Power transformer wire grouping help

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Power transformer wire grouping help

Post by davemojo »

Hi All

I am following some instructing for my first built ever.
I bought the power transformer from Tonefactory.

The power transformer leads color are not fully matching the one I bought from Tonefactory

On the instructions they are saying to:

"The power transformer has twelve leads. Separate these into color-coded pairs and
twist these pairs together:

Two red leads <-- Done
Two green leads <-- Done
Yellow + white <-- Done
Stripes: green/yellow + red/yellow <-- missing Red/Yellow

This transformer is designed for either 120V or 240V operation, depending on
your country’s voltage (120V is standard in the United States). The difference amounts to choosing between two wires :
- 120V uses the black/white striped wire (Not for me)
- 240V uses the black/red striped wire (I have to use this but there is no black/red striped)
The wire you’re not going to use will be safely terminated along with the yellow/
white striped wire, which is also not used in the 74X.

Twist the wire you’re not going to use together with the yellow/white striped wire. "

I have now some different colors I made 2 pictures the wires and the little diagrams can anyone help?
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Re: Power transformer wire grouping help

Post by geoff 1965 »

The instructions don’t match the schematic,
The blue & orange wires are’nt used so either cut them short and seal the ends with heatshrink or solder to an unused isolated tag.
Black is mains negative and white is mains positive “240V”
Ez81 rectifier filament are grey & pink,
The yellow and green/yellow are your centre taps for the heater filament and HT so they are soldered to ground at your star ground point.
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Re: Power transformer wire grouping help

Post by davemojo »

geoff 1965 wrote:
Sat 03/06/21 2:00 pm
The instructions don’t match the schematic,
The blue & orange wires are’nt used so either cut them short and seal the ends with heatshrink or solder to an unused isolated tag.
Black is mains negative and white is mains positive “240V”
Ez81 rectifier filament are grey & pink,
The yellow and green/yellow are your centre taps for the heater filament and HT so they are soldered to ground at your star ground point.
Thanks so the only one I twisted correctly are the 2 kind of green together and the 2 reds?

Correct?
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Re: Power transformer wire grouping help

Post by geoff 1965 »

Yeah the 2 red are your HT to the rectifier and the 2 green are the heater filaments,which schematic/layout are you using?
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Re: Power transformer wire grouping help

Post by davemojo »

geoff 1965 wrote:
Sat 03/06/21 5:48 pm
Yeah the 2 red are your HT to the rectifier and the 2 green are the heater filaments,which schematic/layout are you using?
Thanks for your reply and help I appreciate it. I can tell you here the truth I dove into this project as someone complete novice in electronics. I'm am keyboardist and Organ player this amp goes with my Organ for playing some distorted rock piece in a similar way that Jon Lord was doing.

Thant being said I downloaded a PDF from Stewmac on how to build an 18w and bought all components one by one. I know I shouldn't have done that, but those guidelines with instructions and pictures are the only way that let me understand what is going on and how to proceed. Diagrams and schematics (pure Schematics) are very confusing for me.

I attached the pdf guide, well I have seen some schematics in here and else where and for me there is no such a big difference on how parts are put together, but I could be wrong.

It seems that what is shown in there is how the original Amp was built.

There is also a video I have been watching from

https://www.youtube.com/watch?v=cEV1glu ... x=6&t=206s

Thanks
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Re: Power transformer wire grouping help

Post by geoff 1965 »

that's fair enough,we all have to start somewhere,we have'nt seen much of the stewmac version on the forum so people can look through the pdf and point out anything obvious.
have a read of the links for soldering & grounding on josh's JMPGuitars post and just take your time,double check everything,it helps if you focus on one area at a time.
if you are unsure just ask and keep posting pics of your progress
good luck
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Re: Power transformer wire grouping help

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Re: Power transformer wire grouping help

Post by davemojo »

Hehehehe

I actually ended up with another small issue related to the Alpha pot being used for this build

we have 5 1 Meg and 1 5 K pot

I bought the pots 1 Meg only once from US Mojotoine but never again since here Tonefactory is fully equipped with all the most common things needed for the build.

However the 1 Meg pot are bigger than the one 5k pot I bought at tonefactory, now isn't just smaller that is probably my mistake I bought the wrong one, but the thing I noticed is that there is a small pin on the left side of it that doesn't allow me to fit on the chassis. the one from Mojotone see picture, already mounted, are bigger and don't have any pin.

Anyway where can I can get the right potentiometer? Either someone suggest me where to get the same as the Mojotone one or I can buy all of them back :-) . keep on spending extra money ahaha it will go better for the second build.

I'm in the Netherlands so I would buy only from EU since costs for delivery are limited.
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Re: Power transformer wire grouping help

Post by Bieworm »

That little leg can be broken off with a plier. I always break these off. They serve as a blocking pin so the pots don't move when you mount them tl a chassis. But then the chassis needs a hole that will fit them. I wish there were switches that have that leg.. I find it really hard to mount switches without them moving around
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Re: Power transformer wire grouping help

Post by davemojo »

Bieworm wrote:
Sun 03/07/21 11:27 am
That little leg can be broken off with a plier. I always break these off. They serve as a blocking pin so the pots don't move when you mount them tl a chassis. But then the chassis needs a hole that will fit them. I wish there were switches that have that leg.. I find it really hard to mount switches without them moving around
Yes i got it I actually find out while searching and indeed that lit pin can be cut off with a plier only thing is that I had to buy the 5K 24 mm since the 1 Meg are 24 mm and that is the right size for that chassis thanks so much for clarifying.

Thanks
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Re: Power transformer wire grouping help

Post by davemojo »

I am not sure if I have the right tube socket since I have 3 of one type and 3 of another type, when I purchased them I think for some reasons they shipped them like that but can't recall if was just like that or something went wrong

See photo
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Re: Power transformer wire grouping help

Post by geoff 1965 »

the 3 "flat" sockets are for your EZ81 & 2 EL84's,the 3 with collars are for your preamp & phase inverter tubes "with shielding cans"
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Re: Power transformer wire grouping help

Post by davemojo »

geoff 1965 wrote:
Tue 03/09/21 10:48 am
the 3 "flat" sockets are for your EZ81 & 2 EL84's,the 3 with collars are for your preamp & phase inverter tubes "with shielding cans"
I did actually put all 6 with collar would that be OK? see picture of work done so far, I just setup the workshop at my recording place :-)
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Re: Power transformer wire grouping help

Post by geoff 1965 »

no you'll have to replace the EZ81 & EL84 sockets with the flat ones, if it's a combo you'll also need spring retainers for them.some el84's glass bottles are fatter and probably won't fit inside the collar.
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Re: Power transformer wire grouping help

Post by davemojo »

I have fixed the issue with the valve sockets as specified

Now I have built the input jack and the tremolo,

Questions:

according to the instructions I have the green wire from input jack goes to the volume/tone (pots on the right of input jack) and the other green to the other two pots on the other far right.

The pots are grounded together and the green wire is attached to that ground, correct hope you got what I mean, see pictures

Soldering is the othe rpoint is the first time I am soldering so....imperfections are expected. :-(
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Re: Power transformer wire grouping help

Post by davemojo »

geoff 1965 wrote:
Sat 03/06/21 5:48 pm
Yeah the 2 red are your HT to the rectifier and the 2 green are the heater filaments,which schematic/layout are you using?
Could you please confirm

Are the 2 red wires going to the same Ez81 where you are going to also attach the pink and the grey?

According to my instructions the 2 reds are going to Ez81 lug 1 and 7 and the pink and the grey (in my instructions are yellow and white) are going to lug 4 and 5

See also portion of my guide instructions
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Re: Power transformer wire grouping help

Post by geoff 1965 »

yeah just use pink & grey to 4 & 5 and the 2 red HT to 1 & 7
note; if this was my amp i would put the fuse between the mains positive and power switch.
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Re: Power transformer wire grouping help

Post by davemojo »

Great thank you done just now the reds

So pink to 4 and Grey to 5?
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Re: Power transformer wire grouping help

Post by geoff 1965 »

either way is okay 4 & 5 are connected internally
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Re: Power transformer wire grouping help

Post by davemojo »

geoff 1965 wrote:
Fri 03/12/21 10:50 am
either way is okay 4 & 5 are connected internally
Done should be fine , hehe it is getting challenging but I love to do it.
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