Kaiju for headphones

[PT]

Hello there,

There are a lot of this discussed but not too much definitive answers,
Lets say one wants to run headphones from Kaiju.. just to know how 300B sound on various headphones, abyss diana, Hd800, Lcd5 etc.. quite easy to drive.

What is the best output inpedance wiring? Or best would be to build a rotary selectot swich, 2 ohm for high, 16 ohm for low impedancd etc.
Could there be a recommended resitor impedance+watage value for easy to drive headphones?

Please let me know so I avoid popping some drivers just out of curiosity ;-)

[Doc B.]

Kaiju is intended to run loudspeakers. It will need the DC filament supply installed to be quiet enough for headphones. Wire the output transformers for 2 ohms output and be VERY careful with the output level. You might want to set the level trimpots very low to help protect your headphones from being overdriven. If you blow up your cans it's on you.

[PT]

Risks well understood!
Should I add a resistor across the terminals to increase working load on the amp, or this is not beneficial?

[Paul Joppa]

...
Should I add a resistor across the terminals to increase working load on the amp, or this is not beneficial?

Try it and see! It's a cheap experiment, after all. You can wire some resistors to dual-banana plugs and  just insert or remove them. I'd suggest 2 ohms  and 8 ohms as suitable starting values - assuming you wire the transformers for 2 ohms, as Doc B suggested. A 10-watt rating should be adequate.

It will have some audible effect, likely more on imaging and dynamics than on frequency response.

[PT]

Thanks on the support,
So 2 Ohm output wiring and assortment of large resistors accross the +\- speaker outputs to try.
Volume pot low, I guess best is to test the output voltage (with resistor load) before trying anything, just to be on the safe side.

If power hungry cans are used (K1000, AB1266) I would wire the output for higer resistance, yes?

[Paul Birkeland]

K-1000s work well with the output transformer wired for an 8 ohm load.

[thoven0215]

Besides having more power, how would it using it compare to a mainline or a stereomour with the same upgrades? I am planning to buy one of these amps, and I can't quite make a decision.

[Doc B.]

The Mainline is our top line headphone amp. It's designed to be optimal for headphones. The other amps are not specifically designed for headphones. If you want to hear 300Bs as you initially posted you should work carefully with the Kaiji. Ditto 2A3s and the SteremourII. If you want our best headphone amp rather than wanting to hear 300Bs with your headphones as your priority I would recommend Mainline.

[Paul Birkeland]

To add to what Doc says, the primary reason you'll see folks using the 2A3/300B products with headphones is if they have something power hungry like the K1000.  If you have super sensitive headphones then the Mainline will work a bit better.

[johnsonad]

Just my two cents.  I've done this and wrote about it.  It sounds great but the C2A makes me happier (sounds better to my ears) and the Kaiju went back to speaker duty. Haven't heard the Mainline in my system but I love the C2A for headphones and the Kaiju for speakers.If you have the cash, build all three.  Many on the forum rotate through depending on what they are listening to. 

[PT]

Have followed the advice and have built the Mainline and its very good match for Utopias, Abyss Diana TC.  It even makes my old German Maestro/MB Quart GMP400 sing. Have tried to hook up BeePre2 preamp in between my DAC and Mainline, just to experiment, however, judging from a short listening session, prefer the Mainline hooked up directly. I hope to finish my Kaiju built during the weekend and hook up the AKG K-1000, there should definitely be an improvement, as Mainline is running out of steam for K1K's even at 0 dB setting, HOWEVER after hearing the Mainline I don't believe 300B's can surpass the Mainline Magic on the "Standard power requirements" cans, not even considering the risk of popping headphones on the Kaiju.

Thanks for great advice Bottlehead team.