Mesa 5u4G Tubes Don't Fit

[blazer986]

I picked up some new tubes for my Trem-O-Verb this week (still had the stock mesa's from 98) to give it some new life. I bought a pair of the big bottle 5u4g rectifiers from mesa. I have seen several tverbs running these and didn't think much of it. I had a chance to put them in today and sure enough, they will not fit! I had to take the top vent off to get them in, but went I try to put it back on, it presses down on them pretty hard. I don't think it is a good idea to put so much tension on the tub sockets. I picked up the big bottle rectifiers more for the look than anything - they are pretty cool. I guess it's back to the 5u4gb's :roll:

Anyway I put a quad of SED 6L6's and the personal fav's front end from eurotubes in it. I like it a lot better than the mesa 430's and stock pre-amp. Sounds a lot warmer to me, very smooth. Nothing says hello weekend like a fresh re-tube

 

[Elpelotero]

Do you have a picture? I can't imagine how this would happen.

Also, don't buy just for looks. Rectifier tubes do affect the amp's response. Namely:

5u4gb has the most sag; the slowest attack
5u4g has a faster attack
Gz34 has the fastest attack, almost like silicon diode

 

[blazer986]

I will try to get some pics tomorrow. I will agree with you on the fact rectifier tubes are not just for looks. Apart from the appearance I was trying to tighten up the tverb a bit from where I had it with the gb's. It sounded great while I had them in there - definitely a tighter feel than the 5u4gb. I have had gz34's before and usually run the amp in the diode setting (the two are pretty close in my opinion). I am originally a marshall guy, so I like to enjoy the recto feel for what it is. I think it is a little silly to try to get the rectos too tight, they where made for a loose feel! But, I am trying to get a good sag feel - but it is hard to stray from what you are used to :wink: .

 

[blazer986]

Alright, so I got around to taking some photos tonight. I may just be acting like a goober here, but it seems like the fit on these is really tight. I do prefer the sound of the 5u4g's, tightens things up a bit, but maintains a nice feel. Tried to get a good sense of the clearance on top of the tubes. They are making direct contact with the wood on the headshell and the vent when it is in place. Is this normal?

View from the back:

tube goes up into the vent cut out (vent removed obviously)

And with the vent in place

 

[Elpelotero]

WOW!! That is NOT normal!

Here's a pic of mine by comparison:

There's probably an inch of clearance there. I would call Mesa factory on Monday.

 

[blazer986]

Well I feel a little better that I'm not just being crazy. I'll have to give them a call sometime next week. Maybe they are using a different supplier for these tubes than before? A little odd they would sell tubes too big for their headshells.

 

[blazer986]

I haven't had a chance to call mesa yet, but I took some measurements of the 5u4g I have. From the base of the tube, where it sits against the socket to the top is right at 5''. If you add the length of the pins to it its about 5.5''. I know these newer tubes are shuguang made. Could someone with the older sovtek tubes take a measurement? Or any other brand of big bottle rec tube for that matter? Hopefully I will get a chance to give mesa a ring tomorrow.

I also think the tremoverb headshells may be a little bit shorter than the standard solo heads. I have seen pictures of these shuguang rec tubes fitting in them just fine.

 

[fluff191]

I have those very same coke-bottle Shuguang rectifier tubes in my Recto, and while they are tighter than the stock Mesa ones, they aren't THAT tight! Holy hell!

I would say I have about .5" from the top of the tube to the bottom of the head shell. With them installed, I can pull the chassis out (barely).

Guess you can't use those kind!

 

[R_ADKINS80]

I know with my headshell I have to install my big bottle rectifier tubes at an angle starting with the far right one first. If I start from the left I can't get the far right tube in. This happens with my Mesa and my =C= big bottles but they don't touch the top vent when installed. They have about a quarter inch clearance.

 

[blazer986]

I finally got my hands on some Sovtek big bottle 5U4G's and sure enough they are just a little smaller than the current mesa tube. Still a tight fit, but they are in with a little room to spare this time. Who would have thought - tremoverbs have a little shorter headshell than the solo models.

If anyone wants some like new (1 hour of use) mesa 5U4G's let me know, I'm going to be putting a bunch of odds and ends on ebay soon anyway.

 

[Elpelotero]

How much for the tubes?

 

[blazer986]

$35 shipped and PP'ed. Let me know if you are interested.