goingdownslow Posted May 4, 2019 Share Posted May 4, 2019 (edited) I have a Hartke Kickback combo which I have had since new in 2001. I've never had a problem with it until recently when it has started to make loud crackling noises when I'm playing. What is doing my head in is it won't do it at home. I have the head unit opened up and I've poked around whilst playing, tapping on the circuit board, poking wires and components to no avail. When setting up at the gig it is ok, then into the first number it starts. It seems to be keeping up with the drums which makes me think it is a bad/dry joint somewhere but I can't locate it. It is not anything else in the chain as last week after it kicking off in the first number I swapped over to a backup head using all the same leads into the same speaker and there were no problems. Right now I have the amp set up at home, same settings from the gig, and I'm playing through it whilst a mate thumps on the cab with a rubber mallet (stop laughing at the back) and it is behaving itself. Any suggestions how I can trace this fault? Edited October 10, 2021 by goingdownslow Spelling. Quote Link to comment Share on other sites More sharing options...
itu Posted May 4, 2019 Share Posted May 4, 2019 As it is so old, I would check possible connections between the pre and power amp. This unit does not have an FX loop but there is a headphones connection. Check it out and at least clean it. Some deoxidizer may help. Quote Link to comment Share on other sites More sharing options...
ped Posted May 4, 2019 Share Posted May 4, 2019 My money is on a dry solder joint. I’ve had a few HA3500 heads in the past (they’re excellent!) and two had the same problem. It was fixed at the time by my amp guy but I’m afraid I didn’t remember where the joint was but it must have been fairly obvious. Its a well known and documented issue with these amps I think. Quote Link to comment Share on other sites More sharing options...
Mottlefeeder Posted May 4, 2019 Share Posted May 4, 2019 I have a PDF circuit diagram for a 2005 HA 1200 which shows no plug/socket connections between pre and power amps, but all 120 watts pass through the headphone switching contacts. That would be my starting point. With regard to the more powerful amplifiers, I have had both a Samson and a Hartke with intermittent faults that turned out to be the output relay. This one doesn't have an output relay. David Hartke Kickback HS1200 schematic.pdf 3 Quote Link to comment Share on other sites More sharing options...
goingdownslow Posted May 4, 2019 Author Share Posted May 4, 2019 Had a poke and fiddle with the headphone jack whilst playing and couldn't get it to crackle but I've now given the socket a spray with contact cleaner and inserted a jack multiple times. As I said I have not been able to replicate this fault at home and Tuesday is the next time it will be used in a band setup so I will have to wait and see. Quote Link to comment Share on other sites More sharing options...
MoonBassAlpha Posted May 6, 2019 Share Posted May 6, 2019 Best of luck! Quote Link to comment Share on other sites More sharing options...
goingdownslow Posted May 8, 2019 Author Share Posted May 8, 2019 Back to the drawing board. No crackling on setting up no matter how hard I play but soon as the first number starts it goes crazy. Quote Link to comment Share on other sites More sharing options...
itu Posted May 8, 2019 Share Posted May 8, 2019 So what is different? Something beside your equipment? Something different connected to your equipment? Ground loop? Wireless systems? Quote Link to comment Share on other sites More sharing options...
Phil Starr Posted May 8, 2019 Share Posted May 8, 2019 If this is consistent fault as you describe then there are two things to investigate. It could be increased volume at gigs or something else you are using at the gigs but not at home. I have a kickback and find once you use it with a drummer it struggles with volume, I get round this by backing off the bass a little on the eq. The amp seems capable of driving the speaker beyond it's excursion limits. When you change to a different head you won't have an identical response and that may be what is curing the problem. It could be as simple as a fault you only get on tilting the amp if you play one way at home and another at a gig. I've had problems with Hartke and soldered joints too again in the HA3500. Mine turned out to be in the power supply but high volumes and vibration will find the problem if there is one. A crackle though implies a connection problem, that could be anywhere from your kettle lead all the way back to the mains and anywhere in the signal chain from your bass through all the leads and any fx you use. It could also be radio frequency pickup. anything from a mobile placed near to the amp, someone else's dicky equipment in the band or any number of things. Hope you track it down Quote Link to comment Share on other sites More sharing options...
goingdownslow Posted October 10, 2021 Author Share Posted October 10, 2021 (edited) Update. A couple of weeks back I helped someone on TB in regards to removing the circuit board from this amp as he wanted to change the input jack socket. It had me thinking that mine is 20 years old and a new socket would not go amiss and I would give the board a fresh look at finding the fault. On removing the old jack socket I noticed this.... I have used it since at an outside event and it performed flawlessly. Edited October 11, 2021 by goingdownslow 3 Quote Link to comment Share on other sites More sharing options...
neepheid Posted October 11, 2021 Share Posted October 11, 2021 Glad you got it sorted. I wish I had seen this back in the day - I would have suggested the headphone jack replacement route. A few years ago my amp would regularly and seemingly randomly mute itself (although it happened more when things were loud). Worked out that plugging a jack in and out of there a few times would provide temporary relief. Eventually I replaced the jack socket and the problem was solved. No obvious damage like the one which came out of yours but it was one of these types: When the headphone jack is plugged in, it breaks the contacts shown and sends the signal down the headphone jack instead of passing it through to the speaker and the ground lift is detected by the amp and lights up a mute LED (which was very handy in piecing together what was happening). My guess is that the socket was cheap as chips and the contact(s) had lost their spring and were lifting away causing interruptions in sound and the LED to come on. Haven't had a problem since I replaced the socket. Quote Link to comment Share on other sites More sharing options...
rmorris Posted October 11, 2021 Share Posted October 11, 2021 5 hours ago, neepheid said: Glad you got it sorted. I wish I had seen this back in the day - I would have suggested the headphone jack replacement route. A few years ago my amp would regularly and seemingly randomly mute itself (although it happened more when things were loud). Worked out that plugging a jack in and out of there a few times would provide temporary relief. Eventually I replaced the jack socket and the problem was solved. No obvious damage like the one which came out of yours but it was one of these types: When the headphone jack is plugged in, it breaks the contacts shown and sends the signal down the headphone jack instead of passing it through to the speaker and the ground lift is detected by the amp and lights up a mute LED (which was very handy in piecing together what was happening). My guess is that the socket was cheap as chips and the contact(s) had lost their spring and were lifting away causing interruptions in sound and the LED to come on. Haven't had a problem since I replaced the socket. As it happens I have a similar thing on a Marshall guitar combo' that I recently got free with no loudspeaker (it has one now). Not stopping the amp working but it doesn't short the input as intended with nothing plugged in so it stays a bit noisy. Yes - I can see that while it handles the jack plug okay, it doesn't have enough 'spring' to short when no plug there. It's actually a 'stereo' socket configured to also short some internal points - presumably to stop the OD channel boosting internal noise when there's no input. Obvs not much use when the socket has lost its zing ! Pain to replace because of all the pcb pots etc that mount to the front panel and another socket - 'Aux Input' or similar has the same problem. So I'm thinking to do a bit of metalwork and put in panel mount sockets in parallel. Quote Link to comment Share on other sites More sharing options...
Sheait Posted October 21, 2023 Share Posted October 21, 2023 Hi All, I’ve got a Hartke HA1200 that has similar symptoms to yours Goingdownslow, only mine has the issue all the time. I get a fuzzy crackle sound and sometimes it cuts out altogether. Headphone output works perfectly. Did your jack fix work? Thanks! Quote Link to comment Share on other sites More sharing options...
goingdownslow Posted October 21, 2023 Author Share Posted October 21, 2023 (edited) 43 minutes ago, Sheait said: Hi All, I’ve got a Hartke HA1200 that has similar symptoms to yours Goingdownslow, only mine has the issue all the time. I get a fuzzy crackle sound and sometimes it cuts out altogether. Headphone output works perfectly. Did your jack fix work? Thanks! Replacing the input jack socket completely solved my problem. The headphone jack is fed from the same power amp output as the speaker jack but also contains a switch that disconnects the speaker jack. I would try some Deoxit sprayed in the headphone jack and insert a plug several times to try and clean the switch contacts, and check it for any cracks like I found on mine. Edited October 21, 2023 by goingdownslow spelling Quote Link to comment Share on other sites More sharing options...
Sheait Posted October 25, 2023 Share Posted October 25, 2023 Update Amp got worse before i could get the spray, now only working from the headphone Jack. No output from the speaker. Tried the Deoxit spray and no change. I did it 3 times as recommended (short burst, headphone jack in and out several times leave it 2 mins ) - no joy. I've got a headphone jack on order, so will try that next. @goingdownslow is this similar to the one you used? https://www.ebay.co.uk/itm/184174490058 Quote Link to comment Share on other sites More sharing options...
goingdownslow Posted October 25, 2023 Author Share Posted October 25, 2023 (edited) 1 hour ago, Sheait said: is this similar to the one you used? https://www.ebay.co.uk/itm/184174490058 No. The type you need is this... I bought half a dozen from China for around a fiver. I'll check my mail to see if I can find where from. Edit - Have you checked for loose connections elsewhere... speaker jack, speaker connections? Edited October 25, 2023 by goingdownslow Quote Link to comment Share on other sites More sharing options...
goingdownslow Posted October 25, 2023 Author Share Posted October 25, 2023 I'd bought them on eBay but the link is now broken. I had a quick search but could not find any other than Hartke Amp Parts. Quote Link to comment Share on other sites More sharing options...
Sheait Posted October 26, 2023 Share Posted October 26, 2023 Any chance I could buy one off you ? I've looked for the part number and the only place selling them doesn't ship to the UK !! Obvs, I'll pay shipping too. Quote Link to comment Share on other sites More sharing options...
goingdownslow Posted October 26, 2023 Author Share Posted October 26, 2023 10 hours ago, Sheait said: Any chance I could buy one off you ? I've looked for the part number and the only place selling them doesn't ship to the UK !! Obvs, I'll pay shipping too. Message me your address and I'll try and sort one out. Quote Link to comment Share on other sites More sharing options...
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