Help please. My Hartke HA3500 is sick

Discussion in 'Amps and Cabs [BG]' started by zombie1965, Mar 27, 2016.

  1. Ok so this issue started a few months ago around last september and is getting worse. My head is a HA3500 and is about 10-12 years old. Its been a great amp and is well used.

    When the issue started it presented itself as an intermittent low volume crackle that wold ride on the back of certain notes down the lower end of the fret board. At first It only seemed to happen with my passive bass plugged into the passive input jack and I put the problem down to the bass. I spent an evening replacing the Pots, jack and Capacitor (I thought this was the issue)and re wiring in my bass. and at next practice all seemed solved.... for an hour or so.....then the issue returned.

    I switch to another bass, an active one and plug it into the active socket and all seemed OK.

    Bamboozled by my issue, I continued playing that active bass for a few weeks while trying to solve the problem with the passive jack.

    I took the lid of the head and checked the connections on the jack, they all seem good. Just for good measure I cleaned out the inside of the chassis with an airline and changed the tube for a brand new 12AX7 Groovetube.

    Still the problem persisted with the passive channel.

    We had a few gigs over the Christmas period and I continued with the active channel and active bass with no issues then we had a long break with January and February off.

    First rehearsal this year first week of march, I plug in the active bass and noticed that crackle is present, much like when i first noticed it on the passive channel. I had another cab available, so just to confirm this is the head I plugged in the other cab. The problem persists. I also retried the passive bass, its that bad the amp sounds very sick indeed. I am 100% sure the issue is with the head.

    I have also noticed that when a loud guitar strum is played on a different guitar this can cause a low level crackle on my amp from across the room.
    The crackle seems unaffected by changes to ether the pre amp settings, compressor or EQ but is louder with louder volume settings.

    So i'm asking for help to identify where my problem lies.

    The issue is present on the above video at 4:05 -4:20 ish and again 5:03 Ish

    I'm guessing a bad solder joint somewhere, are there any known week areas? are theses prone to failing with age?

    A bad cap maybe?

    Dodgy transistor?

    Anyone Able to take a stab?

    I have gigs approaching and really need this Damn think back up and running.

    Thanks in advance.
    Last edited: Mar 28, 2016
    Mistahbenn likes this.
  2. If your head has an FX loop, take a short patch cable and insert it into the send and return (complete the loop).

    If this fixes your problem, then the contacts in your FX loop jacks need to be cleaned (it is a common problem as oxidation builds on the contacts).

    ETA - an amp as old as yours probably needs a good cleaning of all the input/output jacks as well as the pots. A little "preventive maintenance" could have her back up and running.
    B-string and zombie1965 like this.
  3. Wow thanks for the quick reply, I shall give that a go in the morning.
  4. No problem.

    Re-read my post above as I added new info.

    Use a product like Caig Deoxit sparingly and work the cable in/out a couple of times.
    zombie1965 likes this.
  5. Check that all equipment is well grounded. Leave nothing to chance. Even if you think it is OK, you don't know for sure until you know for sure. And even then...
    Does this happen at different venues?
    Are you and the guitar that you mentioned connected in some way. Like are you both plugged into a P A system?
    zombie1965 likes this.
  6. I do clean the input/output jacks on quite regular basis with compressed air and switch cleaner, but as I don't really use the FX loop often i have perhaps overlooked them. Its a little to late to try your suggestion at home now, close to 10pm with adjoining neighbors, but I will try in the morning and see what happens.

    Bass_Pounder likes this.
  7. Raf Seibert

    Raf Seibert

    Dec 16, 2013
    Unfortunately, it's precisely because they're not used that the effects loop jacks develop corrosion. Fortunately, they're easy to clean.
    Growlmonkee and zombie1965 like this.
  8. Yes this happens no matter the venue, but the problem is intermittent in that I might get an hour with no issue that it starts, or it might go away after some minuets of playing and return later.

    We are not connected in any meaningful way but we are sharing Electricity supply.

    We both have vocal mics that connect to the PA sometimes he has a mic placed in front of his cab and on the rare occasion i am DI'd into the desk. I really don't know for sure if the crackle sound is sent to FOH via the DI from the head as its rare that we need to send me forward. Usually its just a bass>bigmuff>synth>head>cab set up. I don't recall a gig in the last few months where we have had to send a line from my cab to PA.

    We both share power from a breaker board that I put together years ago. Its Just a couple of RCD units protecting a couple of electrical sockets mounted to a board with a flax and plug to plug it in.

    I will check all the earthing/grounding arrangement in the morning too.
    I did have a tickle from a mic a few gigs back but i am guessing that was crappy venue wiring.

  9. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
    Have you considered having the amp serviced by a tech who understands logical signal flow troubleshooting, and has the proper test equipment to do the job properly?

    Guessing is rarely a successful (or cost effective) troubleshooting method.
    Shortie, Mugre, Growlmonkee and 6 others like this.
  10. Mic tickle is bad. Be sure all your cables are good and that all wall outlets are grounded as well as your homebrew breaker board. The mic is grounded by the cable plugged into an amp, which is grounded by the ground wire in the power cable which gets its ground from whatever power distribution system you have. That in turn is grounded by its connection to the building wiring. Anything wrong anywhere along the way and you can get mic tickle, or worse.
    zombie1965 likes this.
  11. This will certainly be my next step if my efforts tomorrow are unsuccessful, I live in a rural part of the Uk, a good hour from the nearest place to find an amp tech. and i'm sure my amp would be away for a while in this instance. I do have a back up but i Don't realy like it much and its perhaps a bit under powered.

    I am an Electrical engineer by trade, so i'm not shy to have a bit of a go. Electronics is not realy my forte but i'm confident/competent enough to try some basic troubleshooting.

    cheers though, I wont mess round with anything i am not comfortable with.

  12. I will definitely re check. I have a PAT tester and checked all our gear Back in August. but wont hurt to re check. I bet it was the venue though, It had some dodgy looking cabling going on. :woot:
  13. madbass6

    madbass6 Inactive

    Jan 13, 2009
    I do not give consent to use any of my photos ! please respect that. thank you.
    10 12 years old ! Sorry to be the one to inform you, but it looks like its time for a new amp dude !
    murphy likes this.
  14. I was waiting for that one.

    I guess your right but i'm not in a position to do that right now. I have a hankering for an SVT classic and, well, I have not got the spare £.

    Maybe if I can temporary fax this amp, the threat of it being on its way to the knackers yard will prompt me to save for the new one.
  15. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
    Just follow good troubleshooting procedures and it should be pretty straight forward.
    zombie1965 likes this.
  16. madbass6

    madbass6 Inactive

    Jan 13, 2009
    I do not give consent to use any of my photos ! please respect that. thank you.
    It will probably cost more to repair that one then just picking up another used one.(Same one) gd luck..
  17. Pilgrim

    Pilgrim Supporting Member

    This makes no sense. A 10 to 12 year amp is not a candidate for replacement unless there is a major problem, and maybe not then if it's repairable. My 1967 Bassman has had the caps replaced and that's about it. There are tons of 20+ year old amps working fine.
  18. B-string

    B-string Supporting Member

    If you have the Caig DeOXit on hand there are several connector bundles between pc boards. Remove them one at a time and treat with DeOXit and run the connector on and off a couple times. I have seen this be an issue with the HA3500 and other amp heads from the same make and other makes. IIRC the input jacks are on a separate pc board so treat those interconnects as well.

    It hasn't even reached High School age yet.
  19. Thumper19605


    Jun 29, 2013
    The only think that ever failed on mine was the tube, it effects both channels.
    When the tube blows the amp does not work at all.
    Replaced the tube, still working for many years!
    Good luck!
  20. CodyGBass


    Mar 27, 2016
    Sorry that this doesn't help you but I have the same head and have difficulty getting a good sound out of it. Could you please tell me how you have the controls set? Thanks.
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