[Beefy]

I think you may just have a different design philosophy. Just curious, what would you consider to be the best “reference” headphone amp you’ve heard so far? Sounds like you might prefer something like a T4 (parafeed hybrid) amp by ECP audio.

Depends on the phones. My Focal Clear and AMB M3 is by far my favorite *owned* combo. If I was ever going to build a big boy tube amp, it's got to be something that can accommodate sensitive low impedance phones like the Clear. So yeah, the T4 is probably much more my bag than the Elekit as currently available.

I suspect that if I had better high impedance low sensitivity phones than the HD650, the Elekit would be a no-brainer......

 

[JamieMcC]

On the topic of Parafeed the Bottlehead Mainline was designed from the outset as a high performance parafeed headphone amp and it's a very nice sounding amp. There is a transformer upgrade rarely available (from Magnequest direct) that Bottlehead staff did unofficially support but it's a rather spendy custom Nickel autoformer, reportedly it's the dogs danglies. However the trade off is you lose the low impedance setting on the Mainline.

Fwiw the 8900 noticeably outperforms my Mainline and the Mainline is a superb sounding amp imo

 

[Maven86]

Depends on the phones. My Focal Clear and AMB M3 is by far my favorite *owned* combo. If I was ever going to build a big boy tube amp, it's got to be something that can accommodate sensitive low impedance phones like the Clear. So yeah, the T4 is probably much more my bag than the Elekit as currently available.

I suspect that if I had better high impedance low sensitivity phones than the HD650, the Elekit would be a no-brainer......

Just read your manifesto on the bottlehead forum. Love the zeal but was a little surprised the Stratus caught your eye given Donald's design philosophy, especially compared to Elekit.

Anyhow, for one, it seems like you're specifically looking for a DHT build with transformers built to optimize headphones (e.g. multiple secondaries with loads for 32, 100, 300 ohm ect.)? I can't think of any kits off the top of my head but check out Keenan's thread here where he did just that:

https://www.head-fi.org/threads/l0rdgwyns-diy-audio.921105/post-16696208

There are tons of circuits around and you can even have schematics made into PCBs if you know what you want. In the example above, I believe he went to Electraprint to custom wind his transformers but there are a lot more options, you can even go parafeed if that's your thing. As for a mega low impedance requirement... you can have an OPT built with a tertiary winding to enable feedback (NFB)...

Designing something very close to what you want isn't the hard part...whether you'll end up liking the results of some of your design choices will be a different story.

 

[lsantista]

Im about to place an order on the 8900 + the new 8550 pre. Ever since I listened to the 8200+8500 combo last year, with speakers and specially with 500 series senns (didnt have a higher series at the occasion) I was waiting for the opportunity to get an Elekit.
I would initially use it with a Holo Spring 3 that has a non bypassable preamp - DSD 128X: 2.9Vrms (RCA), 5.8Vrms (XLR) and PCM48 NOS: 5.8Vrms (RCA), 11.6Vrms (XLR). That would go to the TU8550 and then to 8900. I understand I don't need the 8550 having the DAC pre module, but I may part setups later, plus I want to try a tube pre on my amps, the 8550 does fit my budget and I dig the looks of the Elekit combo. Also initially, plans are to use it with HD800 and small 8hm speakers with sensibility 88-90 (So Im guessing I will start with 300B). At some point (in life), I'd love to use it with bigger speakers with higher sensibility and also with a transformer box for estats as I love my Stax.

Has anyone here a stock or mostly stock 8900 to give impressions, specially after a few months of use? I want to do a few upgrades - this will be my first time building anything but I will have support, so I ask because Im still not sure what parts I will be able to ship to Brazil and how far I should go with more expensive parts, being a begginer.

Also, how easy/safe is to change AC voltage of this or another similar Elekit? I live in a 220-230V city, but most cities around are 110-120V and I may move next year. From what I gattered so far , specially from this at 6'50 , I will need to keep the other AC inlet unit and basically disassemble the amp's before having access to the AC unit? Would unsoldering and transfering the parts be a simple task with little risk of damaging anything? Is there any other (easier?) workaround to change AC after it has been built? Finally, I should not go for the extra big caps upgrade that dont fit on the cutoffs if I plan to be disassembling the amp, does that make sense?

 

[lsantista]

elekits ordered, will assemble with 220v units. finishing choosing tubes and a practice soldering kit
Also, Im considering ordering custom transformers, maybe potted, output and power. Hoping anyone can pop in with the dimensions that would fit the 8900's top case and the mounting holes so no drilling is needed.

 

[JamieMcC]

Hi all, how time flies I've just realized my TU-8900 has been up and running for over a year now and am happy to report absolutely zero issues in the last 12 months.

 

[Whitigir]

Hi all, how time flies I've just realized my TU-8900 has been up and running for over a year now and am happy to report absolutely zero issues in the last 12 months.

From the foundation architecture of the 8900, it is solid and as reliable as a tank . Thanks for reporting back! I especially love that it can auto bias 2A3 or 300B

 

[smodtactical]

If anyone is interested in grabbing a TU8600S I have one for sale here:

https://www.canuckaudiomart.com/det...-tu8600s-with-lundahl-opts-vcap-odam-tkd-pot/

 

[JamieMcC]

This popped up on my YouTube feed

 

[Whitigir]

This popped up on my YouTube feed

That is a wonder of diy Kit. You can use whatever components you feel fit

 

[JamieMcC]

Lol the silver foil output cap conundrum has been festering away and reared its head again (to be honest the idea has been festering away for some time now).

After reading about the Audionote silver foil capacitors and noticing they uses a Mylar dielectric it reminded me of another capacitor I've used in the past that also uses Mylar and that had a pretty unique sonic signature so just for giggles I've ordered some 0.1uf Russian K75-10 capacitors to go in the TU-8900 they are coming from Ukraine so delivery time might be interesting.

I'm going to bypass them with the utterly fantastic Duelund JDM silver foil bypass caps just for a bit of fun to play about and mix things up a bit. Should make for a very different presentation from the Vcap Cutf!

John L absolutely nails the sonics in his review of the K75-10

"I can report that K75-10 sounds extremely unique, quite different from K40Y PIO and any other true PIO one cares to mention, including Vitamin Q, Jensen, and AmpOhm. It has a very saturated, colorful, textured, and detailed midrange that is thick and juicy. While PIO’s are known for their natural and smooth midrange, K75 seems to add some jest, pop, and color to the proceedings, yielding an apparently more detailed and forceful presentation. Treble and bass is pretty good, especially for an oil cap, but the leading edges are not razor-sharp and precise like premium film caps. Since the midrange is so involving and palpable, the lack of equal force in treble makes it seem a bit dark overall, but as one increases the volume, this becomes less of an issue, and poorly-recorded music is much more tolerable at higher volume.

The sound is rather addicting in its presentation and can even be called delicious in what it does well, kind of reminiscent of biting into a ripe peach. The line dividing “colorful” and “colored” is thin, and while K75-10 likely leans a bit to the latter, I quite enjoy its substantial sound and prefer it to the thin, plasticky sound many other capacitors represent."

 

[lsantista]

First pic with the bigger (0.47) mundorf silver supreme I saved from the phono stage on the 8550 pre.. it didnt fit the 8900 by a smudge, the board underneath didnt let all close in. Had to swap to the Audyn Copper Max 0.1
Other upgrades include silver solders, Allen Bradley / Dale resistors and a few capacitors; Im not the builder. I did buy a wrong potentiometer and furutech NFC plugs that also wouldnt fit.
Am playing mostly with speakers with some good new 300B but already tested with the HD800 and wow!! Also will need to test with the supposedly better NOS 2a3. Will need much more time with it for burn in and to further compare with my beloved CFA3. However, this is 220v and the 8900 is 115v, so a side by side is really unlikely in the short term

 

[xneakers]

Maybe. Not sure what he planned to accomplish with the upgrade but perhaps he was chasing a certain type of sound and not necessarily a better performing amp on paper. Personally, if I had the means to afford iron like that, I’d just have an amp built from the ground up to maximize their potential but….that’s just me.

Likely... Quite interesting to see Finemet + Silver combo... Havent seen such, or I'm missing something...

 

[Maven86]

They’re around. The biggest detriment is cost.

 

[JamieMcC]

After nearly eight years of seeing off all contenders and reigning supreme with a system built around them my hd800 have been sat in the corner gathering dust I honestly can't remember the last time I used them.

I swear when I looked at them today they were giving me the evil eye back!

Hifiman HE-6 and TU-8900 have dethroned them.

The king is dead, long live the king....