Making A Headphone Jack, Fender Princeton 65

[wgpguy]

Just picked up a Fender Princeton 65 (price was right, $80 in good condition). The one thing I don't like is that there is no headphone out jack. Being a college student living in a dorm, it's not very polite to use an amp above a whisper. I have decent experience with electronics.

Would it be as simple as using the Pre-out (signal from the pre-amp) and then solder a switch to the speaker to turn it off? I'm mostly concerned with putting the switch there, any chance of doing damage?

[curtisa]

Using the pre out may work OK. However, there are a few caveats:

It won't sound like a guitar amp - you'll lose the natural high frequency roll-off that the speaker introduces, so it will sound very bright and harsh in the headphones, especially with distortion.

The preamp out may not have enough drive capability to push a set of headphones, which may introduce problems of it's own in terms of further tonal ugliness, distortion or (worst case) destruction of the preamp out stage through continued overloading of the poor little chip feeding the headphones. If you can feed the preamp output into something thats designed to drive a set of headphones (eg stereo, mixer) it'd be better.

Using a switch to disconnect the speaker in a solid state amp should be fine, just make sure that anything you put in there doesn't have a chance to short onto any surrounding metallic parts or circuitry.

Although you may find that plugging something into the preamp output automatically interrupts the signal on the way to the power amp until you complete the external loop into the "pwr in" socket. Try plugging an un-terminated lead into the "pre out" or "pwr in" sockets and see if the speaker cuts off.

Edited June 4, 2008 by curtisa

[Tim37]

you might try a power Attenuator just run make a output on the back of the amp and run a 1/4" jack for a quick hookup then you can just buy an the right headphones 4,8,16 ohms

[mammoth guitars]

Curtis is right, without filtering it will not be such a great sound in the headphones. However, use regular headphones and put a series 32 ohm resistor on the speaker output to the headphone jack. Wire the jack so it disables the speaker when you plug in the headphones ie no need for an extra switch. Neutrik jacks make it real easy.

We have added external speaker jacks to the Frontman amps and the headphone jack mod is nearly the same with just the added resistor.

[wgpguy]

Thanks guys.

The speaker does cut out when something is plugged into the "pwr in", so I assume I can just pop in a 1/4" plug without it being connected to anything and safely cancel out the speaker sound?

I would be using my aviation headset, Telex 150 ANR, I don't know if having something like that would make a difference over regular headphones. I haven't had a chance to try it because they are in the plane and I haven't gone to get them yet. The impedance is 150 ohms mono, 300 stereo.

From what Curtisa has said, I gather that it would be best if I did 1/4 to 1/8" from the pre-out and then into a stereo system and then use the headphone jack on the stereo system? That shouldn't be a problem to do.

Edited June 5, 2008 by wgpguy

[curtisa]

From what Curtisa has said, I gather that it would be best if I did 1/4 to 1/8" from the pre-out and then into a stereo system and then use the headphone jack on the stereo system? That shouldn't be a problem to do.

Yep, that'll do nicely. Be prepared for it not to sound too special though for the afore mentioned reasons.