Practical Devices XM5 - Page 2

I'm pulling the trigger on one tonight!

Thanks Matthew. Practical devices should revise its DAC section or much better to release the amp only for XM5. I'm planning to have another portable setup XM5->ER4P.

Head-fi is a great place to find info on all this stuff. I have been lurking for a few months to figure out what rig I wanted to buy. I decided to spend the bulk of my money on the headphones and then find quality but cheaper amp/souce systems.

I bought an XM-5 recently. Black. This is my first portable amp. I'm using it with an iPOD 5.5G 80GB and either Black Dragon AKG 701's for home (still going through break-in) or Audio Technica 900 limited edition cans for work. The Audio Technica 900's are a closed back system that isolates the sound. Perfect for work. These are the most comfortable headphones i have ever worn. The only complaint is that if its really hot out, the synthetic leather pads can get a little sweaty. At home, the 701's are a bit lighter in sound and more clear but lack some of the bass. Fortunately, the XM-5 has the bass boost which takes care of this. Also, with the open design, the AKG's don't isolate the ambient noise as well. Its fine for home, but you can hear things around you and people can definitely hear your headphones. The only complaint I have about these are the upper head pad has bumps in the leather and one of them is centered on the top of your head. It causes a pressure point and makes my move the headphones around every 15 minutes or so to move the pressure point. I guess I need to bling these out with some red crush velvet.

I put in some OPA 627 opamps and am running it with the BUF634P chips. It sounds great. With the AKG 701's I use the crossfeed at about 15%, treble boost and bass boost. I turn off the bass boost for the Audio Technica's. The OPA627's added a slightly darker/warmer feel to the system. I would say it has lightly more bass but the feel is ever so slightly richer. I would be hard pressed to tell the difference if you swapped them out and asked me which configuration the amp was running in. The entire system is very clear with a good S/N ratio until you turn it up all the way (past 80%). There is so much power that you will probably damage headphones at this range and definitely your eardrums.

One thing I noticed is that you can tell if you have a crappy MP3 really quick. I'll just leave it at that. With good MP3's, the sound is really good. The system with the AKG's is so clear that I can hear vocal tracks or instrument tracks start and stop on some songs with a little bit of background hiss that is correlated with the tracks. Its like I can hear the sound editor splice in the separate tracks. The Audio technica's are much more forgiving and have a warmer feel to the music. You won't hear as much distortion or pops from MP3's with the Audio Technicas that you do wtih the AKG's.

I had a problem with my free interconnect cable that came with the XM-5. I e-mailed the customer service and had a reply, "we'll ship one out today" within an hour. Great customer service....even on the freebies. My interconnect cable was shorting one of the signal wires to the ground at the connector.

I am curious if anyone put the OPA134 opamps in the buffer slots with a diff opamp in the amp slots. I read somewhere on opamp comparisons that this was a pretty good combo to use OPA627 amps with OPA134 buffers on a home audio preamp. I have the stuff to try it, I just didn't want yo blow up my new toy yet.

Not a lot of info on the XM5 here..at least compared to the little Dots and Ibasso Boa, etc. However, I decided to order one 2 days ago. Being a retired computer geek, I liked all the features the XM-5 has. I would have ordered the Boa, but the op-amps can't be rolled, and I just _MAY_ want to explore that option, once I learn more about them. I am getting the AD8397 op-amp, so I will have something to play with. Dunno about rolling the DAC... the writeup looks pretty good to my eyes.

I'll be using it with a laptop (hence the DAC need) and AKG K240S head phones. I'll be comparing it with my Microshar 107B amp...a very plain, but reasonable decent unit...my first amp.

Hope to read more about XM-5 tests....will write my own in a few weeks.

Harvey/ Ga

There was somebody who posted a great review of the XM5. I'll try to find it...

edit

yay
http://www.head-fi.org/forums/f105/r...es-xm5-314305/

Black goes with everything.

Hi Billygodef..

I'm a new XM-5 owner as well. Mine has the AD8397 op-amp. Sounds great with my AKG K240S headphones.

I've discussed different op-amps w/ PD, and the word is that any op-amp with the same pin-out as the OPA134 should work..BUT the pinouts for the buffer sockets are for the BUF634, which is different from most buffer chips.

I'm new to this op-amp stuff, being more versed in discrete transistors from the 'Stone Age". <GG> Like many, I'm learning from Head-Fi's amp rolling gurus.

I have a XM5 since the beginning of this year. It does a nice job driving my triple.fi or my Beyer DT770 using my ipod 5.5g as a source.

I don't use most of its features though. Crossfeed doesn't make a big difference for my ears, and I normally prefer to use a flat eq, without bass or treble boost.

DAC quality is ok, but is only slighty superior to my ipod's line out.

Practical Devices support is very good, and James always replies to my emails very quickly.

sure does, I got mine a few months ago. I like it. PD was cool and gave me a discount for being a previous customer, along with upgrade. They sent it out so fast, they forgot to upgrade it. PD took care of immediately.

PD included the 134 chips with mine. I recently installed them in place of the 8397 chip and have noticed a slight difference in the sound. I can't quite place my finger on it, as I don't have the other to compare. They don't have the max volume that the 8397 has, but the battery life is 10 hrs longer.

I'll probably try and fill the buffer/amp slots with upgraded chips before considering a new amp. I'm not familiar with the amps that are out there to upgrade with. (chipsets)

If you're thinking about filling the buffer slots, they only fit the BUF634 chip.. a non-standard pinout, according to James.

From what I can see from your initial post, you have an XM-5?? (or is it the XM-4?) The BUF634 chips are very expensive from PD..haven't priced them from other sources.

If you have the XM-5 with the OPA134 chips, ask James to sell you an AD 8397
chip on the adapter (DoubleCat chip??)

FYI We've since replaced the DAC in the XM5 due to popular demand; the DAC is now the PCM2702 from BurrBrown/TI - a substantial improvement. We've been shipping the new DAC on all units since June08. Link is here.


Yes, these chips aren't cheap. The last time I talked to TI a few months ago, TI hadn't been able to produce this chip for well over a year, and couldn't say when they'll produce more (I'm wondering if they lost the masks for the silicon die?) - thus, the stock which is still floating around demands a substantial premium from reputable distributors... and we have to pass the cost along. I don't like it, but that's the situation for now. If you know of a source, let me know!