Mesa MKIIC+ build

Toe-Knee · Post by **Toe-Knee** » Mon Jul 22, 2013 5:14 pm

Seen as though the power transformer should be here soon i thought i would start posting up some pics of a mkIIC+ that i'm building. So far i have fully populated the preamp Pcb minus valve sockets as i'm trying to think of a way to not mount them to the pcb for future maintenance ease.

I have been holding off on populating the GEQ and the PSU purely for ease of storage but i have all the parts so here's a quick shot of the Pcbs and chassis before i started.

As you may notice the chassis as great as it is didn't come with any mounting nuts welded in so i got handy with some rivnuts.

Then this final part for today is the bit that took the longest. The simulclass output transformer. I spent literally weeks googling for information regarding this beast and learnt i could just use a 50w marshall OT and mismatch the secondaries but then i would lose my 16ohm tap and i didn't want that.

So i did some more research and found someone who had dissasembled an original unit and noted down the winds, wire guage and lamination sizes. I had to make some slight adjustments to the laminations to accomodate the additional 16ohm tap (not present on the original) and sent the information over to BLS transformers and a couple of weeks later this beauty arrived in the post.

Now I am just waiting on Heyboer as i have been for quite some time now but i've been assured it should be with me soon so I had best get deciding on tolex and such.

clipless bumper · Post by **clipless bumper** » Mon Jul 22, 2013 8:39 pm

wow - nice work.
will be anxious to hear how well it works on first firing.

needless to say - this will be a one-of-a-kind!!

JCDenton6 · Post by **JCDenton6** » Mon Jul 22, 2013 9:21 pm

Killer, I bet this is gonna kick so much ass when it's done! :rawk:

Casey4s · Post by **Casey4s** » Mon Jul 22, 2013 9:31 pm

Off to a great start, I'm looking forward to following your progress.

Toe-Knee · Post by **Toe-Knee** » Tue Jul 23, 2013 1:40 pm

mamberg wrote:wow - nice work.
will be anxious to hear how well it works on first firing.

needless to say - this will be a one-of-a-kind!!

It definitely will be! I'm still not 100% sure on the OT but BLS have an excellent rewind policy so i'm not worrying too much right now.

JCDenton6 wrote:Killer, I bet this is gonna kick so much ass when it's done!

That's what i'm hoping for.

Casey4s wrote:Off to a great start, I'm looking forward to following your progress.

Cheers. Hopefully it shouldn't take too long now. Just waiting on the PT.

I'm thinking some kind of burgundy or electric blue snakeskin for the tolex. Or maybe i'll just go with white so it matches the rest of my rig.

Casey4s · Post by **Casey4s** » Tue Jul 23, 2013 2:08 pm

Go with the white Tolex, I think it looks cooler than the Snakeskin stuff IMHO.

Have fun with your build. :rawk:

LP Freak · Post by **LP Freak** » Wed Jul 24, 2013 4:58 am

Very cool

tlingen · Post by **tlingen** » Thu Sep 12, 2013 2:00 pm

Looks cool! I'll be watching your progress also as I was thinking of buying that kit myself.

Toe-Knee · Post by **Toe-Knee** » Thu Sep 12, 2013 3:22 pm

tlingen wrote:Looks cool! I'll be watching your progress also as I was thinking of buying that kit myself.

There should be a few updates in the next couple of weeks. I have all of the parts now but I just moved house and everything is hectic. Once things are more settled and I have my workshop setup things should fly by!

Also if you get the kit send me a PM as there are a few parts in the schems/pcb silkscreens that arent very apparent initially. I also did a full better BOM as the one that comes with the kit is missing a few parts and has a lot of discontinued products that aren't available anymore.

BillyBlades · Post by **BillyBlades** » Fri Sep 20, 2013 8:22 pm

Dying to.hear one of these.

Toe-Knee · Post by **Toe-Knee** » Tue Sep 24, 2013 1:26 pm

Just started unpacking all of my parts since moving so I can get going on this.

GodBlessTexas · Post by **GodBlessTexas** » Fri Oct 04, 2013 12:57 am

Toe-Knee wrote:Just started unpacking all of my parts since moving so I can get going on this.

Toe-Knee · Post by **Toe-Knee** » Fri Nov 15, 2013 5:48 pm

Just a small update. The headshell has been tolexed. Now for the grill and to decide whether to add silver piping or not....

Annoyingly i'm now on long shifts at work so i'll only get a chance to work on it on sundays from here on out. Hopefully it will be done for christmas.

Toe-Knee · Post by **Toe-Knee** » Mon Dec 16, 2013 3:11 pm

I have been crazily busy at work these last couple of months so I haven't even had a chance to touch this.

Things have finally calmed down so i've jumped back in.

First up here's the headshell & a test fitting ( inside to be painted before I do the shielding & fit the reverb tank)

Heres the octal heaters

and the offboard components (screen grids, grid stoppers)

and here's the OT primaries and the other pair of octals in progress.

and now it's time for food so i'll continue this tomorrow.

Toe-Knee · Post by **Toe-Knee** » Tue Dec 17, 2013 6:18 pm

I ended up staying at work longer than I expected today so there was very little progress.

I managed to finish the octal wiring & the simul class switch though.

I've just noticed a shady looking solder joint on the simul class switch on these photos. That will be fixed tomorrow then onto the mains wiring.

clipless bumper · Post by **clipless bumper** » Tue Dec 17, 2013 10:08 pm

Did you populate the entire board?
This is an awesome project.

Toe-Knee · Post by **Toe-Knee** » Wed Dec 18, 2013 1:25 am

mamberg wrote:Did you populate the entire board?
This is an awesome project.

Yes, well most of it. There are a couple of caps that get left out in the simulclass version. It took quite a while.

K-Bizzle · Post by **K-Bizzle** » Wed Dec 18, 2013 7:56 am

Wow very cool build.

Marc G · Post by **Marc G** » Wed Dec 18, 2013 7:59 am

man.. I wish I had the ability and the patience to do shit like this....

Toe-Knee · Post by **Toe-Knee** » Fri Dec 20, 2013 10:39 am

Marc G wrote:man.. I wish I had the ability and the patience to do shit like this....

Patience is a key factor in this. Other than that learning how to read schematics & solder and you are well on your way!

Toe-Knee · Post by **Toe-Knee** » Fri Dec 20, 2013 10:40 am

I just finished PSU, mains & EQ switching.

Now I'm just waiting on some wire in the post so that I can extend the Output transformer secondaries and finish up.

There are a few little jobs that I can be getting on with though such as the pot wiring and the GEQ.

However I think I deserve to go muck about on the PS4 for a while.

Toe-Knee · Post by **Toe-Knee** » Mon Jan 06, 2014 3:41 pm

It's finished! Well mostly.

I need to lower the EQ voltage a bit & get some new valves in it

After a bit of tidying ill post more pics.

This thing has a ridiculous amount of gain and a pretty funky way to dial it in but I'm loving it so far.

Toe-Knee · Post by **Toe-Knee** » Sun Jan 12, 2014 12:12 pm

Finally i got round to doing a quick clip.

Oddly enough I ended up recording a bit of blackened using the battery settings from the studio notes.

A word of warning. I really suck at mic placement....

https://dl.dropboxusercontent.com/u/980 ... IIC%2B.mp3

amused · Post by **amused** » Sun Jan 12, 2014 1:01 pm

That sounds really good imo

Wookieslayer · Post by **Wookieslayer** » Mon Mar 17, 2014 3:47 am

this is awesome

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Mesa MKIIC+ build

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