BPA300 Round 2 - Page 6

chatziva · 5th February 2009, 08:41 AM

i think the biggest savings from a gb would be on the 3886 chips and the bypass caps...

they add up to a good chunk of money...

rhysh · 5th February 2009, 08:43 AM

Quote:

Originally posted by chatziva
i think the biggest savings from a gb would be on the 3886 chips and the bypass caps...

they add up to a good chunk of money...

This is the general idea. There is a huge saving on the 3886. Plus it avoids people having to order from multiple suppliers.

chatziva · 5th February 2009, 08:54 AM

indeed.

I am attaching my parts list for the BPA to get started if we decide to go ahead on a gb. I was planning to use these parts on the basis on small quantities for my amp

Feel free to change / improve it

best regards
Evan

rhysh · 5th February 2009, 08:57 AM

Thanks, i will use your part numbers for the resistors from farnell. I was thinking more high end capacitors such as nichicon muse ES etc.

tryonziess · 5th February 2009, 10:50 AM

Is there anyway to match 3886 chips. I think in a parallel setup it could be beneficial. This amp puts out a prodigous amount of power for a chipamp and matching will keep everything equal, if it can be done.

Are boards still available. I would like 4. I have built 6 of these amps and they sound awesome.

Thanks Tad

rhysh · 5th February 2009, 11:01 AM

Quote:

Originally posted by tryonziess
Is there anyway to match 3886 chips. I think in a parallel setup it could be beneficial. This amp puts out a prodigous amount of power for a chipamp and matching will keep everything equal, if it can be done.

Are boards still available. I would like 4. I have built 6 of these amps and they sound awesome.

Thanks Tad

It would be possible to match 3886 chips, but the cost would be very high i would expect do to the surplus.

Boards are still available, please add your name to the wiki on the first page.

R

alvane · 5th February 2009, 09:32 PM

Numbers are raising, looks promising.

Quick question about the large capacitor (C1), does it need to be 10uF or will the 4.7uF capacitor chatziva used in his spreadsheet work just as good?
Also, what voltage rating does it need to have? 400/630V seems abit high

chatziva · 5th February 2009, 10:10 PM

Again feel free to improve

I have chosen the 4.7uf caps instead of 10uf because they were cheaper

I have tried Ansar 2.2uf input caps on my experimentation gainclone with good results.

also note that for C9,11,12,14 I have chosen 8x 1000uf instead of 16x 2200uf again due to price. I was going to try and see how that works. Don't underestimate the Ruby's - their ripple current rating is very good

but obviously with a gb we should be able to get more exotic parts for a good price

Evan

HaLo6 · 5th February 2009, 10:24 PM

I would be in for the kit for 4 of the boards (2 monoblocs)... I am getting an extra 2 in case I screw them up (this is my first amp build)

chatziva · 7th February 2009, 02:51 PM

Re chip matching: I can't remember where I've read it but one way to roughly match the chips would be to make sure they have the same serial number - see photo attached.

This number represents location of manufacture i think.

But I would think that if you order a tube of chips they should all have the same serial number anyway, no?

regards
Evan

5th February 2009, 08:41 AM	#51
chatziva diyAudio Member Join Date: Jun 2007 Location: UK	i think the biggest savings from a gb would be on the 3886 chips and the bypass caps... they add up to a good chunk of money... __________________ "I don't remember fighting Godzilla, but that's probably what I would've done"

5th February 2009, 10:10 PM	#58
chatziva diyAudio Member Join Date: Jun 2007 Location: UK	Again feel free to improve I have chosen the 4.7uf caps instead of 10uf because they were cheaper I have tried Ansar 2.2uf input caps on my experimentation gainclone with good results. also note that for C9,11,12,14 I have chosen 8x 1000uf instead of 16x 2200uf again due to price. I was going to try and see how that works. Don't underestimate the Ruby's - their ripple current rating is very good but obviously with a gb we should be able to get more exotic parts for a good price Evan __________________ "I don't remember fighting Godzilla, but that's probably what I would've done"

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5th February 2009, 08:57 AM	#54
rhysh diyAudio Member Join Date: Sep 2008	Thanks, i will use your part numbers for the resistors from farnell. I was thinking more high end capacitors such as nichicon muse ES etc.

5th February 2009, 10:50 AM	#55
tryonziess diyAudio Member Join Date: Apr 2007	Is there anyway to match 3886 chips. I think in a parallel setup it could be beneficial. This amp puts out a prodigous amount of power for a chipamp and matching will keep everything equal, if it can be done. Are boards still available. I would like 4. I have built 6 of these amps and they sound awesome. Thanks Tad

5th February 2009, 09:32 PM	#57
alvane diyAudio Member Join Date: Jan 2009	Numbers are raising, looks promising. Quick question about the large capacitor (C1), does it need to be 10uF or will the 4.7uF capacitor chatziva used in his spreadsheet work just as good? Also, what voltage rating does it need to have? 400/630V seems abit high

5th February 2009, 10:24 PM	#59
HaLo6 diyAudio Member Join Date: Dec 2008	I would be in for the kit for 4 of the boards (2 monoblocs)... I am getting an extra 2 in case I screw them up (this is my first amp build)

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