huangyong 0 Report post Posted August 16, 2004 Gilmore power supply??!! 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. Share this post Link to post Share on other sites
jtfoo 0 Report post Posted August 16, 2004 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! 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 Share this post Link to post Share on other sites
bpribadi 0 Report post Posted August 16, 2004 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 Ok, I will finish my PIMETA first, that's my short term goal So when are you going to finish your pre amp ? Share this post Link to post Share on other sites
jtfoo 0 Report post Posted August 16, 2004 Gilmore power supply??!! 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. Share this post Link to post Share on other sites
aaa 0 Report post Posted August 16, 2004 (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! Share this post Link to post Share on other sites
bpribadi 0 Report post Posted August 17, 2004 I use Microsoft Visio Share this post Link to post Share on other sites
bpribadi 0 Report post Posted August 24, 2004 (edited) 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 Please check the modified board layout on the first post. Edited August 24, 2004 by bpribadi Share this post Link to post Share on other sites
digi01 0 Report post Posted August 24, 2004 bpribadi,great drawing.I will try work on Visio too Share this post Link to post Share on other sites
bpribadi 0 Report post Posted August 24, 2004 Thanks Digi! 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 Share this post Link to post Share on other sites
heady 0 Report post Posted August 24, 2004 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. Share this post Link to post Share on other sites
bpribadi 0 Report post Posted August 25, 2004 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 This regulator is suitable for battery operated device. It also has battery reverse polarity protection, so no need to worry about it 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 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 but I learnt a lot from it ) 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 Thanks for your interest! Bram Share this post Link to post Share on other sites
bpribadi 0 Report post Posted August 27, 2004 Oke, after a lot of modification, here is the board: It's a bit messy because of the modification , 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 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 Share this post Link to post Share on other sites
bpribadi 0 Report post Posted August 28, 2004 My PIMETA finally done In the box. Tight space, precise measurement needed. The die cast case gives it retro look Close Ups: I use DIY interconnect. The cable is very BIG !!! The Setup with Sony XA3000SE SACD deck: Mukegile and I have tested it for a while, need more listening time to give more accurate comments 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 Probably because it paired with Grado RS-1. This PIMETA might be a good match for Senn. I will post more comments later Cheers! Bram Share this post Link to post Share on other sites
Mackie 0 Report post Posted August 28, 2004 Bram, how much is the RCA plug? Looks pretty mean! Share this post Link to post Share on other sites
bpribadi 0 Report post Posted August 28, 2004 I had them for more than 7 years, but just recently terminated. Sorry I completely forget the price 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. Share this post Link to post Share on other sites