POWER FOR DL4 FROM A ZUMA?

Mwnci

Hi, im just trying to get my head round powering a Line 6 DL4 from a Strymon Zuma, can it be done? any tips on cable needed etc?

stickyfiddle

The DL4 will work with an adapter (the input says it needs 9V AC but it gets immediately rectified to DC; the fact that it will run on batteries is further proof). 

You need an adapter that will output 2.5mm centre positive, such as the Diago "green" adapter:

https://www.andertons.co.uk/p/DIAGOPS03/power-supplies/diago-ps03-green-adaptor-centre-positive-25mm-barrel

Mwnci

@stickyfiddle Perfect thanks! ideal!

Jonathanthomas83

@Mwnci did this work? I just bagged a DL4 for £20 without a power supply!

steamabacus

The DL4 can run on the 9V AC power supply usually provided OR you can run it on 12V DC CENTRE POSITIVE. You will need the larger 2.5mm plug size (rather than the usual 2.1mm). Current draw at 12V DC is somewhere between 175-250mA depending on which source you read (probably 200mA will do).

Have a read of this from the Line6 support forum (read down to mrniceguy's post)

Mwnci

Hi @Jonathanthomas83 ;   good find!!  aye i got that green adapter, worked fine

Jonathanthomas83

Mwnci said:

Hi @Jonathanthomas83 ;   good find!!  aye i got that green adapter, worked fine

@Mwnci perfect, the adapter has just been delivered to my local post office, so I'm looking forward to trying it. Let's hope I haven't been sold a dud! :-) Wortha punt for £20, I guess! Thanks again

ICBM

steamabacus said:

The DL4 can run on the 9V AC power supply usually provided OR you can run it on 12V DC CENTRE POSITIVE.

Polarity doesn't matter - the rectifier inside automatically converts either incoming polarity (since AC alternates) to the correct DC.

I'm almost certain the DL-4 will run on 9VDC, in fact - the internal DC voltage is actually only 6V, and is regulated down from 9 to 6 immediately after the rectifier. I think an extra 3V is sufficient to get the regulator operating. I don't have my DL-4 any more to check, but I'm pretty sure I did actually run it on a 9V daisy chain.

Jonathanthomas83

@ICBM I just plugged it into the 9v socket on the Zuma which puts out 500mA and the lights came on for a few seconds and then went out, now nothing. Looking at the back of the DL4,, it says "9vAC 1200mA minimum"...in hindsight, it's a bit late for me to be looking at the back of the unit after the horse has bolted!

Looks like either I've ruined it or it was sold to me as a dud!

Does anyone know of anyone who can fix a buggered DL4?

ICBM

Does it work on batteries?

Powering it with a supply with too *little* voltage or current capability won't damage it, although it could overload the power supply and make that shut down - no properly-designed modern supply would actually be damaged though.

I have to say I'm quite suspicious that a DL-4 for £20 was not likely to have been sold in the full knowledge that it was working, though... given that the going rate is around £100.

steamabacus

Did you read that link I posted earlier @ICBM ? I'd be interested if you think it's accurate. Specifically, the post states ..

"But because you are using a DC supply now, polarity matters! And in the case of this circuit, it must be center-positive to prevent from reverse biasing the semiconductors and blowing them up."

@Jonathanthomas83 ; I don't think the current draw at 9V AC and DC will be the same (the link certainly states otherwise) and I'm not sure whether the DL4 draws ALL of the 1200mA the 9VAC adapter provides.

I've only ever run my own DL4 from the supplied 9VAC adapter but (and this was some years ago so my memory is fuzzy .. and it may not be what you want to hear) I seem to remember a friend powering his DL4 from a standard 9VDC centre negative supply. It worked ... for a while. I can't say for certain what the cause of failure might have been.

steamabacus

Here's the full quote from that link...

"Ok. Here's what's up.

The DL-4, as designed, expects a 9VAC signal, which is non-polarized at the jack. At the power input of the DL-4 is a rectifier/filter that turns the 9VAC into 6VDC. That 6VDC line is tapped to the battery line, which is 4 D batteries (4 * 1.5VDC per battery = 6VDC). That 6VDC is used to generate all the operating voltages within the unit (6VDC, 3.3VDC, 6.6VDC, and 5VDC). Notice that what makes the DL4 REALLY work are all DC voltages.

Now wouldnt it be nice if we could use a DC supply from our VDL Pedal Power to bypass that rectifier circuit? Pay attention.

Diode rectifier/filter circuits CAN accept a DC signal with no damage to the circuit. The rectifier circuit will just simply pass the DC signal (with a voltage drop because of the forward drop of the rectifier diodes). It will rectify an already-rectified signal. Because of the diode voltage drop, you have to feed it a slightly higher DC voltage to get the same output as you would with an AC voltage. That's why the VDL PP has a dip switch to up the DC voltage from 9V to something higher (12-14VDC, lets just say 12VDC for this argument). But because you are using a DC supply now, polarity matters! And in the case of this circuit, it must be center-positive to prevent from reverse biasing the semiconductors and blowing them up.

As far as current draw goes, a circuit will only draw what it needs. So most ratings are given as a maximum expected current draw times some safety factor (usually 50%). So in a worst case scenario, a circuit will draw 100mA, so a designer may recommend a 150mA rated adapter.

That said, you have 2 ways to power a DL4: 9VAC or 12VDC. Remember, AC and DC power draws are measured differently. Straight DC voltage is able to supply more current than an equivalent VAC supply. So at 12VDC, it may only require a max of 200mA, but at 9VAC it may require 1200mA. That's why the VDL guy and the DL4 guy give you different current draw ratings. Also, they both may be assuming 2 different safety factors!

When youre comparing electrical power, you have to make sure youre talking the same voltage levels, voltage types, load, etc. It happens all the time in pro-audio. A car stereo maker will take a peak to peak VAC measurement across some frequency range into a 16ohm speaker and calculate power from that. A tube amp maker will take it from an RMS measurement over a different freq range in an 8ohm speaker. And then the listener wonders why a 200W car stereo is no where NEAR as loud as a 100W tube amp."

Jonathanthomas83

steamabacus said:

Here's the full quote from that link...

"Ok. Here's what's up.

The DL-4, as designed, expects a 9VAC signal, which is non-polarized at the jack. At the power input of the DL-4 is a rectifier/filter that turns the 9VAC into 6VDC. That 6VDC line is tapped to the battery line, which is 4 D batteries (4 * 1.5VDC per battery = 6VDC). That 6VDC is used to generate all the operating voltages within the unit (6VDC, 3.3VDC, 6.6VDC, and 5VDC). Notice that what makes the DL4 REALLY work are all DC voltages.

Now wouldnt it be nice if we could use a DC supply from our VDL Pedal Power to bypass that rectifier circuit? Pay attention.

Diode rectifier/filter circuits CAN accept a DC signal with no damage to the circuit. The rectifier circuit will just simply pass the DC signal (with a voltage drop because of the forward drop of the rectifier diodes). It will rectify an already-rectified signal. Because of the diode voltage drop, you have to feed it a slightly higher DC voltage to get the same output as you would with an AC voltage. That's why the VDL PP has a dip switch to up the DC voltage from 9V to something higher (12-14VDC, lets just say 12VDC for this argument). But because you are using a DC supply now, polarity matters! And in the case of this circuit, it must be center-positive to prevent from reverse biasing the semiconductors and blowing them up.

As far as current draw goes, a circuit will only draw what it needs. So most ratings are given as a maximum expected current draw times some safety factor (usually 50%). So in a worst case scenario, a circuit will draw 100mA, so a designer may recommend a 150mA rated adapter.

That said, you have 2 ways to power a DL4: 9VAC or 12VDC. Remember, AC and DC power draws are measured differently. Straight DC voltage is able to supply more current than an equivalent VAC supply. So at 12VDC, it may only require a max of 200mA, but at 9VAC it may require 1200mA. That's why the VDL guy and the DL4 guy give you different current draw ratings. Also, they both may be assuming 2 different safety factors!

When youre comparing electrical power, you have to make sure youre talking the same voltage levels, voltage types, load, etc. It happens all the time in pro-audio. A car stereo maker will take a peak to peak VAC measurement across some frequency range into a 16ohm speaker and calculate power from that. A tube amp maker will take it from an RMS measurement over a different freq range in an 8ohm speaker. And then the listener wonders why a 200W car stereo is no where NEAR as loud as a 100W tube amp."

@steamabacus thanks, but I got the little Diago cable to be center positive and the correct size. It still doesn't work at 9v or 12v from the Zuma.

@icbm yes me too, mate, dubious about them selling it in its current state. Bellends! I'll try with batteries, thanks!

ICBM

 I did read it, and it’s simply wrong. If the original supply is AC then the polarity of the DC supply cannot matter, because AC alternates! It literally changes from tip positive to tip negative and back, 50 times a second. The rectifier in the pedal produces the correct polarity whichever it is.

The 200mA/1200mA statement is wrong too. It will draw the same current at either, if the supplies are the same voltage (assuming the AC voltage is RMS). In fact it will draw slightly more current at a higher voltage, not less - the extra will be wasted generating heat in the regulator before reaching the final 6V.

@impmann may have some further advice, but in the case of a non-functioning Line 6 pedal like this, the first thing to do is check that all the chips which are mounted in holders are seated tightly. Give each one a squirt of contact cleaner if you have some, and press it firmly into the holder.

boogieman

Anything to stop someone wiring a 6v DC supply directly to the battery terminals? Assuming the polarity is correct, it should work, no? 

ICBM

boogieman said:

Anything to stop someone wiring a 6v DC supply directly to the battery terminals? Assuming the polarity is correct, it should work, no? 

Yes, that will work.