Practical Devices XM5 - Page 8

A DAC simply means the soundcard chip - turning digital mp3/wav files to sound you can actually hear. Your laptop has a DAC, iPod/mp3 players all have a DAC. It's the quality of the chip that matters.

I'm sorry, I should have clarified that I have never used a off-board or separate DAC for audio playback.

-HK sends

Sounds good, treble and bass boost do there job without killing the clarity or removing tons of detail.

How is the noise floor on the XM5, any audible hiss even with the Treble and Bass Boost options on?

While using it as an amp is there any glaring deficiency?

Teaser of info from my upcoming review - I am back from Maui and taking a day to recover from the travel, then I start work on the review again. I agree with your review in many places - the amp is better than the DAC, just like the Predator, and as an amp it rivals some desktop amps to a point. In my case I think the amp sounds warmer than you thought it did, but I suppose I have only been trying it with warm headphones so far and need to try it with others. I was saying before that the XM5 reminds me of a tube hybrid like my TTVJ portable Millet, like brothers, while the Predator is a cousin.

I also think the DAC is on the level of the DAC in the Predator and 2MOVE and it's a little more detailed and spacious than Headstage Lyrix (or Headstage DAC cable). However, using a Micro DAC as DAC or Pico as DAC/Preamp to feed the XM5 does provide the upgrade in sound one expects. Yet the internal DAC is still better than the one built into my Macbook or iMac.

The bass and treble boost are much cleaner than using the iPod EQ, and probably on the same level as the iTunes EQ - although sometimes the bass boost is too much and other times just right, depending on the headphone. For example - with Nuforce NE-8 the bass boost is just right, but with HD600 it is a little more than I'd like, and with D2000 or Edition 9 it is ridiculous/useless.

Since the treble boost is a modest +3 dB @ 10 kHz, it is actually useful for my needs. Even with ER4 & 325i which aren't exactly lacking in treble, treble boost is needed for me with some older jazz recording from the 50's for example.

The bass boost can be too much (+6 dB @ 100 Hz) for many newer recording which tend to have much more bass than older 60's & 70's rock for example...in these cases I do use bass boost with both ER4P/S and 325i.

I would prefer the bass boost to be slightly lower at around 70 Hz. maybe.

Infected Mushroom+bass boost+ER4=

With ER4P:

Using the bass and/or treble boost does not introduce any noise above normal results(see below).

With no source connected, there is no noise until I switch into high gain and then only near the top of the dial. With normal use expect no noise/hiss whatsoever.

Mine has the buffer chips.

My XM-5 came with the AD8397 chip, as I have AKG K-240S 'phones. After a few months, I askes James about other chips, and he sent me the original OPA134's.

I can tell a bit of difference in the top end volume, but the 134's drive my K240's quite nicely.

I doubt that I can discern any difference between the monoblock config. of the two 134 chips vs the dual chip 8397. IIRC, my tin ears seem to hear a very subtle sound difference between the two chips, but to be sure, I'd want 2 units with both chips to be sure.

Many thanks for that review.. I knew that the XM5 was a good amp, but only had the Microshar 107B to compare it to.

I see that you tested the 134's with the buffer chips. My XM5 came with the AD8397 chip, and I'm very pleased with it. IIRC, it puts out more current then the buffered 134's, but is a dual chip, so no monoblock, FWIW.

James sent me a pair of 134's to play with, and my ears have detected a small difference, but I can't really describe it. I'd bet that he's send you an 8397 chip to test if you asked

That's one of the reasons that I chose the XM-5. While the DAC isn't perfect, it's way better'n the sound chip in my notebook. Get the AD8397 chip and rechargeable battery option and you'll be set for just about any headphones available.

Indeed, the 8397 was included in the package. I'll test it some time next week.

Thanks!

-HK sends

Hmmmm...methinks you'll need to remove the BUF634 chips. The 8397 puts out more current then they do, IIRC.

Please let us know how you feel that it compares to the 134 chip. I can detect a difference, but not describe it. do not have the buffers with the 134's.

i am looking for a headph amp for home/studio use, not needing for portable stuff. Are there better amps out there for the same price geared more for this usage or not?

dollar for dollar most home units of the same price will be a better performer than a portable.

Describe what you mean by home/studio and what you plan to do with the amp, and what headphones please.