replacing 120v with 240v transformer

[elsquirrel]

I've had an ensoniq dp/4 effects processor sitting unused for a while because it is has a US voltage transformer inside (120v), and being in Australia they only way I can use it is with a step-down transformer or changing the power supply. I'm investigating the later, and am not sure if it can be done. Ensoniq are now defunct and I also tried to contact the original manufacturer of the transformers but have yet to receive a reply.

My question is this: Is it possible to determine the specifications for a replacement transformer if I'm not able to find any technical information at all? I'm really not that experienced with electronics though I'd like to learn and would like to avoid using a step-down transformer if all possible. (my concern with the step-down is the 50hz/60hz discrepancy).Voltage and Frequency

Just for completeness:
The green wires (the primary side?) are one which clips to the front panel, the on switch I think, and the other runs to a secondary power board, which then connects to a line filter at the rear of the unit. There are 9 secondary wires on one clip.






I also have the service manual, though I couldn't find anything obvious that would help. (Though I may not know what I need to look for).


Would there be some way to run a voltage through the transformer to analyse the secondary voltages maybe? What are the chances of finding something like this stock or easily modifiable? I noticed a manufacturer not far from my who make custom transformers, though I have no idea how expensive it would be.

Any help or ideas at all would be appreciated. Thanks!

[Steve Conner]

Well, from the pictures, at least we can tell that it only has a 120V primary and can't be switched.

You can use an ohmmeter, continuity tester, etc. to find out which of the 9 secondary wires correspond to windings, and then apply 120V to the primary, and measure the voltage of each winding. Take the results to your local transformer maker, or buy several off-the-shelf transformers that add up to the right number and kind of windings.

60Hz transformers will run somewhat hotter on 50Hz, but you can often get away with it.

There might be room in the chassis for a step-down transformer like this one. http://australia.rs-online.com/web/s...duct&R=0504202

Finally, maybe you can buy a broken DP/4 in Australia cheaper than you could get a custom transformer made, and pull the transformer out of it. Just hope that it's not the transformer that is broken.

[elsquirrel]

Hi thanks for the reply,

Unfortunately, the DP/4 seems pretty rare here. I could be waiting for years to find another.

In regards to running the transformer at 50hz, and I were unlucky, what are we talking about, a bit of smoke and some fizzling or possible explosion?

It's surprising because you don't really here that much about problems with frequency, and I assume most people running a step-down would also be dealing with the 50/60hz issue. i.e The step-down transformer sellers explain it doesn't convert frequency but they don't give any warnings of possible failure. It seems rare just from first observations.

I really would prefer to change over the transformer, but it could be a bit out of my league. I have no idea how I would apply the 120v for instance.

[paggerman]

My next door neighbor has a Bassman, a Fender reverb and other equipment which he picked up when living in Canada. He now uses them for gigging regularly with no problems using an external step down transformer. The 60hz thing doesn't seem to be a problem.
A while ago I spoke to a transformer manufacturer in Bayswater, VIC (don't recall the name) about making a power transformer to my specificAtion. They were really helpful and friendly (despite my lack of knowledge) and the price of a custom made PT was little different to a similar spec Hammond from any of the local suppliers, or US suppliers once postage is added. I didn't order, but would enquire again. I'm sure that if you asked they'd take your PT and make an equivalent for the local 230vac supply. Just don't mention the cricket.

The company in Bayswater is Dyne Industries www.dyne.com.au

[J M Fahey]

If it were a simpler transformer with, say, a center.tapped secondary (3 wires) it may be easier (meaning cheaper) to clone, but with a 9 wire one, we are swimming in deeper waters.
Best bet: just use a similar sized (meaning small) step down transformer, don't worry too much about 50/60Hz because any reputable manufacturer usually overdesigns a little.
Post your schematic , it must show the transformer and what it's connected to.
Good luck.

[elsquirrel]

Thanks for the info paggerman, I'll definitely give them a call and see what they say.
If it's not a huge nightmare, I'd rather fit it with a new transformer.

Though I will probably try my luck (YouTube - 110V 220V) with a step-down if it gets too complicated.

J M, all I have is the service manual - it can be downloaded at the bottom of this page.
View topic - Ensoniq DP4 & DPPro and Eventide H3000

[elsquirrel]

Well I borrowed a step-down and it seems to run ok. Though I haven't run it for extended periods of time so I guess that's not really conclusive.

One problem is a noticeable buzzing from the internal transformer of the effects unit. Would this be an indication of the 50Hz/60Hz discrepancy? An inevitable by product of stepping down? Possibly how the transformer would sound anyhow?

I contacted dyne paggerman, and they were very helpful. The reason I balked for now was that they said prices would start at $150. So if it's complicated, I don't know I'm guessing $200 - 250, not to mention I live nowhere near bayswater.

On the other hand a decent step-down is going to set me back $100. And will mean two transformers running under suboptimal conditions and a buzzing noise.

Anyhow, it's a nice sounding effects unit!

[J M Fahey]

Autotransformers are definitely not rocket science.
A small one like you need shouldn't cost more than U$S20.
*If* your transformer buzzes it's a "mechanical" problem, check how you re-mounted it.
Going from no buzz to full buzz can't be attributed to going from 60 to 50Hz.
I live in Argentina (50Hz) where the de facto standard amplifier used by any Pro musician is a (60 Hz) US amplifier (Fender, Peavey, Mesa, Ampeg, GK, etc.) bought in Miami , LA, or NY and used with an external autotransformer, with no ill effects.

[elsquirrel]

I can't say for sure it went from no buzz to the buzzing it has now because I hadn't used it before. It is definitely louder than the regular sound a transformers emits, but you still have to be close to hear it. I rechecked the mounting and it seems fine.

It might be $20 if it was a replaceable part, the problem is it was made in 94' and as far as I can tell the part or anything similar is not available.

[J M Fahey]

Hi elsquirrel.
I was talking about a cheap generic 110/220 external autotransformer.
Good luck.

[Choton]

Hello bro,

um facing the same problem with my Ensoniq VFX... power supply got damaged.. contact with manufacturer company but they didnt answer .. i wanna make by myself.. but for that i need to know, it has 9 pin in output... how many voltages each pin supplies??? can you tell me the rating of voltages... ??????

[km6xz]

Whether it overheats and buzzes from increased internal losses depends a lot on the design and size of the core. The 50 hz transformer will have more metal in the core and running a 60hz transformer might work but it also might be pulling too much current due to the inductance of the 60hz transformer being too low. The 50 hz transformer needs the additional iron for high enough inductive reactance at the lower frequency. I have a 900 watt 60 hz version bass amp here that runs perfectly on 60 hz but 50 pulls too much current by 100 volts and 120 will pull enough to blow the fuses and the toroid transformer buzzes loudly, which it shouldn't. I use a power amplifier driven with a sine wave generator and transformer for testing power supply frequency range and some transformers are fine and others models are not suitable for step down transformer use at 50 hz.

[Choton]

i got it.. but here it individually need 9 different volatges.. thats a big problem for me... searched everywhere but didnt get any answer... kindly if u know help me out there!!

[nickb]

um facing the same problem with my Ensoniq VFX... power supply got damaged.. contact with manufacturer company but they didnt answer .. i wanna make by myself.. but for that i need to know, it has 9 pin in output... how many voltages each pin supplies??? can you tell me the rating of voltages... ??????

What happened? Could it be the transformer is OK but something else in the PSU is broken.

[Choton]

Actually the transformer is damaged... now a days this kind of transformer should be in museum i guess!!! i want to make it by myself ... this transformer's output has 9pin, which has individual voltages.. so i need to know the rating of that voltages.. everything is fine except this one, i checked..