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Low gain amp system matching

Dear Audiogoner,

Need your advise regarding system matching with low gain amplifier.

- Audio Note ANE Spe HE Signature speaker: 98.5 dB when placed in the corner (and that is how it's setup in my room). I believe the impedance of the speaker is above 6 ohm for most of the frequency band.
- Audio Note M3 preamplifier: gain of 15dB with input sensitivity specified as "126mV for 1V output".
- My source/DAC puts out 2V signal.

Given the above, a low gain amp with input sensitivity of 2V for full output would work in my system? The stepped attenuator of M3 has 36 steps. 
radiohead99

Showing 3 responses by kijanki

kijanki's avatar
kijanki
4,446 posts
 
1V output for 126mV input is 18dB (not 15dB)

If your DAC produces 2V nominal, then preamp output will be 2V x 1/0.126 = 15.9V - way too much for an amp with 2V nominal input.
Perhaps your DAC has jumpers to reduce gain by 10dB (like in my Benchmark DAC), otherwise you can insert 10dB attenuator.  Best place would be between amp and preamp, assuming that your preamp can output 15.9Vrms - if not, then between DAC and preamp.


kijanki's avatar
kijanki
4,446 posts
 
@radiohead99   Voltage gain of your preamp is about 8x.  In order to obtain 0dB gain (2V input, 2V output) you need to set wiper at about 50% (12 O'Clock) position (to divide by 8).  Since ideal position would be around 2 O'Clock (with extra gain for soft recordings) you are not much off.  It is all assuming that you have logarithmic audio pot (most likely).  Some companies use linear pot with loading resistor (Benchmark DAC1) - a little bit different characteristic.
kijanki's avatar
kijanki
4,446 posts
 
@lowrider57   They had two versions of M3: pre i post October 2013.  Both have gain of 18dB

Here is user manual that reflects it:  

https://d1b89e86-9572-4311-9f80-60009b280608.filesusr.com/ugd/3e7c3b_cb9f60cb6a26418992b53df75192a77...
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