#1
So I scored a triple Mica GE JG-5751 with an O getter that tested almost new.. for $20 shipped

I thought I'd play around with it in my JCA100H.. what should I expect from this tube soundwise? and what does the "JG" stand for?
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[thread="1166208"]Gibsons Historic Designs[/thread]
Last edited by Flux'D at Jan 3, 2012,
#2
JG is a military part designation. Like all good military designations, it is an acronym for two more acronyms - JAN and GE. JAN is Joint Army Navy (they developed the specs), and GE is General Electric (made the thing).

As for tone - it depends on a bunch of factors, probably too many for a real reliable description beforehand. They're excellent tubes, though, and after a little break-in it ought to sound great. People tend to think of 5751s as slightly lower gain tubes because they're often advertised as such, but in most cases they're interchangeable with modern 12AX7s in that category. You'll probably notice a little less shrillness in the highs, and overall a slightly rounder tone. Best way to know for sure is to use it, though.
#3
Quote by Roc8995
JG is a military part designation. Like all good military designations, it is an acronym for two more acronyms - JAN and GE. JAN is Joint Army Navy (they developed the specs), and GE is General Electric (made the thing).


GE is actually an initialism, not an acronym weeeeeeeeeeeeeeeeeeee
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#4
^I knew GE was the manufacturer (General Electric) and I figured the JG was a military designation but didn't know if it was an acronym for something or not. EDIT: I had to reread Roc's post, so it's an acronym of an acronym and "initialism" . Interesting

I knew they were "70% of the gain" of a regular 12ax7 but didn't know the tonal characteristics of such. Taming the highs a bit would be a great addition to the JCA, with my Flying V through it the amp has a ton of high end bite to it
Endorsed by Dean Guitars 07-10
2003 Gibson Flying V w/ Moon Inlay
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[thread="1166208"]Gibsons Historic Designs[/thread]
Last edited by Flux'D at Jan 3, 2012,
#5
They're billed as 70% of the gain but it really doesn't sound like it. There's a much bigger difference to me between a 12AT7 and a 5751 than a 12AX7 and a 5751, and AT7s are supposedly around 60% of the gain of a 12AX7. I won't pretend to be able to hear percents of gain, but to me a 5751 is a more civilized sounding 12AX7, whereas a 12AT7 will change the headroom and feel of an amp a bit.
#6
^Thanks for that, it should be an interesting tube to play with then. I'm planning on snagging a few more vintage tubes and picking up a few JJ's as well before the day is over, thanks for the info
Endorsed by Dean Guitars 07-10
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[thread="1166208"]Gibsons Historic Designs[/thread]
#7
Stick it in and tell us how it sounds

j/k

Good stuff in here:

http://www.google.com/#pq=jg+5751&hl=en&cp=8&gs_id=b&xhr=t&q=JG+5751+ge&pf=p&sclient=psy-ab&source=hp&pbx=1&oq=JG+5751+&aq=0j&aqi=g-j1&aql=&gs_sm=&gs_upl=&bav=on.2,or.r_gc.r_pw.,cf.osb&fp=2f0b188327e19041&biw=1843&bih=959

including tidbits on what you can expect tonally.

Congrats.

I'd put one in your V1 or Phase Inverter. I think Roc covered it but it will have slightly less gain than a 12AX7 but should be a bit more clear and clean.
Last edited by 311ZOSOVHJH at Jan 3, 2012,
#8
that one has the label printed in green? those are real good ones. the five star gray print ones are nice, but i like the green print GE-JG more.
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#9
Once it arrives I'll definitely be rolling it through the amp haha

It's actually a white label and doesn't have the 5 star thing, but the labels aren't 100% either. On the back it has 62-52, 188?-5 (not sure if that 2nd '8' is an 8 or not) and the GE logo in between the "front" JG-5751 labeled side and the "back".

EDIT: They're gray plates as well, should've included that
Endorsed by Dean Guitars 07-10
2003 Gibson Flying V w/ Moon Inlay
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SVK ELP-C500 Custom

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[thread="1166208"]Gibsons Historic Designs[/thread]
Last edited by Flux'D at Jan 3, 2012,
#10
Finally came in today, pretty nice tube from what little vintage tube experience I have. I think I'm gonna keep it in V1 or V2, though the effect in the PI is nice too. I've got some JJ's coming as well so we'll see after I get them.

In V1 on the crunch: The lows and low mids are backed off but have more clarity to them. The highs are rolled back a bit as well, which is a definite welcome. The distortion of the 100H is smooth and fat and this really adds to it. It seemed to have brought the "grunt" of the amp forward. I can actually roll the treble over halfway and the presence above a quarter without it being too shrill.

Clean: Noticeably less gain and helps to clean up the already gritty cleans on the Jet City. Compared to the Tung Sol Reissue that was previously in V1 this tube is more musical and open for sure. For whatever reason the highs are more pronounced which really bothers me, hopefully the JJ's coming in the mail will tame that.

Verdict: Crunch, its wonderful vs the TS. Clean, would be alright if it weren't for the highs..



Endorsed by Dean Guitars 07-10
2003 Gibson Flying V w/ Moon Inlay
2006 Fender All-American Partscaster
SVK ELP-C500 Custom

1964 Fender Vibro Champ
1989 Peavey VTM60

[thread="1166208"]Gibsons Historic Designs[/thread]
Last edited by Flux'D at Jan 6, 2012,