#1
I decided to give my JCA50H a full retube last week.

After doing some research, I went with, a JJECC803 for V1, JJ ECC83S for the rest of the pre-amp section (balanced for the phase invertor), and JJ 6l6 for the power section. This seems to be what most people are recommending online.

Right away I noticed that my amp sounded like someone threw a thick blanket over my cab. It sort of sounded like the amp had not life (to my ears anyways). I know everyone says that JJ's are a darker sounding tube, but I had no idea they would affect the tone that much.

I messed with my EQ settings a bunch, and the only way I could get the amp to sound close to what I like, is by using my 10-band eq.

I have some old tubes lying around, so I did a bit of experimenting. I ended up pulling the JJ's out of v1-v3 and putting the stock Chinese tubes back in. I tried a tungsol 12ax7 as well, but like the Chinese a little better. I found the tungsol to be a tad bright (which I expected).

I'm just wondering if anyone has any experience with the JCA series, and could recommend me something else to try? Or better yet, does anyone know where I can buy more of the Chinese tubes? I emailed Jet City to see if they sell them, or can tell me where to get them (still waiting on a reply).

Also, when I rebiased my the amp, I found that when I initially turned my probe on, the bias was set at 13.3mA, which is quite a bit lower then the recommended 30-35mA. I'm just curious if this normal for an amp being biased for the first time after leaving the factory? This was the first time I ever biased my own amp, so I wasen't really sure what to expect. Just seemed exceptionally low to me.


Thanks!


SP
Guitars:
PRS Custom 24
Gibson Les Paul 60's Tribute
85' MIJ Strat
97' Snakepit Les Paul
LP Traditional 1960 Zebra
MIJ Tele
MIA Strat

Amps:
Silver Jubilee 2525
Peavey Ultra 112
Jet City JCA50H
66' Bassman
Pink Paisley Princeton RV
74' Vibro Champ
#2
It is normal for the bias to be low from the factory. They do it to be 'safe' and have the tubes last longer.

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#3
What speakers are you using? Cab? Configuration? Etc
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#4
I have a mesa 212 with a crex and v30, and I have a randall with 212 legends and a 115 legend.
Guitars:
PRS Custom 24
Gibson Les Paul 60's Tribute
85' MIJ Strat
97' Snakepit Les Paul
LP Traditional 1960 Zebra
MIJ Tele
MIA Strat

Amps:
Silver Jubilee 2525
Peavey Ultra 112
Jet City JCA50H
66' Bassman
Pink Paisley Princeton RV
74' Vibro Champ
#5
Quote by red.guitar
I have a mesa 212 with a crex and v30, and I have a randall with 212 legends and a 115 legend.


I have the same Randall cab and love it.

I had a jca50 for a few days didn't change the tubes. However it wasn't friendly with v30 iirc
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alright "king of the guitar forum"


Quote by trashedlostfdup
nope i am "GOD of the guitar forum" i think that fits me better.


Quote by andersondb7
youre just being a jerk man.



****** NEW NEW NEW!
2017-07-07 2017-07-07 Update and a Chat On Noise Constraints *** NEW FRIDAY 7/7
2017-04-13 RUN AWAY from COMPUTERS!!! TCE? RANT ALERT!!!
2017-03-02 - Guitar Philosophy 1001- Be Prepared For the Situation (Thursday 2017-03-02)
2017-02-21 How to Hot-Rod the Hell of your Stratocaster for $50! (Tuesday 2017-2-21)
Resentments and Rambling from a Guitar Junkie
---> http://trashedengineering.blogspot.com/
#6
Quote by trashedlostfdup
I have the same Randall cab and love it.

I had a jca50 for a few days didn't change the tubes. However it wasn't friendly with v30 iirc


I usually use my randall with the jca. I love the legends.

I actually quite like the v30s with it as well. I put the crex in with the v30 to smooth out the top end, and fill in the low end.

To be honest, I think the amp just sounds insane when I use both cabs at once. The speakers really compliment each other. I just feel 2 cabs is a bit excessive live, so I mainly use the randall.
Guitars:
PRS Custom 24
Gibson Les Paul 60's Tribute
85' MIJ Strat
97' Snakepit Les Paul
LP Traditional 1960 Zebra
MIJ Tele
MIA Strat

Amps:
Silver Jubilee 2525
Peavey Ultra 112
Jet City JCA50H
66' Bassman
Pink Paisley Princeton RV
74' Vibro Champ
#7
i haven't tried them in a jet city, but tungsol pres are normally a bit brighter than JJs. you'd want to check if they're ok in a cathode follower slot, though (i'm not even sure if the jca has a cathode follower... i guess so, but )

not sure about the power tubes. obviously this is of no use, but JJ 6v6es were fairly bright, i thought. JJ 6L6es may be similar? or not.
I'm an idiot and I accidentally clicked the "Remove all subscriptions" button. If it seems like I'm ignoring you, I'm not, I'm just no longer subscribed to the thread. If you quote me or do the @user thing at me, hopefully it'll notify me through my notifications and I'll get back to you.
Quote by K33nbl4d3
I'll have to put the Classic T models on my to-try list. Shame the finish options there are Anachronism Gold, Nuclear Waste and Aged Clown, because in principle the plaintop is right up my alley.

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Presumably because the CCF (Combined Corksniffing Forces) of MLP and Gibson forums would rise up against them, plunging the land into war.

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#8
I'm happy with the JJ 6l6's. Honestly, I couldn't really hear much of a difference between them and the stock tubes.

I guess I likely end up going with tungsol's.

The guys from Jet City got back to me, and they are not able to sell the tubes.
Guitars:
PRS Custom 24
Gibson Les Paul 60's Tribute
85' MIJ Strat
97' Snakepit Les Paul
LP Traditional 1960 Zebra
MIJ Tele
MIA Strat

Amps:
Silver Jubilee 2525
Peavey Ultra 112
Jet City JCA50H
66' Bassman
Pink Paisley Princeton RV
74' Vibro Champ
#9
Has anyone tried Shuguang 12ax7's?

They appear to be the same Chinese tubes that came stock in the amp, but I cant confirm this for sure.

I heard back from Doug from Jet City. He said he's not sure what they put in the amps. The factory that builds the amps supplies the tubes.

I think I just don't like JJ tubes. I re-tubed my AC30 at the same time, with all JJ's, and I'm pretty disappointed with the tone that I'm getting from it now. Again, it now just sound muddy, like theres a blanket over the cab or something.

I think its just the preamp tubes tho. I can't really seem to hear much difference between the old and new power tubes.
Guitars:
PRS Custom 24
Gibson Les Paul 60's Tribute
85' MIJ Strat
97' Snakepit Les Paul
LP Traditional 1960 Zebra
MIJ Tele
MIA Strat

Amps:
Silver Jubilee 2525
Peavey Ultra 112
Jet City JCA50H
66' Bassman
Pink Paisley Princeton RV
74' Vibro Champ
#10
maybe try asking in the tube thread? Or even in the WTLT thread (say I sent you)? I don't think I've tried them but I'm sure some of those guys have. IIRC some of the shuguangs are meant to be good, but (again IIRC) there are a bunch of different generation ones and I'm way out of my depth with them
I'm an idiot and I accidentally clicked the "Remove all subscriptions" button. If it seems like I'm ignoring you, I'm not, I'm just no longer subscribed to the thread. If you quote me or do the @user thing at me, hopefully it'll notify me through my notifications and I'll get back to you.
Quote by K33nbl4d3
I'll have to put the Classic T models on my to-try list. Shame the finish options there are Anachronism Gold, Nuclear Waste and Aged Clown, because in principle the plaintop is right up my alley.

Quote by K33nbl4d3
Presumably because the CCF (Combined Corksniffing Forces) of MLP and Gibson forums would rise up against them, plunging the land into war.

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Et tu, br00tz?
#11
Will do!

I didn't know that there was a tube thread. Where is it located??
Guitars:
PRS Custom 24
Gibson Les Paul 60's Tribute
85' MIJ Strat
97' Snakepit Les Paul
LP Traditional 1960 Zebra
MIJ Tele
MIA Strat

Amps:
Silver Jubilee 2525
Peavey Ultra 112
Jet City JCA50H
66' Bassman
Pink Paisley Princeton RV
74' Vibro Champ
Last edited by red.guitar at Nov 14, 2013,
#12
I'm an idiot and I accidentally clicked the "Remove all subscriptions" button. If it seems like I'm ignoring you, I'm not, I'm just no longer subscribed to the thread. If you quote me or do the @user thing at me, hopefully it'll notify me through my notifications and I'll get back to you.
Quote by K33nbl4d3
I'll have to put the Classic T models on my to-try list. Shame the finish options there are Anachronism Gold, Nuclear Waste and Aged Clown, because in principle the plaintop is right up my alley.

Quote by K33nbl4d3
Presumably because the CCF (Combined Corksniffing Forces) of MLP and Gibson forums would rise up against them, plunging the land into war.

Quote by T00DEEPBLUE
Et tu, br00tz?
#13
you might want to try a new Mullard 12ax7 in v1, I have one in my Marshall and it sound great.


buy a few different 12ax7's and do a little tube rolling.

Yes Shuguang is most likely what it had from the factory.
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