Jump to content
Gibson Brands Forums

Changing the tubes on your amp


daveinspain

Recommended Posts

I have a Rebel 30, great little amp… Was acting up a bit at my last band rehearsal, might have been fatly cords or connections though. I jiggle the cords and made sure all the ins and outs were good on my pedals. Seemed ok after that but it got me thinking, should I replace the tubes now. We practice once a week for a couple hours. We play maybe 4 or 5 gigs a year and when we are coming up close to a gig we'll practice twice a week for 3 or 4 hours. It's got five 12AX7 - two EL84 and two 6V6 I changed the EL84 and 6V6 about a year and a half ago but have never changed the 12AX7 tubes…

 

Any thoughts on this?

Link to comment
Share on other sites

I too am totally tube ignorant...

 

I have a 1980's era Vox Concert 501 with what I believe to be the original tubes still in it. It sounds great on the gain channel, but too fat on the clean channel like something is off... My daughter actually likes playing thru it that way so I haven't looked into it yet to correct...

 

I don't even know what tubes are in it, all I know is it has a Fane 10" (or maybe it's 12") speaker, is a 50 watt 2-channel tube amp w/reverb and sounds great...

 


According the the Vox USA site it has: either ECC83 or EL34 tubes or both... I can't tell from the diagram note. I don't know if one of those is preamp and one is power section tube types or if they're both a same type of tube in different versions... I'll have to see if I can see anything on the tubes in it...

 

I don't know anything about tube bias, when it's required, or anything and wouldn't know the first thing about replacing them...

Link to comment
Share on other sites

According the the Vox USA site it has: either ECC83 or EL34 tubes or both... I can't tell from the diagram note. I don't know if one of those is preamp and one is power section tube types or if they're both a same type of tube in different versions...

 

The ECC83 is preamp and the EL34 is a power tube.

 

Of the two the EL34 is much more likely to go before the preamp tube but if both have been in a very long time it wouldn't hurt to change them.

Link to comment
Share on other sites

Clean contact surfaces are crucial, for jacks and plugs as well as valves/tubes.

 

Aging and wear strongly depend on vibrations. Amp heads will wear out valves/tubes much less than combo amps. Besides factory tolerances, life expectancy of poweramp valves/tubes will strongly depend on proper bias adjustment.

 

The poweramp of your Egnater Rebel 30 is grid biased and adjustable. There are individual trim pots for EL84 and 6V6 stages.

 

Preamp valves/tubes of high quality provide several ten thousand hours of trouble-free service and might last even decades with typical use, especially in amp heads.

Link to comment
Share on other sites

I had what sounds a bit like the same problem as you, but a few weeks back (intermittent and slightly different to the tone I usually hear). I wasnt too sure what it was until I peered into the back of the head and saw that one of the power tubes was glowing brighter than usual. Once I'd changed it everything was fine. Im glad the amp was cathode biased

Link to comment
Share on other sites

I was happy to find this post as I have a FENDER 75 that I bought brand new in the mid 70's & have never changed tubes, this amp is used at least a couple times a week, about a yr. or so ago I was looking to replace all tubes just for general maintenance but could not find all tubes needed & I think I priced it out for around $100.00, if anybody has a link to further my tube search I'd be most grateful.

Sparky

Link to comment
Share on other sites

I was happy to find this post as I have a FENDER 75 that I bought brand new in the mid 70's & have never changed tubes, this amp is used at least a couple times a week, about a yr. or so ago I was looking to replace all tubes just for general maintenance but could not find all tubes needed & I think I priced it out for around $100.00, if anybody has a link to further my tube search I'd be most grateful.

Sparky

Sparky,

These guys are as good and knowledgeable as they come. They've been recommended by several folks on various forums, and I've used them myself.

 

http://www.eurotubes.com/

Link to comment
Share on other sites

NOS preamplifier tubes can last for decades, but current-production preamplifier tubes have a much shorter useful lifespan.

 

Yup, I've got original blackburn mullards in the preamp and output sections of both of my amps. JJ's I find to sound almost just as good if I'm honest. When you consider price to sound quality, I think the JJ's are much better for the money

Link to comment
Share on other sites

Yup, I've got original blackburn mullards in the preamp and output sections of both of my amps. JJ's I find to sound almost just as good if I'm honest. When you consider price to sound quality, I think the JJ's are much better for the money

Ok Krock you got my interest to

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...