Elekit TU-8900 2A3\300B Single Ended DHT Tube Amp - Build, Impressions, and Review

Elekit TU8900 - Sound Impressions with Headphones

- This is not a warm, lush, wet, tubey, romantic sounding amp. It is neutral in tone and has a hint of tube smoothness and roundness
- You get all the other benefits of a good DHT amp such as, nuances, microdynamics, texture, decay, reverb trails, depth, layering, holography stage/presentation
- Timbre is quite realistic and convincing. I feel it could have been better had it been a touch more warm and rich/wet. The DACs are partly to be blamed for the timbre, as none of these DACs are really great in timbre due to issues in treble
- The amp is not the hardest hitting in the bass, but does have good authority and I would still classify this as a punchy amp for a tube amp. The macrodynamics, tactility, energy, attacks and transients in the mid-range are nothing short of impressive
- Displays excellent technicalities such as separation, imaging precision, details etc. especially with the 2A3 tubes. People who are under the impression that tube amps are all about warmth and lushness will be in for a surprise
- It seems to remove a layer of homogeneity, where you are able to tell apart the differences in recording quality even further. Like I am starting to realise how many albums in my collection are too beautified and scrubbed in the post-processing
- People who are anal about the bass cleanliness and definition, might be slightly disappointed. Not that it is boomy or bloomy. It is well textured and detailed, but it just isn't super clean
- From a harshness perspective, it is a bit on the forgiving side, due to the slight smoothness/roundness, especially with the 300B tubes. But it is not completely forgiving, so system synergy will be important when trying to pair with bright sounding gear
- The amp works great for both 6X0 and 800 series headphones. Tubes and DACs which aren't bright/harsh will result in better synergy, especially with the 800

2A3 vs 300B:
- Update Feb 23, 2022: I recently learnt that the Cossor BlackPlate 300B is not a very competitive tube. I will update this section once I am able to get my hands on a 300B tube of similar caliber as the WE2A3.

8900 vs BW2:
- While the BW2 is often described as an SS amp with tube sound, it can still come across a bit dry and hard when compared to a good tube amp
- Even though the 8900 is not a wet sounding tube amp, it is less dry than the BW2 and is free of the hardness in the treble. Also the attacks in the lower treble is a touch rounder on the 8900
- 8900 also seems more neutral in tone than the BW2, which sounds warm and coloured due to the warmth from the upper-bass/lower-mids
- 8900 is straight up, a notch or 2 better in terms of overall performance and technicalities. It is also a bit cleaner and easier to listen to, despite both amps being equally energetic
- Bass seems to hit perhaps a tad harder on the BW2
- BW2 throws a wide stage for an SS amp of this price, but it is not great with stage depth. 8900's stage doesn't not any wider than BW2's stage, but it is deeper with better layering and more holographic

Spoiler: Elekit 8900 Config:

No NFB, Audyn Copper Max Coupling Caps, Lundahl Amorphous OPT
Tubes: Linlai WE2A3, Linlai Black-Plate 300B, Sylvania Grey-Plate 12BH7A
Connection: HPs connected to Speaker Taps

Spoiler: Gear and Chain:

Chain: Source > DAC > Amp > HPs
Source: Allo USBridge Sig (USB), MacBook (USB), Hiby R6 (Coaxial)
DACs: Wavelight, Bifrost 2, Zen DAC Sig V1, PhiDeca DAC
Amps: Elekit 8900, EC BW2
HPs: Black Screen HD650, HD580, Modded HD800

 

Great review @EagleWings. Actually surprised at the amount of overlap between our experiences.

Over the last month or so, I've rolled a number of different sources. For the most part, nothing fancy. Modi 3, older Yulongs....topping ect.. With regard to timbre, I found the 8900 to be more affected by source than I initially thought. The upside to this was that pairing it with a NOS tube DAC (Abbas 4.1SE) allowed me to fine tune the timbre via tube rolling.

Most of the tonal gripes I faulted the 8900 for, pretty much disappeared after matching and adjusting the source. This along with the output Z adjustments made for some interesting results with headphones that don't get much play because of glaring timbre issues\peaky treble, but are otherwise very capable.

 

Thank you, that is quite reassuring, as I have a 2.3 SE on order. I am yet to roll some tubes on the 8900 as well. So I’m hoping that I could get it to where I like it.

My new found love is a HD580, which has one of the best timbres I have heard on a HP, save for the hot treble. If I can manage to turn down that heat with the Abbas and some tube rolling, it would be spectacular.

 

+1 on the 580. Got one a few weeks ago and it grew on me. It sounds good with virtually every genre I listen to and would probably be one of three headphones I've heard that I would consider a true all rounder.

To me they weren't hot or peaky but I'm a little less treble sensitive than most people I know. Even with that said, I think you'll be good. Coming from the A2, the 4.1 tamed things down pretty noticeably despite it allegedly being the most "analytical" DAC in the Abbas line. I'd place my bet on the 2.3 being a better match.

 

Sweet. Yep, it seems to be a solid performer. Also I am not surprised that you don't find it hot. I don't often see folks complaining about it. Just that I am a bit treble sensitive than average. So I am really looking forward to the Abbas.

 

Sorry a little off topic but +2 on the HD580. Received my JAR580 (black screen) back from JAR not too long ago and thought to myself that it has one of the best timbres I've ever heard - It just sounds so realistic and right. I feel like the slight hot treble had been taken care of by the JAR mod. I've found excellent synergy pairing it with my Pono player balanced output and it's been my main portable rig.

 

@Tama77 , funny you bring up JAR. JAR650 was another headphone that I thought had one of the best timbre on headphones, and with a treble that was inoffensive. So I can see how good a JAR580 must sound. I would love to get mine JAR modded. But I am a bit hesitant because, where I live, headphones have to face some harsh realities, such as, excess dust and a few other weird things. So I have been avoiding any mods that involves removing the stock grills.

 

I received this amp around two days ago after getting it built from a really quality guy (the "Headamp Builder" on etsy, if anyone was curious). I basically wanted a TotL amp that could power speakers and headphones and had a good deal of versatility. For the most part, I stuck with Victor's build, but I did sub the vcap cutf's in with some Duelund tinned copper to provide some additional warmth, and I also had my builder tinker a bit with the resistor network that goes to the headphone out after hearing that series resistors tend to degrade the sound. Thanks to @EagleWings for sharing his schematic with me so that I can switch between the parallel resistor and no resistors at all.

A preliminary warning: this amp has only been burnt in for around 35 hours or so, and it supposedly takes quite a bit more time to burn-in. I've been switching between Tung-Sol and Fivre 12BH7a drivers, with Linlai Elite power tubes. So far, I think this amp is pretty remarkable, albeit with a couple important drawbacks. Firstly, in terms of clarity, layering, sheer sense of space, separation, and microdynamic nuance, it is at least a league better than anything that I have heard before (yes, that includes the ECP 3F and TU-8800). It handles music with an ease and effortlessness I don't think I've ever heard before. In short, it provides a clearer window "into" the music than any other amp I've heard, and I've never once heard it sound remotely congested in a busy passage. Though the stage isn't massive, images are extremely well-localized. Bass, though not particularly slamming, has a supremely nuanced sense of pitch, texture, and control. And the sense of decay, delineation and air around treble notes is at times awe-inspiring: the cymbals in "dreams" seem to run on forever, and one can actually hear with more tangibility the precise changes in volume of these instruments as the strike of the cymbal decays slowly into nothingness. All this is, to say the least, fairly impressive.

That being said, I do have some quibbles with the way that it represents instrument textures in the mid-range. It has a sort of high-end "sheen" to it which tends to lead to a homogenization of mid-range timbres. For what it's worth, this is something I've heard on every amp with Lundahl transformers (including the 3F and 8800), though to a perhaps lesser extent than what is present in the 8900. In short, there's a kind of almost artificial top-end sparkle that crowds out the crunch and presence of mid-range elements like voices and strings while also tending to make their timbres all sound alike. It also is just a tad harsh-sounding, akin to the way that a Focal sounds, albeit without the "metallic" timbre or "edge" to the transients. In fact, the transient edges are, if anything, not adequately well-represented: the amp lacks a certain sense of grunt and bite that even the much cheaper ZMF Pendant OG had. Since this amp also tends to lack any sort of notable warmth or wetness in the mid-range, this can occasionally lead to a sound that is simultaneously sterile and unengaging. For the most part, I don't find myself tapping my foot with this amp despite it having what I think are the best microdynamics I've ever heard - there just isn't enough sense of "realism" and palpability to the instruments or attack in the transients, two things which I think are essential to musical engagement.

For what it's worth, many of these problems have been getting less noticeable as the amp has burnt in, and I also think that they are at least partially due to the pairing with the Soekris 2541, especially since this amp is supposedly quite sensitive to sources. In fact, when I used my loaner r2r Cayin dongle, many of these issues, particularly the timbral ones, entirely disappeared, though the amp did take a hit technically. What I surmise from this is that to a good extent, this amp tends to take on the timbre of the sources that it's used with. In this way, this amp reminds me a good deal of the Focal Utopia - it's extremely revealing and a tad on the thin side, so pairing with the correct components is going to be absolutely essential to getting the most out of it, since its sheer transparency will tend to make it very sensitive to the gear that it is paired with.

I am going to burn-in this amp a good deal more, potentially swap caps, and give it a go with an Abbas 2.3se, since I really do think it would benefit from an aggressive, full-bodied dac (the soekris 2541, which is simultaneously thin, relaxed, and lacking in plankton, seems like exactly the -wrong- kind of pairing for this amp). I will let you all know what I think when I do so, but for now, this amp is not quite the slam dunk which I thought it would be.

 

Awesome write up. Do you know if you were running in feedback or non-feedback? The two modes have very different signatures IMO.

 

I have non-feedback mode at the moment, I haven't even bothered switching to feedback, since I feel like that would tilt things in the other direction from where I want them.

 

Agreed. In hindsight, I think my description would be pretty similar to yours at the 35 hour mark, even with the warmer source I had at the time (Yggdrasil A2).

I do think something like the 2.3 SE will mitigate some of these issues, the amp can be very chameleon like with changes in upstream gear. Though I honestly think it just needs more time in the oven. We’ll see.

 

Has anyone compared the 8900 to the EC Studio B?
best

 

Just passed my 200 hour mark on my baby and was warming up to write my impressions when the fuse blew...


After testing continuity errors on the 12BH7A and the amp not blowing with the rectifiers in, I decided to do the voltage point test again. All within spec up until point 9 and 10, which both are supposed to be 0.

9 is 10 V and 10 is 0.7 V...



Anyone got an idea where to start?

As a note to Dematted post: I think it will warmen up with time! Mine has no harshness left, but it was clearly there for the first 40 hour's or so, maybe even more. (I am running Cossor WE2A3 and Silvania 12BH7A)

 

Interrestingly this point starts off with 0 V when powering up, until gradually rising! Sounds like a tube problem, right?

 

How did you acquire the kit? HifiCollective? If so, I think they're working with Victor Kung, tangentially, so it probably wouldn't hurt to send him an email. He's extraordinarily helpful.

 

Getaudio.eu

I did write Victor after I posted here, and even though I only purchased my tubes and coupling capacitors from him, he is still already helping me the best he can. Fantastic service. Will encourage everyone who can to buy from him.

 

Just in case anyone wanted to know the output Z values for the different headphone settings. Had the missus send Elekit an e-mail and they responded promptly:

LZ-L: 3.1ohm
LZ-M: 7.2ohm
LZ-H: 15ohm
HZ-M: 26ohm
HZ-H: 60ohm

You can also calculate the values yourself using the circuit schematic in the back of the manual. Just sum up the resistor values in the corresponding circuit path and plug them into the calculator below (for resistors in parallel, the value will be inverse e.g 120ohm --> 1/120ohm).

http://www.sengpielaudio.com/calculator-InputOutputImpedance.htm

There's also a formula there for those who are all about that pen and paper method. Compliments to @HiGHFLYiN9 on headfi for the link and resources.