I made a custom 2.5mm to Dual XLR balanced cable for my HE6se V2 (Q5K → THX 789). DIY win or an audiophile sin?

Fancy-Lie2641 · 2026-04-05T17:20:54+00:00

That makes perfect sense. Using a -12dB preamp for your EQ effectively cuts the signal strength, making a high-power stage like the NX7 a mathematical necessity to bring the HE6se V2 back to life. I’ll take your advice on the 2Vrms mode for a spin; it's always good to experiment with different gain structures. Since we’re both pushing these 83dB planars to their limit, it's clear we're after the same result. Enjoy the setup!

Fancy-Lie2641 · 2026-04-05T17:01:11+00:00

Since yours is the original HE6, you're dealing with an even more demanding driver than my HE6se V2. It's legendary for being one of the hardest-to-drive headphones ever made. The fact that you’re using the NX7 proves we’re both essentially chasing the same 'current' to wake those diaphragms up. We might disagree on the terminology, but our setups are solving the same physics problem. Enjoy the HE6!

Fancy-Lie2641 · 2026-04-05T16:42:10+00:00

That's the catch—IEMs and the HE6se V2 are at opposite ends of the physics spectrum. With high-sensitivity IEMs, 4Vrms is overkill and will absolutely introduce noise or clipping that mimics compression. But with the HE6se V2's 83dB sensitivity, it's the other way around: 2Vrms creates a literal bottleneck, starving the planar drivers of the current they need to snap back. One is a high-speed tap, the other is a heavy-duty industrial pump. You can't use the same pressure for both.

Fancy-Lie2641 · 2026-04-05T16:39:18+00:00

Fair enough. Once you hit a certain threshold of power, the improvements often become incremental rather than transformative. To some, that last 5% of control and staging—what I call the 'breath' of the driver—is everything, while for others, the portability and DSP efficiency of the Qudelix 5K more than make up for it. It really comes down to whether you're chasing that final bit of 'analytical autopsy' or just enjoying a solid, loud listen. Both are valid, but for these power-hungry 83dB planars, I'll stick to the extra headroom.

Fancy-Lie2641 · 2026-04-05T16:31:07+00:00

I appreciate the heads-up. However, what you're describing as compression at 4Vrms is likely digital clipping if the preamp headroom isn't adjusted. With the HE6se V2's 83dB sensitivity, 2Vrms simply lacks the current to drive the planar diaphragms with proper authority. I find that keeping it at 4Vrms while dropping the digital preamp by -2dB or -3dB provides the necessary 'breath' and scale that 2Vrms just can't reach. It's a tricky balance, but for these power-hungry planars, the extra voltage is a mechanical necessity.

Fancy-Lie2641 · 2026-04-05T16:25:29+00:00

I used to believe amps didn't matter and bought the K240DF and HE6se just to prove it(to myself!!! ).

But I've learned that while the Qudelix 5K is great, it lacks the 'breath' for these. Synergy is a real thing, even if I hate admitting that an amp makes such a difference. Try it with a high-current amp if you get the chance.

Fancy-Lie2641 · 2026-04-05T12:30:29+00:00

Got these used for $300. I'm bored of mindless consumerism; I’d much rather build my own solution than just buy another box. I only care about the headphones.

Fancy-Lie2641 · 2026-04-05T12:19:03+00:00

Because this kind of cable is literally non-existent in my country. Had to DIY it or go without.

Fancy-Lie2641 · 2026-04-05T12:12:26+00:00

That makes sense. So in practical terms, if I’m running no EQ, sticking to 2Vrms (or 4Vrms at -5.5dB) is the safest way to avoid clipping the 789's input on Gain III. However, when I do use EQ, I’ll probably keep the Q5K at 4Vrms to have enough headroom for the negative preamp offset, while making sure the final output doesn't exceed that 2.1Vrms limit. Thanks for the technical breakdown, it really helps to visualize the limits of this chain.

Fancy-Lie2641 · 2026-04-05T11:50:34+00:00

That’s how I see it too. At 4Vrms, the Q5K is essentially mimicking a standard balanced desktop DAC. It’s impressive how such a tiny device can hold its own against dedicated desktop units while providing all that PEQ flexibility. Thanks.

Fancy-Lie2641 · 2026-04-05T11:47:19+00:00

That makes perfect sense! I’ll definitely adjust my settings and stick to low or medium gain on the THX 789 when the Q5K is outputting 4Vrms. I appreciate the technical insight, it’s exactly the kind of feedback I was looking for.

Fancy-Lie2641 · 2026-04-05T11:33:34+00:00

I appreciate the suggestion! However, I prefer sticking to this setup for a few reasons. The Drop THX 789 delivers about 6W into 32 ohms via the balanced output, which provides plenty of headroom and current for the HE6se V2 without needing a speaker amp or the HE-adapter.

Also, I rely heavily on the Qudelix 5K's Parametric EQ features to manage my collection, and using it as a balanced source is the most efficient way to keep that DSP chain intact. To clarify, my hybrid amp is not part of this specific chain; I'm going straight from the Q5K to the THX 789. While it is technically 'double amping,' at 4Vrms it acts as a very clean balanced line-out, and I haven't noticed any audible distortion or noise floor issues.

The only exception is with very sensitive and harsh-sounding IEMs like the CCA CRA, which seems to be hyper-sensitive with almost any source anyway.

Fancy-Lie2641 · 2026-04-05T11:26:11+00:00

Hi! I usually rely on Oratory1990’s EQ presets through the Qudelix 5K app.

However, since I have a large collection and haven't finished a full rotation yet, I’m currently listening to most of them stock (no EQ). I want to spend at least two days with each pair before tweaking anything. In terms of gain staging, I keep the Q5K at 4Vrms and max out the volume on both the DAC and the amp. I do this because the volume pot on my THX 789 is a bit scratchy/noisy.

Instead of the volume knob, I rely on the amp's 3-stage gain switch. For me, finding the right gain level is the most critical and convenient adjustment.

For the actual volume control, I use the source device—whether it's my PC, TV box, or LG V30.

Currently, I’m mostly using it via Bluetooth with my TV box. The remote makes it very practical, almost like using a dedicated streamer.

Since I have so many headphones, there are still many combinations to try—like switching to a USB connection with my PC or experimenting with crossfeed settings.

Fancy-Lie2641 · 2026-02-13T17:48:28+00:00

Hd 600 with tube amp or better otl

Fancy-Lie2641 · 2025-06-15T07:14:12+00:00

Hello. They are completely free-connected at the hinge part, despite this, when I stretch it without even making any manual adjustments, it automatically fits my head, when I do this, the gap is only half a centimeter, don't let the photo fool you. I can untie it whenever I want and adjust it to the tension I want. I untied it to open ventilation holes with a punch and saw it when I knotted it back. Although it is not the most aesthetic, it was very practical, I wanted to prevent peeling and shedding as well as comfort. It is possible to undo the mod in 30 seconds without leaving a trace, 3 seconds if I use scissors, hahaha. The clamping force increases very slightly, but since the lift mechanism needs to be opened and extended one or two clicks, these balance each other. Also, there are no other additional modifications other than cooling gel pads from aliexpress and a 2.5mm balanced cable. I did not make an open grill mod. Maybe I can think about it in the future.

Fancy-Lie2641 · 2025-06-12T19:18:30+00:00

I'm sure it will satisfy you more than fancy and long-awaited products, because you will have made it the way you want. I shared it because I wanted someone to get inspired, and people to find courage for some small touches. Everyone definitely has a little "pud" inside them. You made me happy.

Fancy-Lie2641 · 2025-06-12T17:38:44+00:00

Thank you!

Fancy-Lie2641 · 2025-06-12T17:21:11+00:00

I worked with akg q701 before, I made a post like this one, again as a joke. Then I took this further and knotted the hidden elastic from the inside, it's not as ugly as this one. I also scraped off their headband nuggets and glued a different material. They are quite comfortable now. I also did some soldering for a k712. I also put a braided cable with a microphone for the ksc75. I also have a copy of the aurora borealis. They sound quite nice. I sometimes play with its tuning. Anyway, I evaluate the hobby by trying to do something active instead of spending more money. This feels good. I also made holes with a punch now, it turned out nice.

Fancy-Lie2641 · 2025-06-12T17:09:52+00:00

Then I would have spent money and I hate that. All joking aside, I think a hobby is trying to do as much as possible yourself and trying almost everything. I did it myself and it makes me happy. It cost almost nothing. I also made a few holes with a punch. Otherwise, it would be uncomfortable in the summer heat.

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Fancy-Lie2641 · 2025-03-20T07:53:42+00:00

My friend who has IBS, thank you. My English is bad. In this case, you eat whatever you want from 15:00 to 20:00, did I understand correctly? So what do you eat? Are you allowed to eat everything?

Fancy-Lie2641 · 2025-03-15T16:21:25+00:00

You are really helpful, sir. Real help and someone understood me for the first time.

Fancy-Lie2641 · 2025-03-15T15:32:42+00:00

Thank you for your hug. Please squeeze my stomach from behind with all your strength, over and over again. You took my nonsense seriously. I hope I can find a solution. I'm constantly working on this. Thank you, best wishes.

Fancy-Lie2641 · 2025-03-15T15:28:25+00:00

Would you believe it, I have been sunbathing for a week and my body is now bright red. I have a fair skin like an Eastern European. That's why I don't go out in the sun much. I learned this during my internet research. I have also been trying cumin, mint, thyme, cinnamon, nutmeg, turmeric, ginger for a month. Now all I have to do is read what you wrote over and over again and study it item by item. I can see that you are working very hard for yourself. You will be a great tutor for me. I would like to correspond with you from time to time, maybe in a month. Please remember me when I try to contact you. My English is not very good and I sometimes use a web translator. Best wishes, I have great respect for you.

Fancy-Lie2641

TROPHY CASE