desperate help.. my dual recto

[willrock]

guys, i need help so bad, my dual recto gets bad feedback on channel 3 at band practice volume! my distance is 8 feet away from my 2x12 cab, i cant crank the volume up and cant enjoy this rectos sweet tone.. i tried tapping the power and pre-amp tubes already and it everything seems ok.., then why would i have this problem? how can i fix this?? its really frustrating.. help recto guys!! pls

 

[WillShred4Food]

What else can you tells us about the signal chain? Pickups, guitar, cables, effects loop?

WillShred

 

[willrock]

i dont run anything on the fx loop.. im using custom dimarzio john petrucci pick-up i suppose since im using ernie ball jp model.. and im using a planet waves cable, straight to the amp.. i think i have a pretty good signal chain going.. i just dont understand the feedback im getting at band practice volume, which i think is not too loud yet to get those feedbacks already.. what dya think?

 

[willrock]

i just got my recto about two weeks ago at guitar center, brand new, so i would say my tubes are still new

 

[Monsta-Tone]

It sounds like a bad Preamp tube. I know they are new, but new tubes have been shipped, and are prone to failure sometimes.

I order about 20 12AX7's at a time. Out of these, at least 1 is bad. I get such a great price on them, under $6 each, that I don't really care. I do hate to throw new tubes away though.


You should get a known good tube and the tube chart in your manual.

Swap out all tubes in the Channel 3 signal chain, one at a time.

Most noises that I've seen with tube amps are tube related.

I've even had amps in my shop that had bad tubes, but the owner had swapped the tubes 1 at a time with new tubes of the same brand, from the same shipment. The amps squealled horribly until I tried a different brand of tube, then the noises went away.

They are made, shipped, and installed by humans, things happen.



If this doesn't work, call the store you got it from. If they give you no satisfaction, call Mesa directly or look for an authorized repair center on their website.

 

[willrock]

thanks monsa-tone, but can i swap some of the preamp tube with different brands? coz i have an electro harmonix 12ax7 here that i havent used yet, maybe i can try?

 

[Baba]

Please forgive me for the dumb question, but I've been playing for over 25 years, and sometimes forget to plug something in.

What happens when you turn the guitar volume down?

 

[willrock]

i have the russian2 preamp tubes and 6l6s for power tubes and 5u4gb rectifier tubes.. is this a good combo of tubes?

 

[willrock]

if i turn my guitar volume knob down, i still can hear a lil buzz which i think is normal.. im talking bout channel 3..

 

[samhill]

Channel 3 is gainsville...more than likely you're getting gain feedback and not necessarily tube issues. Are you getting low end feedback or high end squealies? What happens when you turn the guitar's volume pot down to say 5 or 6? If it's low end rumbly feedback, then try this..when the feedback occurs grab the bridge pickup with your picking hand and hold it firmly..does it go away? If so you might try filling the pickup cavity with some spongy foam to keep the pickup from vibrating, I have also had luck with this trick...take the pickups out and run a bead of hobbyist hot glue between the pickup ring and the pickup(underside so it doesn't show), you may want to drop a blob into the pickup cavity where the pickup height adjustment screw will sit on either side..this will make the pickup very solid and keep it from vibrating. Hot glue is very easy to remove at a later time for pickup swapping or adjustment.
Most of all remember that using high gain requires a lot of playing with the guitar's volume (up/down) to keep the squealies away... a noise gate or reducer like a Hush or Decimator helps greatly in that department.

Mark Day
www.thesamhillband.com

 

[willrock]

i should say its a prematured feedback if thats the right way to describe it.. its a good type a feedback though, like standing in front of the amplifier, but it only hapens in a lower volume and being 8 feet away.. really mind boggling?

 

[Platypus]

Can you describe the feedback..?

Is it high pitched squeals or just like a buzz saw?

Have you done the tube tapping test? Take your heat shields off your preamp tubes and take a sharpie and tap each one, even your power tubes. Usually you will hear a lot of noise on the tube that's having troubles. V1 will make more noise than the others so keep that in mind.

Try switching V1 with V3 and see if it goes away.

 

[willrock]

its not a high squeal, just like facing the guitar really close to the cabs, thats how it sounded like.. its just happening at lower volumes.. i cant crank the volume anymore coz its getting kinda compressed already. its really weird.. i tried tapping all the tubes already too, everything seemed in pretty good shape i think.. i dont know, but i think this amp is acting NOT normal

 

[Platypus]

Just for grins, put it in silicon diode mode, does this help?

Did you tap the rectifier tubes?

Are any of your power tubes brighter than another (aside from the one next to the rectifier)?

 

[willrock]

i tried putting it in the silicon diode mode, it didnt help.. i tapped the rectifier tubes, its quiet.. seems normal.. and the power tubes glows almost just about the same brightness.. i dont know.. weird right?? anyways, i run it on 2x12 cab on 8 ohm spkr out..

 

[Platypus]

Have you done things like eliminate cables? Try another cable, or guitar and see if you can duplicate the results. It may not even be amp related though it sounds like a classic tube problem.

 

[WillShred4Food]

I've scanned this thread a few times, so I'm sorry if you posted this and I just keep missing it. What are your settings? More specifically, how high do you have your presence, treble, and gain?

WillShred

 

[Monsta-Tone]

All of the above, plus:

Just because you tapped on a tube and it didn't implode, doesn't mean that it is working right electrically.

If you've tried new cables, turning the Gain/Presence/Treble down, another guitar, etc. Then you really should try replacing the tubes 1 at a time.

I've had customers that will even go so far as to replace the Power or Output Transformer before bringing it to me (on Vintage Fenders, no less). I swap the tubes, and everything is beautiful.


You can use any brand. Mesa wants you to use their brand, but in pinch, you can use whatever you have on hand that is working good.


Tubes are kind of like light bulbs. Most bad ones won't rattle until you shake the filament loose, and sometimes the best ones rattle a bit.

 

[willrock]

thanks guys, for some reason, it just went away after just swapping the tubes around!! hehe.. magic..weird