Hartke Amp input jack?

[filthyPierre]

Hey,

With Brisbane weather putting the kybosh on my guitar painting I'd scheduled for last weekend, I decided to pull apart a Harkte GT-100 combo amp that a mate gave me a few years ago. I'd used it sporadically as the input jack was wobbly, so I thought I would have a go at seeing if I could fix it.

Not an easy thing to dismantle, it looks like the main board is put in the chassis first, then everything else put in around or on top of it. So that means pulling literally everything out of the chassis just to get the main board so I could desolder the input jack.

So here it is:



You can see it's not quite right. But better than I thought it would be. Nevertheless, I emailed the Electric Factory, who are the Aussie agents for Hartke, asking if I could get a new jack for it. Their answer was a one-liner: "That amp is superceded, parts no longer available". Probably didn't even check, the reply was that quick. Surely that type of jack is used on other Hartke amps as well...

By the look of it, it's not a standard part that Jaycar would stock (already checked, nothing in their website stock looks remotely like it).... but I will probably go down there this weekend and try anyway.

Apart from the ground and live/signal there are two other terminals that are shorted together when there's no plug inserted, and open when there is. From the schematic (snip below), looks like they are used to short the input to ground.



There appears to be enough room for me to put a standard 1/4" jack in the front panel and run fly leads back to the board. Easy enough. But wondering about the implications of not having that short in place when there's no plug inserted. I can only assume that the short is to eliminate spurious noise when there's no cable plugged in, but I could be wrong.

Anybody seen one of these plugs before? Or know where I could get one?

Cheers,

Pete

[andrewdosborne]

I have exactly the same problem with an old Eden 2x10 cab. The 1/4 inch input jack connection is loose and needs to be wobbled to maintain connection from amp. I opened up the guts, almost the same jack as yours soldered onto a small circuit board. I have not removed the input jack from the board yet and am now thinking of upgrading it somehow to a speakon style input jack as a replacement for the old Eden cab appears impossible to source... I'll keep you updated on any findings...

[filthyPierre]

Well, dunno why I didn't try this in the first place, must be the weather (yeah, I'm sticking to that).. googled "guitar amplifier parts" and came across www.amplifiedparts.com

This => https://www.amplifiedparts.com/produ...der-amps-88-99 is an exact match to my jack, same measurements, same pinouts, even labelled the same. So problem solved. LOL. Thanks for reading anyway.

Andrew, try this mob, they may have what you need.

Cheers,

Pete

[andrewdosborne]

Thanks Pete you are a legend I’ve spent hours searching for this part. My Googling skills need some practice lol


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[Simon Barden]

Just to answer the 'what would happen if I used a standard jack" question, yes, you'd just get noise until you plugged a cable in and into your instrument.

I've swapped to using cables with a Neutrik 'silent jack' at one end (with standard Neutrik jack at the other end and Van Damme cable in the middle). No more hum or clunks when unplugging or plugging the lead into your guitar/bass and I've found them 100% reliable. There are some cheap jack sockets that seem to have a slightly shorter length of arm for the tip connection which means the jack body is held slightly away from the edge of the socket - and there can be issued with the collar on the silent jack not being pushed back enough to break the ground connection and let the signal through - but I've only found this on one guitar.

[armchair_spaceman]

pardon the thread dredge but damned glad I found this.

[DrNomis_44]

You could quite easily replace that original input socket with a standard 1/4 inch one and solder it to the circuit board via wires, what I would do is solder a 1M/1% metal film resistor between the Tip and Sleeve connections of the 1/4 inch socket before soldering the wires to it, that way the noise level when nothing's plugged in will be reduced, Marshall and Fender usually include the 1M resistor on the inputs of their amps, using a 1M/1% metal film resistor means that the input signal will see a light load while at the same the input will still be grounded when nothing's plugged in, the best of both worlds.