Lonestar Classic Short Head Reverb Problem

[cb101]

Hi all,

I have a Lonestar with the short head circa 2004. I've had a reverb problem from the beginning. I've changed tanks, leads, tubes and even tried to shield it but channel 1 still makes a serious humming noise at at any setting above three. The higher you set it the more hum and noise. Channel 2 is fine, reverb sounds great. I called Mesa and was told that the close proximity of the transformers to the reverb tank on the short heads is the cause of the problem and can't be fixed. Have any of you had this same problem and were able to fix it?

 

[GuyB]

I don't have a Lonestar but a Transatlantic TA-30 and it has the same problem and the same answer was giving by Mesa to explain it (proximity of the transformer). I guess that we have to live with it but in fact, for me, it is disturbing only at very low volume (playing alone in the house). On gigs or jams, it is'nt really bothering.

 

[ziehmrd]

I at a little loss on this. Isn't the reverb unit the same size in the long, medium, or short headshell version of the amp? How can it be closer to the transformers when all were talking about is a narrower shell. The chassis in relation to the reverb should be the same unless the short head shell is also not as tall. Then I can see why it would be a problem. I was thinking about going from a long to a medium shell for my LSC but don't want to cause any problems if the narrower shells are also shorter in height.

 

[cb101]

On the medium and long shells the reverb tank is displaced to the side and is not directly under the transformers. We're talking about two or three inches but that seems to make a big difference. I experimented by using an external tank just a few inches outside of the head and there is no hum or noise. I was hoping it was just a defective resistor or some other internal part but I guess not.

 

[ziehmrd]

OK, that would seem to make sense but I just looked at my LSC long head and the reverb tank is centered exactly under the chassis although its a bit closer to the front of the head shell so maybe that's the difference. http://www.flickr.com/photos/62536676@N08/5995383209/in/photostream. Here's a picture of a medium head and the tank looks centered, so I don't know.

 

[cb101]

I measured on my short head and the top of the tank is 5/8 of an inch from the main transformer and is squarely positioned under it.

 

[ziehmrd]

Just measured on my long head and there is 1-7/8" between the tank and transformer so it looks like the short head is not as tall.

 

[cb101]

I guess that inch and an eighth or so makes all the difference. Well, after screwing around with this for over two years, I give up. Unhooked the tank and took it out. Just got a new Eventide Space reverb so I guess that will have to do.

 

[GuyB]

Do someone know if it could be possible to isolate the tank from the transformer by putting "something" between them ?

 

[cb101]

I tried a variety of shielding. Tin shielding, various metals layered, a plate of isolation material and nothing worked. Mesa told me that the hum issue was the reason that they discontinued making the short head for the Lonestar. I guess the tank is just too close. I understand from another post that there is a head cabinet maker in Canada that does custom cabinets. One of the guys said he had a short head built that was about an inch higher and he is getting no hum. I believe the company is Saxon Cabs in Canada.

 

[ifailedshapes]

For those interested, here's the thread the OP is referring to: http://forum.grailtone.com/viewtopic.php?f=31&t=36942&start=15

 

[dgr888]

Check my post on Reverb hum for Mark III and other models. The tanks are in closer proximity to the power trans which will induce hum/noise into the reverb input transformer. Try and turn the tank around with the reverb's input transformer at the other end and see if it gets better. Make sure you use the cables in the same position as you cannot swap them if they don't reach or you will still have problems. Mesa used a shielded one on the input and a bare wired one on the output so keep them the same. Also don't change the single wired one for a shielded because you will still get hum. You might also have to shield the tank a little better if the bottom is open. I have found that this IS the fix for the combo's but don't know how well it works in the head versions. Please let everyone know if it helps>>>
dgr888

 

[medwards1969]

Is it effected differently if you run it on 50W Tweed Mode?