Mark IV Arriving In A Few Hours!

[Scottyyy]

Cool, thanks. You got a great deal on the amp itself then.

 

[Old BF Shred]

I have double checked and it is Winged C Svetlana 6L6's that I have bought and seem to get good reviews.Seem to run with no problem either.

I run the SED =C= el-34's in my Ace, and they seem to be very rugged, dependable and long lasting tubes. Plus they sound great, too.
Assuming they match the bias of your amp, you will probably like them a lot!

 

[sparklesmcgraw]

What would the bias of the amp be?

And how would i know what the boas of the tubes are? Nothing on the box of note.

 

[sparklesmcgraw]

Also I have noticed I have a ground swtich on the back of the amp. A, off, b.

Which should this be at, or does it matter??

 

[kmanick]

Also I have noticed I have a ground swtich on the back of the amp. A, off, b.

Which should this be at, or does it matter??

whereever it's the quitest.
My IV i s "off' my III is on "A"

 

[Scottyyy]

Also I have noticed I have a ground swtich on the back of the amp. A, off, b.

Which should this be at, or does it matter??

My Mark III has the same, in the manual it says to switch it only if you're having ground loop problems. If not, leave it in the middle.

also, I sent you a PM.

 

[angelo]

Congrats on the amp.

My suggestion on tubes - especially at the beginning is to keep it simple and well within ranges. After you get to know it, the higher priced tubes may appeal to you. I feel my Mark IV does best with basic boogie tubes (grey or blue for me). While not very adventurous, I like my tones and have since '95.

As far as the EQ - It all depends. I only use it as a solo boost. In which case a soft V with the middle fader just below the line, gives me the volume boost I want. Check out the manual. The middle fader - while certainly IS a tone shaper - is the primary volume knob for the EQ.

Have fun and enjoy.

One more thing - go class AB / Triode and have some real fun playing loudly....

 

[Old BF Shred]

What would the bias of the amp be?

And how would i know what the boas of the tubes are? Nothing on the box of note.

Some will say you can run the idle current of a 6L6 as high as 50 ma. :mrgreen: :!:
But generally, 30 - 35 ma. is far more common.

The only way to be 100% sure is to measure the current through the tube. There are tools for this. A popular one goes by the name of "Bias Probe". There are others that operate in a similar fashion. I would search the internet for these if you are considering buying one.
Also you could/should have a technician measure it for you so you know how your tubes rate. However, this will only help for THAT particular set of tubes.....or if you use the same type/brand/supplier of tubes and use the same rating that they use. If there is nothing on the tube itself to indicate this, then you have no reference to compare.
But at least you'll know if the tubes you now have are close enough to the Mesa spec. Please check your manual or contact Mesa to know exactly what they set idle current (bias) to on the Mk4.

The range for your Mk 4 is likely in the 30-35 ma range, as this is most common. Mesa's own tubes are guaranteed to be in the proper range for your amp. I also know that Groove Tubes rated 4, 5 or 6 will work fine (Mesa told me this). As far as others, you have to measure to find out.
I know that this makes it more difficult to find tubes, without trial and error. Hopefully you have a qualified tech nearby that can tell you what will work in the Mesa. Also TAD would likely know, as do many reputable tube suppliers (here in the States, I like Tube Depot).

Once you find a supplier and rating that works, buying the same ones will ensure you stay within range from now on.

Hope this clarifies....

PS...if the tubes seem to work OK, and don't show any sign of orange or red glow on the plates, you may be fine. But I'd still get it checked to be sure.....

 

[sparklesmcgraw]

Thanks I will look into this.

So if there would be a problem I would most likely see the internal plates of the tunes glowing red?

From what I can see, is that the Tung Sol's filament tends to glow slightly less than the winged C's but certainly don't look dangerously red.

Thanks for all the input.

 

[Herbie the Rad Dorklift]

£900!

What a bargain.

My new Mark IV cost me £2100. Obviously it comes with a 5 year warranty though.