My Meta amp.. (Pics inside)
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Dreamslacker

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Yep.. Just finished my Meta 42 amp. Didn't order the PCB from tangent as I felt I could do it on my own..

Want to say thanks to everyone who was involved in the designing of the amp!
YES, ppl, that includes you!

The difference between my amp and the schematic would be that I'm using:

0.22uF Evox PMR (Metalized polyprop) in parallel with 0.022uF Evox PFR (Poly film w/ metal foil for high speed apps) for my C1. (as advised by puppyslugg)

1M ohm resistor for R2.

I cannot get the TLE2426 voltage splitter so I'm using 2 22K ohm resistors. Removed the diodes because I was having problems using them. Didn't have the patience to troubleshoot the thing.

Using some generic 50K ohm ALPS dual-pot. I say generic because it's by ALPS but not a Blue velvet or Black Beauty. Farnell sells the latter but it's way too pricey (S$63==US$35) for a poor student like me.

The op-amp's are OPA134PA IC's. The only op-amp I can find. The AD823 would have to be ordered from Farnell if I wanted them. Only 2 choices.

Using EL2001CN buffers; Not stacked because I couldn't afford much of these. They're the most expensive single component in the amp.

Total cost of the amp: about S$100 (US$56). Could have been lower but I needed to replace some parts here and there. Like defunct RCA jacks and my older 1/4" jack. (supposed to be from Neutrik according to some website; Cheap stuff.. Only about S$1.50)
 
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Dreamslacker

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Front:


Rear:


Inside:
 
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post-193955
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Dreamslacker

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The amp:


The voltage splitter:


My CD player (okay, it's a discman..
)
 
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post-194015
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JMT

JMT Audio:PPA/META42 Amp Factory
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Congratulations Dreamslacker. Was this your first ever DIY project? If so, taking on a META without a PCB as your cherry buster makes you a stud.
 
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Dreamslacker

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Quote:

Originally posted by JMT
Congratulations Dreamslacker. Was this your first ever DIY project? If so, taking on a META without a PCB as your cherry buster makes you a stud.


I've tried the Cmoy once... It failed because I didn't understand how a voltage splitter worked nor the fact that the op-amp needed a dual-voltage supply.

My 2nd try was the Szekeres Fet amp. In a way it failed. It was too hot, the music was somewhat too metallic.. The hi-hats ringing away and the vocals sounded pretty lame.. And the worse thing was: No gain.. Didn't get any louder..

The Meta 42 is my third try. And this time, I got it right!
I'm one happy guy.. (considering that I don't even have a multimeter) However, I think it can be better.

Namely, getting the TLE2426 for the power. I don't think the 2 resistors are doing very well.
I'll also need to get some better RCA jacks. The ones I have are a little screwed..
One of them has a slightly loose connector so the right-channel can go off if I just slightly twist the RCA plug.

Overall, this is a nice amp. Made me notice some things I did not notice before. Bass is fairly tighter.

As opposed to the onboard headphone amp. on my Terratec DMX Xfire 1024 soundcard. I used to run my CD player to it and use it as an amplifier. No more of that stuff now!

Note: I hope it doesn't take long to load the images. Reduced the files by a few KB each.

 
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finleyville

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how did you post the pics directly to your post without using a hyperlink? I also built a Meta that I would like to share.
 
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Dreamslacker

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Quote:

Originally posted by finleyville
how did you post the pics directly to your post without using a hyperlink? I also built a Meta that I would like to share.


There are 2 ways:
  1. Use the IMG button above the reply textbox.
  2. Use
    tags to encapsulate the URL of the pic.[/list=1]
 
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post-194734
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Voodoochile

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That's a lot of amp for ~$56US!
Thanks for sharing, and congrats on your success.
 
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Dreamslacker

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I seem to have a problem here...

When I play my audio CD's, the left channel seems to be louder. I've no idea if it's because the vocals & drums are recorded on the left channel or something.

However, plugging the headphones into the player and jacking the volume up seems to suggest that it's recorded equally on both channels.

Just to do a quick check with you guys. Does Hotel California seem to have the drums more to the left side?
The acoustic guitar seems smack in the center and the bass guitar a tad softer to the right.
The vocals on the left..

Choral singing seems fine on the right channel. It's disturbing. I might be getting new parts (I suspect it's one of the resistor pairs being unmatched) and re-doing the amp.

No DMM here so I've got to get one too. sigh.. Otherwise, the sound is good. Very nice gain.
 
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post-195023
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Dev

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Hm... Vocal must be in center of stereo panorama, if is not a sound effect.

Check your element's (resistor's) nominals correctly.
 
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Dreamslacker

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Quote:

Originally posted by Dev
Hm... Vocal must be in center of stereo panorama, if is not a sound effect.

Check your element's (resistor's) nominals correctly.


I think it's the capacitors. Must have killed them while mucking around. Haha..

Anyway, will leave the fixing of the amp till December. For now, I've 3 weeks or so to make my last ditch effort for the Cambridge GCE Advanced Level exams.. Argh.. THe perils of a screwed up education system....
 
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