NAD power lamps inside the enclosure

[destroyer X]

I would like to know how those lamps operates...it seems some new models have two supply voltages and those lamps (one to each channel) ligths when power is high.

I do not have an idea how this is operating and i would like to know.

Can you explain that to me?

My source of schematics is Jan Dupont site... and it is not working those days... reason why i cannot download the schematic to study and understand the operation.

Please... if you really know more than i know about... and this is not difficult as i know nothing or half of nothing about... then please go ahead to explain me.

Yes... i have readed the NAD informations about... i want to understand the logics into this operation... were those lamps are installed, in series?... in paralel?... and in series with what?... in paralel with what?.. supply?.. speaker? ... emitters?... where?.... what kind of job are they doing there?...is this a kind of energy wasting? (resistance in series)... or loading? (resistance in paralel)

Boys...to repeat what was already published into the NAD site will not contribute.... there you have marketing informations, and some basic ideas about the circuit... i would like to understand how it operates electronically or electrically.

Thanks in advance by your kindness

regards,

Carlos

[destroyer X]

thank you by the attention.

http://www.youtube.com/watch?v=hO58rNwo1g8

regards,

Carlos

[destroyer X]

I am wondering the meaning of this "s"... stup..?

ahahahahah!

I am feeling myself stupid not to understanding the idea they had.

http://nadelectronics.com/powerdrive-s

[homemodder]

Carlos looks like Nad included some 80s sound to light disco strobes, to improve sales maybe, popular with teenagers all these lights blinking, it goes with the music playing in the background too.



On a more serious note, do you have schematics of this amp??

Thanks for the link the other day, pity they dont have any other values or voltages.

[Eva]

The purpose of the lamps is to cause massive sagging on the (too high) supply rails so that the undersized output stage and heatsink don't melt when high average output power is demanded.

[Mooly]

Eva You beat me too it.

[destroyer X]

And it is good to have her around.

So.... they are trying to have some dinamics... as during some small peak moments, some audio transients, peaks, will be twice or more than twice (4 times more maybe) the average power.

And during continuous tone the supply drops to a lower level good enougth to allow the output transistors (weak ones) to survive.

The lamps are there, in series with the supply to reduce the voltage when needed...interesting Eva.... this use to produce interesting sound...i had in the past one amplifier that had weak supply... so, during peaks was great..but under load, sinus signal entering the power was small.

thank you.

regards,

Carlos

[destroyer X]

I use to download (and upload too) schematics from and to Jan Dupont's site.

The site is "out of the air" for a while... "under maintenance"... under repair.

So, i cannot find the schematic... i have not into my hard drive..... my auxiliary hard drive is Jan Dupont's site.


All i had was sent to Jan Dupont.... and all he had into his site i had recorded into my hard drive ... them my hard drive burned and i lost the data,... now i am waiting Dupont's site to be working to download all the stuff once again to this new hard drive.

In some sense i will be his backup and he will be my backup.

regards,

Carlos

[destroyer X]

there are two supplies windings, two voltages, one goes througth the lamp.

This way, low power transformer, transistors, small heatsinks, a 40 watts amplifier, will be able to produce higher power into peaks..small time power.

Nice that.

I am satisfied, not more doubts.... to my needs, the thread already did the job.

thank you folks.... i have received some article, brochure and explanation and now i have a good understanding how this unit operates....to understand more, and deeply, i will be waiting the schematic.

regards,

Carlos

[destroyer X]

when the amplifier sucks current from the higher voltage rails, means it is producing more power than it can continuously produce without cook the output transistors..... the current crosses the lamp and the lamp heat up... the starting resistance is 1 ohm...when the lamp goes hot the resistance jumps to 4 to 5 ohms, this will create a voltage drop when the high level signal is constant, protecting the output.

When the peaks are not too much long in time...lamp does nothing... goes in series having 1 ohm, producing small voltage drop.

The lamps, seems to me to be automobile halogen lamps, as they have also 1 to 2 ohms resistance.

The higher voltage supply is 40 percent bigger in voltage compared to the smaller voltage supply..... the smaller may be 32 volts more or less and the bigger may be around 45 volts simetrical.

Interesting...very clever, very interesting...for sure produce the peaks we need, having reduced cost, not needing switching as class H asks for....good.

regards,

Carlos