Sifam PPM meter driver question

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Mundox

Well-known member
Joined
Jun 3, 2004
Messages
80
Location
New Zealand
Hey there.
I have these PPM meters/drivers that I need to connect to the +4 outputs of my system. They were taken out from an old O2R setup.
My problem is, the PPM drivers are somehow set up to very high levels, i.e -8dbfs signal is barely showing 5 on the BBC scale. And there's no resistor at the inputs as modification.
I tried all the trimpots on the driver circuits but there's little movement.
Has anybody experienced a similar case, or do you know where I can access some schematics?
Thanks in advance!
 
What are you wanting to use them for? You'd usually have them lined-up for something like PPM4 = -18dBfs. Sounds like maybe there is possibly some amplifier circuitry missing, although I would have thought the driver circuit should be ready as it is without any additional amps.
 
Exactly. Though we are going for -20 dbfs= PPM4
The driver circuit has a bunch of transistors and opamps on it. So I am assuming it is ready for line levels.

I guess I am gonna have to look at these other ones we have in a different room.
That would mean gutting a lot of things though. It's kinda recessed into the furniture.
 
Sorry for getting back late.
I don't see a manufacturer's name on the boards. It only says TV1 30451 or something.
They do look awfully similar to the ones audiox posted. Especially PPM304 but not same.
I might get a pic up here soon.
 

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