Placing Tubes in Mark IV

[amphead]

I recieved Mark IV combo from Guitar Center and I asked them ship the tubes separately. But now I'm not sure about how and where to put which tube. I know (I hope) which are for preamp and which for amp but I'm not sure in which slot. Here are the pics of those tubes. Can someone help me with this?

Thanks!

 

[Rampage]

The small ones (12AX7/ECC83) will go into the preamp stages and the larger ones (6L6) go into the power section of course.

What I am wondering is that you've only got four preamp tubes pictured when the Mark IV runs on five, and you have two KT66/5881s, one 5881, and one 6L6B. I figure they probably missed the shielded preamp tube in V1 and I'm also relatively sure that those powertubes won't cause a problem, it just seems odd.

Check out the PDF user manual (page 17 of the guide, page 21 of the PDF) to see where the preamp tubes go. The power tube sockets are easy to spot; they are the larger white circular ones that are four in a row at the back of the amp.

Installing the tubes isn't a tough task; just line up the pins with the sockets and firmly (yet slowly) push them down into the socket. Usually the power tubes have a guide pin that fits in a slot on the socket for easy installation. As far as the preamp tubes, just rotate them around on top of their corresponding sockets until they catch and you can gently push them into place.

 

[amphead]

Thank you very much for advise! I had them placed like that and yes there isn't shielded tube because it's in the socket. I was just wondering if they have a special place. Especially power tubes. They have a different numbers and lettering so I wasn't sure which one in which socket. I think my Mark doesn't sound like the others. I'm affraid that it's damaged. SO I thought it's because of the tubes.

 

[Rampage]

Well, I'd try putting the Electro-Harmonix tube in the phase inverter and the GT preamp tubes in the rest of the spots.

As far as the power tubes go I would probably try the 5881s in the middle two positions and the other in the outer sockets. I think you will have to keep the amp on Class A and not Simul-Class for the time being as well. Also check and make sure the speaker is hooked up to the correct ohm output.

In all reality you may want to invest in a new tube kit and a new fuse. With a place like Guitar Center you don't know what those speds have done to an amp while it was under their not so watchful eye.

 

[Buddy]

I'd get on the horn PRONTO , and start using word's like :

"What the ****** ****** kind of ****** matched **** ***** tubes are you ***** sending me ! Is this some kind of ********* joke ?
What kind of **** **** ***** ******** business are you running ?
I oughta come down there weilding a tabasco soaked , electric **** ****** Cattle prod , you ********
********* ers !
Were you on ******* , Lsd when you packed this order ?

WHAT ? I AM CALM .
Manager please .

But that's how I'd react to the situation . Yeah , pretty much .

 

[Rampage]

I'd get on the horn PRONTO , and start using word's like :

"What the ****** ****** kind of ****** matched **** ***** tubes are you ***** sending me ! Is this some kind of ********* joke ?
What kind of **** **** ***** ******** business are you running ?
I oughta come down there weilding a tabasco soaked , electric **** ****** Cattle prod , you ********
********* ers !
Were you on ******* , Lsd when you packed this order ?

WHAT ? I AM CALM .
Manager please .

But that's how I'd react to the situation . Yeah , pretty much .

I'd have to agree on that one after thinking about it. Its a load of crap when you spend your hard earned money on something and you get the shaft on a big part of it.

I'd try to milk out a new set of tubes and/or a shipping cost refund.

Thing is though that I would try to stay a little calm and try to "schmooze" a little. In past experiences being too pushy has never ended up in anything good for me.

 

[Buddy]

Right on ,
More with the schmooze , than the (censored) freak out .
But it was fun typing all those ******** !

It seems like a mix & match on the tubes .... "Oh no ! what do we have that will work ?
Maybe they broke a couple , pulling them before the ship .

Got Milk ?

 

[Rampage]

Well, knowing GC, they may have swapped the tubes with some speds just to get them off the floor and keep the better tubes. Hate to think in that direction, but you never know. Hopefully they can work something out because that shouldn't happen. I mean, the tubes aren't even a matched quad. Preamp tube mixing happens a lot of course, but power tubes? Come on.

 

[srf399]

Every amp I've ever purchased I negotiate a new set of tubes...uninstalled to go along with the one's already in the amp. You don't know what kinds of idiots were playing through it on the floor. Call them and tell them the tubes are shot and you want replacements. That's total BS

 

[srf399]

Every amp I've ever purchased I negotiate a new set of tubes...uninstalled to go along with the one's already in the amp. You don't know what kinds of idiots were playing through it on the floor. Call them and tell them the tubes are shot and you want replacements. That's total BS

 

[amphead]

This is from the inside. Look at those cables in the middle of the photo. They are connected to the "Simul Class-Class A" switcher. They look as they shouldn't, right? Look like burned out. I will post some sound clip later.

 

[amphead]

It sounds like this. This is the rythm II channel. :shock:

 

[Living_justice]

could be your settings, wants the lead channel like mate?.

 

[dodger916]

What are your settings, and what guitar/pups are you playing?

 

[mr_fender]

That's total crap. You have completely different power tubes. There's no way they are matched. Also, since you seem to be new to tube amps, stick with Mesa Boogie power tubes! Boogie amps have a fixed bias, so you need tubes that fall within Boogie's specs. Use Boogie power tubes and you'll never have to bias your amp. You don't have to worry about bias with preamp tubes, so you can use any brand of 12AX7 preamp tubes you want. Using mismatched and/or misbiased power tubes will not only sound like crap, but can also damage your amp. Beware!

 

[sixstringmonk]

Is it just my amp, or is the tube task chart/schematic in the manual not identical to the actual layout in the chassis. It was almost backwards or a mirror image of mine IIRC. It threw me for a loop. If one of the tube sockets hadn't been shielded I wouldn't have known which was V1.

 

[Rampage]

Remember that the chart is like you are looking at the chassis as would the reverb tank if it had eyes so indeed it would be a different reflection.

 

[mr_fender]

V1 is usually the tube that is the closest to the amp's input. My '91 Mark IV has the tube names written on the chasis in sharpie. Ghetto, but quite handy.