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MINI DSP 2X4HD AS A PREAMP 5 years 5 months ago #25478

  • jahjahlove
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hi,
The unit works correctly but I don't understand how it can be used as a preamp ...
If I run it directly from the computer I have a rather low volume from the speakers.... too low for proper use...allthough it is the first typical application in the manual....

On the output panel my woofers are tuned at -13dB and the tweeters at - 4 dB....
I had to raise to +12dB both channels on the input panel plus add a preamp to have a proper volume control... the amps potentiometers are at 2/3 of the max...
Both speakers measure (and are equalized) at 91dB sensitivity same as passive crossover on REW...
Input jumpers are set at 2V (since my preamp is outputing at max 2.4V with 1V input).... obviously if the sentivity jupers are set at 4V it is even worse....
In the minidsp control panel volume is at 0dB
am I doing something wrong ?

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Last edit: by jahjahlove.

MINI DSP 2X4HD AS A PREAMP 5 years 5 months ago #25480

  • dreite
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I think you should turn your amplifier potentiometers to maximum vice 2/3, and increase the woofer/tweeter settings while maintaining the relative offset. Your situation looks interesting because, generally, more attenuation is required in the tweeter channel and not the woofer channel.

The 2x4HD unit functions as a "preamp" in that it supports a couple of different inputs and provides a volume control capability.
For digital inputs 0dbFS signals yield 2VRMS outputs and for analog inputs it's unity gain with the jumpers in the normal positions. If you need extra gain you can program a nominal amount (up to 12db) in the 2x4HD output channels.

Dave.
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MINI DSP 2X4HD AS A PREAMP 5 years 5 months ago #25481

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Thanks....
Yes it suprised me aswell for the tweeters ... In fact they are higher but I equalize them down because they roll off very quicky after 10kHz ....plus the amp for the woofer has 29dB gain versus the amp for the tweeter has 26dB gain....
I cannot raise too much the gain on the output because I have JBL compressions and horns and putting the amp direcly on them (a tube amp) makes some blowing in compressions which I had not with passive crossover... It is kind of annoying at low volume or low volume passages in a song... But this is not caused by the mini dsp it is just them amp ... I cannot for the same reason put the potentiometers of the MC175 CE at full gain 2.5V because it blows too much.... this is a real concern cause in bi amping one cannot legitimaltly want a tube amp for the mids and high .... with a SN lower than a SS ....

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Last edit: by jahjahlove.

MINI DSP 2X4HD AS A PREAMP 5 years 4 months ago #25482

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thats it I manage to make it work... I did something wrong.... I still going out of the computer with the jack (headphone) and not the usb.... my mistake....
It s not bad .... will give some comparison.... with and without DAC Preamp.... wood kill me if it was better as I spent 6700 € on both units !
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MINI DSP 2X4HD AS A PREAMP 5 years 4 months ago #25743

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comparison done.... it is much better if i use my dac before the 2x4HD and gets in in analog (even if, in this case there are three conversions) , rather than getting in by my computer or my streamer in digital (only one conversion).... so I bought a nano 2x8...

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MINI DSP 2X4HD AS A PREAMP 1 month 3 weeks ago #56842

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This is an old topic, but I really wonder what the pre amplifier adds to the mini dsp? Does it add 'color' (meaning it changes the input signal)? It needs to pass anyway (again) the mini dsp. 

Basically, if you put water first through a filter and put it afterwards in a dirty bucket, the water will still be dirty (assuming the mini dsp is the 'bad link')

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MINI DSP 2X4HD AS A PREAMP 1 month 3 weeks ago #56843

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well i do not know what to think nowadays... 

The pb with the 2x4HD is that either you enter in analogue and you have 3 conversions, or you enter via digital and you have the crap noisy dac of the mini DSP. 
I bought the 2x8nano to avoid the 3 conversions and use my own dac. But it has to be lowered of 8 to 10 dB at the input in order to get a proper headroom... (the volume meter doens't gets into the red), killing a big deal of the dynamics....
I obtained good results with measurements using the nano, but to my ears the sound is tempered... too "polite" ...

May be one has to stop the correction at 400 Hz like greg timbers advises, to let the medium and high alone....question of taste i suppose...
do you like your girl with plastic surgery or natural ? 

For now i am sick of DSP and use my system without correction. 

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MINI DSP 2X4HD AS A PREAMP 1 month 3 weeks ago #56844

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That's harsh for the mini dsp, but I hear you. I added some siftness by using a hybrid vincent power amp. I got rid of the preamp because I only use it for volume. My tv is my preamp and honestly, it does a good job, it's not that complex. Even a pre amp will get the signal from the tv. Crap in crap out as they say.

Luckily I have a pretty gf, but if she wants bigger boobs, who am I to say no

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MINI DSP 2X4HD AS A PREAMP 1 month 3 weeks ago #56845

  • jahjahlove
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there you go...

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