Wiz MTL build with Burger PCB

fusedbrain

Well-known member
So I'm getting started on a Wizard MTL clone build on one of forum member Burger's PCBs.
It's going to be 100watt build in a Valvestorm project chassis.
I had a Classictone Project PT on the shelf, but getting any more Classictone iron right now is impossible, so the choke and OPT are going to be Hammond. The Hammond OPT is their paper layer wound 100watt project OPT with 2000k primary and flat freq response down to 50hz. Choke is 6H.
Coupling caps are OD716P, and the resistors are Vishay / BC PR02 metal film. Small signal caps are 1000v CDE silver mica and there's one 3kv ceramic snubber on one of the plate resistors. Electro's are all Nichicon.
Should be good :thumbsup:

I have everything I need on hand except the chassis, which has shipped and should be here this week. In the meantime, I've stuffed the PCB and it's ready to go.
I'll update as I go, but here's the PCB for now:
 

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I was going to use these from Valvestorm. Standard Belton socket I think?
General features will be: The channel select and the boosts for the lead and Rhythm channels will be foot-switchable. The boosts will also be on pull pots on the 2 gain controls. Mini toggle on the front for channel select as well, in case the F/Sw is not plugged in. Also mini toggle for Rhythm bright and one for the mid shift. All same as stock Wiz, except I'm probably not going to put any LED's on the front face plate. The F/Sw will have LED's to show status.
I'm going to use one of burger's loop boards as well, but the loop will not be on a F/Sw.

Changes from stock MTL planned so far: There will be a loop return / system master vol after the loop. Stock MTL lead channel has 2 gain stages after the lead master, and rhythm channel has one gain stage after the rhythm master that feed the tone stack via the plate. On the stock Wiz, low master settings affect tone and drive into TS. A post loop master will allow channel vols to be run higher and maintain sensible volume output.
Stock rhythm channel is lack luster on MTL ( MCII is much nicer :D ) There will be some tweaking done in this area for sure, but I need to build the amp first and see where I am.
Stock MTL's have a B+ around 510v-515v ( at least the one I had did anyway ). I will probably target 460v - 470v to allow a wider selection of EL34 power tubes. The only CP EL34's I would use at >500v B+ are JJ or preferred series from the TubeStore. JJ KT77's are also very good at high B+, but KT77 frequency response is not a good match for MTL circuit. There is lots of room in the B+ string to adjust voltages up or down between screens and preamp to achieve the desired tone. Each 12ax7 has it's own B+ node. (dropping resistor and filter cap).
 

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Interesting that you’re doing parallel RC runs to each preamp tube instead of series to allow for voltage increase or decrease for gain control. Should help with noise too.

The post effects loop master, is that something that should be considered on a Marshall or is that specific to the wizard? I have both masters feeding the loop planned in my build, wondering if they should be moved to after the effects loop.
 
glpg80":dksspu4m said:
Interesting that you’re doing parallel RC runs to each preamp tube instead of series to allow for voltage increase or decrease for gain control. Should help with noise too.

The post effects loop master, is that something that should be considered on a Marshall or is that specific to the wizard? I have both masters feeding the loop planned in my build, wondering if they should be moved to after the effects loop.
No, sorry i didn't mean that the B+ string is parallel, just that there is a unusually large # of nodes. They are all in series. Just more places to tweak than usual. :D

The loop return master is being added because there are gain stages after the channel masters. The location of the channel masters is not typical. (***credit to Burger for realizing the impact on the amps operation, and documenting this mod ***)
For example, the Lead channel signal flow is: 4x pre amp gain stages > Lead channel master volume > gain stage > gain stage > tone stack > loop > ( my added loop return volume ) > PI.
Channel master setting has big effect on what happens with 2 additional gain stages + tone stack.
I believe Rick is building amps to be played in stadiums with channel masters opened up considerably. Lower volume tone of most Wizard amps is not as special as wide open tone ( some would debate, but that is the general consensus )
My addition master volume will allow channel masters to be turned up as desired, and should help improve lower volume ( less than wall shaking ) tone.
A similar phenomenon is observed with Diezel VH4. Channel masters turned up 3/4 to full up, with main amp volume used to control output improves tone considerably.
If signal flow was typical: All pre amp gain stages > tone stack > master vol > loop > PI , then additional master would not be required.
 
Ahh makes sense now, I see your dilemma.

Those are the same ones I’m repairing my Marshall with. The pins are numbered on the bottom which help out greatly and the pins feel way more solid than my oem Marshall ones. They’re due for a change for sure. You will like them.
 
Cool project! I like those sockets I've used them in a couple of builds. I also like a Global Master (aka - loop return volume control). For me, once the amp is set and channels balanced, I think it should only take one knob to change volume.
 
So how did this go? I have this board and the MC2 laying around. I'm hoping to finish the Friedman mini burger did after my current project. I love these PCB's. I think he has a ST1 based board coming out soon which will probably be my next project after the Friedman mini.


Each time I try to build something I learn how much I dont know.
 
I was going to post an update later this weekend. I finally got my chassis last week, and I have some time set aside later today and tomorrow to finally get going on this again.
Canada Post has been a complete disaster lately :doh: :doh: :doh:
Stuff is taking forever for them to deliver. For some reason, my chassis sat in Montreal for almost a month according to the tracking info. I live near Toronto. The fuking thing should have never gone anywhere near Montreal.
Yeah, the Burger boards are very nice. I have 3 more loop boards on the way, but I'll probably get them at Christmas the way C.P. is operating.

While I was waiting I kept busy with another little build. Something completely different.
Build post pending about that too. :D
 
fusedbrain":10ei4qui said:
I was going to post an update later this weekend. I finally got my chassis last week, and I have some time set aside later today and tomorrow to finally get going on this again.
Canada Post has been a complete disaster lately :doh: :doh: :doh:
Stuff is taking forever for them to deliver. For some reason, my chassis sat in Montreal for almost a month according to the tracking info. I live near Toronto. The fuking thing should have never gone anywhere near Montreal.
Yeah, the Burger boards are very nice. I have 3 more loop boards on the way, but I'll probably get them at Christmas the way C.P. is operating.

While I was waiting I kept busy with another little build. Something completely different.
Build post pending about that too. :D


I just got 2 loop boards and some faceplates for the Friedman mini from Burger and they just showed up yesterday. He sent them in May. So shipping from Australia is a bit rough at the moment. He said he has some new boards coming in soon which is killing me cause I'm broke after having to move unexpectedly. I think he has ST1 type boards, a new Wizard based board, and a single channel Jose board. I owe V2 some money plus I have to pay my amp tech for an amp he is working on for me before I can think of starting on a new project.

I have the MCII and MTL boards so Im really interested in how yours comes out. Are you using the Valvestorm chassis or did you pick up one from somewhere else?
 
Things have been a mess for me since I posted that last post. Work and life are just crazy right now.
I still haven't got much done. I'm hearing this a lot from all over, so I guess it's not just me.
Yeah I have some more stuff coming from Burger too, but tracking shows it's on a boat now :LOL: :LOL:
I have everything I need for the MTL build now except time.
My MTL build is going in a Valvestorm project chassis.
I will post as soon as I can get some progress made.
 
Hi guys, nice to hear that there is some progress on your builds!!

Shipping delays: we here in Melbourne Australia have just entered a second Covid lockdown, Aus Post International is still in operation but there are some expected delays...

The Marshall ST1 2203/2204/1959/1987 project board is now up on the website. It's completely self contained with all filter caps on board - however if using chassis mounted can caps, you can of course just wire these into the PCB. I've spaced the standoffs as per the ST1 board, so should slot straight into a Marshall spec chassis. Scheme and PCB spec attached FYI.



The 6 noval MCII will be up soon (tube buffered FX loop), and I've nearly completed a CCV style (dirty channel) PCB for the exact circuit I ended up with here:

https://youtu.be/Wi-AgtBSogU
 

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This is beyond cool. I'd love to get down on something like this! Stoked to see how it all turns out for you. I'm sure price wise this hasn't been exactly cheap haha.
 
Congrats Fusedbrain... your putting up a master volume control will be a plus point on the Wizard clone... !! Cant wait to see the build ! Please post pictures progress of this build :)
 
A little update:
So about 10 days ago I finally get some time to really dig into this and get this thing finished......
And I realized I made a reallyy stupid mistake stuffing the PCB: My plan was to build a 100watter using the Classictone 100watt project power transformer. It has 15 volt tap that I was going to use to feed the low voltage rectifier / voltage regulator for the relays and maybe DC on the heaters for a couple of preamp tubes.
Then I realized that I had loaded the PCB with 5 volt relays and a 7805 5v regulator :doh: :doh: :doh:
So now, if I feed the low voltage rectifier with 15v AC, and drop the voltage to 5v, I calculate that I'm going to be dissipating about 4watts of power through the voltage regulator powering all the relays and LED's etc. It's heatsink'd, but that seemded a little risky to me. And no DC heaters possible now either.
So not wanting to try and swap all the relays and the voltage regulator that are soldered into the PCB ( cause the way this is going, I'd probably destroy the board ) I need a 50watt PT with a 5v tap.
The only 50watt PT I have with a 5v tap is laydown, and the only chassis I have that fits the MTL board needs a standup PT. Figures :doh: :doh:
So I had to order a 50 watt standup PT with a 5v AC tap .
The pcb will stay as it is with the 5 v relays, and I'll just run AC elevated heaters for this one.
The new PT will be here this week, and I can finally get this this thing rolling.

I've got an Burger MCII board still to build, so that will get done with the 100watt project PT and I'll use the right parts this time. :LOL: :LOL:
 
In the OP you mentioned voltages in the context of an MTL. What plate voltage are you shooting for with an MCII and does it change for 50W vs 100W? 500vdc or just north of it is about as high as I comfortably go and I'm considering doing a 100W MCII.
 
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