Help me troubleshooting amplifier module

fosforo · 6th November 2006, 01:59 PM

Hi to all,

some time ago i purchased two subwoofer amplifiers made from the italian RCF. They came from model RCF 600AS.
Yesterday, after a couple of week, i've powerd them.
First of all they works. Second, obviously, they have some probles...

The first one has got the controller board wich has balanced input and outputs, the second one no.
I've connected a cd player to the firs one powering a 12" woofer also from RCF.
Here is the first problem,i've found that the output is quite distorted, even at low levels. (The woofer is in perfect working conditions).
So i tried the second one. As i have said before, this one is without controller board, so i used the one from the first module.
This one is working but even with no signal there is an udible hiss coming out from the speaker. It seems that the filter is not working.
So, here's the questions:

1) anyone could help me troubleshooting the amps? (i can rent an oscilloscope from a friend if it is usefull)

2) I would like to remove the active filter to use an external one, is it possible?

Here's the schematics

Thank you

F.

fosforo · 6th November 2006, 02:01 PM

fosforo · 6th November 2006, 02:03 PM

Quote:

Originally posted by fosforo
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fosforo · 6th November 2006, 02:05 PM

Quote:

Originally posted by fosforo

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destroyer X · 6th November 2006, 06:18 PM

Wonderfull name....i will copy your great idea....i will be fosfori ex in another forum...the X will be used to be recognized by old folks.

Congratulazione fratello Romani...molto buona denominazione.
Bienvenutto al mio core.

Congratulations brother...very good name you choice.

regards,

Carlos

fosforo · 7th November 2006, 08:00 AM

Thank you!

richie00boy · 7th November 2006, 08:34 AM

What a bizarre design! The driver/gain stage runs 40 volts higher than the output stage - bit excessive, and they regulate the output stage but not the driver/gain stage (which would better benefit from the regulation I think).

fosforo · 7th November 2006, 08:42 AM

Quote:

Originally posted by richie00boy
What a bizarre design! The driver/gain stage runs 40 volts higher than the output stage - bit excessive, and they regulate the output stage but not the driver/gain stage (which would better benefit from the regulation I think).

Maybe it could be, i'm not so skilled to notice that

Any advice on the problems that i have posted?

Thank you

Fabio

Workhorse · 7th November 2006, 08:49 AM

Hi Fosforo,

Your amp could be modified, but the Schematic of amp section a little bit wrong as it doesnot have Resistors to bootstrap the Step drivers gate , the resistor should have to be there, unless your amp doesnot work, or they might be a mistake in schematic alone....
Your amp is Class-G 2 Tier....

regards,
K a n w a r

Workhorse · 7th November 2006, 08:52 AM

Quote:

Originally posted by richie00boy
What a bizarre design! The driver/gain stage runs 40 volts higher than the output stage - bit excessive, and they regulate the output stage but not the driver/gain stage (which would better benefit from the regulation I think).

Ritchie have a look at the amp...its class-G not Class-AB ....The mosfets are Linear Envelope follower for Step Voltage.....not a regulator

The Design is alright , only you have misunderstood it....

6th November 2006, 06:18 PM	#5
destroyer X diyAudio Member Join Date: Feb 2004 Location: Recife - Brasil Northeast	Fósforo was great Leggionari! Wonderfull name....i will copy your great idea....i will be fosfori ex in another forum...the X will be used to be recognized by old folks. Congratulazione fratello Romani...molto buona denominazione. Bienvenutto al mio core. Congratulations brother...very good name you choice. regards, Carlos __________________ Try to build an amplifier folks ... it is pure adrenaline!.. when not work first time, then becomes a nice challenge...and we usually overcome the trouble... and we feel very well to be mastering the machine.

7th November 2006, 08:34 AM	#7
richie00boy Did it Himself diyAudio Member Join Date: Nov 2003 Location: Gloucestershire, England, UK	What a bizarre design! The driver/gain stage runs 40 volts higher than the output stage - bit excessive, and they regulate the output stage but not the driver/gain stage (which would better benefit from the regulation I think). __________________ www.readresearch.co.uk my website for UK diy audio people - designs, PCBs, kits and more

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7th November 2006, 08:00 AM	#6
fosforo diyAudio Member Join Date: Jun 2006	Thank you!

7th November 2006, 08:49 AM	#9
Workhorse diyAudio Member Join Date: Dec 2004	Hi Fosforo, Your amp could be modified, but the Schematic of amp section a little bit wrong as it doesnot have Resistors to bootstrap the Step drivers gate , the resistor should have to be there, unless your amp doesnot work, or they might be a mistake in schematic alone.... Your amp is Class-G 2 Tier.... regards, K a n w a r

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