#1
So I just bought a Kustom HV30. I was warned all over the internet the HV series had a horrible preamp tube and they were right. I don't really know anything about them so I don't know what brands are good and what type I want. If I turn the gain (essentially preamp volume) all the way down and crank the SS power amp section it sounds pretty decent, so it seems like a good preamp tube would make a nice amp. As of right now, the gain might as well be called the mud knob. Will pretty much any preamp tube fit? It came with an 12ax7. I'm guessing a name-brand 12ax7 would sound better but I don't really know. I want something with a smoother rounder sound. I use a distortion pedal so I'm not looking for something too strong, just some overdrive that can compliment my pedal. I also have heard that changing pickups isn't worth it on a SS amp, but does that hold true for hybrids? I figured with signal feeding into a preamp tube it would have the same effect. Any info would be great, you guys are always helpful.
#3
Thank you for the link. It looks like a lot of people like those tubes. Now, my amp came with a 12ax7. I can, say, put in a 12au7 no problem right?
#4
You can't always assume a 12AU7 will work as a direct replacement for a 12AX7, they often do but sometimes they just blow up. 5751, 12AT7, 12AY7 are all direct replacements. I listed those in decreasing order of gain (70, 60, 45 - a 12AX7 is 100) and the 12AU7 is lowest of all at 19.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#5
Thanks again. I was thinking of going for a lower gain tube, because my BBE AM-64 gives me a nearly perfect distortion sound for my tastes. I just want a little bit of warm overdrive to add to the pedal from the preamp tube. So, if I get a 5751, 12at7 or ay7 they will definitely go right in and work?
#6
yes
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#7
I just looked and the amp actually has an Electro-Harmonix 12ax7 EH Isn't that a respected name?
#8
EH are ok but not great. They are a bit on the tinny, brittle side. A JJ will give you more mids and a generally warmer (some say darker) tone which I think will sound better in your Kustom.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#10
Well thanks for the advice. Just put in the new tube, sounds MUCH better.