What is the maximum amperage on the 15 volt side for the Pro-ject Power Box ds2 Sources

Typical efficiency figures for toroidal transformers are 95% and on the ds2 Power Box Sources back panel stated "120V-50/60Hz 100VA", there're 3X18V-1A jack and 2X9V-2A jack = total 90VA. Its left only 5VA for the 15V and Trigger Out jack! But we also have to considering the actual power consumed by devices that connect to those jacks, so there could be more VA available for the 15V jack. And the inrush current during the start of a motor is significantly higher than the motor running current! Maybe that's the reason why Pro-ject not to list the max. current rating on the 15V jack.

The ds2 Power Box Sources lists 15v DC only, it does not give a listing for the amperage.
I have tried asking Pro-ject but they dont seem to know.

Since Pro-ject can't give you the answer, without a schematic or a Power Box on the test bench, what I can do is just guessing!

Too much attitude, too little "listening" by the op. The direction to the answer was in my posts (several times). I am out. Good luck.

I have the EAT C-Major 15V/1.6A. Designed by the wife of the main guy at pro-ject. They are produced In the same plant. I know the phono pre amp goes to the 18V socket. I have already stated several times throughout this post that the issue is the TT not the pre amp.

So what is it or what was it that requires 18V/~0.5A, per oldhvymec's post?  He refers to "it", and I thought for sure he was referring to the TT.  Now I am just curious.

Hey Robert I could not agree with you more, you are spot on about Miller and imhififan. My TT is the EAT (European Audio Team) C-Major. My phono pre amp is the pro-ject phono box ultra 500 and yes I do own the Power Box DS2 Sources but I only have the phono pre amp connected to it as I have never been comfortable with the fact that the power supply has no amperage rating just voltage. The phono pre amp is not the issue, it's the turntable that i'm wrestling with. The turntable requires 15VDC/1.6A. And no the TT will not work with an 18V power supply, the owners manual even states that and warns against general voltage issues. The issue resides with the power supply not having or not listing in the specs the required Amperage, that's it in a nutshell. (see my previous post) 

I would first of all like to thank everyone for their contributions to my thread it has truly been entertaining and extremely informative. Actually thru it all NO ONE has answered the root question. imhififan has actually come the closest to addressing the issue.  Yes imhififan, the Power Box RS UNI TT (15V/2A) will DEFINATELY work for my turntable because my turntable is (15V/1.6A) but notice that the spec for this unit includes a value for the amps whereas the Power Box DS2 Sources only indicates 15V. This is the issue in a nutshell. My turntable apparently requires that additional 1.6A that the DS2 either does not list in the specs or is incapable of accommodating. This is where it is so simple, 15V/1.6A is greater than 15V.  Period! My question imhififan, is can I get that unit in the states because Henley Audio is in the U.K. I believe this will remedy my problem and like Millercarbon suggested, it's probably NOT a good idea to have the DS2 power Supply run my phono pre amp and the turntable. Again had I not started this thread I would not have learned that. So again to  All, THANK YOU. Stay safe Stay well, Stay home and listen to tunes.
Good Day.

Millercarbon, What the heck are you talking about?  Who wants to get 100A out of a wallwart?  Furthermore, not all wallwarts are simple transformers; some contain rectified power supplies and can directly deliver DC voltage; I suspect that is the type we are talking about, unless I too have misunderstood the OP.


Thanks to oldhvymec, we now know that the OP is off base a bit, as he needs 18VDC (and ~0.5A) into the TT, not 15V, just to begin with.  And any transformer, whether its part of an AC or a rectified DC supply, will get warmer than normal, even hot, if it's overtaxed.  But one can't ask a 15VDC supply to deliver 18VDC.

I believe pro-ject not specs the current rating is the inrush current during the start of a motor is significantly higher than the motor running current and the power supply will have to be able to withstand that inrush current. Therefore Pro-Ject recommend using Power Box RS UNI TT (15V/2A) for turntables with high power consumption and a heavy, mass loaded, platter.

https://www.henleyaudio.co.uk/products/Box-Design-Power-Box-RS-Uni-TT

Right off the spec sheet, it consumes 490 mA. 18v not 15, all the information is there.

Outboard power supply: 18 V/1000 mA DC Power consumption: 490mA DC


What you want to do with it, combine the two? .5 amp? close? and the 1.6. 2.1 max amps @ 15-18v 

Measure it....now you can figure a 150% duty cycle and clean it up.
Switching PS or something. Something clean...

Regards...

Nothing will get hot. It doesn't work that way. 

Okay look, the power supply is first of all a transformer. 120V AC comes in, goes round and round the primary windings of the step down transformer that drops it down to (in this case) 15V AC. Always AC. Transformers work on the principle of induction. The rising and falling magnetic field around the wire induces a current in the secondary winding. Same reason we don't want power cords, speaker cables, etc coiled up. Induction.

Okay so the ratio of primary to secondary windings is what determines the step up or down in voltage. The operative term being: voltage. Hate to get all mathy but V=IR. Or I=V/R. However you want to write it. Point is voltage is proportional to current. In other words you can step the voltage down and have more current, or you can step the voltage up and have less current, but you cannot use a transformer to increase both voltage and current.

Okay so we had a 15A circuit and we stepped the voltage down from 120V to 15V so we should be able to get 100A easy, right? Not so fast! Look at how small that dinky little transformer is. Look at how hair thin the wires are. (Seriously. Open it up. Have a look inside. Live a little.) 

Induction simply is not gonna deliver that kind of current through that thin a wire with that small a set of windings. There's a reason your neighborhood power transformers are as big as they are. Have to be to deliver that much current.

So the wall wart transformer is very low amperage. The 15V comes out the secondary and then goes through a set of rectifier diodes. Diodes allow current to pass one direction only. That's how we get DC. At this point the power is notchy because of the diode switching so the next thing is one or more power supply caps. Their job is to smooth the ripples from the diodes, and provide reserve power for surges and peaks. Look inside any component, they are all the same: transformer, diodes, caps. Just like that. 

Where is the part that is gonna generate any heat? Transformers generate a tiny amount. Diodes a whole lot more. Some need heat sinks. But they are sized to the power needs and so run very stable. Its the transformer that limits the whole thing. 

Just to give some idea what I'm talking about, I forgot that my modded conditioner had one outlet intended for only a CDP and it used a little dinky 20 watt isolation transformer for the CDP. I plugged TWO Dayton SA1000 sub amps into it. Everything ran fine. Well except for the subs clipping at lower volume than I thought they should. But it was very high volume and it was only when I opened the conditioner to do another mod that I noticed my mistake. Point is that dinky little transformer ran two monster sub amps with no heat no problem. Because it was sufficient for the average draw, because the Daytons have their own big power supplies with lots of capacitance. Understand?

The problem in your situation is neither your turntable motor nor your phono stage has that kind of built-in power supply. They both are relying on the connected DC power supply. 

So now you know what to do, right? You can run it and see what happens. Probably no problem. You can measure voltage drop like the other suggested, if you want to get all mathematical about it. You can get another better power supply. Or you can add capacitance. A bigger better cap and you will be good to go.

These things are not that hard. You can learn a lot playing around with this stuff. Diodes that will make a big improvement in SQ are not that expensive (under $10 a lot of them) and even a really good cap might still be less than you would pay for a complete power supply. You might even scavenge one out of some other gear. Cap values affect frequency response in crossovers but in power supplies its straight up more is better. So why not try? Go ahead. Live a little!

Technical specifications Pro-Ject Tube Box DS2 Tubes:

Outboard power supply: 18 V/1000 mA DC Power consumption: 490mA DC, <0,5W in standby Dimension W x D x H (D with sockets) 206mm x 227 (239)mm x 91mm aluminium 240mm x 227 (239)mm x 93mm wood

Trigger output/input: 12V (2,5mm jack) Weight (without power supply): 1500g aluminium 1960g wood

From the spec sheet, does that help?

Regards..

I realize that to detect a voltage sag, you need a voltmeter and access to nodes on the power input side of the tt where you can assess DCV.  That might be a problem.  In which case, you might just hook it up and let the turntable run for an hour or so while monitoring the temperature of the PS chassis.  If it gets hot, stop.

I appreciate your predicament. Since wall warts are not very expensive, why not avoid the issue by using two discrete supplies? In any case, what erik is saying is that if the PS cannot supply 1.6A of current under the load represented by turntable, the result will be that the DC voltage measured at the turntable will sag below 15V. That might or might not noticeably affect performance of the tt, depending of course on how deep is the sag. If there is no voltage sag, then at least you are not vastly exceeding the capability of the PS. But most of us worthy of the appellation "audiophile" would want to know that the PS potential is in excess of what is needed. If you see 15V and the PS does not get hot or very warm to the touch, then you are nevertheless probably OK.

millercarbon,
your explanation was very good and i now have, I believe  a better understanding of amperage however, I still don't know if the power supply is capable of addressing (for a lack of better terms) the draw of the of the turntable. Again, the power supply does NOT give an amperage rating.  So if the turntable "draws" 1.6A is the power supply capable of supplying 1.6A when he amperage is not stated? Thank you all for your responses thus far. I will probably take your advice and not use the power supply for both but now I'm more curious than anything else about the amperage question.

The root of my inquiry is that my turntable requires 15 v DC/1.6 A. 

The root of your problem is a misunderstanding of amperage. The turntable does not require 1.6A, it draws 1.6A. That is to say it will run just fine on a power supply capable of delivering 1.6A or greater. You could connect it to a power supply capable of delivering 100A, it would not hurt a thing. The table only needs 1.6A. That is all it will draw.

This is different than voltage. Voltage is pressure. Too much voltage, then you would have a problem. High enough voltage would simply arc right through everything in its path. 

Its like trying to drink out of a fountain. If the current flow is low it just takes longer to quench your thirst. But if the voltage (pressure) is too high its like a power washer and it blows your face off before you can even take a sip.

 I am attempting to power both my turntable and phono pre amp with the same power supply but I have not done so because of not knowing what the maximum amperage is for the Power Box. 

This is a bad idea regardless. The main task of a power supply is to provide a steady source of power. The turntable especially is highly sensitive to fluctuations in power. Normally the turntable motor power needs fluctuate only microscopically due to stylus drag. The power needs of the phono stage however fluctuate dramatically with the music signal. Worst of all, the same dynamic impulse that drags on the stylus calling for more motor power is also almost simultaneously causing the phono stage to require a lot more power. 

It will work. No doubt about it. If the power supply is good quality it will probably only need to be capable of 5 watts or so to work quite well. Until you compare side by side with two good power supplies, only then will you know how bad it was. I'm simply pointing out the technical problems that explain why its not such a great idea.

The way to tell is to power your turntable and measure the voltage under load.  If it stays at 15V, you are good.