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SOLD!! META42 amp - AD8620, Stacked EL2001

post #1 of 8
1/31/10 at 7:49pm
Thread Starter 
Update: SOLD!

Hello folks,

I don't know if you guys remember me. I was one of those hobbyist DIY-ers here who built and sold META42 amps (among others...) to fellow Head-Fi members.

Up for sale is a META42 amp that served as my personal amp for some time. It's a great sounding amp that's been collecting dust sadly, and needs a new home.

Good working order.

Specs:
AD8620 opamp
4x (!) stacked EL2001 buffers per channel
Class A bias
Alps Blue Velvet pot
1000uF x 4 Panasonic power caps
A rough guess of a gain of ~6 (It was just loud enough for HD600)
RCA input
3.5mm output
Blue LED
Clear aluminum Hammond case, ~8 x 13 x 4 cm
Runs off a wallwart, [edit] included is an Elpac 18VDC supply (see below)

Caveat:
Sometimes it makes popping noises while it powers up, I never figured out why. [see possible technical explanation from linuxworks.] The case also has very minor scratches on the case from just normal usage.

To Europe: 55 Euro shipping included
To USA/Canada: 85 USD shipping included
(I'm located in Germany)

I'm pretty sure this is less than the cost of the parts - hint: the AD8620 opamp and the Alps pot together cost about $25 USD already.

Photos:



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post #2 of 8
2/2/10 at 4:56am
Thread Starter 
bump, and by the way, the screws are missing on the back panel in the photo because I had just opened the case to take a photo of the internals. All screws are there.
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post #3 of 8
2/2/10 at 12:40pm
how long do these noises last upon turning on the amp?
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post #4 of 8
2/2/10 at 12:59pm
if you reduce the cap bank, it could help with turn-on transients.

also, the op-amps just do that and its nothing to really be concerned about. many op-amp designs get around this with a turn-on delay (to hide it!). some discrete designs get around this the 'hard way' but its not cheap that way.

I think every pimeta I have (same general circuit) also pops on turn on/off. its normal.
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post #5 of 8
2/2/10 at 4:26pm
Thread Starter 
Quote:
Originally Posted by marios_mar View Post
how long do these noises last upon turning on the amp?
Not long, couple seconds. Sometimes you don't heard anything remarkable at all.

Quote:
Originally Posted by linuxworks
f you reduce the cap bank, it could help with turn-on transients.

also, the op-amps just do that and its nothing to really be concerned about. many op-amp designs get around this with a turn-on delay (to hide it!). some discrete designs get around this the 'hard way' but its not cheap that way.

I think every pimeta I have (same general circuit) also pops on turn on/off. its normal.
Thank you for the technical explanation. I'm no EE wiz, just handy with the soldering iron.
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post #6 of 8
2/2/10 at 5:00pm
Thread Starter 
Update: the amp will now ship with a power supply. Photo added to original post.

It's an Elpac medical-grade power supply, a switching power supply but probably about the best switcher you can get. (It also has the advantage that it accepts any input voltage from 100VAC to 240VAC). It's the power supply that I used with it the whole time I used this amp. I also compared this with the Elpac linear supplies - I couldn't hear a difference.

I was initially going to use this power supply for something else... but then I realized how annoying it is to buy an amp that has no power supply, so I'm including it in the sale, and the price remains unchanged.
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post #7 of 8
2/4/10 at 8:40pm
Thread Starter 
Price reduction, see original post!
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post #8 of 8
2/7/10 at 4:33am
Thread Starter 
up
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