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Old 30th April 2003, 07:41 PM   #11
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From what Iv'e heard (people saying, not equipment), having the small caps accross the rectifier should help make things quite nice. This is mentioned in the article on power suplies over at ESP, and if you have a look at the scheematics for the bryston range of power amps, they all use them in that configuration, so I would leave them in (I intend to on my projects in any case).
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Old 30th April 2003, 08:09 PM   #12
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could i use 100nf capacitors instead of 22nf ones on the bridges? i have loads of these.
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Old 30th April 2003, 08:14 PM   #13
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you can
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Old 30th April 2003, 11:52 PM   #14
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Default Yes they are required

the .1 ohm resistors are required, at least in this design. What do they do? they serve as a device to "balance" the load across the two op-amps in each "half" of the bridge. Otherwise, one of the chips would do all of the work until it burned up or its protection kicked in, while the other one did nothing. The value of this resistor can vary depending on the chip you decide to use - see the application notes for that chip. If this is your first amp (and I guessing it is), read the note until you understand it.

Its like being a cook. If you don't know how to cook and you are just starting, you generally have to follow the recipe exactly since you don't know what a substitution will do to the cake. Once you have baked a whole bunch of cakes, then you can start making your own.

The only difference is that cakes don't cost as much when you burn them, and generally don't expose you to enough electricity that can kill you.
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Old 1st May 2003, 08:35 AM   #15
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this will be my third amp, ive made 2 strereo gainclones already. thats why im asking before i remove components
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Old 2nd May 2003, 03:23 PM   #16
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what fuse should i use with a 16 channel gainclone all running off the same +/- 12v supply? (im serious)

what is the approx. peak output of the OPA541? there isnt a watt rating on the datasheet.

will i need a fan if i mount my 16 channel gainclone on a peice of 3-6mm aluminium thats about 25cm by 30cm? i was thinking of using a hard drive cooler bolted (with heat transfer compound) onto the underside of the aluminium.

are the capacitors circled in red electrolytic? can i use electrolytic capacitors? can i use 1000uf ones? i have loads

where do the input capacitors go? after the potentiometer? where the blue circles are?

my gainclone isnt really going to be 16 channels, it is going to be 4 channels of 4 chips parrelleled and bridged
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Old 2nd May 2003, 03:26 PM   #17
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oops, image:
Attached Images
File Type: jpg bridged and parrelleled gainclone2.jpg (65.6 KB, 447 views)
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Old 2nd May 2003, 03:48 PM   #18
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Talking Buick

Quote:
Originally posted by Matttcattt
what fuse should i use with a 16 channel gainclone all running off the same +/- 12v supply? (im serious)

will i need a fan if i mount my 16 channel gainclone on a peice of 3-6mm aluminium thats about 25cm by 30cm?

Can you fit 16 chips on that cooler???
16 chips from a single +/- 12v???
Man, I think that voltage is too low, you shoul have at least a (huuuuge) +/- 18 volt transformer.
Fuse?
Don't know, maby some 5A before the primary.

This is on AN-1192 application note:
"7.2.3 Power Supply Circuit
The power supply portion of the amplifier is made up of a
typical unregulated bipolar power supply. The supply is comprised
of an input AC line filter, surge protecting MOVs, a
separate 385VA toroidal transformer for each channel , and
40,000F of supply reservoir capacitance for each supply
voltage rail."

This is for one bridge-parallel channel!
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Old 2nd May 2003, 03:51 PM   #19
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My previous post seams like traffic lights.
Or a christmas tree.
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Old 2nd May 2003, 03:58 PM   #20
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its going to be a car amp max voltage is about +/- 14v, i cant aford more batteries.

it doesnt need that big a power supply does it?

my 2 channel gainclone with a +/-12v supply takes about 2A max, which is about 12VA needed? 12x8=96VA. or am i insane?

at 60watts per chip at 24v is 2.5A max, 2.5x16=40A.

re-thinking needed possibly

maybe i could aford +/-24v supplys

edit: i have 66,000uf on each rail
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