Tweed Super Build

Cjsinla

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I’ve had a tweed Super build for a while but I’ve had trouble getting it to sound good to me. It started life as a a Weber kit, they don’t seem to sell it anymore. But recently I finally got it dialed in after an OT and speaker change. It sounded so good at a recent rehearsal I decided that I needed to build another one. My excuse was that I still had a Mercury Magnetics OT and 2 Weber alnico speakers lying around after the first build. This time I ordered the Mojotone 5f4 Super kit.

I started the new build tonight, put in the tube sockets, the transformers and wired up most of the power supply. The Mojotone PT has taps for 100v, 120v, 200v and 220v. I assume that I need to use heat shrink on any taps I’m not using, right?

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CB91710

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Absolutely... don't trust tape alone. Heat shrink anything not used and dress it out of the way with zip-ties.

Looks like a fun project. I've really had an urge to build a tweed for a long time.
 

Splattle101

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My favourite tweed amp, the 5F4 Super. Well, one of my favourites. I really like the 5E3 cuz it's soooo chewy. Even though it can lack headroom it's hard to pass up. And the 5F1 Champ is a thing of beautiful simplicity with the meanest overdrive. And the 5F6A Bassman is like a Super that's a touch harder and quite a bit louder, and...

...they're all good, dammit.

But I do like the 5F4 in particular.
 

The Ballzz

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Once afflicted, there is no cure for "The Need For Tweed!" It almost doesn't seem to matter what model, they all have their own magical sweet spot! :naughty:
@Splattle101 certainly smells what I'm steppin' in here! :cheers2:

Just My $.02 (or whatever the parts cost!)
Gene
 

CB91710

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My favourite tweed amp, the 5F4 Super. Well, one of my favourites. I really like the 5E3 cuz it's soooo chewy. Even though it can lack headroom it's hard to pass up. And the 5F1 Champ is a thing of beautiful simplicity with the meanest overdrive. And the 5F6A Bassman is like a Super that's a touch harder and quite a bit louder, and...
And to think of all of the original tweeds I've passed on over the years (when they were still cheap "used amps") because I assumed that they were cleaner than Silverface and only suitable for country and Rockabilly. Thought rock was made on Marshall.
 

Cjsinla

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My favourite tweed amp, the 5F4 Super. Well, one of my favourites. I really like the 5E3 cuz it's soooo chewy. Even though it can lack headroom it's hard to pass up. And the 5F1 Champ is a thing of beautiful simplicity with the meanest overdrive. And the 5F6A Bassman is like a Super that's a touch harder and quite a bit louder, and...

...they're all good, dammit.

But I do like the 5F4 in particular.
You helped me with a few of my tweed builds. So far I have a Champ, a Vibrolux, a Deluxe and a Super. The one I have the most trouble bonding with is the Deluxe, which was my first build. Almost nothing beats the Champ for sitting on the couch and watching tv.
 

The Ballzz

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And to think of all of the original tweeds I've passed on over the years (when they were still cheap "used amps") because I assumed that they were cleaner than Silverface and only suitable for country and Rockabilly. Thought rock was made on Marshall.
Now the funny part there is that many Tweeds sound more like a Marshall than like the later Black and Silver Face Fenders! :shock: Not that there is anything "wrong" with those later Fenders, as long as they're being used by someone other than me, :rofl: for the most part.

Just My $.02 & Likely Worth Much Less!
Gene
 
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Pappy58

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Nice...plz keep us up to date with progress :applause:
 

Cjsinla

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A quick question; the 120 AC is fed to the primary winding by a pair of wires, one black and one white. Does it matter which wire goes to the switch and which wire goes to the fuse?

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CB91710

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Honestly... The fuse and switch should be on the same lead, and that is the black wire from the wall outlet.
If the hot is switched and the neutral is fused, then if the fuse blows, there is still 110 passing through the transformer.
The direction at the transformer really doesn't matter, but for consistency, I would connect black to black (hot) and white to white (neutral)

Edit: Yikes... MT held true to the original design, switching and fusing opposite leads, and also included the "death cap" and ground switch.
That portion of the circuit is not needed with a 3-wire plug. It is a holdover from the days before polarized plugs, and used to reference the chassis to ground through the cap. If the ground switch was the wrong way, it would result in more hum, but if (when) the cap shorts, it can dump 110 directly to the chassis and give you a nasty (lethal) shock from your lips on the mic.

Edit 2: OK, that's better... the schematic shows the ground switch, and it threw me because I saw the orange drop and black wire on the 2nd switch... but I see that is the Standby switch and the ground switch is just a blank filler in the wiring diagram.
So the schematic matches the Fender design, but they *did* eliminate the death cap from the kit instructions.

Honestly, you will likely never encounter a problem with the fuse and switch being on opposite legs. The two potentially serious issues are:
If the fuse is on the hot leg, changing the fuse, it will still be hot
If the fuse is on the neutral, if the transformer shorts internally, the fuse may or may not blow, but your switch will become the fuse.

Personally, I'd replace the switch with a Double-Pole and switch both legs ahead of the fuse, *OR* wire the fuse and the switch both to hot.
 
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Cjsinla

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Honestly... The fuse and switch should be on the same lead, and that is the black wire from the wall outlet.
If the hot is switched and the neutral is fused, then if the fuse blows, there is still 110 passing through the transformer.
The direction at the transformer really doesn't matter, but for consistency, I would connect black to black (hot) and white to white (neutral)

Edit: Yikes... MT held true to the original design, switching and fusing opposite leads, and also included the "death cap" and ground switch.
That portion of the circuit is not needed with a 3-wire plug. It is a holdover from the days before polarized plugs, and used to reference the chassis to ground through the cap. If the ground switch was the wrong way, it would result in more hum, but if (when) the cap shorts, it can dump 110 directly to the chassis and give you a nasty (lethal) shock from your lips on the mic.

Edit 2: OK, that's better... the schematic shows the ground switch, and it threw me because I saw the orange drop and black wire on the 2nd switch... but I see that is the Standby switch and the ground switch is just a blank filler in the wiring diagram.
So the schematic matches the Fender design, but they *did* eliminate the death cap from the kit instructions.

Honestly, you will likely never encounter a problem with the fuse and switch being on opposite legs. The two potentially serious issues are:
If the fuse is on the hot leg, changing the fuse, it will still be hot
If the fuse is on the neutral, if the transformer shorts internally, the fuse may or may not blow, but your switch will become the fuse.

Personally, I'd replace the switch with a Double-Pole and switch both legs ahead of the fuse, *OR* wire the fuse and the switch both to hot.
So I need to attach the black wire from the plug to the switch and the white wire to the fuse?
 

CB91710

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So I need to attach the black wire from the plug to the switch and the white wire to the fuse?
I think it would be safest to put the fuse on the hot leg, and make sure to unplug it before changing the fuse if it blows.
That way, if the transformer shorts, it won't send AC into the chassis after the fuse blows.

Seriously, it's not a good design, I'd seek input from @Soul Tramp or one of the other resident amp experts.
 

Soul Tramp

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I think it would be safest to put the fuse on the hot leg, and make sure to unplug it before changing the fuse if it blows.
That way, if the transformer shorts, it won't send AC into the chassis after the fuse blows.

Seriously, it's not a good design, I'd seek input from @Soul Tramp or one of the other resident amp experts.
You are absolutely right. The black PT wire should go to the switch, fuse, and "Load" leg of the IEC connector.

I want to type something very judgemental about lazy/bad/dangerous power supply designs, but will refrain.
 

Cjsinla

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You are absolutely right. The black PT wire should go to the switch, fuse, and "Load" leg of the IEC connector.

I want to type something very judgemental about lazy/bad/dangerous power supply designs, but will refrain.
I believe on previous builds I learned to put the AC from the wall to the end pin on the fuse holder. That way you won’t get shocked when trying to change the fuse. The PT has a 0v black and a 120v white wire. Right now, I have the 0v black wire on the fuse holder and the white 120v wire on the switch. My original question was, is this OK?

To complete the wiring for the power, I plan to attach the plug like this: black wire to the end of the fuse holder and white wire to the other side of the (AC) switch and green to ground. Is that OK?

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CB91710

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I believe on previous builds I learned to put the AC from the wall to the end pin on the fuse holder. That way you won’t get shocked when trying to change the fuse. The PT has a 0v black and a 120v white wire. Right now, I have the 0v black wire on the fuse holder and the white 120v wire on the switch. My original question was, is this OK?

To complete the wiring for the power, I plan to attach the plug like this: black wire to the end of the fuse holder and white wire to the other side of the (AC) switch and green to ground. Is that OK?
That is the least offensive way to do it... at least the fuse breaks the hot should the transformer short to ground internally.
Push the new fuse into the cap and you're good when installing a new one.
 

Soul Tramp

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Best to keep the resistors elevated above the board so there's an air gap below. And be sure not to let the resistors touch any other component.
 

Cjsinla

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Best to keep the resistors elevated above the board so there's an air gap below. And be sure not to let the resistors touch any other component.
Right. I think I learned that from you!
 


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