TreAdidas
100+ Head-Fier
- Joined
- Jan 30, 2007
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Howdy All,
Got a question regarding the output sensitivity of the MPX3 when used as a preamp.
I purchased an MPX3 with the notion that I would use it as a preamp 80% of the time and a headphone amp around 20% of the time. I wanted to bypass the preamp portion of my vintage Sansui AU-20000 integrated amplifier. This integrated amplifier is an overall formidable performer, but the preamp section is downright noisy. Luckily the preamp and amplifier sections are fully discrete and connected via a jumper which is easily bypassed. As such, there are RCA inputs on the back of the amp that feed directly to the amplifier section of the unit.
Unfortunately, when I hook the MPX3 up to my amplifier (with the preamp bypassed of course), the volume is outrageously loud even with the MPX3 set at the lowest volume setting. Additionally, the microphonics are unbearable. Merely running my finger over the volume pot yields tangible to borderline potent microphonics even with the MPX3's volume at zero.
I attempted to correct the problem by inserting a 12db inline attenuator (link: Parts Express:Harrison Labs 12 dB RCA Line Level Attenuator Pair) between the MPX3 preamp outputs and the RCA "main" inputs on the amplifier section of the Sansui. This offered negligible improvement in both volume and microphonics.
I do not know the input sensitivity nor impedance of my amplifier and do I know the output sensitivity nor output impedance of the MPX3. I am by no means an electrical expert but are these possibly my culprits? Moreover, is there anything I can do to clear this up or am I just out of luck as I am trying to pair up two unpairable pieces of equipment?
Got a question regarding the output sensitivity of the MPX3 when used as a preamp.
I purchased an MPX3 with the notion that I would use it as a preamp 80% of the time and a headphone amp around 20% of the time. I wanted to bypass the preamp portion of my vintage Sansui AU-20000 integrated amplifier. This integrated amplifier is an overall formidable performer, but the preamp section is downright noisy. Luckily the preamp and amplifier sections are fully discrete and connected via a jumper which is easily bypassed. As such, there are RCA inputs on the back of the amp that feed directly to the amplifier section of the unit.
Unfortunately, when I hook the MPX3 up to my amplifier (with the preamp bypassed of course), the volume is outrageously loud even with the MPX3 set at the lowest volume setting. Additionally, the microphonics are unbearable. Merely running my finger over the volume pot yields tangible to borderline potent microphonics even with the MPX3's volume at zero.
I attempted to correct the problem by inserting a 12db inline attenuator (link: Parts Express:Harrison Labs 12 dB RCA Line Level Attenuator Pair) between the MPX3 preamp outputs and the RCA "main" inputs on the amplifier section of the Sansui. This offered negligible improvement in both volume and microphonics.
I do not know the input sensitivity nor impedance of my amplifier and do I know the output sensitivity nor output impedance of the MPX3. I am by no means an electrical expert but are these possibly my culprits? Moreover, is there anything I can do to clear this up or am I just out of luck as I am trying to pair up two unpairable pieces of equipment?