questions about vibracaster

[cnspedalbuilder]

Wow, this is more complicated than I imagined! OK, so maybe the 12V option isn't the best, but let's explore.

I'm using a Decibel Eleven Hot Stone Deluxe power supply, which I think is transformer based: "Custom magnetically shielded toroidal transformer". So that should work, right?

To make it easier, you can just use an 78L09 regulator.

Sorry can you elaborate?

As it stands, I'm seeing the +12V DC in split to two lines. I might be able to use the 400mA output from the power supply, but more likely will have to use the 200mA output. One goes to all of the +V inputs for the Vibracaster. The other needs to go down in voltage before going in to the MAX1044, presumably by using a series resistor.

Hmm, maybe it's best to keep these as two separate pedals, huh?

[Marcos - Munky]

To make it easier, you can just use an 78L09 regulator.

Sorry can you elaborate?

78L09 is a regulator that have 9V as the output. Pretty common on guitar pedal power supplies.

Hmm, maybe it's best to keep these as two separate pedals, huh?

Your problem is not on building them together - that's an easy task. Your problem is how to power them. You need to get a power supply just for a tube pedal because of the current the heater needs.

I still wouldn't trust a 200mA 12V supply to do this job.  I don't know what the start-up (cold) heater current might be, but I think it's more than double.

I got 12.3 ohm from pins 4 to 5 of a 12AX7 I have here. Rounding that number, it's a 1A start-up current. Maybe a 200mA transformer based power supply can handle it since it's just a quick peak, but a switching power supply surely woudn't work.

[rankot]

I still don't get why you're so stubborn  in putting 12V into the heaters, when you have 9V supply with more than enough power to run them at 6.3V? All my tube based pedals are built with dropping resistors in series with 6.3V heaters, they all work fine and it is the simplest possible solution. If you need 12V or 18V for B+ (or even more), you can always use LT1054 to step up 9V, because anode current is never above 100mA.

[cnspedalbuilder]

I still don't get why you're so stubborn  in putting 12V into the heaters, when you have 9V supply with more than enough power to run them at 6.3V?

Haha, no I thought the 12V option would be easier. I can see that is not the case! I suppose the simplest thing altogether is to box everything separately. I have to go back and forth between 2 bands in different places, so I'd like to use just one power supply so that there is less to lug around and plug in. Also I have limited pedalboard space, so for all these reasons, it's better to have a combined box that takes only one DC in from the same power supply that I use for everything. Who says you can't have it all? 

OK, so I've ordered the parts (10R 2 Watt 5% resistor was the closest I could get to 9.1) and will build over the coming weeks/months time permitting. I will probably come back with a little schematic or layout to make sure I've combined everything right before getting started. Thanks for all your help!

[Ben N]

Holy guacamole, that was a long time ago!

Good things are timeless.