Re: Why no headphone jack on tube amps?

Charmed Snark wrote:

On 28 Jun 2007, "David Martel" <marte005@xxxxxxxxxxxxx> wrote in
alt.guitar.beginner:


Snark,

Using a power soak, I call it a dummy load,


Ya, I think "Power Soak" was a brand name (still?). I had one about 25 years ago, but yes, essentially it is a dummy load.


Some one posted about a Peavey amp with a headphone feature but
complained that the tone was poor. I suspect that losing the
speakers' contribution to the tone will require some sort of
dedicated EQ circuit for the headphones.

Dave M.


Well, it's not just freq response (which is what EQ can adjust for), but that the speaker's physical characteriscs and motion colours the sound (both in the air, and to some effect this gets reflected back into the final stage of the amp).

....and now that it appears that there IS a voltage dropping resistor, we also have the complication that there's 100 ohms in series with the headphones. This will really mess with the distortion characteristics of the power tube, it'll sound different. It'll also lower the output level. And you will also risk flyback voltages, punched insulation in the OPT, and arced tube sockets if you crank it. I think it's a bad design.


Obviously any reflected
"electronic influence" also to some extent flavours your power amp distortion and sound qualities.

But at the end of the day, what you have to determine is whether it is "good enough". At this level you'll have many people in disagreement over what is good enough. But your opinion is the only one that counts here. ;-)

First and foremost is the safety of the finals in the amp (a suitable load). Second is the sound level in your earphone jack.

The best way to settle it for yourself is to simply borrow a dummy load, and wire up an external jack arrangement (get 3 jacks and just wire it up without a box). This will give you the power level you want in your earphones by suitable choices of resistor. Just watch out for the power level of your resistors (5 to 10W should be plenty good for earphones, assuming a good choice of resistance values used).

Then if you like it, you can house that in a little box. Have 1 speaker input jack, a dummy load jack and a earphone jack. If you want to get fancy you can add a monitor jack for recording purposes (again, some suggest this ain't good enough for recording, but I beg to differ, until I try it for myself ;-)

Snark.

.

Relevant Pages

  • Re: Why no headphone jack on tube amps?
    ... I think "Power Soak" was a brand name. ... 25 years ago, but yes, essentially it is a dummy load. ... Second is the sound level in your earphone jack. ...
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  • Re: Why no headphone jack on tube amps?
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