Power Supply Question

[Paleo Pete]

Went to band practice last week, other guitar player handed me a couple of old pedals he had sitting in a shed for 10 years or more. After I cleaned up the cobwebs and bug smears...ickkk...I have a working Dan Electro Dan Echo, big frame metal housing made best I can tell mid 90's, that sounds great and a Cool Cat Chorus, same big metal housing. Both built like tanks, I figured if either one didn't work I could still carry it in the car for personal protection...

Anyway the echo is standard 9 VDC, no problems, works fine on my existing multi wire power supply setup, I used it onstage this weekend and it worked perfect, sounds very good. Just looked it up, they go for up to $90 on the bay, down to around $45 or so well used. Not bad for a freebie and it just may take the place of the old Arion Analog Delay I've used since 1990. The Arion can (and did this weekend) work fine for the acoustic.

The chorus is 18 VDC and uses two 9V batteries or a wall wart. So I dug one out, loud hum, didn't work right...I just found another in a resale shop today, 19VDC, right polarity, 200mA while the label says 300mA max.

Tried it a few minutes ago and it seems to work perfect, didn't seem to have any problems at all, but I only used it about 10 minutes. Sounds great too.

I don't think the 1 volt difference will do any damage, if I understand it right, higher amperage would be a problem, not a minor voltage mismatch. Will the 19 volt wall wart be likely to cause any damage to the pedal if I use it on a regular basis onstage? I think it should be ok, but thought it might be best to check with you guys. If it will, I'm gonna be a happy camper, the thing seems to sound very nice and is built like a tank, comments I've seen so far indicate most people like both pedals really well and they are said to hold up well too. Both seem to be noiseless when run by themselves plugged into the Fender Champ at home individually. And if I do have to clock somebody with one, it will probably keep working...

[J M Fahey]

19V instead of 18V is no big deal; to boot old pedals were designed considering carbon batteries, the cheapest and most common ones, and when just out of the package they put out a little more than plain 9V anyway, say around 9.5V each, so ...... I guess you are covered

[foxking]

Sometime this extra one volt can damage you circuit, make sure it has some internal voltage regulator circuit and Fuses. Othervise the this 1 V is enough to fry it up.

[eschertron]

The wall warts I've checked out seem to be poorly regulated, that is, they are significantly higher than rated voltage with a small load. If you can get a schem for the unit check that out, otherwise expect it to be OK.
I got a Pigtronix unit that comes with a 12vdc adapter. Documentation says up to 18vdc is fine, allows for extra headroom I guess? Personally I wouldn't think its a big deal.

[Paleo Pete]

19V instead of 18V is no big deal; to boot old pedals were designed considering carbon batteries, the cheapest and most common ones, and when just out of the package they put out a little more than plain 9V anyway, say around 9.5V each, so ...... I guess you are covered

That's what I'm thinking. Batteries and wall warts both are not all that accurate voltage, and with most things a small voltage difference shouldn't be a problem, it's higher amperage than recommended I'd be worried about. This one works great with 200mA, max is printed on the back at 300mA, I was more worried about it not being enough, but since most pedals I've seen usually run in the 200-250mA range, that's pretty standard so I'm thinking it should be ok. Worked great last night, but only tried it a few minutes. Sounds very good, I'll plug it in later and tinker with it some more, but so far it looks like it'll be a good one. I've seen much more expensive units that didn't sound any better...Come to think of it I don't think the rack mount digital delay I used years ago sounded as good in chorus mode...

Thanks guys, I don't think it should be a problem but wanted to double check.

foxking - Sorry but I'm going to trust the opinions of the guys I know have been here for years and have an exceptional reputation.

[52 Bill]

That's what I'm thinking. Batteries and wall warts both are not all that accurate voltage, and with most things a small voltage difference shouldn't be a problem, it's higher amperage than recommended I'd be worried about. This one works great with 200mA, max is printed on the back at 300mA, I was more worried about it not being enough, but since most pedals I've seen usually run in the 200-250mA range, that's pretty standard so I'm thinking it should be ok. Worked great last night, but only tried it a few minutes. Sounds very good, I'll plug it in later and tinker with it some more, but so far it looks like it'll be a good one. I've seen much more expensive units that didn't sound any better...Come to think of it I don't think the rack mount digital delay I used years ago sounded as good in chorus mode...

Have you actually measured the output voltage of the "19vdc" adapter? You should do this both with the adapter disconnected from the pedal and with the pedal connected. That will give you the best answer as to the safety question. If the voltage is 18-19 volts on the high end when loaded with the circuit, then there shouldn't be any problems.

As for current, you can actually measure what the pedal is drawing with your multimeter.

[Paleo Pete]

Bill - I have measured it not plugged in, 24 or 25 volts. Hard to tell with an older analog meter and I'm not sure how accurate it is either. Most of my 9V wall warts run about 14 or 15V. The one I use every gig says 15 so I'm not surprised at all it shows higher than the listed 19VDC. That's not plugged into a pedal though. Don't think I've ever seen one that did read what it was supposed to.

Not sure how I would measure it plugged in, don't know that much about it, but I would think the resistance when it's plugged in would tend to reduce voltage. Going to try though, at least check and see what it shows if I can find the first place it goes after the jack. Wish I could find my digital meter...I have an older one and a rat chewed the probes, I have a half dozen pieces of wire now.

As I said though, I'm not that worried, batteries are usually higher than the 9V they are supposed to be, so I'm pretty sure the circuits are capable of handling a minor mismatch.

[Enzo]

The resistance is within it. ANy adaptor will put out its rated voltage only at the max current. If it says 9v @ 500ma, if you draw 50ma from it, the voltage will be higher. The exception would be REGULATED supplies, but very few are.

How to measure the output voltage plugged in? Take the bottom off of whatever it plugs into, and measure at the power jack termnials.

[Paleo Pete]

How to measure the output voltage plugged in? Take the bottom off of whatever it plugs into, and measure at the power jack termnials.

Thanks, that's what I thought. But not even near positive...won't be hard to find, it has a small board a little bigger than matchbook size mounted on posts above the main board, that's where the input/output/power jacks are. I opened it up a couple of nights ago to clean out the cobwebs but didn't look for where anything is soldered on, didn't have the power supply yet.

Thanks for the info.