question on rectifier tube (5u4g)

[mattyk182]

i posted a topic before but no one responded and i just left a message with mesa. since now i only have one rectifier tube, does that mean that i can still play with it but i will only get 50 watts out of the amp until i replace the tube? i need to know because i have shows coming up. btw, i own a dual rectifier. thanks for any answers!

 

[ryjan]

What amp are you talking about. If you are playing a dual rec or a Roadster I believe if you flip to diode rectification you can play without the recto tubes in. Someone correct me if I'm wrong before he blows his amp up. :shock:

 

[mattyk182]

i am playing a 3 channel dual rectifier. i need someone to confirm that i can play without one 5u4g and if so, what do i need to have the switches on in the back so i dont mess my amp up. thanks!

 

[fluff191]

You can only play with one Rectifier tube if you pull the 2 outer OR 2 inner tubes to reduce the total watts to 50 watts.

Why dont you just switch over to diodes until you get another tube?

And if you do have the rectification switched to diodes, you do not have to have the rectifier tubes in the amp.

 

[mattyk182]

are you ABSOLUTELY sure that if i put it on high power diodes that i will be fine missing the tube? im sorry but i really want to make sure because of how expensive this amp is. thanks so much for the answers.

 

[fluff191]

Yes. Im running one of my Rectos like that right now. It will be fine.

The diode setting completely bypasses the rectifier tube circuit.

 

[mattyk182]

in diode mode, does that make it solid state?

 

[fluff191]

Yes. The rectification will be solid state and a bit tighter sounding.

 

[mattyk182]

ok thank you so much for the advice. your a life savior. im still undecided if i want to remove 2 tubes it make it 50 watts or just go to diode. i guess i will have to figure it out on my own. thanks again!

 

[fluff191]

Dont remove the tubes. You CAN do it, but its just safer to switch it to diodes. That and if you do remove tubes, it will double the impedance of the speaker out jacks, which is a whole other issue.

Honestly dude you are splitting hairs. Switch it to diodes and rock out!

 

[mikey383]

i am playing a 3 channel dual rectifier. i need someone to confirm that i can play without one 5u4g and if so, what do i need to have the switches on in the back so i dont mess my amp up. thanks!

You can play with only one rec tube and all 4 power tubes, but expect a helluva lot of sag from that one tube, and don't expect it to last long.

Just switch to diodes like Fluff said. It doesn't make the amp solid state, it just uses a solid state rectifier system to supply DC voltage to the tubes. You still have tube power, just tighter and punchier due to higher voltages on the tubes.

 

[droptrd]

+1

i am playing a 3 channel dual rectifier. i need someone to confirm that i can play without one 5u4g and if so, what do i need to have the switches on in the back so i dont mess my amp up. thanks!

You can play with only one rec tube and all 4 power tubes, but expect a helluva lot of sag from that one tube, and don't expect it to last long.

Just switch to diodes like Fluff said. It doesn't make the amp solid state, it just uses a solid state rectifier system to supply DC voltage to the tubes. You still have tube power, just tighter and punchier due to higher voltages on the tubes.

 

[NoGlassNoClass]

Switch to Diode and pull the other rectifier tube out as well...if it fails, it can still blow the fuse even with the amp set to diode. Just yank both of them out and rock on.

 

[mattyk182]

thanks! will do until i get the new tube.

 

[Triple Cheeseburger]

sorry to hi-jack the thread, i have 2 rectifier tubes that both while still work fine (i think?!) they have dark marks around the bottom of the tube. this to me looks like they are burning out or something. I have had this amp close to a year, is it normal for rectifier tubes to only last this long? (i bought the amp new) or do i have a problem?

 

[94Tremoverb]

They're probably just fine. Rectifiers seem to either work or not, they don't wear out slowly like power tubes. You can test them easily - pull one, switch the amp to Vacuum Tube and see if it runs. If it does, the tube in it is good. Now do the same with the other one.

You can safely run the amp with all four power tubes and only one rectifier as long as you don't crank it full up. If the amp is running at half power or less, the tube is not under any more load than it would be with both tubes in and the amp at full power. It's kind of hard to tell where half power is from the volume controls, but it's pretty loud really. If you can still get a completely clean sound on channel 1 with the master dimed and even when you hit the strings really hard, chances are you're under half power when you're playing normally at the same volume.

I've been running my Tremoverb at home with one rectifier since I needed to borrow one of the 5U4s to get an old Fender amp going, and the only difference I noticed is a slightly bigger volume drop between Diode and Vacuum Tube.