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Purifi EVAL1 / Pregain, enable or disable?

beren777

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My assumption is that the answer is "it won't matter, you aren't going to hear a difference either way" but is it best to leave the pregain enabled or disabled on the EVAL1? I can reach acceptable volume levels in either configuration, but even after reading through Amir's reviews I am unclear whether there is any real gain (sorry) to disabling it for the average "look I can assemble a Ghent case" DIYer such as myself.
 

NTK

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Without the pre-gain stage, you will need a signal source that can output a little over 9 Vrms to drive the Purifi 1ET400A to full output.

Your source will also need to be OK with driving a 2.2 kΩ (single ended) or 4.4 kΩ (balanced) load. My guess is that most pre-amps or DACs would be fine with this.
 

zappa

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Just FYI, If you bypass the buffer, PURIFI recommend to use the balanced signal.
 
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beren777

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Just FYI, If you bypass the buffer, PURIFI recommend to use the balanced signal.

Is there any risk of damage if unbalanced is used, or is it purely a performance/quality issue?
 

zappa

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I don't know if there are any risks of damage, but you would need a quite high signal to clip the amp, more than 14 Vrms (Purifi said).
JimB said : With 8V (rms) output, you'll be slightly short of full output power into 8 ohms. To get full rated output, you'd want at least 9V capability.
 

nimar

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I don't know if there are any risks of damage, but you would need a quite high signal to clip the amp, more than 14 Vrms (Purifi said).
JimB said : With 8V (rms) output, you'll be slightly short of full output power into 8 ohms. To get full rated output, you'd want at least 9V capability.
Is that 14Vrms value with the gain disabled. Do you know the figure with the gain stage? I know Amir said it reached full at 1.5V
 
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