IEMs/Headphones Pair up.
The sound of any source, either if it is a DAP, DAC/amp, or a portable usb DAC/amp dongle, is based on pair up synergy with different earphones and headphones. After all, you are hearing the sound signature of earphones/headphones connected to the Source. In this section of my review, I will go over how various earphones and headphones pair up with RU7, and mention volume setting (v) and gain setting (mostly High Gain). All connections were balanced. RU7 was connected to my Galaxy S22 phone with volume set at the max (on the phone), and I was using HibyMusic app. I will also go over changes between different DSD formats and my personal preference.
IEMs.
Oriolus Traillii (v29, HG) – natural dynamic full-bodied tonality with a balanced sound sig; great retrieval of details; punchy deep bass, natural detailed mids, treble with a good definition and natural sparkle; big soundstage expansion with nearly holographic imaging; black background. No hissing. DSD64 made treble a bit too smooth, DSD128 helped with improvement in detail retrieval, while DSD256 added more airiness to the treble. Here, I preferred DSD256.
UM Mest MKII (v28, HG) – I can still hear a mild U-shaped sound signature, with mids not as forward as with RU6, but the advantage here is different DSD formats. Bass has plenty of weight, deep sub-bass rumble, and strong mid-bass punch which hits with a great authority; mids/vocals are clear, detailed, natural; treble is crisp and clear, but will vary. 64 gives you a smoother treble, 128 more air, and 256 was a bit too much energy for my taste. Soundstage is very big and so does imaging, creating 3D holographic effect. No hissing here. I preferred DSD64 in this pair up.
Empire Ears Odin (v27, HG) – very balanced sound sig with a natural revealing tonality. Bass has a deep sub-bass rumble and tight mid-bass punch, both above neutral level. Mids are very detailed, layered, revealing but not too bright or sterile, actually with a good level of neutral body. Treble is crisp and natural, very good non-fatigue extension. Here with treble, in 64 it was a bit too smooth, loosing some air, while 256 was a bit too crisp, so I settled on 128. Soundstage is wide open and 3D holographic. I noticed no hissing even in high gain. I preferred DSD128 in this pair up.
CFA Solaris 2020 (v17, HG) – when I was trying to pair up RU6 with Solaris, I had to switch to low gain in order to avoid hissing with these sensitive iems. With RU7, high gain was perfect and it was just a matter of choosing between different DSD formats. The sound has a natural smoother tonality, good bass extension with a textured sub-bass rumble, natural detailed mids, and clear and detailed treble that had a rather natural tonality, not as peaky as with RU6. With DSD64, treble was smoother, gaining more clarity with DSD128, and then giving you more air and better treble extension when switched to DSD256. I think DSD256 was my favorite here.
FiR Audio XE6 and RN6 (v28, HG) – with XE6 I hear a mildly L-shaped signature with a big bold speaker like bass, thanks to XE6 kinetic bass drivers, smooth natural mids and vocals which are a bit recessed, and natural detailed treble. That’s how I described XE6 with RU6, and it sounded similar with RU7, except I had to switch to DSD256 to bring out more details in treble and a bit more clarity in mids. DSD64 made the sound a bit muddy. Then… I decided to use RN6 while in DSD256, and it was hard to go back to XE6 because RU7 made RN6 bass tighter, stronger, bolder, deeper, and more articulate, cleaned up mids, even positioned them slightly forward, and extended treble with more airiness.
It’s hard for me to pick the favorite IEM pair up since I enjoyed all of them with RU7. I didn’t have to worry about hissing and stayed in HG, and depending on pair up synergy had a choice of different DSD formats.
Full Size.
Beyerdynamic T5p 2nd (v36, HG) – a very natural detailed tonality with a balanced signature. It actually sounded pretty good. The bass had a tight punchy kick, good sub-bass extension, not as elevated, but still closer to balanced. Mids have a neutral lower mids, clear detailed upper mids and vocals, and detailed crunchy treble with a nice airy sparkle. I kept it at DSD256 to give mids more clarity. Perhaps adding C9 would have elevated the bass, like it did with RU6, but it wasn’t necessary here since RU7 was able to drive T5p 2nd without any problem.
Meze Audio Empyrean (v41, HG) – no problem driving Empyrean and the pair up was a lot better with RU7 than RU6. There was no need to use C9 amp, I was able to drive Empyrean directly from balanced output of RU7, and the overall tuning had a more balanced signature, with deep punchy bass, natural detailed mids, and clear detailed treble. Mids are a bit more forward, but they are not overpowering the bass and they don’t drown the treble. Actually, was a very enjoyable pair up, especially in DSD256.
Audio-Technica ATH R70x (v59, HG) – with higher output power of RU7, I didn’t have to raise the volume as high here in comparison to RU6 where it was up to 74. The sound is more balanced, with a deeper sub-bass extension, more forward detailed mids/vocals, and airy extended treble. This was a big improvement over the pair up with RU6 where the bass lost its power, being overpowered by mids. Now, the signature was more balanced, and I preferred DSD256 format to give mids more clarity and treble better extension.
When I was testing these headphones with RU6, adding C9 amplifier was absolutely necessary. RU7 with its higher output power had a much better synergy with these headphones without a need for an external amp. You can still add the amplifier, but it wasn’t really a deal breaker with RU7.
Twister6 Reviews 
I’d love to hear more about the differences between the RU7 and the RU7 paired with the C9.
Thanks!
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In general, C9 is a very powerful amp that will color the sound. RU7 by itself has plenty of power for most of the iems and even some harder to drive headphones. Adding C9 will enhance it (more output current, even higher power, choice of solid state and dual NuTube “coloring”) which adds more body to the sound and changes pair up synergy depending on what you are trying to drive. Keep in mind, C9 will hiss with as sensitive iems. So for more sensitive or average iems to keep the sound more transparent and with deeper blacker background, perhaps stick with RU7. But at the end of the day, it is up to you and how you want to refine the sound.
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Hi Twister6, Great review, thank you!
With ddHiFi TC28i Pro and mFI07S, were you able to use the iPhone to drive the Cayin RU7 to at least Vol:50, High gain, DSD256?
I am currently using iPhone 11 Max Pro with Cayin RU6 and ddHifi mFI09S. I get stuttering / music cutting out at Vol:55, High gain. With the TC28i Pro, I wonder if it is the phone being charged or the Cayin RU7. Thanks!
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Which iems or headphones? Actually, just tried iPhone XS MAX with TC28i Pro, RU7, and Meze Empyrean headphones, RU7 DSD256, volume up to 65, high gain, no stuttering.
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Thanks – I was using Fatfreq Maestro Mini on EA CODE23 on the iPhone 11 Max Pro and Cayin RU-6, vol.: 55-65 and high gain. The music would stutter or cut out when the bass kicks in. I reckon its due to the iPhone limitation. I’ll give this a try then.
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Thank you for the excellent review of RU 7. Here’s what I wanted to ask you : I have sennheiser i 900 headphones and they are constantly plugging, even in DSD 64 mode after volume level 45. I have already ordered the ddHIFi adapters you mentioned, but I am not sure about the success of the future design. Are the sennheiser such a big load for the iPhone? Perhaps the purchase of a cheap android phone is necessary? I listen to the Qobuz streaming service.
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I don’t have IE900 to try it, thus hard to tell. DSD64 at volume 45 shouldn’t give you a problem. Have you tried using RU7 with your laptop, just a sanity check with IE900 without iPhone current limitation problem.
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Thanks for the quick response. Yes, I used on windows 11, via Ruun, no problems with either Sennheiser or Audeze LCD 2 in any modes. I also noticed that when streaming higher resolutions the plugging comes faster. Nevertheless, as a person with a long experience of listening to classic high end systems, I recognize the baby RU 7 as an excellent result. But the situation with the iPhone is extremely frustrating, and there are no reviews about it except yours.
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Hi, thanks for the nice review ☺️
I read the short comparison with the ru6 (which I own)!
I wonder if switching to ru7 is a valid update, I read that the treble is less brilliant in 7, do you mean that it can be less “”””ringing “”””? I find it hard neither in the instruments nor in the voices with “s” and “c” (like rammstein and ghost) in ru6, although it is quite sharp and it seems to me that ru6 has the voices quite close up too! is ru 7 smoother?
thanks (sorry for the mistakes I use google translate)
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Thanks for the extensive review. I just got mine this week and am currently testing it with my various earphones and headphones. While I like what the dac can do, I want to know if during your testing, you encountered occasional short delay/pause during playback, i.e. similar pause to the one would encounter when increasing volume passing the volume segment. For each playback, I would experience 2-3 delays. Just for reference, my files are mostly flac with 24/44.1 or higher resolution and DSD64, and I’m testing the dac using my Mi9. I wonder if this phenomenon would change later on after further burn-in. Your input would be very much appreciated.
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Mi9, is that a phone, Android? I assume? What payback app are you using? Does it happen with every app? Have you tried using RU7 with another source, maybe your laptop to see if it happening in there as well?
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Yeah, running it from android phones (LG v50 and Xiaomi Mi9) using HiByMusic and UAPP with USB exclusive mode. There are some differences in the audio output, but the pause is there. It may have to do with the USB audio setting. I will play more with them. However, on LG V50 music player, there was no pause, but it is not outputting bit-perfect when it comes to certain files. So, I thought I’d give it more burn-in time since I didn’t do it in the beginning at all. Reading reviews here and there, it seems others have given 70+ burn-in time. On windows, currently it gives pops and clicks sounds like what you’d encounter when playing an LP back in the days (don’t know if turntable still doing that these days since I haven’t used one in aeons) truly analog sound. 😀
Thanks again for your reply. I take it you didn’t experience the pause based on your response.
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Okay, I figured out why this happened: DSD mode has to be set to DoP for this device. Though the specs say there’s support for DSD64, 128, and 256, it does not offer native dsd decoding support. Changing the DSD mode in my app to DoP solved this.
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Hello, nice review there. Planning to upgrade from dap to dongle. I said upgrade because it seems like it on the ru7. But of course I’m not sure, just an assumption. I’m currently using my old dx160. And the dap is no longer performing well with so many issues, planning to go phone dongle setup. My question would be does my plan make any sense? Or dx160 will still stand superior against ru7 phone setup. Thanks! Appreciate the review and your response if ever.
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Well, considering you will be using RU7 with your smartphone, this probably does qualify it as an upgrade over DX160, in both the sound and “system” performance since your smartphone will be faster and more robust running the latest apps.
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Hi Twister,
Went to most of your publications here and want to say CONGRATS. Great info with details and comprehensively presented.
Now, regarding the RU7 – I am having the RU6 and love it, also I have the Hiby RS2 and Mojo2. Is it worth getting the RU7 or I’d better save more and got to N7 or DX320?
The dilemma b/n N7 and DX320 is also quite big for me.
Please, advice! I listen mainly rock & metal (Deep Purple, White Snake, WASP, OZZY, Metallica) but I am also a big fan of Pink Floyd, Santana and Moby, Robert Miles. Not too much fan of female vocals like Adele, Agillera, … I value extremely big soundstage replay and balance (fair neutrality) – I hate too much (sub)bass or too much treble, and too forward (in the face) vocals but like clear nuances and details. My favorite ‘modern’ IEMS are Z1R, MMK2, Helios.
Thank you in advance!
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Hi,Thanks for the great review. I was wondering if you know if the current iPhones that have a USB-C instead of Lightning connector still have the iPhone current limitation problem. Was that a Lightening-specific issue or is that an Apple issue in general?Thanks in advance!
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From all the comments on head-fi in RU7 thread, I have not come across anybody with issues using RU7 with new iPhones. So, let’s assume it works OK?
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I have an iPhone 15 with USB-C and haven’t run into the current limitation problem. The problem I do have is rapid battery drain. I’ve ordered a DDHiFi TC28C Pro from AliExpress to solve the problem.
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Hi,
Thanks for the reply. Glad to hear you’re not having the current limitation problem with your iPhone 15, but the rapid battery drain is definitely a bummer. Good to know the DDHiFi TC28C Pro offers a solution, but it kind of affects the portability for on-the-go use if you also have to carry around a power bank.
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Hi,Thanks for your reply. Glad to hear you’re not having the current limitation problem with your iPhone 15, but the rapid battery drain is a bummer. Good to know the DDHiFI TC28C Pro is a solution, but it kind of affects the portability if you also have to carry around a power bank.
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