Elekit 8600 as Headphone amp: Making the good better
Aug 5, 2020 at 11:25 PM Thread Starter Post #1 of 2

scottme

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Hi all,

TLDR: Exploring modding the Elekit TU8600 to make it a better headphone amp.

An Elekit 8600S (Lundahl) is on the way to me. My current gear is Oppo105 => Headamp GSX2 => Audeze LCD 3 and Abyss 1266 phi CC.

The GSX2 is excellent and provides a nice preamp function for my Yaqin amp. It is just powerful enough to drive the 1266 at max 2W balanced out (a bit flat unbalanced). It is extremely fast, but perhaps on the cold side. I very much like the vacuum tube sound, and would love to be able to afford a Woo Audio WA33....

Some other amps considered (USD):
Little Dot LDY2 ~ 3700 (balanced)
Original OPA-3A ~ 2400 (balanced)
Cayin HA-300 ~ 4000 (balanced)
Woo Audio WA22 > 2000 (balanced)
Woo Audio WA5LE > 3700 (balanced)
( I see a trend here :) )

So why the TU8600? The 8600 has an excellent reputation (some say better than equiv. Woo gear), including the right amount of solid state (rectifier/choke) and tubey goodness to optimise the musical experience. It will hopefully provide more warmth to my headphone experience, and drive the 1266s with more authority. It will be my first 300b amp, while learning lots on the way (have built other tube amps).

I have enough knowledge to be dangerous, but some of the more indepth electrical theory is beyond my ability at this stage.

So, how could we make the 8600 even better (beyond the standard parts upgrade)? Is it worth the time/$/effort? The 8600 has a good SE headphone out with switchable impendance, but I beleive the output power may not be enough to get the best from the 1266s (maybe good for the LCD3 100omhs though)

Overall:
Compared to the WA33, the 8600 is SE all the way. Theory says that in general, SE sounds inferior to balanced - competing amps certainly think so. So is it practical or desirable to add balanced inputs / outputs to enhance the signal without compromising its musicality in any way?

INPUT:
Would it be worthwhile wedging a balanced => SE input board to the rear panel? The cable runs are short (<1m).

Example board (no affiliation):
https://connexelectronic.com/product/balanced-input-phase-shifter/

OUTPUT:
An easy and sensible mod is adding a switchable output on the rear to the 8ohm speaker outs and a 4 pin xlr connector. Theory (see below link) says that 8 ohm speaker outs are a nice match for the 1266's 60ohm impedance, while providing way more than enough juice to satisfy the 1266's power hungry drivers in the linear range. There are reports of a very pleasing result doing this.

https://www.headphonesty.com/2019/0...ers,likely create audible playback distortion.

Would adding an SE -> balanced out circuit off the output secondaries (8ohms) provide the ultimate 8600 + 1266 listening experience? Is this even possible at up to 5W?

Apologies for the short novel, but would really appreciate any thoughts on this topic. Cheers!
 
Aug 7, 2020 at 1:01 PM Post #2 of 2

HiGHFLYiN9

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For the input, you'd need to add a pair of transformers/resistors for the balanced input and isolate the XLRs from the chassis and run that to a 4-pole potentiometer, and then the circuit probably has plenty of ground references linking both channels rendering it a spurious use of time anyway. Balanced is a nice feature, but there really isn't any value to be derived in trying to shoehorn it in a circuit that wasn't designed for it. There are plenty of good sounding single-ended amps out there like the Linear Tube Audio MicroZOTL 3. I'd take that over plenty of balanced amps. I'm sure the 8600S is better than quite a few balanced amps as well.

FYI the Cayin HA-300 is also very good if you decide to upgrade. It's more traditional warm sounding than the MicroZOTL which is very neutral. Different strokes for different folks.
 

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