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?).

Wasn't that the Scholtz model that was notorious for bad contacts on the switch and using only power resistors (unfriendly to many higher powered vintage amps)?


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

It's the fact that there is an impedance curve, and the fact that an output transformer reflects that impedance back to the output tube plates as different loads at different frequencies.



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.

I'd be wary of using a non reactive dummy load on high powered amps, and I'd use a dropping resistor then maybe a wire wound or L-pad for volume adjustment on the headphones. That way, you adjust for amp tone, then set your headphones volume to the tone (instead of possibly having to BLAST your ears before you hit power tube crunch).
.

Relevant Pages

  • Re: Why no headphone jack on tube amps?
    ... I think "Power Soak" was a brand name. ... I had one about 25 years ago, but yes, essentially it is a dummy load. ... The best way to settle it for yourself is to simply borrow a dummy load, and wire up an external jack arrangement. ... a dummy load jack and a earphone jack. ...
    (alt.guitar.beginner)
  • 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. ...
    (alt.guitar.beginner)
  • Re: Marshall 6100 problem?
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    ... GFX-65 uses audio taper in volume control potentiometers so this is ... The power amp uses voicing configuration that is based on current ... About the external speaker jack: There is indeed an external speaker ...
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  • Re: Tubes
    ... dropped the speaker voltage to a line level " ... A line out isn't the best solution, because you won't get any power tube distortion. ... " Since your amp is cheaper than many pedals, ... " FORGET headphones with this amp, unless you buy a good dummy load! ...
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