I need advise for three channel Parallel LM4780 project.

Padel · 20th November 2005, 07:53 PM

Hi all,

I'm building two, three chanells amplifiers based on parallel LM4780 chips for my three way speakers.

Just completed the amplifier and power supply boards, I choose high capacitance (10000uF) for the bass amplifiers and low capacitance (1000uF) for the mid and tremble amplifiers. Each amplifier module has its own Power supply PCB.

I still need enclosures and power transormers.
Sound wise, is there any good reason not to use a single transformer (24v+24v secondaries @ 1000VA) to supply all three PS modules and amplifiers?

Is it better to use different secondaries (i.e. 24v+24v+24v+24v+24v+24v @ 1000VA) for each module and even better to use different transformers?

Regards
P

pinkmouse · 20th November 2005, 07:55 PM

I would go for two traffos, one driving the woofers, and the other the mids and highs.

Padel · 20th November 2005, 07:58 PM

Quote:

Originally posted by pinkmouse
I would go for two traffos, one driving the woofers, and the other the mids and highs.

Is this going to be better than multiple secondaries?
Thanks for the reply.

P

Padel · 21st November 2005, 04:07 PM

Anyone???

UrSv · 21st November 2005, 04:49 PM

I would go for the big transformer but run separate bridges.

Padel · 21st November 2005, 11:39 PM

Quote:

Originally posted by UrSv
I would go for the big transformer but run separate bridges.

This what I'm thinking, but would I have the full advantages of tri-amp this way?

Regards
P

moamps · 21st November 2005, 11:53 PM

My vote goes to:

two monoblocks,
two transformers in a each monoblock; bass + mid/high.

Regards,
Milan

Padel · 22nd November 2005, 12:07 AM

Quote:

Originally posted by moamps
My vote goes to:

two monoblocks,
two transformers in a each monoblock; bass + mid/high.

Regards,
Milan

It is two monoblocks, three channels each.

P

carlosfm · 22nd November 2005, 12:27 AM

Quote:

Originally posted by Padel
Is it better to use different secondaries (i.e. 24v+24v+24v+24v+24v+24v @ 1000VA) for each module and even better to use different transformers?

Different secondaries is better.
Even better is separate transformer for each drive unit/amp/channel.
That would give you two trafos (one per channer) with 6 24V secondaries each, or (even better) 6 trafos with 2x24V each.
As you already have independent PSUs for each amp, it's just a question of trafos.
And that depend$ on how much you wanna $pend.

20th November 2005, 07:53 PM	#1
Padel diyAudio Member Join Date: Aug 2003 Location: Greece	I need advise for three channel Parallel LM4780 project. Hi all, I'm building two, three chanells amplifiers based on parallel LM4780 chips for my three way speakers. Just completed the amplifier and power supply boards, I choose high capacitance (10000uF) for the bass amplifiers and low capacitance (1000uF) for the mid and tremble amplifiers. Each amplifier module has its own Power supply PCB. I still need enclosures and power transormers. Sound wise, is there any good reason not to use a single transformer (24v+24v secondaries @ 1000VA) to supply all three PS modules and amplifiers? Is it better to use different secondaries (i.e. 24v+24v+24v+24v+24v+24v @ 1000VA) for each module and even better to use different transformers? Regards P

20th November 2005, 07:55 PM	#2
pinkmouse diyAudio Moderator Join Date: Apr 2002 Location: Chatham, England	I would go for two traffos, one driving the woofers, and the other the mids and highs. __________________ Al I conceive of nothing, in religion, science or philosophy, that is more than the proper thing to wear, for a while. Charles Fort

21st November 2005, 04:49 PM	#5
UrSv diyAudio Member Join Date: Jan 2002 Location: Sweden	I would go for the big transformer but run separate bridges. __________________ UrSv Those who say it can't be done should not stop those who are doing it.

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21st November 2005, 04:07 PM	#4
Padel diyAudio Member Join Date: Aug 2003 Location: Greece	Anyone???

21st November 2005, 11:53 PM	#7
moamps diyAudio Member Join Date: Oct 2002 Location: Croatia	My vote goes to: two monoblocks, two transformers in a each monoblock; bass + mid/high. Regards, Milan

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