Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Solid State Amplifiers => The Newcomer's Forum => Topic started by: somebody77 on November 03, 2009, 07:49:17 AM

Title: amplifier died...
Post by: somebody77 on November 03, 2009, 07:49:17 AM
i have a hartke bass amp, and the last time i was playing, at the end in a hurry i just unplugged it from electricity, forgetting it was at half volume (200 watt) and with switch on. there was a loud bang at the same time i did it and i realised i forgot to turn it off properly.. then i forgot about it and now when i wanted to play, it doesnt give me anything.. (it turns on and all but no sound) i wasnt using it since then so that is the cause i guess only that i dont know what part could be bad? i checked only fuse and tube, they are ok.. any suggestions where should i look to discover the problem? and yes the bang was really loud... but speakers are good.
Title: Re: amplifier died...
Post by: joecool85 on November 03, 2009, 11:41:09 AM
Are you sure the speakers are good?  I would thoroughly test them first before you make that statement.
Title: Re: amplifier died...
Post by: Enzo on November 03, 2009, 11:05:37 PM
Unplugging from the wall and turning the power switch off are the same thing to the amp - the mains power stops.

Please do connect your speakers and the same speasker cord to some other amp and test them.

If your amp is now silent qand the speakers good, then I'd look in the amp for blown fuses.  Does your model have a speaker fuse on the rear panel?  if not, look inside.

What amp do you have?   A 200 watt model?   Turning the volume control to half does not limit power.
Title: Re: amplifier died...
Post by: somebody77 on November 04, 2009, 04:08:39 AM
well the speakers are good i tested them and also plug other speakers to amp and there was still no sound.. the thing is i only found one fuse and that was an incoming voltage fuse.. which is ok, and thats why the amp turns on and seems working.. can there be any hidden fuses anywhere else? i looked but couldnt find any..
Title: Re: amplifier died...
Post by: J M Fahey on November 04, 2009, 09:53:40 AM
Hi Somebody7.
Don't know about the H2000 ones, but their big brothers, the H3500 and H7000's, which I regularly repair, have relay protected outputs. If for some reason your power amp blows or misbehaves, that relay cuts the speaker out.
Play some bass (or an MP3) through it, and check if you have some audio out of the send out (you can plug it into another amp) and/or engage the compression circuit and chech whether the compression light blinks following the music.
Now that you are at it, send some music into the return jack to check it too.
Good luck.
Juan Manuel Fahey
Title: Re: amplifier died...
Post by: somebody77 on November 04, 2009, 10:22:32 AM
thanx for answering, well i tried by playing some mp3 thru it and i got music at the send out and the compression light blinks also.. but the other thing about sending music to return jack i didnt hear nothing anywhere.. so should i consider a bad relay (are those things burning frequently?) at least in my case? thanx
Title: Re: amplifier died...
Post by: J M Fahey on November 04, 2009, 12:06:29 PM
Sorry to say so, but I think you have a very healthy relay (thank God for it, or you would have dead speakers too) and a dead or very sick power amplifier.
The relay is just doing its job, protecting your speakers.
I think the great noise you heard, lasting for a second, was the amplifier sending DC into your speakers and the relay cutting that off.