the problem.  If the voltage is too low though you'll have to replace R10. These are all low voltage parts, so you don't need to go crazy with high voltage, fusible, yadda yadda but something thermally stable would ensure correct readings even in warm road cases. $1 tops. You could replace R10 with a 1%, thermally stable resistor, this will give you the best reliability regardless of your environment. Not needed for me. :)

So if you are a traveling roadie and need a dead-accurate voltage reading, you know what to do.

Thursday, May 5, 2016

Fiio X5II and E12A - Mont Blanc Edition

The E12A headphone amplifier is specially marketed for the low impedance and low sensitivity of in ear monitors.  While usable with any portable device that uses a 3.5mm stereo jack, the special X5II stacking kit makes it a breeze to attach your X5II semi-permanently. The amp itself comes with a number of Livestrong-like bands that help attach it to most portable devices.

As noted elsewhere, the biggest failing of the X5II seems to be the built in headphone amplifier. If it was just weak across the board it would still be useful.  Unfortunately by itself it sounds hard and gutless. As if only a tweeter was playing.  This is a little bit of an exaggeration, but it helps illustrate the problem with sound quality. Neither of my headphones played nicely with it despite having a broad (20 and 60 Ohm) variation in impedance.

The E12A, like the K5, really opens up the sound. You get much more spacious and neutral sounding playback. Also, and one other reviewer mentioned this, the X5II seems to break in.  Yes, I know it's nuts, but if you absolutely can't stand it at first, put it in a drawer and let it play for 4-5 hours before you listen again, then tell me I'm nuts.

Anyway, with either add-on amplifier the X5II is a much much better sounding DAP. However, even at sales prices I'm now out $471  ($299 + $160 + $16) in total and I don't have the slim profile of the iPod classic, and I dare say the Tobleron shaped Pono may actually fit my pockets better.


Oddly, the dual SD cards in the X5II are seen as 2 separate cards by my Windows 7 PC and Media Monkey. To keep from going completely crazy I ended up moving all of my classical collection to SD 2, and keeping all the Pop, modern and world on SD1.  I guess that's fine, but in the 21st century it's surprising to find a digital device that doesn't take care of stuff like this for you.

Another issue is that each device charges independently.

Lastly, un-strapping the X5II to place in the K5 is kind of a bother. It seems you need to commit to using the X5 as either your commuter player, or your desktop player with easy to drive headphones. This combination is not going to be able to do all things for you. Not that any other solution would either.


Overall, the X5II/E12A is a much better sounding solution than the X5II alone. It's much clearer and warmer than my 160 GBbyte iPod classic (currently snuggled into the glove box of my car) but it's still not as good as the $399 Pono. The Pono still sounds warmer and sweeter without any loss of detail, but the X5II/E12A is a really good combination and credible good sounding alternative.

Wednesday, May 4, 2016

Headphone Impedance

We often see speaker impedance charts from reviews, but rarely do we see them in headphones, so I thought it might be fun to do so for my two reference headphones.

One nice exception are reviews from InnerFideility which do include this information.  Why should we care about headphone impedance? The lower the impedance at a given frequency, the more current an amplifier must provide. Portable headphone amplifiers are especially limited in current drive. This causes the sound to track the impedance curve instead of the music. So, in general, a headphone with a higher impedance and low phase angle will be easier to drive to the same high quality sound. They will tend to sound more consistent across different headphone amplifiers.

To do this I used my trusted Dayton Audio Test System v. 2. Of course most use this for speaker testing, but what are headphones but speakers you can wear?

I have two completely different headphones I have been using as my standards. They're probably now considered quite old.  The headphones I turn to most often are the AKG K712.

The impedance plot was a solid 60 Ohms or more.

My other set of references are Shure E4c in ear monitors. I'm not even sure they used that term when I purchased them. They are definitely the most "discerning" or "demanding" of the two. While they have fantastic noise isolation, the bass doesn't open up except with the best headphone amps.  All others need not bother. This should not be a good thing! What buyers really should look for are headphones that play great with cheap amps. The minimum impedance here is a punishing (for portable amps) 24 Ohms.

The only portable player so far that I have heard play this very well is the Pono. I just wish the Pono had more features that would make it a no brainer.  The amplifier part of the player is just simply outstanding. I need to get either easier IEM's or bite the bullet and get a Pono. The other sub-$1k player that played these well was the UFO DSD DAC, until it died. 

Sunday, May 1, 2016

Affordable Headphone Solutions From Pono, Fiio, Oppo and others

I have been in the market for a headphone listening solution for a couple of years. I'm not quite sure what it is exactly, but my thoughts were something like a portable player and/or headphone amplifier/DAC.  This all started since the Apple iPod Classic was discontinued and I got a great deal on an AKG K712. I still have the iPod, but it's married to my car which is iPod only. The iPod Classic sounds fine, but not the best I've heard, and it's limited and fixed storage size has been an issue.

In the mean time my search for solutions continues. 

So, what IS ideal?  That varies from person to person, but they are, from most important:
  • Sounds great
  • $500 or less. 
  • Battery operated (i.e. portable)
  • Supports 128 GBytes or more
  • Support for Tidal music streaming
  • Nice if it can double as desktop DAC/amp
I've also been struck by how completely off some reviews have been compared to my ears. They tend to be universally positive with colorful and nuanced critiques regardless of the source. I really have to wonder about the reviewers. In any event, I present my own list:

Pono PMPOppo HA-1Fiio X5IIFiio X7EchoBox ExplorerUFO
Approx. Cost$399$1,200$299$650$449$430
Maximum Storage192N/A2561921 Micro SD Slot??N/A
Sound QualityExcellentSadisticSadistic-ish??????Very very good
Wi Fi TidalNoN/ANoYesYesN/A
DACESSESSBurr BrownESSBurr Brown???


As I have written before, the sound of the Pono Portable Music Player, regardless of headphones, is always excellent, musical and enjoyable. It handled both my AKG and Shure IEM's so convincingly and smoothly that is has been my reference standard for what a portable Digital Audio Player (DAP) should be. However it is hampered by a few things which have kept me from pulling the plug on one for myself: Size, features and storage.

The size is too chunky, the apps are non-existant and storage is limited to about 192 GBytes. There's no way to stream music from a NAS or online service.  If it had BluTooth connectivity (and BluTooth could do high resolution music) so I can play from my phone it would be hands down unbeatable.


I purchased a UFO DSD DAC from Blue Coast Records at a show and it worked for about 2 months before it died from what I believe were power supply  and overheating issues. Among the USB DAC's I've listened to under $1,000 the sound quality was simply outstanding, and almost as good as the Pono player. If mine had not died so quickly it would be an easy recommendation.  If you buy, make sure it's from a reputable vendor (such as Blue Coast Records) and save your receipt.  In a sense, it IS portable in that it can be driven from the USB out of a phone or tablet, which works surprisingly well given the limited power a phone could supply but it is far too chunky for a pocket.

Oppo HA-1

This is a beautiful looking headphone amplifier and DAC from Oppo that I really wanted to like. The Oppo 103 BluRay player with it's 7.1 analog outputs makes my home theater life so simple and beautiful and easy to integrate with my music listening that I could not be happier or conceive of buying another brand of BluRay player, ever.

Then I come to this "thing" released by Oppo as the HA-1. Are they serious, or just being cynical? I can't tell really. What a hard, strident and difficult to listen to treble and limp sounding bass. I heard it at the 2015 California Audio Show, the same show where I heard the UFO DSD DAC, driven by a Macbook Air. It was literally the worst sound at the entire show, of any kind, and I heard some really bad rooms and bad music at that show. I thought perhaps it was me but I mentioned this to a fellow audiophile who owned one for about two months who described it as "fingernails on a chalkboard." It's a real shame because it's beefy, sexy and comes from a company I really appreciate for it's high quality products and connection to consumers. Perhaps it performs much better with their own headphones? I never found out. For about a third of the price, the UFO DSD DAC easily sounds better and takes up less space.

Fiio X5II (2nd Generation)

The Fiio X5II is an extremely well reviewed player that is now in it's second generation, as well as heavily discounted from it's original $500 to around $300. With the glowing and numerous consumer reviews, and Fiio, like Oppo, showing very good customer engagement, I was certain this would be a good player for my commute. Unfortunately, cold and alone it's barely listenable. The treble is such an ear drill it literally makes them feel hot after twenty to thirty minutes of listening. It's like when you've been out in the sun too long and your eyes ache? Imagine that in my ears. It's not hyperbole, it's exactly what it feels like. By itself I really can't recommend this player. The closest experience I've had to this is the Oppo HD-1, or speakers from Triangle.  Ouch. Not all is lost however for with an outboard amplifier this is a very good source.

Fiio X5II/K5 Combination

As an article at EnjoyTheMusic points out that the Fiio K5 headphone amplifier really improved the sound of the X7.  I have not heard the X7 at all, but It seems from my listening to the X5II/K5 combination that the K5 does in fact improve the sound quality of the player. Using the K5 the listening experience is much more balanced. The midrange and bass are no longer shy, the treble softens up, channel separation (or something like it) gets really good. Thanks to the K5 I'm not as ready to throw in the towel than if I had purchased the X5II by itself. Also, while I usually review with the AKG K712 my outdoor headphones are Shure in-ear-monitors, so I need to give them a good long listen in the streets to see if that is a reasonable arrangement.

I have also recently reviewed the Fiio E12A Mont Blanc Edition portable amplifier, which also does an admirable job of driving difficult headphones from the X5II.  If you are only looking for a portable solution, that may be your dream ticket. 

EchoBox Explorer

The $449 Explorer is an indy Android / Wifi DAP in a dapper looking whiskey flask design. It will constantly remind you to drink, so probably not good for those dealing with addiction issues, and what audiophile isn't? Still, it looks promising at a reasonable price. Like the X7, it aims to be an Android answer to the iPod Touch challenge. For those not familiar with the iPod Touch, they are essentially iPhones without calling abilities and as a result can run the full suite of iOS apps that don't require calling. To my knowledge only the X7 and Explorer are reasonably good Android equivalents.

Sadly I've never seen one in real life so cannot comment except to say they look very interesting!

Lessons Learned

I. The resolution of the playback files is much less important than the sound of the player.
 I'm not saying crappy MP3 files sound as good as everything else.  What I am saying is that the sound quality and balance of the player is a much bigger factor to my enjoyment of the music than the file resolution. This may not be true in my home system, but  it is here. I would much rather have the Pono sound at 44.1kHz/16 bit FLAC than the Oppo at any file quality.

II. Online audio reviews, even when apparently independent, are often completely off the mark.

III. DAC chip makers don't matter as much as the amplifiers.
Some audiophiles ascribe to the idea that DAC chips from manufacturer X are always better than Y, but putting together this report and going over my past experiences I can't agree with that at all. I've listened to ESS and Burr Brown devices and have found great and bad examples of both. My current and previous home DAC's had Burr Brown chips in them. The Pono uses an ESS chip.  The X5 uses Burr Brown. The Oppo 103 uses Cirrus Logic. There's no correlation in my experience that either chip is inherently better or worse.

I'll write more on this as I gain more experience. As always, please for the sake of the Dark Goddess of Coffee and Chocolate I worship, use your own ears to spend your own money. Buy what you like, always.