AudioCircle
Audio/Video Gear and Systems => Headphone Mania => Topic started by: viggen on 8 Jan 2017, 08:01 pm
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I got a spare desktop tube amp (APPJ) that I'd like to hook up headphones to the speaker taps. I recall seeing some boxes selling on ebay that has speaker line inputs on the back and a headphone output on the front. I cannot find anything like that anymore.
Is there anything like that on the market?
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Adapter plug.
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Two important questions first:
Are your headphones wired up with a 4-pin XLR?
Does your tube amp have a shared ground on the negative terminals?
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Headphone will most likely be 3.5mm. And, amp only has banana out. 1 black and 3 red for each channel so, yes, ground is shared.
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Usually speakers amps are too noisy for a good hp, sound will be compromissed.
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Ok wait, there's 3 red taps per 1 black? ok so this is a transformer or autoformer coupled tube amp then. There's extra considerations that must take place. And no, that's not a guarantee that the output blacks have a shared common ground; you'd have to doublecheck with a multimeter.
In this scenario though, the best thing to do is reterminate your headphone to a 4-pin XLR "balanced" configuration and keep left and right completely separate. You will also want to to slap a resistor across the outputs to protect the amp. Really, something like this is the simplest boxed solution:
http://hifiman.com/products/detail/84
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Thanks that's what I am looking for but was hoping for TRS input instead of XLR for flexibility. But, perhaps I can get a headphone with detachable cables.
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Unless you know with absolute certainty that your amp's negative terminals are a shared ground, you should never connect a TRS jack to your amplifier. Connecting a 3-pole device to a potentially 4-pole device is a recipe for magic smoke.
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Also some output amp circuits cant be bridged.
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Ok wait, there's 3 red taps per 1 black? ok so this is a transformer or autoformer coupled tube amp then. There's extra considerations that must take place. And no, that's not a guarantee that the output blacks have a shared common ground; you'd have to doublecheck with a multimeter.
In this scenario though, the best thing to do is reterminate your headphone to a 4-pin XLR "balanced" configuration and keep left and right completely separate. You will also want to to slap a resistor across the outputs to protect the amp. Really, something like this is the simplest boxed solution:
http://hifiman.com/products/detail/84
those 3 red taps mean for loading at 16 ohm ,8 ohm and 4 ohm .
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http://www.zynsonix.com/Speaker-Amp-to-Headphone-Converter-Box_p_36.html
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http://www.zynsonix.com/Speaker-Amp-to-Headphone-Converter-Box_p_36.html
a bit expensive.
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In this scenario though, the best thing to do is reterminate your headphone to a 4-pin XLR "balanced" configuration and keep left and right completely separate. You will also want to to slap a resistor across the outputs to protect the amp. Really, something like this is the simplest boxed solution:
http://hifiman.com/products/detail/84
I've used this box with good success with my MiniWatt amp (very similar if not identical to your APPJ amp). Great pairing for the hard to drive HE-5LE from HiFiMan.
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http://www.zynsonix.com/Speaker-Amp-to-Headphone-Converter-Box_p_36.html
There is a DIY version:
http://www.diyaudioblog.com/2015/06/speaker-amp-to-headphone-converter-box.html
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Even with the DIY version, do not build it unless you know with absolute certainty that your amp's negative terminals are a shared ground.
These converter boxes are basically just L-pads that merge the negative terminals together. Be aware that this will also potentially pooch your output impedance. Depending on your headphone, this can affect the frequency response.
edit: for all the hooplah, you can also just buy a proper headphone amp for cheaper than a converter box
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+1. HP works in the few miliVolts range, some speakers amps volume pots dont have the fine mV tuning need for a hp.