Insider info on Mark IV bass EQ?

[jukesgtr]

Hey Guys,

I am just interested in learning why Mesa/Boogie decided to have a circuit in MK4 that results in flubbiness (accoding to the manual) when the pre-amp lows are pushed higher with some distortion in? It must not be the power tubes or speaker because you can get great low end by adjusting the graphic EQ. Tks!

 

[Monsta-Tone]

I asked this same question when I bought my Mark IV.

I was told that it was due to the placement of the EQ before most of the Gain stages.

If you look at the schematics, the Mark IV is basically a Twin Reverb with 2 or 3 extra Gain stages.

The DC series amps have basically the same Preamp, but the EQ is after the 2nd Gain stage, unlike the Mark IV which has the EQ after the 1st Gain stage.




I asked why they don't change the Tone Stack Capacitors to a lower value so that there is less Bass present in the early stages of the Preamp.

They simply said, "The Mark IV is a great amp. Why would we change it?"

To me it sounded like, "Why would we admit that we might need to change anything."



Even though I love Mesa amps, I don't understand why they insist on placing disclaimers in their manuals.

"To avoid those pesky tube microphonics, do not turn the Gain to 10."


Why can't they just say, "We punish our Preamp tubes like mutha's, so be careful."

 

[jukesgtr]

Wow, thanks Monsta-tone for this info!!! The quality of lows really is the only negative thing (if no graphic EQ activated) I have noticed in this amp so far, not talking about its weight...

 

[Monsta-Tone]

I found that keeping the Bass below 4, I was able to get lots of Bass out of the Lead channel.

I think that most of it depends on the speakers being used. I was using a 2x12 cab with Mojotone BV12M's and a Combo cab with a Weber Thames Ceramic speaker. Both setups sounded very fat at higher volumes.


It is a bummer though that you can't go above 4.

 

[jukesgtr]

Mine is a combo and I also have a semi-open ext cab that defenitively helps with lows. It sounds good with Graphic EQ without the cab too. I recently bought this rig and still need to play with the controls....

 

[SFW]

As with most Mark series amps, keeping the Bass at 3 or below is the key.

Mesa/Boogie Mark IV Clips:
R2 rock Crunch 1
R2 Rock Crunch 2
R2 Rock Crunch 3

Lead Rock Tones
Lead Metal Tone
Lead Rock Wankage

 

[jukesgtr]

Yeah, I'll keep it at 3 or 4...tks.

 

[Monsta-Tone]

I think your choice in tubes is the key to getting the most bass out of your amp. I've had the best luck with JJ's and Mesa, I really don't like the Mesa/Sovtek tubes.


Also, your speaker choice will make a huge difference in your tone. I was using mine as a head with a THD cab that has 2 Mojotone BV12M Greenback clones. Very good bass.

I also used it as a Combo with a Weber ceramic Thames speaker. Ted Weber said he designed it to be like a Vintage 30, but with more bass and better power rating. It can handle 80 watts as compared to the Vin 30 at 60 watts.

I really didn't like the MC-90 speaker I originally had in there, it sounded great, but was a bit stiff. It was 5 years old, so I know it was broken in. On the other hand, I used that MC-90 for 2 years with a Dual Rectifier and it sounded amazingly tight and beautiful. Every amp is different. What sounds good with 1 amp might not sound good with another.

 

[jukesgtr]

I think your choice in tubes is the key to getting the most bass out of your amp. I've had the best luck with JJ's and Mesa, I really don't like the Mesa/Sovtek tubes.


Also, your speaker choice will make a huge difference in your tone. I was using mine as a head with a THD cab that has 2 Mojotone BV12M Greenback clones. Very good bass.

I also used it as a Combo with a Weber ceramic Thames speaker. Ted Weber said he designed it to be like a Vintage 30, but with more bass and better power rating. It can handle 80 watts as compared to the Vin 30 at 60 watts.

I really didn't like the MC-90 speaker I originally had in there, it sounded great, but was a bit stiff. It was 5 years old, so I know it was broken in. On the other hand, I used that MC-90 for 2 years with a Dual Rectifier and it sounded amazingly tight and beautiful. Every amp is different. What sounds good with 1 amp might not sound good with another.

I have 4 x Mesa 6L6 in the amp now, they sound better than 6L6/EL34 combination that was in it originally, I think 6L6s have more and better bottom end. I am going to get my next set from JJ.

I also read on H-C that channel masters at least at "5" improve MK4's bottom end.

The speaker in the amp is labeled EVM 400W and I have wide ext. cab with MC-90, it is a good sounding rig and that ext cab improves lows.

 

[Monsta-Tone]

I really like those Wide Body Ext cabs. I might have to pick another one up.

I used to play in a Classic Rock cover band a few years ago. I used a 2-channel Dual Rectifier set to Spongy, Tube Rectifier and a Wide Body 1x12 cab with an MC-90.

I could reproduce almost any 70's & 80's Rock tone that I wanted.



I really like the MC-90 speaker in a 1x12, but have had better luck with other speakers in larger cabs.

 

[jukesgtr]

I really like those Wide Body Ext cabs. I might have to pick another one up.

I bought a used one in absolutely mint condition.

 

[jargapix]

As with most Mark series amps, keeping the Bass at 3 or below is the key.

Mesa/Boogie Mark IV Clips:
R2 rock Crunch 1
R2 Rock Crunch 2
R2 Rock Crunch 3

Lead Rock Tones
Lead Metal Tone
Lead Rock Wankage

Those clips sounded great! Could you put up the settings you used? Thanks!

JA

 

[Aart]

As with most Mark series amps, keeping the Bass at 3 or below is the key.

Mesa/Boogie Mark IV Clips:
R2 rock Crunch 1
R2 Rock Crunch 2
R2 Rock Crunch 3

Lead Rock Tones
Lead Metal Tone
Lead Rock Wankage

what settings did you use on the lead metal clip?

 

[Aart]

bump, swf, can you post the setting u used on the lead metal clip?

 

[SFW]

Here's how I EQ the lead channel for the clips you heard.

Lead Gain: 8 (P)
Treble: 7.5
Bass: 3 (3.5)
Mids: 5
Lead Drive: 8 (P)
Lead Pres: 3
Ch Vol: 3
Master: to taste

The graphic EQ and the setting on the back are the same as the info I gave in the thread. One of the biggest factors in my tone is the use of EL34 in the outer powertube scokets. With the EL34s, the tone is more balanced across the spectrum. With all 6L6s, the tone is more aggressive. Both sound good, but I prefer the balance that the EL34s give. They also help with the tone achived on R2- giving it a more "British" flavor. I hope this helps.

 

[SFW]

Those clips sounded great! Could you put up the settings you used? Thanks!

JA

R2 settings:

R2 Gain: 10 (pulled)
Bass: 4 (3.5)
Mids: 5
Treb: 8 (sometimes 10)
Pres: 3 to 4
Master: to taste. I think I had both channel volume and Master on "3" for these clips.

Graphic: in inches from center-

80HZ 1/4 above
240 - center
750 - 1/4 below
2200 - 1/8 below
6600 - 1/4 below

 

[highroller]

I bought a used Mark IV (1991) a year ago, I installed brand new Elctro-Harmonix tubes in the preamp stage and Svetlana in power amp (all 6L6) stages.

I play with an Ibanez RG-42 with Dimarzio Evolution pickups and a Jackson RR-3 w/ Duncan Designed pickups.

I found that my lead sound is a kind of "sterile" at low to medium volume, I have not much gain or natural sustain. I tweaked the amp every imaginary way (Tweed, class A, Full, Simulclass...ect) with no good result.

I heard your clips and my amp definitevely lack gain and sustain.

Anyone have experienced sustaining problem with their Mark IV ?

Someone suggested me to use EL-34 and Class A to increase gain. I will see if it can cure the problem.

Comments welcome !

 

[jargapix]

Cool man...thanks! i had pretty uch the same settings except for the Presence.I had mine around 7...I've now set it at 5 to get a nice balance.


JA