Pure Power Dual AC by MRC

I've looked at and read about thise, and think they are a very well made unit with a lot of good features (meters, breakers).  Upside is it has all these features and costs less the $350 at discount: good price.

Downsides, which have kept me from buiying it are:

1) It provides 60 cycle AC variable voltage output - as per traditional O gauge toy trains: to run a train slowly you set the throttle to perhaps only 7 or 8 volts.  Modern units like the Z4000 and ZW-L  provide something different: they actually send about 18 volts to the track but chop the waveform in time, not voltage.  The result is better low speed perfomrnace - slower and particularly smoother. 

 

2) I think the unit gets its 270 watt rating as two sides at 135 watts each.  But both sides are limited to 7 amps max current, versus 10 for Z4000 and ZW-L.  That means each side can theoretically go up to 147 watts (at the maximum 21 volts), which seems enough to run any single train.  But: most of my hungry trains (Pullmore motors, etc.) run fast at around 16 volts, and that means 7 amps times 16 volts is only 102 watts.  Much better than a CW-80's 80 watts, but far short of the 150-160 watts (10 amps times 15-16 volts) you really can get at those voltages from a Z4000 or ZW-L.  You have to decide is 100 watts is enough: I have two multi-Pullmor, incadsecent light passenger trains that demand 115-125 watts when running.  They aren't that special.

 

Still, all this said, it is a well made unit, with mid range output, meters, bell and whistle buttons, etc., for less than half the price of ZW-Ls, etc.

I recently bought one used, and it's a well made transformer.  Note that unlike the old PW-ZW, the 270 watts is actually an output rating, not the input rating.  While it's true you can only get roughly 7 amps out of each side continuously, it is a true 270 watt output transformer.

 

The breakers are rated at 7A, but it takes a while for them to trip at that current.  I ran one for 15 minutes with an 8A load (measured) and the breaker hadn't tripped.  Adding a couple more amps immediately tripped the breaker.  This was the same for both sides.

 

Given the surge capability of probably several more amps, I think this an excellent transformer.  For $350, I'd probably go with Lee's suggestion and get the Z4000, they regularly show up around $400, the extra money is well worth it. 

 

I opened mine up to check it out since it was a used unit.  It's very well made, and the carbon wipers look much more robust than the wimpy little rollers used in many Lionel PW transformers, they look like they'll last a long time!  Very clean construction overall.

I bought one of these several years ago shortly after they came out for $225 at Just Trains, while the ZW and MTH transformers were hard to find for less than $400.  It's a great transformer, and I'm very satisfied with it after years of TMCC (mostly) operation.

 

The only problem I've had was "pegging" an ammeter (twice I think).  But MRC (Frank, Service Dept.) took care of it without charge.  I recommend it.

 

          paul m.

I the same as Paul got it around the same time. I have used it for years in a tmcc environment with no issues. I think it claims to do sine wave which not exactly sure what that is. I also have used their dual power 027 pack which produced 270 watts as well as this seems to be the newer model of it.

I believe the ammeters have shunts inside, if they get loose, the ammeter would probably get way more juice than it needs.

I have one that I purchased when they first came out, about 10 years ago I believe. It has been trouble free and MRC seems good about backing their products. Probably the biggest negative about it, which has been discussed on the forum, is how much most engines slow down when you press the horn/whistle button.

 

I also have a MTH Z4000 that I have had almost 15 years and has also been trouble free. At the time I purchased the MRC, the street price was about $200 vs $400 for the Z4000. This is not the case today. The price for the MRC is almost $300 today vs about $400 for the MTH Z4000. 

 

If I were buying one today, based on my experience of having both types of transformers for many years, I would pay the extra $100 for the Z4000.

I have had mine for about 10 years and use it for public displays running TMCC.  No problems. I appreciate the big meters and the fact that the two circuit breakers seem fast acting.

 

Yes, if you are running conventional, the locomotive will slow down if you use the horn or the whistle. Since I am running TMCC at public displays this is not an issue for me.

 

Pure Power refers to the sine wave output of current the transformer produces. It is kind to PW engines and even easily runs early QSI and MTH PS 1 units, which can tend to be balky with chopped wave transformers.

 

If you can get one for about 250 dollars, they are worth it.

 

Ed Boyle

The whistle/bell controls are probably the least desirable feature of these transformers, as they use the series diode string to generate the DC voltage offset.  This will drop the total voltage to the locomotive.  The scheme is reliable, it does cause the locomotive to slow when the function is invoked.

It "claims" to do sine waves because it's just a large variable transformer, and it does indeed do "sine waves".   The modern electronic transformers have electronic voltage control that produces chopped sine waves, some locomotives have issues with those waveforms.

As another poster suggested, I'd go for MTH's Z-4000 for a little more money.  I bought my Pure Power Dual used for $125 about 8 years ago and it gets a lot of use.  The only thing I needed to ever fix was a loose connection off the direction button on one channel.  John is correct about trains (drastically) slowing down if you use the horn button from the transformer (no problem if you sound horn from a remote).  I've never had a problem regarding the sine wave form and engine performance, and I run a lot of different engines (PS1/PS2/TMCC/Legacy).  Ironically, I have had accessory lighting pulse from using chopped wave forms supplied from a CW-80.

 

Stack

I've often thought shorting a couple of diodes in these transformers would still give you enough DC offset and minimize the problem with locomotives slowing.  It would be an easy test, might be worth it to conventional runners. 

 

Another solution would be to rewire the diode strings so they're always present and short many of them for whistle/bell functions.  This reduces the maximum voltage available, but eliminates the slowdown for the whistle/bell functions. 

 

FWIW, I believe there are six diodes in the string, I've found 5 work in every case I've checked.  I built a whistle/bell box with five diodes and the buttons shorted four of them to generate the offset.  Might be worth consideration...

 

But both sides are limited to 7 amps max current,

The meters show 10 amps.  I have used mine for 5 years in a DCS/Legacy/TMCC environment without any issues. It mixes well with my 3 Z4000s, 4 180 Lionel bricks, and two PW ZWs on my layout.

Lee, the Z-4000 is a sine-wave output unit, not chopped. Put a scope on it and see for yourself. (If the output is routed through a TIU variable channel, then the track voltage is chopped by the TIU to vary it.)

I've had mine for years.  Bought it for around $200.  It was the most power for the money I could find.  I run a pair of Williams engines and passenger cars with it most of the time and it does just fine.  Whistle and horn function is not the best, but it does work.  I like it well enough, I'm not interested in the power brick type transformers.  I wouldn't mind owning a good old ZW someday.

Actually, I have been puzzled for some time by the Z4000.  I looked at its waveform about five years ago -- dragged it and my old (1954) Marx transformer down to our lab and hooked them up and put a pure resistive load on them.  The Marx produced a pure sine wave at variable voltages up to around 40 watts load and then began to shows signs of core saturation - as you would expect.  The Z4000 did not look entirely sine wave to me. I recall it looked to be electronicly, not transformer generated --"notched" at the zero crossings, not smooth there. Frankly I don't remember the details beyond concluding it had about four times the power of the Marx but some sort of electronics inside in control of the waveform or something. 

 

Regardless, what I do know from experience is that, while it does not control trains at low settings as well as the ZW-L, it does better - not as well but noticeably better - than my pure-sine wave variable transformers like my postwar Marx and Lionel (from the same time period) transformers.  For example I tested both the Lionel 0-4-0 Shifters I own for the lowest speed each will run at and pull six cars and a caboose while going smoothly all the way around my layout.  All voltages are measured not with the the unit's meters but with the same digital multimeter set to AC. 

ZW-L - 7.9 volts ---> scale 19 mph 

Z4K   - 8.4 volts ---> scale 26 mph

Marx or Lionel ---> 9.5 volts = 31 mph  - no difference at all between the two in what slowest speed they give.

Of course, with chopped or synthesized outputs, the voltmeter, designed for 60 cycle readings, might not be accurate, but that really does not matter - I take the Marx to be a pure sine wave which means both the other units are something else - the Z4K might be very close to sine - apparently it is, but it does something to run trains better than just a transformer alone. 

 

Sort of not important to me, though.  Its over the the side on a shelf and I guess I will sell it now that I have the ZW-L, good as it is.

 

 

I bought the MRC transformer used. It is  not great in  terms of whistle or bell but

other than that it is superb. It you can get it for $200 or less, grab it.

I have two ZW's and two Type V that are shelf queen since I got the MRC.

 

Al W.

I have had my MRC Dual for about 6 years and am quite happy with it.  I just got a second one (new at auction) to be used when I get my layout expansion done. 

 

I like the fact that it has both analog amp and voltage meters.  Another plus is that the street price is usually in the $250 area.

 

Jim

I scored mine for $125 shipped.  At that price, I couldn't pass it up. 

I grabbed a used one for about $150.00 several years ago. I use it to run my accessories and misc. lights.

The Golden gate Lionel club has three of them for operating the layout. The only problem they had is that the direction/whistle/bell buttons have broken on several occasions and so we finally jumpered them out. It was no problem to do that because we already had these buttons on the control panel from when we used old postwar ZW transformers.

 

I do not know if the MRC buttons were just fragile, or the ham fisted clods in the culb were too rough on them.

 

Probably a little of both.

I use the old post-war-Lionel days method of raising the voltage simultaneously with pushing the horn or bell button, and, of course, lowering it again as you release the button.

How do you "use" this method with this transformer?

Sorry I'm a little tardy on replying back to you guys, I just want to thank all of you for the great answers to my questions about the MRC power pack.  Based on the many fine answers, I think I'll either pick up a new Z-4000 or maybe a nice used one.  So thanks again for all the honest answers and the good advice they are truly appreciated.