RD 112-65 Popping/crackling in High Power mode
Inherited an RD 112-65 (1980 model) from a friend. Cool amp. I have original speaker but currently has an eminence RWB in it...
Sounds great in low power mode, but when switched to high power, it makes a bad pop/crackle sound.... Any ideas before I break down and take it to a tech?
Member for
11 years
Member for
11 yearsA little more info is needed
Sorry for the late reply....
The noise you say you are getting - is it there even with no signal? If so does the level vary with either of the gain and/or volume controls? If the noise is not there with not signal, popping and general "blargh" sound is often associated with the drive transistors in these amps. If the resistors on the tube sockets are bad, and I agree with Mike "210" that these can cook over time simply because of heat exposure, the noise would be there in both hi and lo modes.
Anyway, I hesitate to speculate further until we get more info. There are numerous troubleshooting avenues to go down with a bit of guidance.
At least we can be fairly certain that your OT is good - that's one of the more expensive items to replace.
Cheers,
Lars Verholt
Member for
11 years
I HAVE seen them crackle only
I HAVE seen them crackle only in high mode but like Lars says, it probably shouldn't. The other thing that might crackle is plain old dirty tube sockets. Again, they SHOULD do it on both but the high side does present extra challenges to dirt. Wiggle the hell out of the tubes and see if THAT'S the crackle. Just wiggling them is usually enough to clean them unless they are badly corroded. Besides, it doesn't cost anything! Mike.
Just a wild ass guess but the
Just a wild ass guess but the old carbon comp resistors on the tube sockets COULD be cracked, bad. Just a wild guess but they DO go bad over time when exposed to the heat. Mike.