Mark IV Problems.

[Mikeandratm]

Hey folks, been reading this forum for a while but didn't join up till today so go easy on the Newbie. Ok here's the problem.

I bought a used Mark IV Widebody Combo from the States early last year. I live in Scotland so I have an external Step-Down Transformer to convert the voltage. For a year straight I've used a Boss GT-6 straight into the front of the amp and left on the clean channel. Reason for this is because the lead channel seems incredibly bad. Thin, Ice Pick distortion. I've tweaked and tweaked but no Cigar. Then restricted to bedroom use , I figured I should buy an attenuator and that should fix the problem. So I spend £250 on a THD HotPlate. Hooked it up and the sound really did not improve even the slightest.

I really do not know what to do anymore.

Advice anyone?

 

[zeppman]

Did you ever replace the tubes? The first thing most people suggest to do when buying a used tube amp is replacing all the tubes, and even the caps if it is more than 10-15 years old.

 

[Mikeandratm]

Did you ever replace the tubes? The first thing most people suggest to do when buying a used tube amp is replacing all the tubes, and even the caps if it is more than 10-15 years old.

That's actually the only thing I've not done.

Does the problem I have, sound like a tube problem?

 

[Mikeandratm]

Anyone?

 

[scottywompas]

I have a MKIV widebody and the lead channel is anything but ice pick distortion. have you downloaded the manual for it from the boogie site.

http://www.mesaboogie.com/manuals/user_manuals.htm

this is very helpfull in explaining the range and interactions of all the controls and switches on the amp. It was usefull for me. New tubes and the manual should solve your problem.

Scott

 

[Mikeandratm]

I have a MKIV widebody and the lead channel is anything but ice pick distortion. have you downloaded the manual for it from the boogie site.

http://www.mesaboogie.com/manuals/user_manuals.htm

this is very helpfull in explaining the range and interactions of all the controls and switches on the amp. It was usefull for me. New tubes and the manual should solve your problem.

Scott

Absolutely.

I've been over it a 1000 times. Even the pre-sets in the manual totally sound off.

 

[highroller]

I had similar problems with my 1991 Mark IV, sterile distortion, low amount of sustain. I installed a new set of preamp tubes, replaced the 6L6 in the outer socket for EL-34 and I changed all the filter caps and voila, I now get a fuller distortion with more sustain !!!

The tone is what it differentiate the Mark IV from other amps, but it take some time to explore all the possibilities ! With the guitar plugged straight into the amp you should get a nice distortion with enough creamy sustain at position 8 on the Lead Gain and 7 on the Lead Drive using medium output pickups like a Dimarzio FRED or a Seymour Duncan Custom.

 

[Boogiebabies]

Change the preamp tubes. I would not go an replace the filter caps. I have three 20+ year old and one 14 year old DR and the filter caps are just fine. If I start to get a flubby bass and hum I will change them. I have seen a few dozen IIC upgrades, some recent, that had the original 22 year old filter caps.

 

[Mikeandratm]

Ok.

Tubes - Should I use Mesa ones only? They are incredibly expensive over here. Is it possible to use other manufacturers?

I tried searching the tube forum for this, but I couldn't find a straight answer.

 

[mangley]

Check the power you are getting from the step down transformer.

 

[Mikeandratm]

Check the power you are getting from the step down transformer.

How'd you mean.

http://www.powerscoots.co.uk/acatalog/Voltage_Converters.html

The one I use is the Second from the Bottom.

 

[mangley]

Which of these are you using. The Mk4 draws a fair amount of current. You may not be getting enough juice to drive the amp properly.

 

[Mikeandratm]

Which of these are you using. The Mk4 draws a fair amount of current. You may not be getting enough juice to drive the amp properly.

Second from the Bottom.

"200W Desktop AC/AC Converter 230V to 110V"

 

[SFW]

Replacing the tubes will help dramatically. You can use JJ or any other quality tube manufacture. The Mark IV's lead channel sound be very smooth and thick.

Here are some Lead clips:

Lead Rock Tones
Lead Metal Tone
Lead Rock Wankage

All the clips are amp into the board with NO extra EQ going on. Just strait from the amp.

 

[Mikeandratm]

Thanks to a big help from SFW, I've finally got a desired tone from this amp and it sounds incredible.

The problem was nothing to do with tubes, caps or converters. Just a severe case of really **** EQ'ing on my behalf but hey, we learn from our mistakes right?

Thanks to everyone for replying and helping out!

 

[prometheus]

Replacing the tubes will help dramatically. You can use JJ or any other quality tube manufacture. The Mark IV's lead channel sound be very smooth and thick.

Here are some Lead clips:

Lead Rock Tones
Lead Metal Tone
Lead Rock Wankage

All the clips are amp into the board with NO extra EQ going on. Just strait from the amp.

Thats the sound i want. every time i go try an amp thats the tone that it is judged by. (waves hand like a jedi knight) you will give me your amp.