Ceriatone Forum

British Style => 18 Watt => Topic started by: Drew_D on August 04, 2009, 06:08:42 PM



Title: 36 Watt Squeals when Vol and Master dimed
Post by: Drew_D on August 04, 2009, 06:08:42 PM

 I have this 36 watt that squeals when the Master and Vol knobs are both dimed.  The squeal starts at about 8 on either knob when the other is dimed. 

Is there a fix for this or is it the nature of the beast. It sounds great otherwise.


Title: Re: 36 Watt Squeals when Vol and Master dimed
Post by: hywelg on August 04, 2009, 09:08:07 PM
If you have the EF86 version then it'll be that valve. Very prone to microphonics. Had the same in my Dc-30. You need a Mullard EF86, never get any problem with that valve.


Title: Re: 36 Watt Squeals when Vol and Master dimed
Post by: Drew_D on August 04, 2009, 09:38:08 PM

 It's not the ef86 version.
Funny thing is I have several NOS Mullard EF86's laying around doing nothing right now.
Maybe after I get this problem sorted out I'll add an ef86.  ;D 


Title: Re: 36 Watt Squeals when Vol and Master dimed
Post by: Alpedra on September 20, 2009, 09:15:11 PM
So... did you find out what was the problem?


Title: Re: 36 Watt Squeals when Vol and Master dimed
Post by: Drew_D on October 02, 2009, 10:53:37 AM
I took it to my tech in Florida. He said the phase inverter circuit was overloaded causing ocsillations. He changed the master vol and vol pots to lower values and the problem went away.