[Zurv]

https://www.china-hifi-audio.com/en...tegrated-amp-power-amplifier-headphone-p-2268

Anyone try these? Seem like a good price (ie, sub $800).
It is a shame they don't sell them with no tubes. I'd personally try them for $400-$500 and use the tubes i already have. (like gold lion power tubes and some NOS 6SN7s


Specs:
Frequency effect: 10Hz 40kHz (+/-0.5db)
Total harmonic distortion: 1% (1kHz)
Signal to noise ratio: 91dB
Input sensitivity: 380mv (when Integrated amp input), 820mv (when pure power amp input)
Input impedance: 100KΩ
Output impedance: 4Ω, 8Ω
Rated output power:
25W+25W (RMS triode working state) (KT88, 6550EH or EL34)
45W+45W (RMS ultra-linear working state) (KT88, 6550EH)
40W+40W (RMS ultra-linear working state) (EL34)
Preamp stage power supply filtering Tube: 6SN7*1
Voltage amplifier stage Tube: 6SL7*2
Driver stage Tube: 6SN7*2
Power vacuum tube: KT88*4 or 6550EH*4 or EL34*4

 

[Zurv]

A review, but sadly he doesn't talk about it as a headphone anmp (which is what i'd use it for)


(manual bias is.. meh.. but they make it pretty ez. ie, they don't have auto-bias.)

 

[mudnut]

I have one on order on blind faith. There's currently a backorder of about 2-3 weeks. I have the schematics but no idea what I am looking at. If anyone's interested in taking a look, let me know and I'll send it to you. Also I was told by a dealer that the output impedance is 150 Ω .

I will be using it primarily with headphones. I would love to know its output power at various common impedances (e.g. 32 Ω , 50 Ω , 300 Ω , 600 Ω ). Sadly, I couldn't find such information or any reviews on how it pairs with headphones.

 

[Zurv]

please report back when you get it!
which tubes did you pick?
If you need more power you can always change the power tubes (KT88 or 6550EH or EL34) - The Gold lion KT88 are nice IMO.
you can also look at my fav 6SN7 tubes.. the CBS 5962
the driver tubes have the biggest impact on sound. (which are the 6SN7)

If you do play around with the tubes, get it from a real place and have them tested. unmatched tubes can end up having the right/left channels be different from one another.
i've had good success with upscaleaudio.com, tubedepot.com, and tubemonger.com

 

[mudnut]

I found someone who's selling an R8 and asked if he tried the headphone out and he said it's ok but not great. Yong Lee from China Hifi Audio made a similar comment when I asked him. I think this being an integrated amp, the headphone out is more for convenience and its output power and SQ are likely neutered compared to speaker output. i.e. it doesn't have a 'direct drive' mode like the Emotiva A100.

I will give the headphone out a try when I receive it but I have a hunch that I'll most likely be running my headphones through speaker out with an adapter, especially since I only have planar magnetics right now.

Thank you for the recommendations on tube dealers. I ordered the KT88 version along with Shuguang CV-181Z, Psvane CV-181T MK2, Psvane WE6SL7+ to start with. Though, admittedly, I am not really a tube roller so I'd probably stick with those unless I run into something that truly pique my interest.

 

[Zurv]

You can try to use the taps on the back to run the headphones. That might work out better than the headphone jack if that sub system isn't up to the level of the rest of the unit.

Most places making headphone cables will give you can option to use banana. (but an adaptor cable vs a full run might be the better option.)

(costly option from moon-audio as a random example)

we are also on the right forum to ask about stuff like that too

what headphones are you using and connection on them?

 

[mudnut]

I received the R8 and have used it for about 10 hours over two days now (using non-stock tubes in my previous post). Took about 2 1/2 weeks from order to delivery - not bad. I am not versed in audiophile parlance so I'll just keep it simple. The amp came freshly built - I can still smell the paint, and came double boxed and well protected. I heard no noises from the amp itself or through the headphones when the unit is on standby. It is very quiet.

If I were picky, I'd say the power cord receptacle is a bit shallow so the plug may sit kinda loose and wiggly. Ultimately it's fine as long as no one fiddles with it. The only other thing that could be an annoyance is that the amp doesn't keep your selection once turned off so it always defaults to "CD" input and "TR" mode. Since I prefer UL mode, it's an extra step when I want to use the amp. I did switch my DAC input from "AUX1' to 'CD' to have one less button to push. If Willsenton had used toggle and rotary switches this hassle would've been avoided.

I used my LCD-4 and HE1000 V2 on the headphone out and it was surprisingly good! The caveat being using ultra-linear (UL) mode instead triode (TR), the latter sounded soft and anemic to me. Comfortable listening level is about 9-10 o'clock position for either headphones in UL mode.

The LCD-4 at 200 ohms in particular paired nicely with the amp's 150 ohm output impedance. Soundstage was large and holographic yet retained all the details. Bass extension was deep and impactful. In fact the LCD-4 works so well with the headphone out, I would be totally fine not hooking it up to speaker tap. The experience with HE1000 V2 was also excellent, I actually felt air vibrating inside the earcups at times when bass hit. Vocals and instruments sound more full, more body (compare to my Liquid Platinum) and I was hearing nuances for the first time in certain songs. Nonetheless, I think the HE1000 V2 can be improved by using speaker tap. I have an HE6se with adapter arriving next week and I'll test it out. I also have a Verite open on the way from ZMF and I have a hunch that it being 300 ohms, would work spectacularly with the R8's headphone out.

It's worth noting the actual delivered price might be (substantially) higher than "sub $ 800" as it doesn't include shipping and tax. Nonetheless, I am very satisfied with the R8 and happy with the purchase.

 

[Zurv]

Did you bias the tubes? I can’t tell from the pix if the meter is in the center?

 

[mudnut]

The amp actually came biased, though not perfectly. Two of the tubes had the bias needle sitting too close to the lower limit of the acceptable range so I just biased them all. Took maybe 2 minutes.

The needle sits all the way to the left until you touch the bias toggle switch then it jumps to wherever the tube is biased and you just fine tune its position using the included screw driver.

 

[mudnut]

Got the HE6se with speaker adapter and tried it out. It felt bright and sometimes harsh in UL mode whereas TR was softer but resolution suffered. The R8 currently only has about 30 hours on it so I think both the amp and the HE6se need more time to burn in. Perhaps the HE adapter also degraded sound quality. I also tried the HE6se on headphone out and it was underwhelming and definitely worse than the HE adapter. I ordered an XLR to banana adapter and will try the HE6se via speaker tap directly.

I also tested my LCD-4 and HE1000 V2 on the HE adapter and both exhibited hissing noise and sound quality was inferior to headphone out so it seems I'll only be using the HE6se on speaker tap. Fortunately, the LCD-4 and HE1000 V2 both sounded spectacularly through headphone output.

 

[elricofchaos72]

Got the HE6se with speaker adapter and tried it out. It felt bright and sometimes harsh in UL mode whereas TR was softer but resolution suffered. The R8 currently only has about 30 hours on it so I think both the amp and the HE6se need more time to burn in. Perhaps the HE adapter also degraded sound quality. I also tried the HE6se on headphone out and it was underwhelming and definitely worse than the HE adapter. I ordered an XLR to banana adapter and will try the HE6se via speaker tap directly.

I also tested my LCD-4 and HE1000 V2 on the HE adapter and both exhibited hissing noise and sound quality was inferior to headphone out so it seems I'll only be using the HE6se on speaker tap. Fortunately, the LCD-4 and HE1000 V2 both sounded spectacularly through headphone output.

I have the HE Adapter as well for use with my Abyss PHI CC and the Benchmark AHB2. The HE is just a resistor in parallel. It doesnt do anything to sound except keep your HP from exploding by, as in my case, using a 100W amp directly.

But please let us know how your direct connection to taps works out. I do the same with a smaller Class A amp as well.

 

[mudnut]

Found out why HE6se sounded bad via HE adapter when I noticed the same with direct connection. Turns out it was the crappy cable I got off Ebay. I swapped it out with Hifiman factory cable and the sound improved dramatically. I was never a believer of how cables can affect sound quality. After this experience, I ordered a Draug 3 cable chain (headphone -> speaker tap) pronto!

It's good to know that the HE adapter doesn't temper with sound quality. Does something like the iFi iEMatch degrade sound quality or does it just attenuate?

 

[elricofchaos72]

Found out why HE6se sounded bad via HE adapter when I noticed the same with direct connection. Turns out it was the crappy cable I got off Ebay. I swapped it out with Hifiman factory cable and the sound improved dramatically. I was never a believer of how cables can affect sound quality. After this experience, I ordered a Draug 3 cable chain (headphone -> speaker tap) pronto!

It's good to know that the HE adapter doesn't temper with sound quality. Does something like the iFi iEMatch degrade sound quality or does it just attenuate?

I had a feeling the HE wasnt the issue. I was able to listen to the Nordost Heimdall 2 HP cables and certainly heard a difference over stock Audeze cables. I would imagine for Hifiman you could experience the same.

I own both iFi IEMatch versions and find them extremely useful with sources such as tube amplifiers or anything with background noise. They do NOT degrade sound. They lower the noise floor and increase resolution depending on your source. Helps with impedance matching with solid state amplifiers as well. It has two levels of attenuation which is quite useful. It is a tool that you will use sometimes not every time.

 

[mudnut]

Just want to share an update in case anyone run into the same noise issue with the Willsenton R8. I've been getting slight hissing noises with my headphones on the R8 but it wasn't noticeable while the music was playing. That is until I got the ZMF Verite which I can actually hear hissing while music is playing. I tried AC power conditioners, different USB and power cords, iFi power conditioner, various USB filters (iFi iPurifier3, iFi iDenfender, AudioQuest Jitterbug), just when I was about to give up, I found this 2-channel RCA ground loop isolator that connects between my DAC and the R8 and to my amazement, it works! Now the background is dead quiet in both TR and UL modes.

I was getting noises on both the headphone out and the HE adapter. Now I can connect all my headphones (LCD4, HE1000 V2, Verite Open, HE6se) all through the Hifiman HE adapter and get pure, untainted background; the amp sounded pretty good before but now it's just dreamy!

There are several RCA isolators that I found on Amazon and I am pretty sure they'd all work. But the isolator I bought is "Stinger Select SSGLI Ground Loop Isolator" https://www.amazon.com/gp/product/B074QYKW2Z/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

 

[iFi audio]

I tried AC power conditioners, different USB and power cords, iFi power conditioner, various USB filters (iFi iPurifier3, iFi iDenfender, AudioQuest Jitterbug), just when I was about to give up, I found this 2-channel RCA ground loop isolator that connects between my DAC and the R8 and to my amazement, it works! Now the background is dead quiet in both TR and UL modes.

You had a ground loop in-between your components somewhere it seems. Of iFi products you listed, none would address it, and iDefender3.0 breaks ground loops on USB lines specifically. Of our range Groundhod is the one that would most likely do it for you, but it's good to know that you were able to solve the problem and now can enjoy clean background