Join me on a magical journey: Metro Plexi Superlead Build

[FourT6and2]

I need to rewire the power switch and fuses. This "classic" way of wiring it is dangerous and can cause a shock. I need to put the Mains Fuse between the switch and wall. This means I have to move some wires around. I hope I have enough wire-length to do this! And I'm still a little confused about what goes where with this change. So, I need to find a layout or something.

 

[LP Freak]

You didn't opt for the IEC outlet huh? That power cord always hanging out the back is a PITA.

 

[Bierschinken]

Hey,

I´m reading your Thread on the Metroboard too, nice work so far

Pretty easy on the fuse-issue:

Run the first wire from the mains to the fuse and the from the fuse to your powerswitch.
The second wire from the mains goes straight to the switch.
Then it goes to your PT.

Hope that helps.

- Swen

EDIT: LP freak, is there an official option for an IEC outlet? - I'm attracted by the 50W Plexi but yes, the power cord is indeed a PITA.

 

[FourT6and2]

Hey,

I´m reading your Thread on the Metroboard too, nice work so far

Pretty easy on the fuse-issue:

Run the first wire from the mains to the fuse and the from the fuse to your powerswitch.
The second wire from the mains goes straight to the switch.
Then it goes to your PT.

Hope that helps.

- Swen

EDIT: LP freak, is there an official option for an IEC outlet? - I'm attracted by the 50W Plexi but yes, the power cord is indeed a PITA.

I wish I had an IEC outlet, but I have no way of drilling out a rectangular hole for one.

I understand the concept of rewiring the fuse. But I don't know which wires to move where. Especially since my transformer is different than the one most people have in their kits. I need an actual layout diagram showing the same colored leads that I have. Or someone who can look at my photos and say, "ok put that orange wire here and that purple wire there."

 

[LP Freak]

Hey,

I´m reading your Thread on the Metroboard too, nice work so far

Pretty easy on the fuse-issue:

Run the first wire from the mains to the fuse and the from the fuse to your powerswitch.
The second wire from the mains goes straight to the switch.
Then it goes to your PT.

Hope that helps.

- Swen

EDIT: LP freak, is there an official option for an IEC outlet? - I'm attracted by the 50W Plexi but yes, the power cord is indeed a PITA.

I wish I had an IEC outlet, but I have no way of drilling out a rectangular hole for one.

I understand the concept of rewiring the fuse. But I don't know which wires to move where. Especially since my transformer is different than the one most people have in their kits. I need an actual layout diagram showing the same colored leads that I have. Or someone who can look at my photos and say, "ok put that orange wire here and that purple wire there."

No, there's not an option. You have to drill it and cut it out yourself. It's pretty easy. Just put some masking tape on the chassis and cut it out with a jig saw. I put these on every amp I built. It's best to do before you start, but you can still do it. Just take your time.

 

[Bierschinken]

Hey,

Just put some masking tape on the chassis and cut it out with a jig saw. I put these on every amp I built. It's best to do before you start, but you can still do it. Just take your time.

Yep, did that on a lot of builds and vintage "player" amps. But i find it a PITA do cut it so that the IEC outlet fits neat and tightly.
I´m gonna get me a rectangular metal punch, but there pretty expensive. Hope Santa is a kind guy this year

I understand the concept of rewiring the fuse. [...] I need an actual layout diagram showing the same colored leads that I have. Or someone who can look at my photos and say, "ok put that orange wire here and that purple wire there."

Okay, let´s figure this out; what PT do you have? There are lots of SLP-Style PTs on the MM page so I don´t want to confuse a thing.

After that, we´ll check which wire has to go where

- Swen

 

[duesentrieb]

The chassis is aluminum/aluminium, right? So adding a rect. cut out shouldn't be that hard - or get those rect. punch drills from RS - probably Mike Fortin or Dan can help you . . .

I also replied to the HCAF thread with another idea . . .

 

[FourT6and2]

Hey,

Just put some masking tape on the chassis and cut it out with a jig saw. I put these on every amp I built. It's best to do before you start, but you can still do it. Just take your time.

Yep, did that on a lot of builds and vintage "player" amps. But i find it a PITA do cut it so that the IEC outlet fits neat and tightly.
I´m gonna get me a rectangular metal punch, but there pretty expensive. Hope Santa is a kind guy this year

I understand the concept of rewiring the fuse. [...] I need an actual layout diagram showing the same colored leads that I have. Or someone who can look at my photos and say, "ok put that orange wire here and that purple wire there."

Okay, let´s figure this out; what PT do you have? There are lots of SLP-Style PTs on the MM page so I don´t want to confuse a thing.

After that, we´ll check which wire has to go where

- Swen

I have the Mercury Magnetics ToneClone MP100-460 Power Transformer. Here's it's schematic:

Right now, I have it wired like this:

Orange primary: tip of mains fuse
Red primary (120V power switch
Blue and Violet: not used

Blue/White: Standby switch
Yellow: filter cap
Grey: Standby switch
Black/Black: heaters
Green: center tap ground
Green: Bias ground
White: Bias to the board
Brown/Brown: not used

I have the red lead from the light wired to the power switch and the black lead to the mains fuse tip along with the orange PT primary.

The chassis is aluminum/aluminium, right? So adding a rect. cut out shouldn't be that hard - or get those rect. punch drills from RS - probably Mike Fortin or Dan can help you . . .

I also replied to the HCAF thread with another idea . . .

Are you VH4 over there? I have a few of those washers. I don't think there's room on the PT and OT bolts for them???

 

[duesentrieb]

Yup, thats me.

Wiring looks correct to me.

 

[FourT6and2]

Yup, thats me.

Wiring looks correct to me.

Yeah, it's fine. But I was told I should rewire it because right now there is still live voltage in the chassis even if the fuse blows and the power switch is off. The fuse should go before the switch. Kind of like this, I think:

This is my wiring right now. I need to figure out what to move where, to get it as safe as possible. So there's no risk of shock. I think I need to move the orange lead from the PT Primary to the power cord along with the black lead from the light. The other side of the power cord goes to the fuse tip. Then another jumper from the fuse body to the power switch. I think...

 

[duesentrieb]

Switch both, orange and red, problem solved, DPDT switch needed.
One of them (in your cable you should have brown and blue - and earth of course) is fused before it goes to the switch.

 

[duesentrieb]

this should help you:

http://www.drtube.com/schematics/marshall/78614-3.gif

 

[duesentrieb]

about the washers - here's a JTM45/Metro, where Larry installed them (on top and bottom), not sure if he used longer screws though . . .

 

[FourT6and2]

Switch both, orange and red, problem solved, DPDT switch needed.
One of them (in your cable you should have brown and blue - and earth of course) is fused before it goes to the switch.

Still confused.

Why do I need a DPDT switch? My power cable has white, green and black. From my understanding, I should connect orange to the power's neutral lead, the fuse to the power's live lead, the red PT primary stays the same and I run the power switch to the fuse.

 

[duesentrieb]

Thats germany "vs" america - I forgot that your mains plug just fits into one direction into the wall, so you have always "L" where it should be - in germany (and other places in europe) you can flip the mains plug, so any electrical device needs to be switched on N and L on/off. Also the color codes for 120V (w, g, b) seem to be different.

Sorry for the confusion. My fault.

 

[FourT6and2]

Olaf, which one of these is correct and the safest?

1. The lamp will function correctly. This is the best way, right?

2. The lamp will function correctly. If the lamp goes to the fuse tip, instead, it will still power on/off even when the fuse is blown, right? So it should go to the side of the fuse.

3. The lamp will always be on.

4. The lamp will always be on.

5.

 

[duesentrieb]

No 5 is correct with a SPDT switch. The lamp is in parallel and gets 120V. Don't run the lamp in series, it will act like a fuse - if lamp is broken, the amp won't work. I still prefer a different wiring though

I will draw you something, takes until tomorrow my time though, I don't have a scanner at home.

Do I understand correctly (and looking at your pics) that you already have a DPDT on/off switch installed?

 

[jerrydyer]

NICE
you keeping it stock or going high gain?

 

[duesentrieb]

Please have a look - this is how it is done: http://www.ceriatone.com/images/layoutP ... hat504.jpg
a DPDT switch -
from L to fuse to switch right side
from N to switch left side
from transformer "0" to the "N-side" (left) - lower PIn
from transformer "120" side to the "L-side" - lower Pin

then the 120V lamp is soldered to where "0" and "120" of the transfomer are at the switch - the lower pins on the left and right side.

 

[FourT6and2]

Please have a look - this is how it is done: http://www.ceriatone.com/images/layoutP ... hat504.jpg
a DPDT switch -
from L to fuse to switch right side
from N to switch left side
from transformer "0" to the "N-side" (left) - lower PIn
from transformer "120" side to the "L-side" - lower Pin

then the 120V lamp is soldered to where "0" and "120" of the transfomer are at the switch - the lower pins on the left and right side.

No, I have DPST switches. Could you draw me a layout? That would help greatly.