questions about gainclones

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i want to try bridging and parrelleling gainclones, which should i try first and what circuit/s should i use?

what chips should i use when bridging?

in theory can the input capacitor be any value? maplin have some nice 8uf ones for £5 :devilr: and 15uf for £10 :cool:

i am ordering some chips: OPA548T, OPA541AM, OPA541AP, OPA549S and OPA549T, what other chips should i try (not just the gainclone chip itself, balancing ones for bridging)?

i ordered some OPA549 from Texas Instroments a while ago (a month+) and i havent recieved them, are they really being bought up that fast that they stay out of stock?
 
is this the simplest circuit for bridging and parelleling? are the 1kR input resistors necesary? are the 0.1R resistors between the outputs and the speaker necesary? is the LF412CP the correct opamp for U5?
 

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I'll bite..............

The 5k resistors are to bleed the 33KuF caps when the Mains power is shut Off - this would be a "normal" type of safety precaution.

22nf - There has been a very good input by a person whose name I forgot (Please excuse me for that) about "Snubber" caps and how their use may actually make it worse. I wouldn't use them, although I WOULD use a MUR or other Fast/Soft rectifier Diode.

If you just want to try it, you just have to build it. Then make ONE change at a time to see if you like it better.
johnm
 
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).
 
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. :bigeyes:
 
what fuse should i use with a 16 channel gainclone all running off the same +/- 12v supply? :devilr: (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 :cool: 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 :D :cool: :devilr:
 
Buick

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

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

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

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
40,000µF of supply reservoir capacitance for each supply
voltage rail."

This is for one bridge-parallel channel!:bigeyes:
 
its going to be a car amp :D 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. :bigeyes:

re-thinking needed possibly :D

maybe i could aford +/-24v supplys :rolleyes:

edit: i have 66,000uf on each rail :cool:
 
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