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First Hi-Fi System

RickSanchez

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Set up on a 57 North Plank 42" walnut media console - $1130
  • Mostly solid walnut with some veneer
  • Cabinet for locking up mostly power supply / surge protector, but also open shelving to keep gear like the amp cool
You should add some budget for active cooling. Noctua fans are great, and there are pre-built solutions (cabinet fans / component fans) as well. If you're really pushing your amp I don't think that cabinet is going to offer you as much ventilation as you need.
 
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ash87

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How big is the room?

Depending on size, you might benefit from a sub or two.
Room is 12x20, with 8' open to a dining area on the long side. Couch is against the long wall with the opening.

I eventually want to add stereo subs. That's also why I was eyeing the miniDSP flex. I don't know a whole lot about room correction, but from the little Iv'e learned it makes a big impact when bringing subs into the equation.
 
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ash87

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I started looking at passive preamps from Goldpoint and Marchand. Digging deeper, I'm uncovering all kinds of details about input and output impedance, buffer stages, amplifier gain, DAC voltage out, etc. Most of what I find online distills down to "passive preamps are great in a well designed system", mostly about having a low source output impedance and a high amp input impedance. The Modius outputs 75 ohms and 4 volts, a passive preamp may have a 10k or 20k resistor, and the hypex has a 1.8k ohms with 26 db of gain.

If source to amp impedance needs to go low to high 75>10k>1.8k doesn't seem like a good idea (sans a buffer stage).
Whereas something like a Schitt Aegir at 22k makes more sense.

Please feel free to chime in or point me to some literature on the topic. A common dismissal of passive preamps is that they don't sound good with longer interconnects.
 

NTK

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... the hypex has a 1.8k ohms with 26 db of gain.
Input impedance is 100 kohm. The 1.8 kohm input impedance is for the unbuffered input of the UcD180 OEM version, which is different from the one in the Hypex DIY kit (UcD180 High Grade Version).

ucd180.png


[Edit] The worst case output impedance with a 10 kohm pot is when the wiper is at the middle (when ignoring the 75 ohm output impedance of the DAC). The source impedance at that point will be equivalent to two 5 kohm resistors in parallel, which equals to 2.5 kohm. It is well under the recommended source impedance of 7 kohm, so I think you are safe.
 
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ash87

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Ok, that makes sense. Thanks. I was looking at the stepped attenuators from Goldpoint, they offer custom resistance values. If Hypex recommends a source impedance of 7k, would it make sense to choose a 10k Goldpoint attentuator?

 

NTK

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Ok, that makes sense. Thanks. I was looking at the stepped attenuators from Goldpoint, they offer custom resistance values. If Hypex recommends a source impedance of 7k, would it make sense to choose a 10k Goldpoint attentuator?

Sorry. What I should have said is the Hypex recommended maximum source impedance is 7 kohm. The Goldpoint 10k attenuator should work, but IMHO, unnecessarily expensive for a simple job.
 
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