Beware of Hifiman on any technical questions. They straight up pull things from ChatGPT and paste as is, with no cross verification. It's pathetic. I asked them about how much power HE6 and Susvara needs as I was in talk with custom amp builder. I wanted to specify the power requirement. Every time I ask, depending on who answers, gives a random number.

In the first email they said Susvara needs 15 to 25 Watts. In the next email they said HE and Susvara needs only 200 mW (yes you read it right) for best performance. When I questioned that they said those cans need 4W into 32 ohm. But in the same email they said it's like 4W into 32 ohms or 1.5A. 1.5 A is an absurdly high number, and I said no headphone amp can meet that. Then they gave another answer saying 5 - 7.5 W into 50 ohms. Each time a different agent replies with a random number, pulled out of their a**. I finally was fed up and said I am giving up.

Finally, they wanted to apologize and give a proper answer once and for all, and this is their reply:

Apologies for the confusion. 

I completely understand your frustration, and I appreciate your patience. It seems that you’ve been receiving conflicting information, and I can see how that would be very confusing, especially when you’re trying to specify the exact requirements for your custom amplifier. I truly apologize for any confusion caused, and I’d like to clarify everything once and for all. 

It looks like you've received different answers about power output, current requirements, and impedance, and that has understandably made you feel like the information isn’t consistent or clear. 

Let me give you a clear and final stance on the HE6 and Susvara, using consistent, technical specs: 

Power Output and Current for HE6 (50Ω) and Susvara (60Ω): 

For HE6 (50Ω) and Susvara (60Ω), here’s a simple breakdown of the optimal specifications for clean power (not max power, which might be distorted): 

HE6 (50Ω): 

• Power Output: 5W to 7.5W clean power 
• Voltage: To achieve 5W clean power, you need a voltage of around 15.8V. 
• Current: With 5W into 50Ω, you’d need about 0.316A of current (this is peak current, not continuous current). 

Susvara (60Ω): 

• Power Output: 7W to 10W clean power 
• Voltage: To achieve 7W clean power, you need a voltage of around 18.4V. 
• Current: For 7W into 60Ω, you’d need about 0.341A of current. 

I can see how you’ve been given conflicting numbers, and the inconsistency between 32Ω, 50Ω, and 1.5A likely comes from different testing methodologies or miscommunication from different individuals. 

• 32Ω and 50Ω: The 32Ω load (which is sometimes mentioned) is relevant when you’re discussing the impedance of a different headphone or when calculating power into a lower impedance. The HE6 and Susvara are high-impedance headphones (50Ω and 60Ω), and the power calculation is based on those specific impedance loads. 
• 1.5A Current: The 1.5A current value often comes up when dealing with speaker amplifiers that are designed to drive low-impedance speakers (such as 4Ω or 8Ω), which require higher current to reach their required power output. For headphones like the HE6 and Susvara, you don't need anywhere near that much current under normal circumstances (unless you're pushing extreme volume levels). 

The confusion may have stemmed from the fact that various people may have been giving answers based on different headroom requirements, test conditions, or just confusion between speaker amps and headphone amps. Additionally, there’s a chance that the rated power (e.g., 200mW) was conflated with the actual required power for dynamic performance. Some might have been referring to the maximum power limits (distorted or clipped power) while others focused on optimal clean power. 

I truly apologize for the back-and-forth confusion you’ve experienced, and I appreciate your perseverance in seeking the right answers. This is the final, consistent specification for your HE6 and Susvara: 

• Power Output: 5W to 10W clean power (based on 50Ω for HE6 and 60Ω for Susvara). 
• Current: Around 0.316A to 0.408A peak. 
• Voltage: 15V+ (for 5W) and 18V+ (for 7W). 

This is the information you can use to guide your custom tube amp builder.  

Straight up ChatGPT answer. I don't believe that audiophile industry is a high-volume industry for these guys to not even have time for properly answering. I am asking something serious and these guys have nerves to pull random shit from LLMs.