Dodgy EQ

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   Hi, i bought a duel 30 eq from ebay, when i plugged it in it put a huge hum into the signal chain, when i pressed the eq in buttons one channel worked and one channel went quiet but still worked a bit, i tried again later and both channels went quiet when introduced but the hum seemed less, i took it apart and gave it all a spray and clean, one channel is perfect no colour no hum, sounds very nice to be honest, this is the channel that initially did not work, the channel that worked initially now goes quiet when introduced, strange, any help or suggestions would be great, cheers guys.

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concept-10 Members Profile Send Private Message Find Members Posts Add to Buddy List Young Croc Joined: 17 May 2016 Status: Offline Points: 1293	Post Options Post Reply Quote concept-10 Report Post Thanks(0) Quote Reply Topic: Dodgy EQ Posted: 12 June 2016 at 12:09pm
	Hi, i bought a duel 30 eq from ebay, when i plugged it in it put a huge hum into the signal chain, when i pressed the eq in buttons one channel worked and one channel went quiet but still worked a bit, i tried again later and both channels went quiet when introduced but the hum seemed less, i took it apart and gave it all a spray and clean, one channel is perfect no colour no hum, sounds very nice to be honest, this is the channel that initially did not work, the channel that worked initially now goes quiet when introduced, strange, any help or suggestions would be great, cheers guys.

concept-10 Members Profile Send Private Message Find Members Posts Add to Buddy List Young Croc Joined: 17 May 2016 Status: Offline Points: 1293	Post Options Post Reply Quote concept-10 Report Post Thanks(0) Quote Reply Posted: 12 June 2016 at 1:40pm
	Update, the big hum is back, both channels now working but very loud, the channel that worked fine had no discernible volume change when set at 0db and taken in or out of the chain, now both channels set at 0db will increase output massively when introduced, confused.

Earplug Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 03 January 2012 Location: Europe Status: Offline Points: 7216	Post Options Post Reply Quote Earplug Report Post Thanks(0) Quote Reply Posted: 12 June 2016 at 1:49pm
	What eq is it? I´d just send it back.
	Earplugs Are For Wimps!

concept-10 Members Profile Send Private Message Find Members Posts Add to Buddy List Young Croc Joined: 17 May 2016 Status: Offline Points: 1293	Post Options Post Reply Quote concept-10 Report Post Thanks(0) Quote Reply Posted: 12 June 2016 at 1:53pm
	It cost next to nothing so i'm not that stressed about returning it, but i would like to fix it.

mini-mad Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 13 July 2012 Location: london Status: Offline Points: 6903	Post Options Post Reply Quote mini-mad Report Post Thanks(0) Quote Reply Posted: 12 June 2016 at 2:27pm
	start from the top.... is the psu inside well regulated?.... is the dc coming out of it iratic?
	If it sounds like a gorilla is trying to escape, turn it down.

Earplug Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 03 January 2012 Location: Europe Status: Offline Points: 7216	Post Options Post Reply Quote Earplug Report Post Thanks(0) Quote Reply Posted: 12 June 2016 at 4:23pm
	Ok, understood. +1 on the PSU. Check the earthing and filter caps. Most hum will come from there.
	Earplugs Are For Wimps!

concept-10 Members Profile Send Private Message Find Members Posts Add to Buddy List Young Croc Joined: 17 May 2016 Status: Offline Points: 1293	Post Options Post Reply Quote concept-10 Report Post Thanks(0) Quote Reply Posted: 12 June 2016 at 4:50pm
	Thanks, i will measure it first.

djkeet Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 26 December 2011 Location: England Status: Offline Points: 462	Post Options Post Reply Quote djkeet Report Post Thanks(0) Quote Reply Posted: 12 June 2016 at 5:27pm
	Have you eliminated connectors and leads as being a cause?
	Soundbite

concept-10 Members Profile Send Private Message Find Members Posts Add to Buddy List Young Croc Joined: 17 May 2016 Status: Offline Points: 1293	Post Options Post Reply Quote concept-10 Report Post Thanks(0) Quote Reply Posted: 12 June 2016 at 5:47pm
	[QUOTE=djkeet]Have you eliminated connectors and leads as being a cause?[/QUOT I think so, i have disconnected everything, given it a spray and clean, every time i touch it it seems to change, strange. I'm going to strip it down again, it is a Rocktorch gr60, made in England but no info on the net at all, when one channel was working, it was very good, so i do want to repair it, i will put up some photos. cheers.

concept-10 Members Profile Send Private Message Find Members Posts Add to Buddy List Young Croc Joined: 17 May 2016 Status: Offline Points: 1293	Post Options Post Reply Quote concept-10 Report Post Thanks(0) Quote Reply Posted: 12 June 2016 at 5:50pm


concept-10 Members Profile Send Private Message Find Members Posts Add to Buddy List Young Croc Joined: 17 May 2016 Status: Offline Points: 1293	Post Options Post Reply Quote concept-10 Report Post Thanks(0) Quote Reply Posted: 12 June 2016 at 8:26pm
	Measured psu and all seems ok

concept-10 Members Profile Send Private Message Find Members Posts Add to Buddy List Young Croc Joined: 17 May 2016 Status: Offline Points: 1293	Post Options Post Reply Quote concept-10 Report Post Thanks(0) Quote Reply Posted: 12 June 2016 at 8:28pm