#1
So i decided to try different tubes in my ADA MP-1 since i think the tubes in it were original. I bought two JJ ECC83S and two Tung sol 12AX7 to try out different combinations. However after changing the tubes the sound was noticeably weaker. It had a lot less gain with same preset than the original. When i switched the old ones back everything was normal.

I also tried to clean the tube sockets but that did not help. I am not expert with tubes but i think it should not sound that much different compared to old tubes. Any ideas what problem might be?
#3
yeah thats what i thought too but they seem to light up normally and no burn marks or anything so i am quite confused.
#4
Quote by dlhf
yeah thats what i thought too but they seem to light up normally and no burn marks or anything so i am quite confused.


Switch 1 in at a time and see if a new one is bad.
Quote by DeathByDestroyr
See, it's important that people clarify when they say "metal", because I pretty much always assume they are a Cannibal Corpse fanboi.
#5
From http://voices.yahoo.com/when-replace-vacuum-tubes-5693728.html?cat=33...


"Bad power amp tubes will glow excessively bright and hot, while bad preamp tubes will not glow at all."

"If the tubes are structurally sound and have a normal, warm glow, the next step is to check for microphonics, the characteristic tubes display when they amplify external vibrations which act upon the bulb itself. Take a pencil (or similarly soft, slender wooden rod) and gently tap each tube in the preamp section (small tubes). If the tapping noise comes out of the speakers, then the tube is normal and "healthy". A bad tube will emit a bell-like ring when tapped, and should therefore be replaced. Check the power tubes in the same manner.""
#7
thanks for help, will switch them around when i get back home tomorrow
#8
I'm not sure how old your ADA MP-1 is, but there is a chance that the old tubes were jus better tubes, too

I mean, if they're older American or even European made tubes, then those have much better build and sound quality than anything modern.

Definitely check to make sure it's not a bad tube first, though, as that's much mroe likely. Out of curiosity, what tubes were originally in it?