Bought a second hand ENGL Blackmore. ESP guitar with EMGs & an ISP Decimator. Played it three time with band rehearsing & I'm seeing the following get worse (was ok first time)...
1. Real loss of gain - it's a higg gain amp with active pickups & I'm needing to crank gain to 10 to get even a classic rock sound.
2. Screech/squeal - any sort of volume from guitar on high gain & I get this ear piercing screech. Basically unplayable. Not feedback - I can get 'real' feedback but going close to amp & then if I increase gain or volume the screech kicks on over the feedback.
3. Intermittent sort of interference on the tone.
Squeal only happens on high gain channel - also tried two guitars & same issue. Other guitar had passives.
Bought on Ebay & no return possible, so obviously need to get this fixed. Is it the tubes? Seller said it was a about 5 yr old (mint condition) but hardly played for about 2-3 yrs.