[Taphil]

Quote:

Originally posted by acs236 Taphil, I have a META42 with the AD845... if you could, I'd like to hear your comments comparing the AD823 to the 845 in your setup -- when you recive the 845, of course.

Will do. How's the battery life with the AD845? With the AD823 using Plainview 9.6V NiMH batteries (11.1V when fully charged), I'm estimating my battery life is around 30 hours. But I've never done actual testing. With the last battery I drained, it worked down to about 3.5V, but for NiMH batteries I assume it's not good to let the charge go that low. Anyone know if this is true?

 

[DanG]

I've owned or had enough listening time to the following portable amps to make judgments on them: old Headroom Cosmic, JMT-build CHA47 in altoid tin, Jan Meier Porta-Corda, Headroom TA 4.5V, Headroom Airhead 4.5V. If one is to include portability as a graded aspect without the benefit of customized bags, I'd rank thus:

1. Porta Corda -- Very small but has great sound, great battery life, and a cool detachable belt clip. Also has crossfeed.

2. JMT-build CHA47 in Altoid tin -- also good sound (though not as good as porta corda), also small, no belt clip, worse battery life (maybe 20-25 against 40-50 on PC), a little more fragile.

3. Old Headroom Cosmic -- pretty good sound but large and heavy, battery case is bulky and has ill-conceived connection to amp, batteries expensive and heavy. Also was overpriced when it was being sold new. Seems like a good deal at under $300 though if you can find it used in good condition.

 

[RickG]

1. HeadRoom Cosmic - I like to refer to this amp as transportable...great for trips (hotel rooms), but not genuinely a portable amp. Still my best sound for travel (especially with the Etys).

Because I don't consider the Cosmic a true portable amp, I'll list three more:

2. META42 JMT built...closest thing to my Cosmic.

3. JMT-built CHA47

4. TAH.....yes, I like it more than my Porta Corda!

 

[acs236]

I'm not sure the battery life exactly. Tangent left a "Heavy Duty" panasonic 9v in there when I got it. I'm not sure how much juice it had left, but I imagine it was pretty much new because it lasted for at least 15 hours (probably more, I wasn't really timing). I used it for about 3 weeks, at least an hour every weekday, but closer to 1.5 hours.

Quote:

Originally posted by Taphil Will do. How's the battery life with the AD845? With the AD823 using Plainview 9.6V NiMH batteries (11.1V when fully charged), I'm estimating my battery life is around 30 hours. But I've never done actual testing. With the last battery I drained, it worked down to about 3.5V, but for NiMH batteries I assume it's not good to let the charge go that low. Anyone know if this is true?

 

[KurtW]

1. META42 in blue Serpac H65-9v case, AD8620, single 9.6V battery

Tie for second place but way behind #1:
2. Porta-Corda; can sound a little bright with phones that lean that way
2. CMOY/Hanson w/crossfeed, AD2132. A bit laid back.

I like the size of the Porta-Corda, which is slightly smaller than the other two which are in the same case but different colors. All draw about 10-11 mA, giving good battery life. I built the two DIY amps using a prefab PC board (META and Hanson, respectively). I've also put the CMOY/Hanson in a special edition Altoids case; smaller but not as rugged. I used to have a TA, but I prefer all of the above to it.

 

[kelly]

I read a thread like this one and can't help but think...
"mmm PDAC.... come to Kelly, PDAC"

 

[Taphil]

I change my mind. #1 is the META42 with the AD845.

acs236 -
I tested using a Sony pcdp with line-out, to a straightwire mini-mini, to the amp, and then to the HD600. Testing material was just a bunch of songs I know well - U2, Radiohead, Foo Fighters, Pearl Jam, Moby - listening to various segements of songs to pick out the detail and differences. To test between the two chips, I just turned off the amp, switched the chips out of their sockets, and turned the amp back on - total switch time was 8 seconds.

I like the AD845 more than the AD823. When I switched the chips, I noticed an immediate difference with the lows. With the 845, the bass has more detail as it was less muddy a lot clearer. I suppose this is attributable to the 845 being faster sounding, as Tangent said in his review, and indeed the music, or at least the lows, sounds faster, fuller, less laid-back and melllow. In addition, the bass seemed to go deeper and have a greater presense in the songs I was testing with, but it wasn't warmer or colored at all. The music seemed to be more alive and aggressive with the 845. It also brought more openess to the music but at the same time a strong sense of closeness. The highs were more defined, controlled, and much smoother, but the improvement was quite subtle compared to the low end. Overall, the 845 sounded noticably better and more musical with the 845, to a point where I didn't have to struggle to pick out differences from the 823. My impression is that it made the 600's sound better, as though it were somehow driven better. I really appreciate the 600's more than before, especially when I was previously questioning whether my purchase of the 600 was a worthwhile upgrade.

 

[Ari]

Quote:

Originally posted by RickG 1. HeadRoom Cosmic - I like to refer to this amp as transportable...great for trips (hotel rooms), but not genuinely a portable amp. Still my best sound for travel (especially with the Etys). Because I don't consider the Cosmic a true portable amp, I'll list three more: 2. META42 JMT built...closest thing to my Cosmic. 3. JMT-built CHA47 4. TAH.....yes, I like it more than my Porta Corda!

Hi Rick!! What is the configuration on your Meta 42 JMT?
Thanks, Ari

 

[Ari]

Thanks Eric. Will email you !
Very kind


Quote:

Originally posted by eric343 Ari: For information on the META42, I highly reccommend Tangent's excellent META42 Pages. If you're looking to get one built, you have three options: 1. Send a PM/email to Head-Fi member JMT. 2. Fill out the Amplifier Quotation form and order a META42 from Tangent. 3. Visit my page and send an email to eric343(at)2alpha(dot)com, and I'll build one for you.

 

[andrzejpw]

Right now, its

1. Cosmic
2. JMT built cmoy
3. Porta Corda
4. Airhead

In the 2 weeks, I'm expecting something to go in the number 2 spot. Heck, maybe it'll even fulfill number 1.

 

[SumB]

1. Earmax Pro
2. Earmax Pro
3. Earmax Pro

 

[andrzejpw]

Oh, how I wish I could here the Earmax. . . doesn't it run on AC power though?

 

[Hirsch]

1.
2. Grado HPA-1
3. Grado RA-1

The number one slot is empty because I haven't put together a 12 volt battery pack for the ZOTL yet.

 

[SumB]

A battery powered PSU is (or was) available for the Earmax, aptly named the PackMax. I wish I would've scanned the manual before selling as there was an advertisment and shot of it.

 

[andrzejpw]

Wow, now there's a good system.