KurtW META42 Portable Amp
Dec 1, 2002 at 5:12 AM Thread Starter Post #1 of 25

vandit

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With only 6+ hrs burn in time, it's simply amazing!

My setup is:
Sennheiser HD280 Pro
KurtW META42 Portable Amp: AD8620, Triple Buffers, runs on wall outlet and 9V battery
Nomad Jukebox
SB Audigy 1
1 foot mini to mini Kimber Kable

Everything is packed into an explosion of energy: the bass is like someone slugging you on the face, rather then someone slapping you on the face (very crisp, clean), you can hear the decay of the cymbals shrilling off into silence, vocals are defined, mids pack alot more punch.

Very good worksmanship skills, as the amp looks flawless
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The case is blue, with a bright blue LED centered right in the middle of the board
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So if you're looking for a META42 portable amp, KurtW is the man to PM
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One very happy customer,
vandit
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Dec 1, 2002 at 5:41 AM Post #2 of 25
I'm glad to hear it! I'm probably going to get an HA-1, which means that someday down the line I might ship it off to Kurt to beocme a Corda Blue. Have fun!
 
Dec 1, 2002 at 9:07 AM Post #6 of 25
Ah, the triple buffered AD8620. Very cool. Did you buy the wallwart from Kurt or did you pick that up in a store? Which sounds better, battery or the wall wart?
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Dec 1, 2002 at 10:01 AM Post #7 of 25
I have the same setup from Kurt (except red case, so it may sound a bit different). With NS500V>Outlaws>META42>ER6 I honestly can't tell a difference between wallwart and batteries (I use a plainview). But the ER6 actually doesn't benefit much from the Meta. That's actually a deceptive comment, the sound does vastly improve in many different ways (most notably in bass, body, and highs), but the changes are very subtle. I guess the best way to describe it is adding to the ER6's neutral characteristics, much like an RA-1 would do. There is a huge difference between No Meta and Meta with my HP890s, completely changes the sound and soundstage as well, but I didn't try testing them.

So I guess I would have to try out the battery/no battery test with something that is more influenced with the amp.
 
Dec 1, 2002 at 5:04 PM Post #8 of 25
Quote:

Originally posted by kelly
Ah, the triple buffered AD8620. Very cool. Did you buy the wallwart from Kurt or did you pick that up in a store? Which sounds better, battery or the wall wart?
smily_headphones1.gif


KurtW supplied my wallwart, the brand is MCC in case if you wanted to know
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Also, i cannot tell the difference between battery or wallwart. The only thing that changes is the brightness of blue LED, although it has been said that greater voltages "12V" compared to "9V" will give the op amp some performance boost.

META42 lover,
vandit
 
Dec 1, 2002 at 5:15 PM Post #9 of 25
Quote:

Originally posted by HappymaN
Pictures?
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coming soon...
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Quote:

Originally posted by Luvya
Congrats! I just sent out my payment to KurtW today! Hope I get the same enjoyment as you do
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trust me, you will
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vandit
 
Dec 1, 2002 at 9:09 PM Post #10 of 25
Thanks for the kind comments.

I would like to elaborate on the external power with the walwart. What I supplied was not only the walwart but more importantly a regulator/filter box that goes between the walwart and the META42 amp. Walwarts can put out quite a bit of noise. I use the LM317 1.5A voltage regulator for 0.01%/V line regulation, short circuit protection and 80dB ripple rejection, with an additional 3000uF capacitance for filtering. This give you 18.2 volts that measures and sounds as quiet as batteries.

NiMH batteries have lower impedance than alkaline batteries so they make pretty good power sources. The Plainview battery puts out around 10v. When measured with a load the distortion is slightly lower with the 18v supply vs 10 volts, but at least with low impedance headphones I've also found it hard to tell the difference. With higher impedance headphones the higher supply voltage can be beneficial.
 
Dec 2, 2002 at 1:21 AM Post #11 of 25
Quote:

Originally posted by KurtW
Thanks for the kind comments.

I would like to elaborate on the external power with the walwart. What I supplied was not only the walwart but more importantly a regulator/filter box that goes between the walwart and the META42 amp. Walwarts can put out quite a bit of noise. I use the LM317 1.5A voltage regulator for 0.01%/V line regulation, short circuit protection and 80dB ripple rejection, with an additional 3000uF capacitance for filtering. This give you 18.2 volts that measures and sounds as quiet as batteries.

NiMH batteries have lower impedance than alkaline batteries so they make pretty good power sources. The Plainview battery puts out around 10v. When measured with a load the distortion is slightly lower with the 18v supply vs 10 volts, but at least with low impedance headphones I've also found it hard to tell the difference. With higher impedance headphones the higher supply voltage can be beneficial.


ah so thats what the box thinggy with the red light is hahaha
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where can i get these rechargable batteries btw?

KurtW fan,
vandit
 
Dec 8, 2002 at 12:14 AM Post #14 of 25
Let me add my enthusiastic endorsement for the KurtW META42. I just got mine today and I am very impressed. Excellent workmanship, and Kurt was a total pleasure to deal with. What I got was:

- Translucent blue Serpac H-65-9V case, measuring 2.75" x 4.94" x .94" high
- AD8620 dual op amp socketed so I can switch opamps
- Cascode FET current sources to operate the op amp in Class A mode
- 2 EL2001 output buffers per channel
- EL2001 buffer in power supply with TLE2426 railspliter
- Power supply: four 470uF electrolytic caps, as well as two 6.8uF Wima poly caps
- 3 Amp Crowbar diode to protect against a reversed battery
- DC-coupled circuitry
- Vishay/Dale 1% Metal Film resistors
- Sockets for all output buffer ICs and gain resistors
- Switchable Blend function with internal pot for tweaking value
- White LED inside the blue translucent case
- Output resistors replaced with jumpers (using sockets so you can put resistors back in if desired)
- Set for a gain of 9.6
-Measured standby current of 12.3 mA

I don't know if this an absolutely "maxed out" meta42, but it sure sounds good!

I'm using ER4P's and the amp is fantastic with them. I was previously using a Total Airhead (2AA design) and the meta is much more open, more detail, FAR better bass. BTW, I just don't understand the "etys have no bass" comments. I find the bass amazing, and especially so with this amp.

This setup seems so good, I am wondering what is there that can really be much better than the combo of the ER4P and the META42?
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Talk about leading the witness....
 
Dec 8, 2002 at 2:04 AM Post #15 of 25
Can anyone explain the difference between using the double vs the triple buffers on KurtW's Meta 42. I too am having one built and am wondering if I should go with the triple buffers instead of the double version. I know the triple buffers will use up battery power faster ( As I recall KurtW's serpac meta 42 will last about 12 hours on a 9v battery with double buffers ) but I think it all boils down to the headphone impedance I have a pair of grado 80's which are 32 ohms and am purchasing a pair of sennheiser HD580's which are 300 ohms does anybody know how the number of stacked output buffers efects these headphones and why you would want more than two per channel?

JIM
 

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