Modhouse Tungsten Measurements & Official Discussion

“Enough headroom” could mean almost anything. You have to take into account your average listening level, the output level of your source, the gain and maximum power of the amplifier, and finally how much headroom you consider to be enough.

First, here’s the raw power requirements for the Tungsten DS:

Assuming a balanced source, outputting at the input-limit of the A70 Pro, and balanced output into your headphones, you could expect the following from the A70 Pro:

If your source can’t manage 9.8Vrms (BAL) then you won’t get the rated power in low-gain, and in high-gain you need to ensure you stay at 2.0Vrms or below - which for balanced might require using attenuation on the source (normal BAL is 4.0Vrms [sometimes 4.4Vrms]), which can compromise dynamic range/SNR.

You’re looking at things like a Lyr+ or Jotunheim 2, to get into a similar power-delivery level at under $1,000. Maybe other options, though none come to mind presently.

I should probably add the Tungsten to the “standard impedance chart” for power delivery on my amplifier power tool, since it’s. such an outlier in terms of (lack of) efficiency/sensitivity.

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Anecdotally, reports are that Lyr doesn’t deliver enough voltage to handle Tungsten SS (not clear to me whether it can handle DS?), though Jotunheim apparently does.

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That’s a good point.

I don’t know what the voltage rails are for Lyr+ nor, more importantly, how much of that they can swing at the output, so it is definitely something to check on.

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According to a post on headfi… “According to Schiit, the Lyr+ will push 7.2 Vrms into 150 ohms. The Lyr 3 is rated at 5 Vrms. The Jot 2 outputs 9.6 Vrms via XLR out into the same impedance.” 20 Vrms is reported to be the ideal for maximum Tungsten performance, though many reports say Jotunheim drives it quite well.

I have not substantiated these numbers separately yet.

I am also given to understand that the output voltage from the amp is somewhat a product of the input voltage from the dac AND the db of listening, so figuring out the optimal power for Tungsten in particular is quite a complex undertaking. Which just reinforces why I decided Caldera was the planar for me. :wink:

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Wow that is super helpful, especially since I just ordered the A70 Pro a few days ago :grin: I figured that would give me a good impression of what the Tungstens can do, but if it turns out the A70 is too clinical/neutral sounding, I wanted to see what good pairings others find, apart from $3000 tube amps :blush:

Thank you for the education :pray:

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I updated my tool, specifically the “Amplifier Power/Drive Reference” to include both the single and double-sided versions of the Tungsten in its output.

Bear in mind that since most manufacturers do not publish their voltage/current drive capabilities independently (typically just power by impedance), the indicated values are calculated and may not always be accurate (unless shown in green).

Thus an amplifier with very high current capability, but relatively small voltage swing, may run out of voltage before hitting the indicated power numbers (or vice versa) - yielding lower available power in that instance.

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Where does this calculation come from? Is it something specific to the Topping A70 Pro or do I need to worry about this type of limitation with any amp I am using?

In this case, the numbers come straight off the Topping A70 Pro specifications.

BUT … the fundamental behavior is common to all amplifiers.

The amount of power they actually deliver vs. what they CAN deliver is dependent on the input signal level, how far it is attenuated (volume setting), and the gain setting on the gain stage.

If your amplifier is designed to output its maximum voltage from a standard 4.0 Vrms balanced source, and your source only supplies 2.0 Vrms at maximum output, then even at max volume (zero attenuation), the amplifier is only going to deliver half the voltage it is capable of. And for a given impedance load, that’ll halve the power delivered also.

Similarly, if you feed a single-ended amplifier expecting a 2 Vrms line-level signal off a USB dongle DAC/amp that can only output 1 Vrms, then you’re only ever going to see half the maximum power from the amplifier even at max volume.

In most cases it’s not a “big” factor … everything hovers around the 2 Vrms SE/4 Vrms BAL I/O expectations, and then you choose the gain setting (where selectable) as desired and will get most/all of the available power appropriately.

But with the A70 Pro, for example, you’d have to either run the source attenuated, in HIGH gain or have significantly less range on the A70 Pro’s volume dial as a result. OR run it in LO gain, and lose about half the available power even at the A70 Pros max setting.

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Thanks! That all makes sense and I knew that output depended on source voltage in that way. It just really surprised me that you were recommending staying at a lower than 4V source voltage for the balanced inputs on high gain. I’ve never seen that before.

You don’t have to; you’ll just lose ~half the usable range on the A70 Pro’s volume dial at 4Vrms.

Unfortunately for a normal line-level XLR output, if you use low gain you’ll lose about half the voltage output capacity of the amplifier, so it’s a bit odd either way.

An unfortunate product of a having a ~20 dB gain range and only two gain settings.

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@Svadhyaya Do you live near anywhere that will have an audio show, like CanJam, Axpona or CAF? If so, I’d recommend taking your Tungsten to the show and try it out on different amps.

You might be surprised that an amp that shouldn’t work on paper might sound nice to you. For instance, I tried the Tungsten on a Geshelli amp a few weeks ago at Capital Audio Fest and it sounded surprisingly good to me, even though the Geshelli should not have been powerful enough. A friend of mine agreed that he liked the Tungsten on the Geshelli too, although he liked it more on the more expensive Headamp CFA3 amp.

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CanJam SoCal would work but that’s a long wait… I saw the Geshelli on ZReviews video of the Tungsten, he liked it too.

I have no idea when these headphones are actually gonna arrive with the lead times and all, so I’m gonna keep looking for people’s recommendations for amps

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@Resolve Is the SS version going to be evaluated at some point? Be very interested to know how it compares to the DS version.

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Looking very promising. I’ve been trying to snatch one for myself during their last few drops but to no avail…

One thing I am wondering is, how does the upper treble sound? Hifiman planars typically bug me with their excess energy at around 11-13khz. Judging from the FRs the Tungsten might be a little smoother in this range (compared to overall treble energy).

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No issues there for me, at least nothing too noticeable.

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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.

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The symbol for Tungsten is W because the original name for the element was Wolfram, from the mineral Wolframite. Tungsten is Swedish for “heavy stone”, the Specific Gravity of Tungsten is 19.2, one of the densest of all the elements.

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Would you say a A&S Mogwai SE is good for the Tungsten? What output would be best? 8ohm, 32ohm or 300ohm output?

A&S website states this for the Mogwai 300ohm power:

Power as measured with KT88 power tubes and 5AR4 rectifier
8ohm power: 8.2Watts RMS @ 1khz
Noise on 8ohm tapp @ 350uV RMS

32ohm power: 4.6Watts RMS @ 1khz
Noise on 32ohm tapp @ 400uV RMS

300ohm power: 5.2Watts RMS @ 1khz
Noise on 300ohm tapp @ 700uVV RMS

Should be ok :grinning:

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I heard that Flux Lab Fa-10 worked well.

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tbh I have no idea about those calculations or what is being talked about here, I just wanted to know if the ifi pro ican signature is a good amp for the tungsten. :innocent: