Modhouse Tungsten Measurements & Official Discussion

A bit of info on driving requirements and a few amp suggestions:

The tungsten have quite unique driving requirements in that they need a significant amount of voltage compared to other headphones. They don’t need all that much actual power or current (half the current of a Susvara for example), and so the challenge is not finding amps that can handle high current situations, but rather finding ones where the max voltage output is suitably high (and they have enough gain).

The problem is, amplifier power at 32 Ohm mostly just tells you about current, not voltage. To know the max voltage an amp can supply you ideally need a 300 Ohm power spec.

For most people listening around 85-90dB, you are probably going to want to look for amplifiers that can supply 20V output (1.3W @ 300 Ohm), and assuming you have a 4V output DAC, an amp with at least 14dB Gain.

This is a general application though. Those that listen quieter will be fine on amps with 10V output (0.33W @ 300 Ohm) or less, and those that listen louder or if you’re wanting to apply significant bass EQ will probably need to look for amps that can do 30-40V output (3.0-5.3W @ 300 Ohm).

I’ve listed some suggestion amps below but a couple points of note:

  • You do NOT need a speaker amp. You only need a speaker amp if you listen loud (and if a 20V headphone amp cannot get them to your listening level, you REALLY should be working on listening quieter if possible as you are listening at levels that will cause hearing damage over time)
  • There’s a lot of debate about whether amp X, Y, or Z can/can’t drive tungsten. But realistically, with the sensitivity of the tungsten, it’s 100% dependent on your listening level. An amp might work for someone else but not for you if you listen even just a few dB louder
  • Don’t worry if your amp is close to max on the volume. That’s actually a good thing. Being close to max means you have an optimised gain structure for your headphones/listening level. The pot being at noon for your listening level just means you’ve got some potential dynamic range you’re throwing away because you’re attenuating the signal a bunch as the gain is higher than you need.
  • The 32 Ohm power spec of an amp tells you nothing about whether they can/can’t drive tungsten.
  • Using a hotter output DAC will only help if your amplifier has a very high output voltage limit. In most cases, an amp will clip on high gain with a 4V DAC at somepoint, using a hotter output DAC just means that it’ll clip earlier. It isn’t unlocking any additional power/headroom
  • DON’T USE CLASS D AMPLIFIERS FOR HEADPHONES! Class D amplifiers are not always safe to use for a variety of reasons and will also often cause an unwanted treble boost. A number of people have recommended the Fosi amps as they’re affordable. These amps are potentially dangerous to your headphones and/or hearing to use on headphones due to their load dependent behaviour that massively over-amplifies high and ultrasonic frequency content when a high impedance load like tungsten is used.

Suggested amps for quieter listeners:

  • Honestly most headphone amps will work fine. Examples both at the more affordable end like the Topping A90, Singxer SA-1, Schiit Midgard etc and at the higher end such as the Earmen CH-Amp, Benchmark HPA4 and Zahl HM1 will all work absolutely fine. Voltage requirement scales logarithmically, so if you don’t listen all that loud, you probably don’t need to fret too much about your choice of amp. (I’m using the Zahl HM1 which has a 10.6V output limit just fine for instance)

Suggested amps with 20V output (suitable for most listeners):

  • Holo Bliss
  • Ferrum OOR
  • Topping A70 Pro
  • Fiio K9 Pro

Suggested amps with >30V output (suitable for loud listeners):

  • CFA3 (HeadAmp or DIY)
  • Benchmark AHB2 (requires preamplifier)
  • Soncoz SGP1 (requires preamplifier)
  • Woo WA33

There will of course be others, but general rule of thumb is look for amps that have power spec approaching 1.5W @ 300 Ohm.