#1
Hey guys,

My JCA22h is still packing the stock Chinese tubes and it's about time I try something better and see how that affects the overall sound of the amp, specially since is not that expensive to do so. I play a lot of Metallica, 80's metal and rock and Mastodon.
So I know a lot of people have experimented with changing tubes on this particular amp, therefore I did a little research to see the general opinion. I was just hoping that you guys could help me make a final decision.
The tubes schematic on the amp is:

V1a Shared Crunch/OD
V1b Crunch
V2 OD
V3a Shared Crunch/OD
V3b Cathode Follower
V4 Loop
V5 Phase Inverter

In the PI the 12ax7-lps seems like a given but in the others I don't know what to go for. A 5751 or a 12at7 in the V1 seems to add headroom and clear the amp a bit, which could be useful if it makes it easier to get cleans on the crunch channel as long as it doesn't remove too much gain on the drive channel since I'm using high gain often, although I don't usually get past 6~7. Most people seem to like that and think it still packs more than enough gain. Apart from that something I did see mentioned a lot is that I should stay away from JJ's on the V1 because it will get muddy. The amp has a thick loose bass and is overall a bright amp and sometimes the top end can get indeed overwhelming and fizzy, so I'd like to tame it a bit a remove some harsh frequencies to turn it more pleasant and round sounding without loosing bite. What say you?
Last edited by RuiGuitar at May 28, 2017,
#3
JJ's are overall the best brand of tubes you can buy that aren't NOS. Saying one brand of tubes is too muddy is kinda silly. Tubes are not always made consistently due to the nature of their construction and it depends far too much on the particular amp in question and how it is being run to make a sweeping generalisation about how one brand of tubes sound.

If you want a brighter amp that has more headroom, replace the 12AX7 in V1 for a 5751.

If the amp is still too loose in the low end and still doesn't have enough gain, it sounds like you're the perfect candidate for a tubescreamer-style overdrive pedal set up as a clean boost.
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#4
T00DEEPBLUE Actually I'm already running a Boss sd-1 in front of the amp and I'll be ordering an EQ anytime soon also, so I'm just curious about how changing the preamp valves affects the overall tone. About JJ's getting this particular amp muddy and dark was just the general opinion I got when searching on the topic.Just pointing that out. Most people that had tried JJ's on V1 didn't like it. Basically I'm just wondering what's the big difference between brands, since I'm already set on getting something like this:

V2 JJ 12ax7
V3 JJ 12ax7
V4 JJ 12ax7
V5 Sovtek 12ax7lps

For V1 I'll probably order both a 12ax7 and a 5751 and see what suits me better. Also, the JJ ECC83 is pointed out like a good choice to tame overly bright amps, which I guess the JCA22h is, so it means it'll get rid of harsh high frequencies and eliminate fizz?
Last edited by RuiGuitar at May 28, 2017,
#5
Quote by RuiGuitar
T00DEEPBLUE Actually I'm already running a Boss sd-1 in front of the amp and I'll be ordering an EQ anytime soon also, so I'm just curious about how changing the preamp valves affects the overall tone. About JJ's getting this particular amp muddy and dark was just the general opinion I got when searching on the topic.Just pointing that out. Most people that had tried JJ's on V1 didn't like it. Basically I'm just wondering what's the big difference between brands, since I'm already set on getting something like this:

V2 JJ 12ax7
V3 JJ 12ax7
V4 JJ 12ax7
V5 Sovtek 12ax7lps

For V1 I'll probably order both a 12ax7 and a 5751 and see what suits me better. Also, the JJ ECC83 is pointed out like a good choice to tame overly bright amps, which I guess the JCA22h is, so it means it'll get rid of harsh high frequencies and eliminate fizz?


You could always ask one of the tube places (Tube Store, Tube Depot, Tube Doctor, etc...) recommends if you want to compare brands.

https://www.tubedepot.com/t/tubes/tube-sets-by-amp

As a counter argument to the other post up here, in my experience some tube brands are muddier or brighter than others when used with a certain amp or guitar.  Not all tubes are created equal.  12AX7s are cheap enough that you might want to purchase 3 or 4 and compare them.  In an amp like the 22 the V1 slot will have the most impact, so try out different options there, and the ones you don't like in V1 put in the other slots (they'll have less of an impact).
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#6
8Len8 I'm located in Europe actually. Right now my checklist looks like this:

x4 JJ 12ax7
x1 Sovtek 12ax7lps
x1 JJ 5751
x1 Sovtek 5751

The Sovtek 12ax7lps is set in the V5 and since V2,V3 and V4 doens't seem to make much impact I'll get the cheap JJ's. Then it all comes down to comparing the JJ 12ax7, the JJ 5751 and Sovtek 5751 in V1. Anything else I should be aware of? Am I buying too much?

Ps: What is a good place to buy in Europe? I'm looking at tube town right now.
Last edited by RuiGuitar at May 28, 2017,
#7
I have no idea about buying tubes outside the US. Most guitar amp forums have a list of good tube dealers like this:

https://www.thegearpage.net/board/index.php?threads/online-tube-dealer-sticky.1197164/

You might be over thinking things. In high gain amps I don't think tubes have as big an impact. I'd just start out with a variety and fine tune it over time.
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#8
Quote by 8Len8
I have no idea about buying tubes outside the US.  Most guitar amp forums have a list of good tube dealers like this:

https://www.thegearpage.net/board/index.php?threads/online-tube-dealer-sticky.1197164/

You might be over thinking things.  In high gain amps I don't think tubes have as big an impact.  I'd just start out with a variety and fine tune it over time.

Yeah I guess I am. Can't help it  

that's actually useful, thanks!
#9
Tubes have a huge impact on my little single ended amps not sure how much they affect something like you have. In my experience 5751's and au7's are a bit mellower (to much so for me) and JJ ax7's have the most hair. Tighter and crisper then anything else I've tried. Mullard and tung-sol were the closest to each other in tone and range. EH was right in the middle between JJ and Mullard which is what I ended up in the power section in both my amps el84 and 6v6. I'd like to say try a few, but that's going to be expensive for you.
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#10
scott58 People claim it is a must in this amp, however still haven't had the opportunity to try and see/hear for myself. Yeah I'll just order a few a try them.

Another question about opening the amp up. In order to remove the front panel I know I need to start by unscrewing the back grill out. Then I need to stick my hand in there to reach the screws, so is there anything there that I shouldn't touch? Only the two transformers are popping out. 
#11
Shouldn't be any problems. I unplug from a power source when I change tubes, but I'm working with the simplest of amps. Maybe check out a few YouTube videos to be more comfortable with it.
Dean Icon PZ
Line 6 Variax 700
Dean V-Wing
Dean ML 79 SilverBurst
MXR M 108
H2O Chorus/Echo
Valve Junior (V3 Head/Cab and Combo)
VHT Special 6
Phonic 620 Power Pod PA
Wampler Super Plextortion
Line 6 Pod HD