Raven labs pmb

[hess]

I know one of the advantages of the raven labs pmb is battery power, but I am curious about the power supply. Online photos show 1/8 stereo plug from the Raven Labs Power Supply with tip -9v, ring +9v and sleeve 0v. However, there appears to be only two wires/conductors between the 1/8 plug and wallwart in some of the photos, suggesting its an 18v supply.

Anyone out there have a Raven Labs Power Supply? If so, any chance you could confirm this ... or better yet, measure the unplugged resistance and “plugged in” dc voltage between 1) tip and sleeve, 2) tip and ring and 3) ring and sleeve?

If not, no worries, it works great on two 9v batteries.

Thanks!

[Shoreline Music]

The PMB was one of the finest bits of electronics I ever sold. But the power supplies they originally shipped with were junk.

I seem to recall that Larry (AGF user ljguitar) still plays one; it might be worth contacting him to see what he's using.

[hess]

Thank you for your response. Interesting and good to know. I’ll give this thread a couple days and if no further response I’ll contact Larry.

[sdelsolray]

All Raven Labs units (PMB, True Blue EQ, etc.) used a 18v wall wart power supply in addition to the ability to be powered by two 9v internal batteries. It's been some time, but IIRC the 18 wall wart had some design quirk such that nearly all currently available 18v wall warts will not work.

[Doug Young]

An isolated pedal power supply with a custom wired cable (reversing the polarity of one) might work. I have not tried this.

I have two pmbs, but the power supplies crapped out long ago, so I just use batteries with them when I use them.

[RobKay]

Raven labs pmb power supply is zero, plus nine volts, minus nine volts, its a three pin plug.......im not sure if + is on the end or middle pin, if you need to find out i can always check it out on my test meter.
Rob

[ljguitar]

Originally Posted by hess

I know one of the advantages of the raven labs pmb is battery power, but I am curious about the power supply. Online photos show 1/8 stereo plug from the Raven Labs Power Supply with tip -9v, ring +9v and sleeve 0v. However, there appears to be only two wires/conductors between the 1/8 plug and wallwart in some of the photos, suggesting its an 18v supply.

Anyone out there have a Raven Labs Power Supply? If so, any chance you could confirm this ... or better yet, measure the unplugged resistance and “plugged in” dc voltage between 1) tip and sleeve, 2) tip and ring and 3) ring and sleeve?

If not, no worries, it works great on two 9v batteries.

Thanks!

Hi Hess

I own two Raven PMB preamps…a I and-a II (a little musical humor). I've never seen a preamp, and prefer them because they are battery powered.

I find on aggressive stages, chasing down buzzes, pops and hums is much more prevalent when using a power supply with stage gear.

I tried hard to find one, but never did…

[hess]

Thank you all for your responses! I agree batteries are an advantage and make things easier, but this power supply has my curiosity.

Sdelsolray, the 18v power supply makes sense for only two wires from the transformer. I see a couple caps and resistors at the power input that likely get +9v, 0v and -9v from the 18v. Perhaps the design quirk is the TRS 1/8 plug with +18v across ring wrt tip and the sleeve not used?

RobKay, if you have a working power supply please check the voltages with your meter. Specifically please measure ring wrt tip, tip wrt sleeve, ring wrt sleeve. Online photos show tip is -9v, ring +9v and sleeve 0v. But I see only two wires from the transformer, so it’s likely around +18v for the ring wrt tip measurement and 0v for the other two. Thank you.

[RobKay]

I built the psu for my pmb, its a 3 pin plug and cable coming from the psu. I used a +9 /_9 regulated system to feed the pmb, the ics in the pmb use a split rail system. I cant remember the polarity but will check it out next few days, i hardwired the psu straight into the unit because that tiny psu plug was only small and frail and a pain in the butt😁
Rob(uk)

[hess]

RobKay, your bi-polar psu build is the way to go ... if plugging in.

I removed the cover and looked at the power section of the pmb. I thought there might be some circuitry for converting an 18v input to +9v and -9v but there is not. It needs a +9v and -9v bi-polar power supply or batteries.

[M Hayden]

Originally Posted by Doug Young

An isolated pedal power supply with a custom wired cable (reversing the polarity of one) might work. I have not tried this.

I have two pmbs, but the power supplies crapped out long ago, so I just use batteries with them when I use them.

I also have a couple of PMBs, and I wired up a supply using a Voodoo Labs 4x4 power supply, using the high-current (400mA) outputs to power them - the Raven specifies 300mA per side as the power requirement.

The wiring joins two independent 400mA supply lines from the Voodoo (the 4x4 has isolated grounds, so this is possible) and makes the following connections:

Supply 1:-9V line to 3.5mm stereo plug tip
Supply 2: +9 line to 3.5mm stereo plug ring
Supplies 1 & 2 unused lines to 3.5mm stereo plug ground sleeve


Here's a diagram: https://drive.google.com/file/d/1yo1...ew?usp=sharing



it works like a charm, and because of the pass-through nature of the power supply design, it's possible to jumper from the first PMB's 3.5mm output power to the input power on the next one.

The cabling for this took all of a half-hour to solder and heat-shrink, and it's proven reasonably durable. Still, there's a backup cable just in case.

[hess]

Thank you M Hayden. Very nice

[M Hayden]

hess, hope it helps!

One of the key things to keep in mind when dealing with a PMB is to really, really listen to the instructions, and NOT PLUG ANYTHING IN WHILE IT'S HOT.

PS the wiring I showed also provides power for the USIP, which is basically two PMBs in a rack-mount unit. I built a couple of cables for a friend who has one and it's helped the reliability of his rack quite a bit.