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My PIMETA


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#16 huangyong

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Posted 16 August 2004 - 06:34 PM

Gilmore power supply??!! w00t.gif w00t.gif
Interested!!
But there is a problem of sourcing opa548 in singapore..
and the GIlmore PSU uses 4 5uF Solen Caps.
my experience tells me that add in 5uF of Solen Cap in the PSU will extent the high and soundstage.

#17 jtfoo

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Posted 16 August 2004 - 10:02 PM

QUOTE (bpribadi @ Aug 16 2004, 06:14 PM)
He.. He.. sorry to ask, but I'm too lazy to browse headwize. Don't mind to give us the shortcut for the power supply?

Why you use META2 for the Jung multiloop? Why not the PPA one?

Thanks! headphone.gif

I omit the gnd channel buffering so it looks like a meta42. No distinction between input & output gnd, so much easier.




Here's the powersupply schamatics, taken from heawize, http://headwize.com/projects/showfile.php?...ilmore3_prj.htm

user posted image
The volume of my amp goes to 11!!! Does yours?

#18 bpribadi

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Posted 16 August 2004 - 10:12 PM

Thanks jtfoo!

I think if you going to drive Op-Amps only, you don't need the +/- 48 volts, and you can change the transformer with the dual 18V - 500mA.

Gillmore... yeah... very tempting... probably later after the PPA, or Gillmore first before PPA, ..... confuse wacko.gif Ok, I will finish my PIMETA first, that's my short term goal yes.gif

So when are you going to finish your pre amp ?

#19 jtfoo

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Posted 16 August 2004 - 10:18 PM

QUOTE (huangyong @ Aug 16 2004, 06:34 PM)
Gilmore power supply??!! w00t.gif w00t.gif
Interested!!
But there is a problem of sourcing opa548 in singapore..
and the GIlmore PSU uses 4 5uF Solen Caps.
my experience tells me that add in 5uF of Solen Cap in the PSU will extent the high and soundstage.

Did he use Solen??, I didn't know, instead I got a few polycarbonate 4.7uF from Koba. I might change them to solen then.

The volume of my amp goes to 11!!! Does yours?

#20 aaa

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Posted 17 August 2004 - 12:00 AM

QUOTE (bpribadi @ Aug 13 2004, 11:02 AM)
user posted image
(Board layout has been modified on Aug 16)


may I know what software you used to draw this?
It looks much easier to design and edit with such software than with paper and pen.
Thanks!

#21 bpribadi

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Posted 17 August 2004 - 03:50 PM

I use Microsoft Visio wink.gif

#22 bpribadi

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Posted 24 August 2004 - 02:20 PM

The previous schematic has error on the power supply, the ground buffer should be put before the regulator, and resistors for voltage divider should be added before the buffer.

So after trial and error, I simplified the power supply design, so now it became cheaper and smaller wink.gif Please check the modified board layout on the first post.

Edited by bpribadi, 24 August 2004 - 02:34 PM.


#23 digi01

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Posted 24 August 2004 - 02:56 PM

bpribadi,great drawing.I will try work on Visio too holiday.gif
diy

#24 bpribadi

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Posted 24 August 2004 - 03:41 PM

Thanks Digi! happy.gif

Here is the power supply schematic with LDO regulator LM2941. It has reverse polarity protection, so input diode is not necessary, and it only needs around 0.6 volt higher input voltage than the output. And the price is also reasonable yes.gif

user posted image

#25 heady

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Posted 24 August 2004 - 06:34 PM

bpribadi, is this what you are going to use for your pimeta? Can I ask what voltage is the powersupply? And, how much is the regulator?

Thanks.

"He sip no sup and he crave no crumb,
as he sigh for the love of a lady"

Yeoman of the Guard - Gilbert and Sullivan

#26 bpribadi

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Posted 25 August 2004 - 10:09 AM

The regulator price is SGD 3.66 before GST. The wonderful thing from this regulator is, adjustable, yet only need around 0.6 volt higher input voltage. Compare to the LM317 which needs 5 volts higher voltage ohmy.gif This regulator is suitable for battery operated device. It also has battery reverse polarity protection, so no need to worry about it happy.gif

I set the voltage at +7 and -7 volts, so it can be powered by any common 15 volts adapter (which is ussually has output more than 16 volts), or 2x 9V batteries.

The board is ready! I didn't use the layout above, because I had made it base on the previous layout which is actually a waste (using + and - regulators). Anyway the board has undergo a lot of modification, because of some mistake I made on the previous power supply design. And I'm glad I just made it right last night tongue.gif But it won't looks the same as the new layout.

Just a note to those who are going to use LM2991 as a negative voltage regulator, I put 33uF tantalum between the refernce voltage (the adjusment pin) and the ground, and it caused instability. So now I only put the 100nF, and it is stable now. (it took a few hours trouble shooting to found it wacko.gif but I learnt a lot from it tongue.gif )

Now I'm preparing all the cabling and the box, cutting and drilling hole here and there.

I will post some picture when they are ready yes.gif

Thanks for your interest!
Bram

#27 bpribadi

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Posted 27 August 2004 - 12:27 PM

Oke, after a lot of modification, here is the board:

user posted image

It's a bit messy because of the modification no.gif , and I left the negative regulator there because it would be to much to take it out and follow the new layout. But next time if I build a PIMETA again, I will follow the new layout.

I didn't plan porperly for the ground buffer heatsink, so it push the two capacitors to the side.

The main op-amp currently is the free from AD, AD8620 on my selfmade DIP-8 adapter (don't know when Huangyong will deliver the adapter from digi).

Now I'm putting it in the box, connecting all the connectors and pot. Oooo my, I hate the Neutrik socket, it is so big, need to cut 23mm dia hole, and it is a pain, because I can't find 23 mm hole saw, and I only have 20 mm one. So, you know, file here and there until the hole fit the socket no.gif If you want to cut hole for this socket, you can use 22mm hole saw (Kaichin sell it) and then file the holw a little bit.

I will update with more fotos later wink.gif


#28 bpribadi

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Posted 28 August 2004 - 10:23 AM

My PIMETA finally done biggrin.gif

In the box. Tight space, precise measurement needed.
user posted image

The die cast case gives it retro look tongue.gif
user posted image

Close Ups:
user posted image

I use DIY interconnect. The cable is very BIG !!! party.gif
user posted image

The Setup with Sony XA3000SE SACD deck:
user posted image

user posted image

Mukegile and I have tested it for a while, need more listening time to give more accurate comments yes.gif

In short, the sound of this amp is:
Very bright, very revealing, fast and detailed.

Good for soft music, light jazz, and vocal, as you will hear the whole details, the mechanical sounds of the instruments, as well as the very subtle breath of the singer. The Sony SACD player headphone output sounds soft, slow, and mellow compare to My Pimeta.

But for loud music as rock, after 5 minutes (with reasonable listeing volume), I think I will need paracetamol. It's so hot, that it fries my ears and head no.gif Probably because it paired with Grado RS-1. This PIMETA might be a good match for Senn.

I will post more comments later headphone.gif

Cheers!
Bram

#29 Mackie

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Posted 28 August 2004 - 10:28 AM

Bram, how much is the RCA plug? Looks pretty mean!
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#30 bpribadi

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Posted 28 August 2004 - 10:34 AM

I had them for more than 7 years, but just recently terminated. Sorry I completely forget the price no.gif

It is a locking type RCA. Means, you have to loosen the outer (white metallic) cylinder cover, plug in, and then tighten it again. It will push the ground contacts to the socket's ground. After that it will be very hard to plug off. We need to loosen it again, to plug it out.