1 Topic by flextone (edited by flextone 2011-03-09 16:00:26)

  • Registered: 2007-06-21
  • Posts: 52

Topic: FF400 outputs to -10dBV poweramp inputs

Hi,

I got a pair of new passive monitors and I'm looking for an amp. As I hate fans, and a good amp is a good amp, I thought I'd look into second hand hifi power amplifiers. The problem is of course the mismatch between the FF's +4dBu outputs and the amps unbalanced -10dBV inputs. Sending the amplifier a +4dBu level can potentially harm it, and what about that balanced/unbalanced issue?

How can I overcome this? I can't change the output sensitivity to -10 because I need my other outputs at +4. And buying attenuators to put between the FF and amp is kinda silly, I'd rather look for a reasonable PA poweramp and hope the fans don't drive me mad.

Thanks for your time.

  • viper
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Re: FF400 outputs to -10dBV poweramp inputs

Hi,

if you don't need the output faders for global volume control: What about lowering the output fader by 8.8dB, which will give you the same level at 0dBFS as if you would have switched to -10dBV. Of course you could even match the level exactly to the amplifiers needs instead of taking the -8.8dB.

Greetings,
viper

3 Reply by flextone (edited by flextone 2011-03-10 00:46:42)

  • Registered: 2007-06-21
  • Posts: 52

Re: FF400 outputs to -10dBV poweramp inputs

But aren't I loosing quality this way? Roughly 1.5 bits to be exact. Not enough to make a difference?

And yes, I do need it for level control unless I get a passive line attenuator like the SM pro audio Nanopatch.

I guess it would just make more sense to get a PA poweramp. Just need to find one with a quite fan.

  • viper
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Re: FF400 outputs to -10dBV poweramp inputs

You can try to hear a difference - but I bet you won't hear any.

The FF 400 has 113dBA dynamic range. So if you take away lets even say 13dB you are still at 100dBA dynamic range. In an environment with 20dBSPL noisefloor you would have to listen at more than 120dbSPL peak to get in trouble with the fireface's noisefloor, if I am not getting something wrong here. And 120dBSPL is insane...
Additionally I expect most hifi power amplifiers to have less than 100dBA dynamic range anyway.

But - just try it if that would be a solution for you.

BTW: The potential problems with unbalanced cable connections might be the more challenging thing. But here as well - try it.

  • From: Houston, TX
  • Registered: 2007-05-11
  • Posts: 1,191

Re: FF400 outputs to -10dBV poweramp inputs

I wouldn't sweat it.  The fact that you will be running a single-ended RCA connection to the amp will drop 6dB right there - and some amps have input gains (like my Sony TA-N80ES, TA-N77ES, and TA-N55ES all have).  I will give you $100 if you can hear a "difference in resolution" of 1.5bits by dropping the Totalmix fader down to deal with the hot output levels :-)

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6 Reply by flextone (edited by flextone 2011-03-10 08:57:55)

  • Registered: 2007-06-21
  • Posts: 52

Re: FF400 outputs to -10dBV poweramp inputs

Then I can keep the level fader at -12db, and use a Nanopatch to control the monitoring level, I guess.

But doesn't "servo balanced" mean that when used as unbalanced there's no loss of level?

7 Reply by MC

  • MC
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Re: FF400 outputs to -10dBV poweramp inputs

If you connect the wires, see manual. If not then you have an automatic loss of 6 dB, which would suit your needs well...

Regards
Matthias Carstens
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8 Reply by flextone (edited by flextone 2011-03-10 12:14:40)

  • Registered: 2007-06-21
  • Posts: 52

Re: FF400 outputs to -10dBV poweramp inputs

I see. You mean that if I connect ring to ground I won't loose the 6db? What about a mono TS cable? This always confuses me. It's been a while since I soldered cables, sorry smile

  • Registered: 2007-06-16
  • Posts: 214

Re: FF400 outputs to -10dBV poweramp inputs

mono cable with mono plug has ring connceted to the ground fryingpan

  • Registered: 2007-06-21
  • Posts: 52

Re: FF400 outputs to -10dBV poweramp inputs

That's what I meant. So with mono TS to RCA I won't loose the 6db? And with TRS with the cables connected also no loss? Did I get this right?

  • viper
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Re: FF400 outputs to -10dBV poweramp inputs

Yes, you did.

But as Matthias said it would be another option to intentionally lose the 6dB as that might already be enough for you.

Then you would have to use a TRS to RCA cable, where Ring and Sleeve are NOT shorted and the RCA plug is connected to Tip and Sleeve.

  • Registered: 2007-06-21
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Re: FF400 outputs to -10dBV poweramp inputs

I'll shed those 6dB's gladly.