# gainclone for sub

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#### temp123456

cant choose what chip to use for powering a subwoofer,i need 12v chip with very simple shematic,and to push about 50w(more-better) on 1 channel?
Any sugestions?

#### AndrewT

None !

12V single supply limits the output voltage to <4Vac (=11.3Vpp)
4Vac into 8r0 is ~2W
into 4r0 is ~4W
into 2r0 is ~8W
into 1r0 is getting silly.

do the sums.

#### linuxworks

dc to dc converters would raise your voltage (for the car, I assume)

#### temp123456

i mean to use at home with pc psu which can give max 24v,so it should be something for me

#### temp123456

None !

12V single supply limits the output voltage to <4Vac (=11.3Vpp)
4Vac into 8r0 is ~2W
into 4r0 is ~4W
into 2r0 is ~8W
into 1r0 is getting silly.
so the max power of 12v supply is 8w in 2ohm?? Í m confused

#### MJL21193

so the max power of 12v supply is 8w in 2ohm?? Í m confused

To increase the output power, you need to increase the voltage.
Convert 24DC to rms AC (best case) and you get ~8VAC (that's (V*.707)/2.
Power is calculated like this: P=Vrms^2/Rload.
P=64/Rload. If Rload is a 2 ohm speaker, it will deliver ~32 watts rms.

#### AndrewT

using your 24Vdc singe supply, you could build a balanced amplifier that would deliver double the power into double the load impedance.
Design your amps to drive 2ohm (reactive) load and you can get 64W into 4ohm.

This is quite a task to design and build some 32W into 2ohm amplifiers and then balance or bridge them.

#### temp123456

how about getting 20w from 24v supply to power a 4ohm speaker?

#### AndrewT

the maximum you can get from a single 24Vdc supply to power a 4r0 resistor is ~16W.
In practice you will get less than this probably around 12W.

You would have to build a balanced amplifier or a pair of bridged 2ohm amplifiers to get more than 12 to 16W into 4ohms.

#### pacificblue

The TDA1562 could be your choice, if you can get hold of it. It is a BTL class-H amp with integrated voltage multiplier, so you get all the tricks to get more power out of an existing voltage in one package. It can deliver 55 W into 4 Ohm from 14,4 V at a reasonable THD of 0,5 %. A little less from 12 V.

Other than that you could buy a (maybe used) car amp. They have integrated SMPS to increase the rail voltage. Don't forget however that your PC's power supply must be up to the task of delivering that much power, too.

#### kuldeepsingh

but whats the constraint for using only 12 or 24 V supply only? the current availability is also an issue.
if its for car, then get a DC-DC converter and for home use, nothing beats the good old transformer.

#### temp123456

The TDA1562 could be your choice, if you can get hold of it. It is a BTL class-H amp with integrated voltage multiplier, so you get all the tricks to get more power out of an existing voltage in one package. It can deliver 55 W into 4 Ohm from 14,4 V at a reasonable THD of 0,5 %. A little less from 12 V.

Other than that you could buy a (maybe used) car amp. They have integrated SMPS to increase the rail voltage. Don't forget however that your PC's power supply must be up to the task of delivering that much power, too.

any similiar to this one?
TDA1562 isn't avaliable in my store

#### bobodioulasso

Starting from 12V for a home use is a silly constraint.

A power supply only is:
A transformer
A rectifier bridge
A pair of capacitors.
And you can choose the voltage that suits to you.

#### pacificblue

When you depend on a single store, you should rather ask them what they can recommend from their stock.

#### bcmbob

The TDA1562 could be your choice, if you can get hold of it. It is a BTL class-H amp with integrated voltage multiplier, so you get all the tricks to get more power out of an existing voltage in one package. It can deliver 55 W into 4 Ohm from 14,4 V at a reasonable THD of 0,5 %. A little less from 12 V.

Other than that you could buy a (maybe used) car amp. They have integrated SMPS to increase the rail voltage. Don't forget however that your PC's power supply must be up to the task of delivering that much power, too.

Several years ago I bought a top of the line (at that time) Radio Shack car amp to be powered by a PC power supply. The results were disappointing. There are much larger PC PS units now at much better prices. Can you supply any additional information on using 12V amp/PC power supply combination? My intent would be to mono everything to drive a sub for a in-home setting.

#### temp123456

wait a secound. i build a tda1554 amp and i use 14-15v line from pc psu,so it doesnt have all 2x22w power,correct?
Would adding larger cap than 2200uf found ín amp shematic deliver more power?

#### AndrewT

probably not.
Would it reduce the ripple on the supply? yes.
Would that reduced ripple allow more continuous maximum power to be delivered? Yes.

#### pacificblue

The datasheet says 14,4 V give 2x22 W at 10 % THD or 2x17 W at 0,5 % THD.
If you had not noticed that your TDA1554 has less power than you thought before reading this thread, you don't need more power than it has now.

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