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Hartke 2500 - intermittent power/volume(?) fluctuations on start up


steve-bbb
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My 2500 head has just developed a wee problem - thought at first it was a fractured dodgy indtrument cable as the problem was affected when wiggling the cable about in the input jack socket but not so sure as it seems to have the same issue with both the passive and the active inputs (usual cab used is a hydrive 4x10)

on first powering up the head it doesnt seem to cut into full power or volume for some several minutes - with both input gain and main vol up at almost max it kicks out a puny amount of volume and power which sounds more like the master volume is on about 1-2

then it will just behave itself and kicks in and all is fine - this problem only started after i decided to hook an extra cab up one evening - namely an ashdown 1x15 - when it promptly failed to play up at its usual power level so i disconnected it and it took about 15 minutes for it to settle down and behave itself - have used an extra 1x15 cab before ( a hartke which i recently sold) so didnt think the [url="http://www.musiciansfriend.com/amplifiers-effects/ashdown-mag-115-1x15-deep-bass-cabinet"]ashdown cab[/url] would be a problem as its an 8 ohm cab same as the old hartke 115XL i used to use regularly)

after it seems to have settled down i leave the power on and it seems to behave for the rest of the evening but is just the first 5 to 10 minutes it seems to have a mind of it's own and not sure what the problem might be - any clues please

thanks

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  • 2 weeks later...

[quote name='barkin' timestamp='1346941262' post='1795107']
Did you manage to crack this ? Just curious, in case my HA2500 misbehaves in the future...
[/quote]

err sort of ..last night at rehearsal it did the same thing on start up and then after about half hour of playing at only half volume it just fizzled out and packed in completely

:o :huh: :( :( :(

edit - ive checked inside and no obvious loose connections or crap solder joints - i also checked my leads and was quite surprised that they were really poorlysoldered and some were dodgy so i stripped them all back and re-soldered them - unfrotunatley this did not seem to cure it - the prob sounded like a component within the amp failing and fizzing out slowly whilst was being played

[b]is it possible that connecting a cab up to a head that if the cab has faults (ie such as wiring/impedance issues) that it can affect the head and cause problems? and if so how easily/quickly could any damage occur[/b]

this problem started the very first time i hooked up a loaned ashdown 15" 8ohm cab (as an extension to my usual 4x10) - i had previously used the head many times successfully with my hartke 4x10 and 1x15 cabs with no probs at all

Edited by steve-bbb
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just been giving it a wee test

switch on and it starts up but at very low intermiitent poower fl;uctuating and distorting
gradually gets slightly louder with occasional spluttering and increasing in power
eventually 'pops' a few times as the power seems to kick in at full level - this seems to take about 10-15 minutes

stays stable for about half hour ish (as it did last night)

left it switched on and went back to it about 20 minutes later again and is back to stage 1 again crackling and distorting but this time because it has been on some time and probably reached some sort of working temperature range it cuts into full power much quicker - this time in about 30-60 seconds

:(

edit - just found this [url="http://www.talkbass.com/forum/f15/help-multiple-broken-hartke-ha2500-heads-445012/"]http://www.talkbass....0-heads-445012/ [/url]

and also this from t***bass ...the shame! :o
[i]A friend and I bought our Hartke 3500 MOSFET's in 1992 and they are both still going strong and problem-free today. Another friend bought one used (of the same vintage) six years ago that had an intermittent problem where it would drop in volume slightly, then jump back up. It turned out to be a bad solder joint on one of the power transistors that had cracked due to normal heating/cooling, because the joint had been weak to begin with. A five minute solder touch-up job repaired the problem and it's run like a tank ever since.[/i]

edit the edit - also found this [url="http://basschat.co.uk/topic/135436-hartke-ha2500-problem/"]http://basschat.co.u...ha2500-problem/[/url]
and checking through what i can at moment

edit.... just checked two different speaker cables both good

the two speaker outs on the back of the amp though, one feels nice and clean when plug inserted however the other fells a bit 'off sorts' like something slightly out of place inside it - however the problem is exactly the same regardless of which speaker out is used

Edited by steve-bbb
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That's a pain :(

Have you tried the effects loop send/return? Might give a clue as to if it's the pre or power stage? Also, IIRC those sockets have some kind of switching arrangement - might be worth giving 'em a dose of switch cleaner and giving them the beans with a jack plug.

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  • 4 weeks later...

[quote name='barkin' timestamp='1347301809' post='1799103']
That's a pain :(

Have you tried the effects loop send/return? Might give a clue as to if it's the pre or power stage? Also, IIRC those sockets have some kind of switching arrangement - might be worth giving 'em a dose of switch cleaner and giving them the beans with a jack plug.
[/quote]

I took it to a local amp specialist and he said it was something to do with those sockets on the small board at the back and that it was internal in the sockets/wiring - apparently they are non-standard hartke spec sockets - albeit regular 1/4 inch - but not sockets that you can replace from maplins

is working a treat now

note to self - must check to make sure both preamps and master are not maxxed and the EQ maxed and the contouring maxxed before testing it!! :crazy:

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