Power Supply handling, the Spyder, and Digitech X Series

[aaronkessman]

I recently got a Digitech X series reverb, and have to say it's quite good. I was wondering whether I could safely hook it up to my spyder through the 9V battery snap. My Spyder's trannies are all 125mA, i think. On the digitech spec sheet, it says power consumption is 4.8W  *with their wallwart PS*. At 9V this would be 530mA. It seems like a lot of the time, wallwart adapters supply a different voltage than the 9V battery, and nothing on the pedal states what the wallwart output voltage is. Should i just try supplying 9VDC from my Spyder through the 9V battery clip in the pedal?

Thanks for advice,

Aaron

[cd]

What do they list for battery runtime?  Around 5 hours?  If you estimate a standard alkaline at 500mAh, in 5 hours that would be 100mA.  

You know what the best thing to do is, right? Measure the current draw from a battery yourself

[aaronkessman]

you dont mean to simply measure current through the battery with a DMM?

if not, how do i do this with the circuit drawing normal power?

[Ge_Whiz]

I've got two of those Digitech X-series pedals (reverb and phase). They sound great - but they EAT current. They could easily overload a small wall-wart if you're not careful.  

[aaronkessman]

right...which is what i'm trying to figure out

anyone?

[El Caballo]

The PS200R power supply Digitech sells for the X-Series pedals only puts out 300mA @ 9.6V, or 2.9W.  

This means that either their manuals are wrong, or the PS200R is putting out a lot more power than it's rated for.  I suspect the former -- if it really drew half an amp, a 9V battery wouldn't last an hour.  The battery life sucks, but it doesn't suck that much.

[Ge_Whiz]

right...which is what i'm trying to figure out

anyone?

Okay, I'll try to be clearer. I suspect that AT TIMES the current demanded by the X-series pedals could be close to the 300 mA limit of their power supply. If each of your Spyder supplies is only good for 125 mA, DON'T use it UNTIL you have measured the current draw in several different circumstances and convinced yourself that 125 mA will be sufficient.

CLEARER STILL: I wouldn't use the Spyder.  

[aaronkessman]

ok guys, thanks for the input I'll check the specs on the rectifier/filtration circuit components in my spyder. I may be able to sub one of the trannies for a higher rated one.

but it just might be easier and cheaper to just buy the digitech PS.

Aaron

[niftydog]

First up, I think you need to check to be sure about the transformers in your Spyder. They are often rated with respect to the primary AC voltage, which is quite a lot of wattage even if they are only 125mA. Therefore, this does not translate directly to DC output current.

Chances are that the limiting factor in your Spyder is possibly not the transformer, but I'd say it's more likely to be the regulator. Non-heatsinked regulators can't take much current before they go into thermal shutdown mode. A standard 7809 reg can handle up to 1A, properly heatsinked.

[aaronkessman]

mouser pn 513-NJM78L09A - 0.1A regulator. no deal.

thanks nifty.