| | Distortion issue - SVT 4 Pro
Hey All, new here and could use some of your knowledge on my head. I did a search and have found nothing with the same symptoms that I'm experiencing. If there is a thread and i missed it I do apologize:
SVT 4 PRO head with Ampeg 8x10e cab - Running Mono with XLR wired +1 +2 on head side. Plenty of power*
I run no affects, just plug in and go with a korg rack tuner running through the tuner out input.
Warwick Standard Corvette 5 with passive pups/ active aguilar preamp.
Corvette Proline 4 active MEC.
I've had this rig for a year now, purchased used, and had it dialed in and sounding amazing. In the last month I've had a issues with faint noises and distortion coming through. It suddenly sounds "farty" and clippy, at times much like a blown speaker but not constant and not as bad. I removed the cloth grill and tried to locate the speaker(s) but it is faintly in all, and all the same. This leads me to think its a issue with the head.
I tried swapping out the preamp tubes with 12ax7s (new) my guitarist had on hand, the sound was the same.
I have tried running a cord in the return/send (mono) effects loop as I've heard dirt and grime can get in there causing unwanted noise. No change in sound.
One thing that I believe is new that I've noticed on my head (if you have a pro 4 and active bass maybe you can plug in and help me out here) is that the gain light flashes at all times no matter the level of gain. Gain on 0 and light flashes when picking with my active controls on, on my bass at full volume. If i turn down the bass/treble active controls it won't do this.
I believe this may be the cause of my unwanted distortion, but don't have enough knowledge about amps to know what this means, if anything (as i know that light functions more as a signal light rather than a clipping light).
It could be that I never noticed it before, but I doubt it as I set my gain to flash solidly when I accent riffs with heavy picking, then adjust my master volume for desired output.
The previous owner took the head into a tech complaining about low output levels. All voltages tested correctly and soldering points were sound, as i suspected he did not have the cable wired +1 +2.
Due to this I got a good price on the rig, but now I wonder if he may have done some damage to the head by not having the speaker cable wired properly.
Any input would be greatly appreciated. Or any trouble shooting tips I may have overlooked/failed to find.
This is the second time I've posted about this. I didn't recieve a reply last time, but I'm hoping I explained my situation better in this post.