The Mark IV thread....!!

[hydesg]

does all Mark IV have internal wirable transformer? as in i can wire from the standard 117v to a 230v version internally? so that i dont need to use the step down transformer


the mark iv is brand new which i have just gotten yesterday.

here it is

by the way, it is normal to have some noise on the lead channel?
would an ISP decimator ni the loop cure the noise?

 

[srf399]

That is a beautiful looking MKIV head.

 

[petejt]

does all Mark IV have internal wirable transformer? as in i can wire from the standard 117v to a 230v version internally? so that i dont need to use the step down transformer


the mark iv is brand new which i have just gotten yesterday.

here it is

by the way, it is normal to have some noise on the lead channel?
would an ISP decimator ni the loop cure the noise?

Congratulations!!



Yes, it is normal to get some slight noise on the lead channel. An ISP Decimator in the loop (and in front) will definitely cure it.
Mind you, the noise is far less than most other high gain amps.

 

[Living_justice]

you should be able to change to 230v, my dual has been changed to 230v uk power, send to a good tech tho.

 

[Shep]

you should be able to change to 230v, my dual has been changed to 230v uk power, send to a good tech tho.

no, not all trannys have the 230/240 tap.. it's Lucky when you do find one like that..

 

[boogietone]

[/quote]For live performances or playing by yourself, you can use Lead with EQ for rhythm and Lead without EQ for soloing or vice versa (personal preference).[/quote]

How do you use Lead with EQ for rythym and Lead without EQ for soloing? I ask because Lead with EQ for me is quite a bit louder than Lead without EQ on my MKIV. Am I doing something wrong?
Thanks!

 

[Shep]

you scoop out the mid's and don't boost anything..there for it only taking out the tone..

 

[boogietone]

Thanks-I'll give it shot. I really like tone the with or without the EQ. What a great amp!

 

[boogietone]

So, about a week ago, I tried switching my MKIV into my MKIII head cabinet and MKIII into my MKIV's combo cabinet. I had everything apart when I realized that my reverb tank was too big and there wouldn't be any room the fan. So I had to switch them back. Before doing so, I cleaned the MKIV's guts with an electronic cleaner from RadioShack. Put the MKIV back into the combo cabinet and fired it up. After a couple pops some blue smoke and that telltale burning electrical smell it died. Fuse blew. Looked everything over and thought I plugged the fan in backwards. Turned it on again, fuse blew. Then I noticed I forgot to plug the speaker back in and that in moving the amp around I had bumped the master volume WAY up. Well, everything works except for the fan. The only problem is, the lead channel is pretty noisy now. Swapped all the tubes and stuff and still no joy. R1 and R2 seem okay. But lead has a scatchy sound to it in the background and occasional pops and seems unaffected by me playing or not. Even with all the cords disconnected except the speaker of course it is the same. Maybe gets a bit worse the longer I'm playing. Anyways, whaddaya think? I think I fried a cap somewhere. But obviously I don't know much about working on tube amps. Any ideas would be much appreciated. Probably be sending this into Mesa and playing the MKIII-which I also love.
Thanks and sorry for the long post.

 

[Shep]

check inside for burn spot's.. what sort of electronic cleaner was it.. ? did it leave any residue on the boards?

 

[boogietone]

Bad set of tubes ended up being the culprit. Put them in my MKIII and the same thing happened. I wouldn't have put those tubes in my MKIII but I thought they were good and my problem was me cleaning my MKIV. Well, now I know. The MKIII just blew a fuse and fried a resistor but everything works fine.
Here's pic of the III's blown resistor. Is this a screen resistor?

 

[fpoon]

I believe so.

 

[Dizzy]

no, not all trannys have the 230/240 tap.. it's Lucky when you do find one like that..

Hi all,

1st Poster here on an amp-quest for a MkIV.

Is there a quick way to tell if the tranny has the 230/240V tap ?

Thanks

 

[eltrain858]

Is there a quick way to tell if the tranny has the 230/240V tap ?
Thanks

Ask it :lol:

 

[AdmiralB]

Is this a screen resistor?

No. On most Mesa amps (and all the Mark series) the screen resistors are mounted directly to the power tube sockets. They span from pin 4 on the socket to the terminal strips mounted between the power tubes.

That resistor in your pic is a Dale .6W unit, the only Mesa amp I know of that uses those for the screens...and places them on the PCB...is the Heartbreaker, and it uses two of them in parallel for each tube.

I suspect one of your power tubes has arced from the heater to the plate. Look at the bases of all of them, you're looking for a carbon track probably between pins 2 and 3.

 

[boogietone]

Is this a screen resistor?

No. On most Mesa amps (and all the Mark series) the screen resistors are mounted directly to the power tube sockets. They span from pin 4 on the socket to the terminal strips mounted between the power tubes.

That resistor in your pic is a Dale .6W unit, the only Mesa amp I know of that uses those for the screens...and places them on the PCB...is the Heartbreaker, and it uses two of them in parallel for each tube.

I suspect one of your power tubes has arced from the heater to the plate. Look at the bases of all of them, you're looking for a carbon track probably between pins 2 and 3.

Thanks! When I had it apart that was all I could find wrong. I'll look again though. It plays and sounds just fine though despite that resistor being burned. I also looked inside my MKIV and couldn't find anything wrong. I definitely think you're right though about it arcing. There was quite a flash of light behind the amp when it happened. Thanks again!

 

[DStout]

Hi all,

I am thinking of upgrading to a Mark IV (short head with a 1x12 EV Thiele cabinet).

Is it possible to extend the cable for the footswitch. What kind of connector does it have?

I would like to use a pedalsnake for all my cables (guitar to amp, FX loop, 9/12 V power for FX and the footswitch).

Best regards,

Douke

 

[bsic]

Hi all!!

Well after demo'ing a Stiletto, Express, Rectoverb, and MarkIV many times over the last 2 months, i decided on a mark iv. Got a mint 2006 model used at GC.

The thing that SUCKS is, my wife volunteered to watch a friends 8 month old this weekend. Between him and my 2 year old, Im full time helpin the wife and wont be able to play it until tomorrow!!! TORTURE!!!!!!

Im sure ill have lots of questions for you all as i get acquainted with it. Reading this thread was great background info as i tried to narrow my choices... this board rocks.

 

[UsrName]

Hi all,

I am thinking of upgrading to a Mark IV (short head with a 1x12 EV Thiele cabinet).

Is it possible to extend the cable for the footswitch. What kind of connector does it have?

I would like to use a pedalsnake for all my cables (guitar to amp, FX loop, 9/12 V power for FX and the footswitch).

Best regards,

Douke

I'm not sure what the proper name for the connector is, but it's not a normal one. It does have a pretty long cable, though. Looks like about 20 feet! Good luck!

 

[UsrName]

Hey all! I just picked up a Recto 2x12 cab to get a little bigger sound at practice. I really like the low end and volume this cab gives me. However, the V30s seem kinda harsh to me, and they are broken in.

Has anyone else tried any of the other speakers in this cab, (EV, C90, others, mixed, etc.)? Results? Thanks.