HELP! Lone Star 1x12:ringing/buzzing noise only on one note.

[DoTheDo]

My overall suggestion would be that if you are taking this amp back to the store, don't spend your own money on tubes. Suggest to the store that if they plan on trying to sell this item, they are probably gonna have to retube it, and maybe they should just supply a whole new set for you for now so you can use it. You are their customer, and you are spending a good chunk of money. Its not like this is a $100 practice amp...

Thanks zeppman.

I've ordered a new LS. As soon as it comes in this one goes back to the store. The store has supplied me with a pair of 6L6s and some 12AX7s at no cost. I've got nothing to loose by trying to troubleshoot this before my gig tomorrow night.

So, you're saying that I CAN leave the amp on while swaping the preamp tubes in and out? I know this can be done with the power tubes (removing only one at a time as per manual). But wasn't sure about preamp tubes. Since I've got pontially 9 tubes to verify just wanted to this the safest and of course most efficient way.

 

[zeppman]

dothedo: No, I'm saying I don't know if you can switch pre-amp with the power on. I would call mesa before you try if it is not addressed in the manual. Depending on how many 12ax7s they gave you, I would just replace all of them.

 

[Surfcaster]

I'm pretty sure you can remove any tube while in standby...power tubes for sure. But it doesn't hurt to be safe and check with Mesa or an amp tech to be sure...obviously none of my advice comes with a money-back guarantee!!

 

[DoTheDo]

Hey everyone,

I checked the amp last night and it turns out that the ringing sound is coming from the Rectifier tube 5U4G. When I remove the tube the ringing stops. If I keep the rectifier switch to Diode and stay at 100watts on both channel 1 and 2 do you know if the amp can be operated safely without this tube? At least until I get a new one.

Thanks again for all your help

 

[RR]

Yes, in rectifier in the silicon mode you don't require the 5U4G tube since the silicon and 5U4B tube do the same thing : supply power to the power stage tubes.

But do replace the 5U4G tube. For me, I use tube rectifier about 90% of time because I like the "sag" tone characteristics. But that's my preference.

 

[DoTheDo]

Yes, in rectifier in the silicon mode you don't require the 5U4G tube since the silicon and 5U4B tube do the same thing : supply power to the power stage tubes.

But do replace the 5U4G tube. For me, I use tube rectifier about 90% of time because I like the "sag" tone characteristics. But that's my preference.

Thanks RR. I will replace the 5U4 tube (I'll request a free one since the amp is still under warranty). But I have a gig tonight and may not be able to get to the store in time to pick up the tube. So, as you've indicated if I remove the tube but keep the rectifier switch to diodes and channels at 100w then I should be fine.

Care to explain the diferences between rectifier and diodes mode? What exactly is sag.

Thanks for your help on this.

 

[RR]

Care to explain the diferences between rectifier and diodes mode? What exactly is sag.

Thanks for your help on this.

Its a bit hard to explain and best experience tube rectifier -vs- solid state, hear the difference.

"Sag" is a term used by boutique amp builder or vintage amps. Some guitarists have an ear for it other guitarist can't tell the difference.

Tube rectifier(s) has this warmness rich harmonic and more noticeable when you push the amp (play master volume up) and less preamp volume drive.

The "downside" or rather trade-off using tube rectifiers, its very inefficient supplying voltage to the power stage tube. Its not as loud compared to using the silicon. I can't recall if it was SRV's guitar / amp tech (forgot his name, Rene Martinez[?]), he even removed the unreliable rectifier tube and replace it with solid state rectifier on his amps.

[Please correct me if I'm wrong or misquoted]

Actually this technology using tube rectifier was practically abandoned by the late 60's amp builder switching to the more reliable and efficient solid state or as well M/B calls it "silicon".

Ever since boutique tube amp building became popular and recreating vintage amps (Fender Bassman in particular) rectifier tube technology resurfaced. Guitarists with a trained ear claiming there's this special harmonics that the tube rectifier gives out compare to the silicon.

So tube rectifier technology came to the fore front.

When Randall Smith was working and designing on the Dual Rectifier, he decided incorporate both tubes and silicon rectifiers with the amp user getting to select either. He even patent this technology (he wish he patent cascading preamp so every hi gain amp builders would have been paying royalities to him).
Matchless, Bad Cat to name a few were paying royalities to Randall Smith patent. (I think the patent runs out after 7 years).

Now correct me if I'm wrong 'cause this is how I sorted out things.

So gave you some history on tube rectifier technology.

Best is to experience either mode when you replace the 5U4. Hope this helps or are you more confuse than ever?

 

[DoTheDo]

Care to explain the diferences between rectifier and diodes mode? What exactly is sag.

Thanks for your help on this.

Best is to experience either mode when you replace the 5U4. Hope this helps or are you more confuse than ever?

Actually your explanation was very helpful. Thanks. I have another question for you specific to the Mesa Boogie Lone Star (perhaps other Boogies work the same way). Does the tube rectifier kick in when the amp is set to 100 watts or is it specifically a power distribution required when the amp is set to 50 watts.

I did manage to pick up a new 5U4 tube today and will replace it tonight just in time for my gig.

Thanks again for your help.

 

[RR]

Actually your explanation was very helpful. Thanks. I have another question for you specific to the Mesa Boogie Lone Star (perhaps other Boogies work the same way). Does the tube rectifier kick in when the amp is set to 100 watts or is it specifically a power distribution required when the amp is set to 50 watts.

I did manage to pick up a new 5U4 tube today and will replace it tonight just in time for my gig.

Thanks again for your help.

First of all, I'm envious of you LoneStar owners because I have yet to own a LoneStar (actually I'm looking into Lone Star Special since I don't want to purchase an AC30 Vox then have to put a stomp box --never owned a stomp box since I used M/B preamp gains, the natural way) but one 5U4 supplies 50 watts to a pair of power stage tubes that's why you see two 5U4 in a 100 watt M/B (or three 5U4 in Tri- 150 watts).

A silicon rectifier will supply power regardless 50 watt, 100watt (even 150 watts for the Tridents, or Triple Rectifiers).

I'm not sure how the channel assignments on Lone Stars if you could assign tube rectifier for a particular channel and silicon for the other channel.

Did I sort of answer your questions on the power supply to the stage power tubes?