Disclaimer: I’m only talking about headphone chains. Speaker people read if you want to, but it’s a totally different game.
That being said…
I have found that a Preamp is CRITICAL, and deserves as much attention as anything else in your chain.
Why? I’ll present 3 common situations.
- The signal coming out of your source is too hot. A 2V source going into an AMPLIFIER is just not optimal for the specific requirements of headphones. Your prized headphone amp at 9 on the pot is not ideal, to put in kindly.
If you have high quality volume control on your source, or your amp properly accepts 2V+, such that your amp can operate in its sweet spot, this doesn’t apply to you.
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Your destination to source impedance ratio is likely too low. 10:1 is OK. 100:1 or more is better. Below 10:1 is unacceptable.
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You’re going unbalanced into your amp. Balanced signals are a better design. If your source does not output a balanced signal (many don’t) and your amp does take a balanced signal, you need to make that happen.
Corollary 1: Active Preamps are inferior to the best Passives (read below) because they introduce another active stage. You risk losing as much as you gain.
Corollary 2: Passive Transformer preamps (aka TVCs) are superior to all others because a proper design will get you 1, 2 and 3, passively, as a matter of course. They are the right tool.
Looking at the HiFi preamp market, I cannot believe how many offerings cannot fix 1,2,3… and want to charge you 5 grand to not do so… AND they introduce an active stage
Don’t get me wrong, designers are clever. They can and will minimize the drawbacks of an active Pre. My point is that it is not optimal and often way more costly than it needs to be.
I’m not here to recommend specific devices either; I’m not a salesman, and part of the satisfaction is finding your own components. You want high quality transformers that will allow you to adjust gain DOWN. You do not want just a box with a resistor/potentiometer.
Adding the right Pre to my system has added girth and impact to bass, tonal focus and density across the frequency spectrum, and the ability to listen at low volumes with all elements from softest to loudest perfectly clear and separate. Tutti elements with all instruments at once fill the soundstage with force.
One more thing. If you’re happy with what you got, and it doesn’t follow the above, then great. Don’t let me rain on your parade. This is just food for thought. Do you.
In closing, the right Pre will allow you to grab system synergy out of thin air if the specs on your gear mismatch as outlined above. IMO,YMMV and all that BS.
What has been your experience with TVCs? What is your source? I’m exclusively using CD or SACD, mostly the latter on my Denon player.