#1
Okay I posted this question in another forum but after almost a week no answer so Ill try here, Ill just post the relevant question first....
.... to my original point, the 'lil 'Champ'600 I procured has a 'Electro Harmonix' 6v6 (which I don't think is stock??), and a unmarked what I assume is a Chinese 12ax7, for the preamp, as I understand the Chinese tubes are stock ?
So basically I am wondering if I should take the plunge and buy a quality Pre tube, some articles say the change in tone will be negligible, if at all noticeable, others say it will become a new amp? Who to believe ?
Thus I thought I could not hurt to get involved her at UG and put this to some other readers.
What are your experiences with tube switchover's,are the Chinese 12ax7 really that bad, the amp sounds fairly decent to my ears.
Any help is really appreciated.
- Mike Latimer.

So to restate, how much tonal difference is there in different brands of pre tubes, should I just wait till the original needs replacing or do you think I should go ahead and throw a better quality 12ax7 in there, to my amateur ears it sounds pretty good ?
Im just looking for honest opinions, so please, you need not worry about hurting my feelings, I'm new to tubes so much to learn I'm sure.
Thanks again.
Mike.
#2
Go ahead and replace! I always replace the tubes in my amps if they are low-grade Chinese.

There are great current production tubes available. I like to experiment with these three:

-JJ EC83 (~$10)
-JJ EC803 (~$15)
-Tung Sol Reiusse (~$15)

JJ's tend to warm up and smooth things out (reduce "fizzy" tones and add richness to the midrange) and the Tung Sol is popular IMO because it is very clear and detailed.

Replacing the V1 tube (the one closest in position to your input jack) will have the biggest impact on tone. So if you don't want to dive in to a full retube, just replace that one. In this case you are in luck... the "plunge" only costs about $10!
Last edited by cGoEcYk at Jan 3, 2014,
#3
Quote by Grais
how much tonal difference is there in different brands of pre tubes, should I just wait till the original needs replacing or do you think I should go ahead and throw a better quality 12ax7 in there, to my amateur ears it sounds pretty good ?
Im just looking for honest opinions, so please, you need not worry about hurting my feelings, I'm new to tubes so much to learn I'm sure.
Thanks again.
Mike.


we won't be able to tell you what you will think of a preamp tube change. such things are highly subjective, hence why you run across a wide range of opinions on the results.

a new 12ax7 costs roughly 15 bucks, i think it is worth it to replace the preamp tubes and see if you notice a difference.
punk isn't dead, it's always smelled that way.

"A perfection of means, and confusion of aims, seems to be our main problem."
-ae
#4
I found a local radio shop that sells used old tubes. I've been trying GE, RCA, and a couple different Jjs (not old) in different slots in my amps and it always seems to make a difference. I've got a GE 12ax7 in my Rebel 20 v1 now, its a bit nastier sounding then the usual jj12at7 that I've preferred in the past. I may go back though. I like variety.
So yeah, preamp tubes are kinda fun to screw around with because they tweak the sound a lil while keeping the overall tone, which I'd assume is why anyone buys any amp.

I'll pass on the advice; start a tube collection and experiment.
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#5
Sounds like good advice, thank all.
Ill grab a couple of different tubes and do a little testing. I am really loving this amp have not really had a chance to take her over 6-7, and I play with a processor in front but it sounds so nice and even, the champ seems to add a really warm 'glowy' effect. Looking for new speaker, I know of th available ones but wouldn't mind experimenting and finding something a lil cheaper, any ideas ?
Grais.
#6
Not all chinese tubes are bad. There are three common types: 12AX7A, 12AX7B and 12AX7C. The last letter denotes generation with chinese tubes. 12AX7C are actually quite decent tubes. 12AX7A are rubbish (which are normally what is used by amp companies as OEM) and the B's aren't a lot better.

JJ 6V6's are excellent for when you want to replace that.
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