Adding a 9V reg supply to dumbleator...

[Structo]

Sounds like a cool idea.

I was going to make a pedal snake to my board that had everything in it like,
shielded cable to and from the pedal board, to and from the loop, plus pedal power.

I tried one I bought second hand and I soon realized that unless I used top
notch shielded guitar cable, it muffled the tone.

But I do use a Visual Sounds One Spot and a multi plug, 8 connector cable.

You can buy just the cable build your own.
http://www.amazon.com/Visual-Sound-Spot ... B000XXBHA6

[surfsup]

Structo I have one of those daisychain cords already. They are great.

Okay so new question. If i am hooking up the 9V pedal supply tranny to the IEC jack directly, shoudl I put a fuse between the live and the tranny on one leg of the primary? Since the current draw will be max 1A, I assume a 1a 250v fuse would be fine?

[martin manning]

Power in = power out + losses. Power out = 9V x 1.0A = 9W, maybe add 20% for transformer and reg losses, so make it 10.8W. At the primary voltage 10.8W/120V = 0.09A... 0.1A should be good.

[surfsup]

Martin thanks again! I now understand using wattage for this and it makes sense...

[surfsup]

Okay please check this schemo and layout for me please. Thanks in advance:

[John_P_WI]

Surf,

I'm a little confused here. You list 18 vac in the transformer notes but show 18 vdc on the drawing. Also the Xicon data sheet is very vague. Can you confirm that loaded this is a 9v-0-9v transformer. If this is full wave rectified with center tap as shown and is 18 vac as listed in the spec then will the voltage will not be too high? (18 vac / 0.707) minus the diode drop will give approx 24 volts at the first filter cap! That will be asking the voltage regulator to drop a lot.

Also 12.6 v is listed on the drawing at the first filter cap, but 11 v input is shown at the regulator.

Finally, I would expect to see a 10 uf or greater cap on the output. Maybe I'm obtuse here, but it seems that not all of the transformer info is given. Experimentation may be the key.

[surfsup]

Surf,

I'm a little confused here. You list 18 vac in the transformer notes but show 18 vdc on the drawing.

mistyping, it should say 18vac on the secondary.

If this is full wave rectified with center tap as shown and 18-0-18 then the voltage will be too high (18 vac / 0.707) minus the diode drop, will give approx 24 volts at the first filter cap!

Should be 9-0-9 like most other transformers I've seen, anyway. 18*.707 = 12.6vdc which I have on the schemo. now that you mention it I hope it is so. Otherwise I would expect them to list it as 36vct. But this was returned doing a mouser search with a bunch of other similar trannies so I expect it to be 9-0-9.

Also 12.6 v is listed on the drawing at the first filter cap, but 11 v input is shown at the regulator.

The 11v reference is the minimum for the 7809, I just put it on there as a reference. With the diode drop, the rectified voltage should be ~11v but the wall voltage here is 125vac not 115vac so it will be about 8% higher, or approximately 12vdc into the 7809.

Finally, I would expect to see a 10 uf or greater cap on the output. Maybe I'm obtuse here, but it seems that not all of the transformer info is given. Experimentation may be the key.

We'll see...I already ordered it up.

[John_P_WI]

Yeah brain fart on my part, should be 9-0-9 giving the 12.6 v that you suspect.... Too much going on at the same time.... Sorry about that.