Mark IV - Retube Fee?

[Blasted]

I'm new to this tube amp thing. A while back I bought a Mark IV. It has the Mesa 5881 tubes in it. It was recommended to me to switch those out with the EL34/6L6 combination to get a better (more powerful) tone, as the 5881s are a less powerful tube.

When I first bought the amp, I took it into a tech to fix a broken pot, and give it a once over. The services were reasonably priced, and he was an authorized Mesa tech.

Anyway, since I was interested in swapping out the tubes, I asked the tech how much it would be. He said $80 for the tubes ($40 a pair), plus an additional "re-tube charge."

Is this normal? I though that if I swapped with other Mesa brand tubes, that no technical adjustments (bias) would need to be made. Is there any point of going through the tech to get the tubes, or should I just order them off the Mesa website and swap them myself? Its just as easy as pulling one tube out, and sticking another in, right?

Thanks!

 

[Paul Secondino]

To address your questions and thoughts in order :

1. EL34's aren't a more powerful tube than a 5881. And as far as power output, the 5881 is very similar to a 6L6. You wont change the power of your amp by using all 6l6 or a combination of El34 / 6L6. At least not to any appreciable level. The purpose of using EL34 and 6l6 tubes in the Mesa is because it is a simulclass amp and the Mark 4 bias supply is split to be able to feed the outer sockets with more current /negative bias voltage to allow the EL34's to run hot enough to sound good.

2.It takes about 10 minutes to re tube your amp so $80.00 is ok for the tubes but he shouldn't charge you for more than 15 to 30 minutes tops to complete the job. But since there is no adjustable trim pot in your Mesa , there's no way to quickly alter the bias. So if your tech claims he can set the bias without lifting the fixed resistor and replacing it, he is lying to you.Ask about that. He should at least clean and re tension all the tube sockets. Re tension means to check the copper contacts inside the sockets and manipulate them to ensure excellent contact between them and the prongs on your power tubes.

3.You can easily replace the tubes your self. Carefully pull out the old tubes and insert the new Mesa tubes. In the way of technique, it is good practice to clean the sockets out and re tension them .IF you don't know how, you can learn by reading online tutorials.

4.Almost all Mesa Boogie amps are biased too cold. This means your tubes are not saturating well and you're losing potential tone.My Mark 4 has a hot set of 6l6 in it and each tube only draws about 24 mA .The stock Mesa tubes were only drawing 19 to 20 mA. 6l6's in a Mark 4 should be drawing at least 35mA to even begin to sound like they're working.

 

[Blasted]

Thanks.

For the record, he didn't say that he had to adjust the bias, just that there would be a "retube charge." I am just trying to determine what would be included for this charge. Sounds like it would include cleaning the sockets and re-tensioning them... which sounds like its something I can do on my own.

We had already discussed the possibility of doing a bias mod, which I had declined, because I decided to just stick with boogie tubes... no bias adjustment needed.

Also, to clear it up, I had heard that the 5881 was less powerful than the 6l6, not the el34. As I understand it, the el34s are use to break up the distortion a little earlier, and slightly alter the tone.

 

[acorkos]

....there would be a "retube charge." I am just trying to determine what would be included for this charge.

probably removing the new tubes from the box and installing them in the tube sockets (from which he removed the old tubes)

 

[sixtonoize]

Also, to clear it up, I had heard that the 5881 was less powerful than the 6l6, not the el34. As I understand it, the el34s are use to break up the distortion a little earlier, and slightly alter the tone.

They are both equally powerful at 25 watts a tube. A 6L6GC is slightly more powerful at 30 watts per tube. A 6L6 is essentially the same thing as a 5881...a 6L6GC is a higher power version. You can substitute a 6L6GC for a 5881, but not reverse. A lot of times, a 5881/6L6 can't handle the voltage.

Though an EL34 produces the same amount of power, it breaks up at a lower volume and has a smoother break-up. A 5881 stays cleaner for longer, but breaks up harder. EL34s also tend to have more midrange emphasis with less bass and treble.

 

[user 9884]

....there would be a "retube charge." I am just trying to determine what would be included for this charge.

probably removing the new tubes from the box and installing them in the tube sockets (from which he removed the old tubes)

My thoughts exactly.