Mesa MarkV / Saturation 'mod'

Discussion for the new Mark V

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Markageddon
Mark III
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Re: Mesa MarkV / Saturation 'mod'

Post by Markageddon » Thu Apr 26, 2018 1:37 am

Yeah its clearly designed to be able to accomodate that tube.

Simplest solution is invariably best. I think its mainly in the dialling/playing after that.
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bandit2013
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Re: Mesa MarkV / Saturation 'mod'

Post by bandit2013 » Thu Apr 26, 2018 6:28 am

It is a learning experience when it comes to mods. Not something I want to do though. I have long dropped the idea I could turn the Mark V into a JP-2C killer. However with the IIC+ and GEQ mod it came very close. C18 was a bit overboard on my behalf. However when running two cabs though the 4 ohm taps it sounded really good. Amp gets much brighter on the 8 ohm tap with a single load. I would have to say prior to removal of C18, the Mark V was almost a dead ringer for the JP-2C character but with three flavors of punch to choose from when I had it hooked up to the Vertical 212 cab (same one I am using with the JP-2C). Dynamics are there too so there is some similarities. When it comes to the Power supply and OT that is where the differences are between the two (not to mention the position of the FX loop relative to the GEQ and that the GEQ is not the same as that used on the MKIV and earlier all the way to the IIC+ and I would assume the JP-2C has the same design as the original.) For some time, the TC-100 had been the focal point as it fits the style of music I play as well as my band mates when they come over. My gear does not travel with me to other places as I have a small practice amp for that. If I played gigs it would either be the JP-2C or the TC-100 or both. Mark V combo is a bit heavy to lug around, especially with an EV in it.

Wayno
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Re: Mesa MarkV / Saturation 'mod'

Post by Wayno » Thu Apr 26, 2018 1:16 pm

Practice went really well last night. Defo think C18 is gonna stay stock. iiC+ mode is nigh on perfect for me now through the vert 2x12. The more crunchy character compared to the iV modes smoothness is my thing for sure. At home messing around iV mode is great for lead playing but out live and up loud I just prefer the rougher iiC+ mode. Now it has the balls it was missing before, I love it. Seems a little more saturated than before too? I think that's maybe down to the extended frequency range from the pull deep mod filling out the sound and the coupling cap allowing it through. Definitely thicker sounding than before, perfect. Band mates all commented on how much better it sounded too.

One other thing I noticed too, on CH3 I always used to have to drop the 750Hz slider to at least half way between middle and bottom to get rid of the honkyness especially in iiC+ mode. Last night I ended up with a smile rather than a V on the EQ with the 750 slider dead centre. No honkyness, just crunch. Happy days indeed. Cuts through the bass and drums nicely without stepping on any toes either. Everyone's a winner!
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APEMAN
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Re: Mesa MarkV / Saturation 'mod'

Post by APEMAN » Sun Apr 29, 2018 2:13 am

hey everyone!
as I said before, I think there is one more easy thing that can be done. The ch3 treble and bass pot swap was a big win for my amp. It is so much easier to dial in the perfect amount of b m and t now. The sound became more open, feels like more headroom and definition in the gain character. It began when I measured the pot values. The bass pot with its 250k was fine but the treble with its 180k was far off so a simple swap was the cure here. If you feel confident with a soldering iron, give it a try! Cheers!

Wayno
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Re: Mesa MarkV / Saturation 'mod'

Post by Wayno » Sun Apr 29, 2018 8:33 am

APEMAN wrote:hey everyone!
as I said before, I think there is one more easy thing that can be done. The ch3 treble and bass pot swap was a big win for my amp. It is so much easier to dial in the perfect amount of b m and t now. The sound became more open, feels like more headroom and definition in the gain character. It began when I measured the pot values. The bass pot with its 250k was fine but the treble with its 180k was far off so a simple swap was the cure here. If you feel confident with a soldering iron, give it a try! Cheers!
Definitely a worthwhile thing to check and will be sure to check mine the next time I have the chassis out. Probably won't be for a while now though as my V is fully rockin so gonna concentrate on improving technique for a bit.
Her highness the Veenus
(Mark V/V4 & V7 12AT7 Combo)

2 x 12 Vertical Cab
GSP1101

Gibson LP Studio with alnico ii pro
Schecter C1-XXX with emg 81/85 18v
Jackson Dinky XL with Duncan designed???
Sigma DNC-1STE

bandit2013
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Re: Mesa MarkV / Saturation 'mod'

Post by bandit2013 » Sun Apr 29, 2018 8:44 am

I will not recommend removal of the C18 cap. My bad for posting such information earlier. Should wait and see how things go and then reveal what is good. That was difficult to replace but still manageable.

I will experiment with disconnect of the V6A mod just to get a feel how different the amp sounds with and without it. I did that one first before the GEQ mod. Wonder if there will be much of a difference. A pull pot would be ideal for that. I have no plans on drilling any holes in the chassis to mount a mini toggle switch but I may think about that and stick it on the rear of the chassis. A pull pot would be more ideal since that would not require drilling the chassis. Would rather leave the metal as stock as possible.

APEMAN
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Re: Mesa MarkV / Saturation 'mod'

Post by APEMAN » Thu May 03, 2018 2:12 am

Thanks for pointing that out bandit! The C18 removal was a point on my to-do-list since I realized that MarkIVs didn't use this cap. Maybe we reached that perfect point and it can't get any better... still I'm very very happy with my amp.

bandit2013
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Re: Mesa MarkV / Saturation 'mod'

Post by bandit2013 » Thu May 03, 2018 5:59 am

The C18 removal was not a bad deal though, it sounded good but lacked the edge and it took away more than I expected. Without the C18 you wind up with bass dominance and single notes when played over a sustained chord do not ring out like they did with the C18. I much prefer having that note definition. Also pinch off harmonics and sustain were much better with the C18 than without. For me it was worth the experiment.

mace
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Re: Mesa MarkV / Saturation 'mod'

Post by mace » Thu May 03, 2018 6:29 am

APEMAN wrote:hey everyone!
as I said before, I think there is one more easy thing that can be done. The ch3 treble and bass pot swap was a big win for my amp. It is so much easier to dial in the perfect amount of b m and t now. The sound became more open, feels like more headroom and definition in the gain character. It began when I measured the pot values. The bass pot with its 250k was fine but the treble with its 180k was far off so a simple swap was the cure here. If you feel confident with a soldering iron, give it a try! Cheers!
How does one go about measuring the resistance of the pot? Which contact points do you put the ohmmeter?

Should both bass and treble pots be 250k?

Thanks.
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kocher
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Re: Mesa MarkV / Saturation 'mod'

Post by kocher » Thu May 03, 2018 11:11 am

mace wrote: How does one go about measuring the resistance of the pot? Which contact points do you put the ohmmeter?

Should both bass and treble pots be 250k?

Thanks.
You would need to desolder a pot to measure it properly. Turn the pot to "0" and measure the resistance going from the middle lug to the other two. One lug should read zero Ohms and the other would read your pot value.

After turn the pot to "10" and measure again. It should be the same result with the lugs switched.

On channel 3 the pot values are:
Treble: 200k log
Mids: 10k log
Bass: 250k log

The pot values for the other channels differ from that. Just check a schematic if you are unsure.

APEMAN
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Re: Mesa MarkV / Saturation 'mod'

Post by APEMAN » Thu May 03, 2018 12:47 pm

As for the bass... I would never put the bass on CH3 on 100% - I use to set it to around 9 o'clock. Therefore, the pot swap changed my bass setting from 8:45 to 9:30 - which is fine for me.

Schematic values:
__T__M__B__C18_Model
190k 10k 250k yes MarkII
190k 10k 250k yes MarkIII
250k 10k 250k no_MarkIV
200k 10k 250k yes MarkV
180k 10k 250k yes MarkV apemans model measured value
250k 10k 250k yes JPIIC


Look here:
http://forum.grailtone.com/viewtopic.php?f=33&t=74669

bandit2013
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Re: Mesa MarkV / Saturation 'mod'

Post by bandit2013 » Fri May 04, 2018 5:55 am

I generally do not run bass past 11am, it generally stays between 9am and 11am. Also it depends on gain setting, voice selected and type of speaker being driven or what cabinet I am using.

APEMAN
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Re: Mesa MarkV / Saturation 'mod'

Post by APEMAN » Fri May 04, 2018 8:39 am

So bass- and middlewise there will be no problem with the pot swap. But the treble pots overall resistance (200k or 250k) influences the whole characteristics of the pre-gainstage filter network.

IronSean
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Re: Mesa MarkV / Saturation 'mod'

Post by IronSean » Wed May 09, 2018 11:58 am

APEMAN wrote:As for the bass... I would never put the bass on CH3 on 100% - I use to set it to around 9 o'clock. Therefore, the pot swap changed my bass setting from 8:45 to 9:30 - which is fine for me.

Schematic values:
__T__M__B__C18_Model
190k 10k 250k yes MarkII
190k 10k 250k yes MarkIII
250k 10k 250k no_MarkIV
200k 10k 250k yes MarkV
180k 10k 250k yes MarkV apemans model measured value
250k 10k 250k yes JPIIC


Look here:
http://forum.grailtone.com/viewtopic.php?f=33&t=74669
In that thread you said all other amps have a 250K for the Treble pot, but it looks like only the Mark IV and JPIIC have a 250K pot for the treble pot and the 180-200K is in line with the other Mark series amps?
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APEMAN
Mark III
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Re: Mesa MarkV / Saturation 'mod'

Post by APEMAN » Thu May 10, 2018 2:12 pm

Yes you are right, sorry for that - I will change this flase statement - to that time I had my nose deep in the IV and JPIIC schematics and I thought the JPIIC would be a 100% true IIC+ and I didn't believe the older schematics I found in the net. Back in the days they said those schematics contain wrong values and mistakes.

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