Standard vs Fully customised META42
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Duncan

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Hi.

I have a completely standard (9 volt) META42, and am swaying heavily towards getting an all singing, all dancing home based (AC powered) version - with better op-amps, running as class A etc etc...

Could anyone please tell me the main sonic (and any other) differences between the two?
 
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eric343

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It depends how much you're going to spend on the final "all out" amp. If you want a $350 model, most of the difference will probably come from the vastly improved power supply (1x9V really isn't enough for maximum performance) and better power supply capacitors, if any. Also, if you get some stacked buffers, they'll definitely make a difference.

On the OTHER hand, if you want a $660+ "insano" amplifier, complete with stepped attenuator and everything else...

In any case, I think that stacking buffers and using a 10:1 power supply rail capacitance ratio (1x2200uF, 1x220uF per rail increases total capacitance and minimizes ESR) will make a lot of difference - compared to an ETA42[AD8610] or my PortaMETA[AD823], the "insano" amp I just sent off had vastly improved bass (waaay tighter, deeper, etc) and cleaner highs. Among other things...
 
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morsel

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Duncan, there is no such thing as a "completely standard (9V) META42", so it is impossible to accurately answer your question without knowing every detail about your existing amp, such as what opamp, buffers, and capacitors you are using, as well as what headphones you have, which can significantly affect performance in compromise configurations.

Oops, I just noticed you mentioned Sennheiser HD580 headphones. Those are 250 Ohms, too high for a single 9V battery. I am guessing you get significant distortion at high volume.
 
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andrzejpw

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Could someone clear this up for me? Does a META42 use 823s, while an ETA42 uses 8610s?
 
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JMT

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The META uses whatever op-amp your heart desires and your wallet allows. When Duncan refers to the "standard" META, he is using the term relative to how I descibed it to him. AD823 op-amps, small Serpac case, Panasonic pot, mini input and output, no stacked buffers, generic 470µF PS caps. In my vernacular, you then begin tweaking from there: Cerafines, Alps, AD843/8620/8610, Class A, Neutrik, enclosure, inputs, power supply, etc.
 
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eric343

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I'd pretty much agree with JMT, although I start with 220uF 16V Cerafines in a different case.
 
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puppyslugg

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Duncan,

I think you would improve the performance of present Meta by simply using 2x9v batteries in series. Your Senn. 580hd would benefit from the increase voltage. If your Meta has sockets for the opamps, you could try swapping the IC's. BTW, what opamps are in your unit now?
 
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Duncan

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Puppy... AD823, unsocketed

I'm kinda useless with DIY Electronics, show me a problem computer, and i'll diagnose, strip down, rebuild in no time at all... but leave me with a soldering iron... never expect anything to work ever again


I'm NOT saying that my 9V META is sounding bad, far from it... I could update my signature again... but I don't think anyone would be able to keep up with me... I'm now weening myself off of my 300ohm HD580s, and on to my 32ohm CD1700s... renowned for being warm and syrupy... but the extra treble detail of the META does magical things to the Sonys... they sound really amazing, punchy, lively, fast...


So, all I was after really was a consensus of whether a great portable amp turns into a monster home amp if you throw more money at it, and swap its batteries for a DC connector

Thanks
 
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JMT

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Quote:

Puppy... AD823, unsocketed


Duncan, check that again. I do believe your op-amp is socketed.
 
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Duncan

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Oops, my bad...

I've opened up the case, and can see that the AD823 IS socketed... it was one of the other two ICs that I saw through the case, and presumed, wrongly to be the opamp
 
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disturbed

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I would be very intrested in a META that is customized to bring out the true potential of the Etymotics ER-4S/4P and the Senn HD-600
 
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andrzejpw

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Hmm, that would be interesting. Is there anything that you need to "customize" for the hd580s?
 
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Duncan

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Quote:

Originally posted by andrzejpw
Hmm, that would be interesting. Is there anything that you need to "customize" for the hd580s?


Two things so far as I know andrzejpw...

There is the volume gain, and also the caps... I don't know the full ins and outs... that is why I appear so naive, but I see mention of 220µ and 270µ caps quite a lot... so, obviously some room for change... and probably there are a lot more varied caps when you look into it from a DIY perspective
 
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tangent

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The biggest single improvement you can make to a META42 is to use a better op-amp. This in turn tends to require more voltage, which means a bigger power supply, which means a bigger case, which allows bigger I/O connectors and bigger caps..... It all snowballs from that one improvement, but everything else after that op-amp upgrade is a tweak.
 
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