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BPA300 Round 2

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#43
Can These Be Used For A PA Amp?

Hello Everybody,

Has anybody tried to use a BPA300 design for a PA system? The speakers would be 8 ohms but could be changed to 4 ohms since I haven't built them yet. I want an amp that has some power but enough headroom to reduce clipping. if there is a problem with the amp, being homemade they would be easier for me to fix (I would already have repair parts). Live PA work doesn't require high end sound quality but the equipment does need to be robust. Will this fit the bill? I'm thinking some sort of soft start, speaker protection, a stepped attenuator front end with hi Z and balanced inputs would be all that is needed, any comments? Oh ya, I know it would be cheaper to buy some Crown DC300's but this will be a lot more fun not to mention the bragging rights.

Thanks,

Mark
 
#44
Home audio and PA should never be crossed, unless for personal use due to health and safety risks. You dont want to be held responsible for a venue burning down becuase your amps dont have the required safety features. This has been discussed mant times on the forum but i will leave it up to you to decide.

In theroy, the amplifier will be fine for light PA use. Use overkill heatsinks and an oversized power supply.
 
#45
rhysh said:
I have got a deal for the price break we require, just need 20 more pcb's to be taken.
Click to expand...

Hi Rhysh,

I like to join this GB for 4 boards.
Wiki updated.

rhysh said:
Just to let everyone know, i will do ALL your SMD soldering for $5 (to cover the cost of solder and time), plus the price of the resistors.
Click to expand...

Please advise total costs of the SMD resistors/capacitors
if I need your help to solder them on board.

Cheers

TS
 
#49
chatziva said:
when you say kits, do you mean parts only? or parts & pcb's?

I would be definitely interested in parts only for 4 boards

regards
Evan
Click to expand...


Parts only, as this is a group buy anyway people will be supplied with boards to use with the kits 😉

Not a problem as you allready have yours.
 
#50
great stuff, count me in for parts for 4 boards then

i was looking at farnell the other day and noticed that the susumu 0.1% resistors are quite good value. however that's true for small quantities, you might be able to strike a good deal on welwyn or vishay resistors depending on demand quantities

best regards
Evan
 
#55
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
 
#56
tryonziess said:
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
Click to expand...

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
 
#57
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 🙂
 
#58
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
 
#60
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
 

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