Headphone out on Rouge Audio Sphinx

Tdogzthmn

Active Member
I have the Sphinx v2 from Rouge and love it with my speakers, however I've felt that the headphone out on the amp leaves much to be desired. I'm wondering if anyone else who owns a Sphinx also feels the same.

I own several pairs of headphones which I enjoy using on occasion and was excited to have an integrated amp with headphone out. Unfortunately I've felt that the sound and gain from the headphone section isn't much different than my laptop. I find that I need a lot of volume to achieve normal listening levels and the signal clips a lot when turned up. My primary headphones are the AKG K400 (120ohms) and the K240DF (600 ohms).

Its disappointing because the speaker outputs sound fantastic and have plenty of power.
 
It would sound to me like the Rogue is using a separate op-amp to drive headphones as opposed to the regular amplifier going through voltage reducer or whatever those things are called. There's a few things you can do. Feed a separate headphone amp from the 'fixed' output on the back. To drive the headphones off the speaker taps you can buy or make a headphone tap. It's basically a collection of resistors reducing the signal enough so that headphones can operate off of it. A company with a strange name, Vinyl Flat, makes one called the Can Opener. It's relatively inexpensive. Is your Rogue a tube output or solid state output? If it's tube then you just have to be careful about not connecting a voltage reducer without a set of headphones plugged in. You don't want to turn on a tube amplifier without showing it a load, and that can do that.

I have the K401(120ohm) and the K240M (600ohm). My new low end Yamaha receiver drives both fine because the design of the receiver includes a voltage reducer already, basically feeding the headphones from the same internal amplifier as the speakers. My dedicated headphone amp drives them fine as well, but finding one of those isn't always cheap? When mine was still in production it was retailing for $400.

If money was no option, I'd probably buy a Woo Audio single ended amp for about $800 for the headphones alone. But you know how money and wants go.

Vinyl Flat Can Opener on Steve Hoffman: http://forums.stevehoffman.tv/threads/the-can-opener-passive-headphone-jack.313867/

I don't know how I feel about this guy naming this after himself, but it includes schematics and instructions: https://robrobinette.com/RobinetteBox.htm#Instructions_

A more expensive one: http://www.zynsonix.com/Speaker-Amp-to-Headphone-Converter-Box_p_36.html with a blog about it's construction http://www.diyaudioblog.com/2015/06/speaker-amp-to-headphone-converter-box.html
 
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I have a Bottlehead SEX 2.1 amp for my headphones that sounds amazing with headphones so I'm covered.

Mostly I was just dissatisfied with the headphone out on the Sphinx since the amp is great overall.
 
A speaker switcher and a cheaper box would be a great way to give the Sphinx a whirl with headphones then.
 
Doing more reading real quick. So the Sphinx uses a tubed preamp and a Class D amp. That's great for speakers but it does also mean that the headphone output on the amp itself is absolutely a separate opamp.

I have read that some Class D amps have common grounds. I don't know much about amp construction, but attaching a headphone converter box and a pair of headphones to an amp with a common ground could be trouble.

I would contact Rogue before trying. :(
 
Thanks for the suggestion, I might just reach out to Rouge to get a better idea of the headphone circuit and its capabilities.
 
Thanks for the suggestion, I might just reach out to Rouge to get a better idea of the headphone circuit and its capabilities.

Were you ever able to get in touch with Mark at Rogue? I agree with your assessment with regards to the headphone jack, and before I do any more research I thought I'd see if you could offer any enlightenment.
 
Were you ever able to get in touch with Mark at Rogue? I agree with your assessment with regards to the headphone jack, and before I do any more research I thought I'd see if you could offer any enlightenment.

Never got in touch with Rouge as I have since sold the amp and moved on to another. Overall the rouge was great but for the price I would have liked a better functioning headphone output and lower noise floor.
 
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