I don’t know where you live but here in my area in Edison New Jersey there are a lot of electronics dealers that people from Asia sell stuff and I’m sure you can find an AC step up transformer for that. Sent from: My extremely complicated, hand held electronic device.

On Apr 28, 2021, at 4:56 PM, John Heritage via vcf-midatlantic <vcf-midatlantic@lists.vcfed.org> wrote:

I have thought about just running 240V - but it's possible the computer could be moved to different places in the house, etc.. I have wire but would still need to buy a breaker and the receptacle - so might as well just get a step up transformer for the price..

...

On Wed, Apr 28, 2021 at 4:47 PM Bruce via vcf-midatlantic < vcf-midatlantic@lists.vcfed.org> wrote:

You might first check whether your location (home?) has 230VAC available. That's fairly common and might be within specs of the 240V power supply. Bruce NJ

On Wed, Apr 28, 2021 at 4:34 PM John Heritage via vcf-midatlantic < vcf-midatlantic@lists.vcfed.org> wrote:

...

Hey folks

I have a new Amiga PSU coming on from icomp that is 240V only. I'm looking for recommendations for a 120 to 240V step up transformer rated for at least 100W (so it doesnt have to work hard). Preferably silent. Etc.

Also what should I avoid in this space ?

P.S. This PSU is the "CA PSU" from icomp - and not an original commodore unit (as they are hard to find and old) nor one of the meanwell based units on ebay that have problems with accelerated amigas. I do have a cheap one and while it can do my slightly expanded 1200 it's hard fail on an expanded 500.

Thanks !

Yep - that's exactly what i'm looking for advice on -- I think transformers are pretty standard/minimalist, but just looking for some links or models of 'ready to use' step up transformers that will plug into my US 120V outlet and give me a 240V UK or EU style plug output.. thanks! On Wed, Apr 28, 2021 at 4:49 PM Ethan O'Toole <telmnstr@757.org> wrote:

...

Hey folks I have a new Amiga PSU coming on from icomp that is 240V only. I'm looking for recommendations for a 120 to 240V step up transformer rated for at least 100W (so it doesnt have to work hard). Preferably silent. Etc. Also what should I avoid in this space ?

I mean you can get a transformer that will take 110 and put out 220 before the Amiga PSU.

The Amiga runs on voltages that you could find on any ATX power supply. You could make a cable that would go from the funky square DIN to a PC motherboard ATX connector and use any old ATX Flex PSU.

- Ethan

Not "ready-to-use" but maybe something close to what you need (don't quote me on the exact model, just an example): https://www.mouser.com/ProductDetail/Hammond-Manufacturing/229A230?qs=Bs%2Fg... On Wed, Apr 28, 2021 at 4:57 PM John Heritage via vcf-midatlantic < vcf-midatlantic@lists.vcfed.org> wrote:

Yep - that's exactly what i'm looking for advice on -- I think transformers are pretty standard/minimalist, but just looking for some links or models of 'ready to use' step up transformers that will plug into my US 120V outlet and give me a 240V UK or EU style plug output..

thanks!

On Wed, Apr 28, 2021 at 4:49 PM Ethan O'Toole <telmnstr@757.org> wrote:

...

...

Hey folks I have a new Amiga PSU coming on from icomp that is 240V only. I'm looking for recommendations for a 120 to 240V step up transformer rated for at least 100W (so it doesnt have to work hard). Preferably silent. Etc. Also what should I avoid in this space ?

I mean you can get a transformer that will take 110 and put out 220 before the Amiga PSU.

The Amiga runs on voltages that you could find on any ATX power supply. You could make a cable that would go from the funky square DIN to a PC motherboard ATX connector and use any old ATX Flex PSU.

- Ethan

Per the guy who designed it (iComp.De - he makes tons of amiga/commodore custom electronics) - the input frequency doesn't matter: does 60 hz / 240V power vs 50 hz / 240V power matter for this power supply if I go the transformer route? It shouldn't - it's a simple rectifier design where grid frequency is not used for anything. On Wed, Apr 28, 2021 at 8:13 PM W2HX <w2hx@w2hx.com> wrote:

Are you sure the PS in the amiga is expecting 60 Hertz power? It might be expecting 50 Hz depending on where it is from. This is a bigger problem that a transformer won't solve

-----Original Message----- From: vcf-midatlantic <vcf-midatlantic-bounces@lists.vcfed.org> On Behalf Of John Heritage via vcf-midatlantic Sent: Wednesday, April 28, 2021 4:57 PM To: Ethan O'Toole <telmnstr@757.org> Cc: John Heritage <john.heritage@gmail.com>; John Heritage via vcf-midatlantic <vcf-midatlantic@lists.vcfed.org> Subject: Re: [vcf-midatlantic] OT - 120v to 240v step up recommendations

Yep - that's exactly what i'm looking for advice on -- I think transformers are pretty standard/minimalist, but just looking for some links or models of 'ready to use' step up transformers that will plug into my US 120V outlet and give me a 240V UK or EU style plug output..

thanks!

On Wed, Apr 28, 2021 at 4:49 PM Ethan O'Toole <telmnstr@757.org> wrote:

...

...

Hey folks I have a new Amiga PSU coming on from icomp that is 240V only. I'm looking for recommendations for a 120 to 240V step up transformer rated for at least 100W (so it doesnt have to work hard). Preferably silent. Etc. Also what should I avoid in this space ?

I mean you can get a transformer that will take 110 and put out 220 before the Amiga PSU.

The Amiga runs on voltages that you could find on any ATX power supply. You could make a cable that would go from the funky square DIN to a PC motherboard ATX connector and use any old ATX Flex PSU.

- Ethan

Even if the grid frequency is "not used for anything" it can still matter. Some older, larger computers used resonant transformers and these simply won't work. Going from the UK/EU 50Hz world to the US 60Hz world is not usually a problem. In general transformers are slightly more efficient at 60hz. Going the other way can be a problem and US transformers can run warm and over heat. Dave G4UGM

-----Original Message----- From: vcf-midatlantic <vcf-midatlantic-bounces@lists.vcfed.org> On Behalf Of John Heritage via vcf-midatlantic Sent: 02 May 2021 00:45 To: W2HX <w2hx@w2hx.com> Cc: John Heritage <john.heritage@gmail.com>; vcf-midatlantic <vcf- midatlantic@lists.vcfed.org> Subject: Re: [vcf-midatlantic] OT - 120v to 240v step up recommendations

Per the guy who designed it (iComp.De - he makes tons of amiga/commodore custom electronics) - the input frequency doesn't matter:

does 60 hz / 240V power vs 50 hz / 240V power matter for this power supply if I go the transformer route?

It shouldn't - it's a simple rectifier design where grid frequency is not used for anything.

On Wed, Apr 28, 2021 at 8:13 PM W2HX <w2hx@w2hx.com> wrote:

...

Are you sure the PS in the amiga is expecting 60 Hertz power? It might be expecting 50 Hz depending on where it is from. This is a bigger problem that a transformer won't solve

-----Original Message----- From: vcf-midatlantic <vcf-midatlantic-bounces@lists.vcfed.org> On Behalf Of John Heritage via vcf-midatlantic Sent: Wednesday, April 28, 2021 4:57 PM To: Ethan O'Toole <telmnstr@757.org> Cc: John Heritage <john.heritage@gmail.com>; John Heritage via vcf-midatlantic <vcf-midatlantic@lists.vcfed.org> Subject: Re: [vcf-midatlantic] OT - 120v to 240v step up recommendations

Yep - that's exactly what i'm looking for advice on -- I think transformers are pretty standard/minimalist, but just looking for some links or models of 'ready to use' step up transformers that will plug into my US 120V outlet and give me a 240V UK or EU style plug output..

thanks!

On Wed, Apr 28, 2021 at 4:49 PM Ethan O'Toole <telmnstr@757.org> wrote:

...

...

Hey folks I have a new Amiga PSU coming on from icomp that is 240V only. I'm looking for recommendations for a 120 to 240V step up transformer rated for at least 100W (so it doesnt have to work hard). Preferably silent. Etc. Also what should I avoid in this space ?

I mean you can get a transformer that will take 110 and put out 220 before the Amiga PSU.

The Amiga runs on voltages that you could find on any ATX power supply. You could make a cable that would go from the funky square DIN to a PC motherboard ATX connector and use any old ATX Flex PSU.

- Ethan

John, I like to keep equipment original so would not be tempted to mess. In addition is the new supply accurate. I run my NTSC CoCo off a transformer and its fine. The AC does permeate a little past the transformer, so the diodes and smoothing capacitor will usually see 100Hz or 120Hz ripple. (a full wave bridge rectifier acts as a frequency doubler.) In theory there could be components tuned to this frequency, but even so they would usually not have a high enough “Q” for you to notice or to affect the operation. Dave From: John Heritage <john.heritage@gmail.com> Sent: 02 May 2021 12:14 To: dave.g4ugm@gmail.com Cc: vcf-midatlantic <vcf-midatlantic@lists.vcfed.org>; W2HX <w2hx@w2hx.com> Subject: Re: [vcf-midatlantic] OT - 120v to 240v step up recommendations Thanks Dave, Dave, and everyone - I reality do appreciate the comments and thoughts. The computer in question is the Commodore Amiga 500 (Rev 5A / NTSC) and is definitely working fine with my other (120VAC@60Hz to DC output) power supply. So I'm assuming the only 'risk' item here for 60 hz input would be the (AC to DC) power supply created by the engineer and not anything on the computer itself. In this case I'm planning to run here in the US (= 60 hz AC) so worst case it would be a '50 hz transformer running at 60hz'. Does the frequency of the mains carry over to the DC side somehow? One other option the guy mentioned was wiring a 12V/5A DC power supply directly to the DC to DC converter within the new Amiga power supply, bypassing the AC to DC conversion. This would have the benefit of being a smaller, more power efficient (less conversions) and slightly cheaper solution. Thanks! On Sun, May 2, 2021 at 4:38 AM <dave.g4ugm@gmail.com <mailto:dave.g4ugm@gmail.com> > wrote: Even if the grid frequency is "not used for anything" it can still matter. Some older, larger computers used resonant transformers and these simply won't work. Going from the UK/EU 50Hz world to the US 60Hz world is not usually a problem. In general transformers are slightly more efficient at 60hz. Going the other way can be a problem and US transformers can run warm and over heat. Dave G4UGM

-----Original Message----- From: vcf-midatlantic <vcf-midatlantic-bounces@lists.vcfed.org <mailto:vcf-midatlantic-bounces@lists.vcfed.org> > On Behalf Of John Heritage via vcf-midatlantic Sent: 02 May 2021 00:45 To: W2HX <w2hx@w2hx.com <mailto:w2hx@w2hx.com> > Cc: John Heritage <john.heritage@gmail.com <mailto:john.heritage@gmail.com> >; vcf-midatlantic <vcf- midatlantic@lists.vcfed.org <mailto:midatlantic@lists.vcfed.org> > Subject: Re: [vcf-midatlantic] OT - 120v to 240v step up recommendations

Per the guy who designed it (iComp.De - he makes tons of amiga/commodore custom electronics) - the input frequency doesn't matter:

does 60 hz / 240V power vs 50 hz / 240V power matter for this power supply if I go the transformer route?

It shouldn't - it's a simple rectifier design where grid frequency is not used for anything.

On Wed, Apr 28, 2021 at 8:13 PM W2HX <w2hx@w2hx.com <mailto:w2hx@w2hx.com> > wrote:

...

Are you sure the PS in the amiga is expecting 60 Hertz power? It might be expecting 50 Hz depending on where it is from. This is a bigger problem that a transformer won't solve

-----Original Message----- From: vcf-midatlantic <vcf-midatlantic-bounces@lists.vcfed.org <mailto:vcf-midatlantic-bounces@lists.vcfed.org> > On Behalf Of John Heritage via vcf-midatlantic Sent: Wednesday, April 28, 2021 4:57 PM To: Ethan O'Toole <telmnstr@757.org <mailto:telmnstr@757.org> > Cc: John Heritage <john.heritage@gmail.com <mailto:john.heritage@gmail.com> >; John Heritage via vcf-midatlantic <vcf-midatlantic@lists.vcfed.org <mailto:vcf-midatlantic@lists.vcfed.org> > Subject: Re: [vcf-midatlantic] OT - 120v to 240v step up recommendations

Yep - that's exactly what i'm looking for advice on -- I think transformers are pretty standard/minimalist, but just looking for some links or models of 'ready to use' step up transformers that will plug into my US 120V outlet and give me a 240V UK or EU style plug output..

thanks!

On Wed, Apr 28, 2021 at 4:49 PM Ethan O'Toole <telmnstr@757.org <mailto:telmnstr@757.org> > wrote:

...

...

Hey folks I have a new Amiga PSU coming on from icomp that is 240V only. I'm looking for recommendations for a 120 to 240V step up transformer rated for at least 100W (so it doesnt have to work hard). Preferably silent. Etc. Also what should I avoid in this space ?

I mean you can get a transformer that will take 110 and put out 220 before the Amiga PSU.

The Amiga runs on voltages that you could find on any ATX power supply. You could make a cable that would go from the funky square DIN to a PC motherboard ATX connector and use any old ATX Flex PSU.

- Ethan

I see a lot of very complicated explanations and responses, and a lot of very technical "what-if's" attempting to consider every single angle. After all, electronics is the passion of many, myself included. But at the end of the day, it's a power supply. For a home computer. It's been designed to work with ordinary household power - it's not going to be super picky about tiny differences in voltage, and basically nothing in this entire realm is going to have a problem with a difference in frequency. That really only affects AC synchronous motors like in a record player or something. A step-up transformer is more than sufficient, just get one that's beefy enough to handle whatever you intend to run. Being that this is an Amiga, it doesn't exactly pull a ton of power, so nearly anything should be fine. I have a whole bunch of equipment from foreign countries. For operating 240v hardware, I have a couple of step up transformers. One is simply the isolation transformer scavenged from an old arcade machine - one that had multiple input taps. I'm using it backwards, restrapped as 240v, operating it as a step-up. No idea what the wattage is, but it was meant to power an arcade monitor, so probably around 100W or so. Ish. It works fine, I've powered lots of British, Soviet, and other European machines on this thing, Another step-up I use is actually a travel converter meant to be used as a step-down, to power 120V stuff overseas, converting 240V to 120V. It's an autotransformer, so it does not isolate in any way, and this is likely how most transformers you see on Amazon are built, because it's cheaper. I've rewired it backwards so it converts the 120V up to 240V. This also works just fine and I've powered lots of foreign equipment off of it. Nearly every product on Amazon has some "scary reviews" thanks to people that simply don't know how to use it. My favorite being from some lithium batteries, two different people complained they caused their devices to catch fire and nearly burn down their house, with photo evidence. One of these photos shows the batteries, burnt and swollen, in the compartment of the device. One of which is installed backwards. So, huh. You take two 10,000mah batteries, and short them out with each other by installing one battery backwards in a device that uses two batteries in parallel, and it catches fire? Who knew? Silly physics. What will it think of next? It should have *known* what this user intended the batteries to do, and not allowed them to explode like that. So, yes. You have to take reviews with a grain of salt. While people may have had horrible experiences, there is a reasonable chance these experiences were self inflicted. And yes - precise US line voltage is technically 117V, and I'm pretty sure the UK is technically 230V, etc, etc. But the line voltage will vary from area to area, and sag during periods of high usage and on circuits that are heavily loaded. Any device designed for use in the home will be tolerant of these sorts of voltage drifts, and the voltage regulation in the power supply of any given home computer, TV set, or piece of stereo equipment will be able to handle a reasonable amount of deviation. In the end, it really doesn't matter - close enough is close enough - 220, 221, whatever it takes. It's fine. Any given step-up transformer should have no problem powering an Amiga, and any reasonably designed power supply is going to work just fine on either 50 or 60hz, and within any reasonable deviation of it's intended input voltage. Power in houses is FAR from perfect. -Ian On Sun, May 2, 2021 at 8:56 AM John Heritage via vcf-midatlantic <vcf-midatlantic@lists.vcfed.org> wrote:

Ok so you recommend just getting a step up transformer and be done with it ?

Any brands you recommend that are UL or similar? (Or anyone else recommend?) . The models on amazon almost all seem to have at least a percentage of very scary reviews..

On Sun, May 2, 2021, 8:03 AM <dave.g4ugm@gmail.com> wrote:

...

John,

I like to keep equipment original so would not be tempted to mess. In addition is the new supply accurate. I run my NTSC CoCo off a transformer and its fine.

The AC does permeate a little past the transformer, so the diodes and smoothing capacitor will usually see 100Hz or 120Hz ripple. (a full wave bridge rectifier acts as a frequency doubler.)

In theory there could be components tuned to this frequency, but even so they would usually not have a high enough “Q” for you to notice or to affect the operation.

Dave

*From:* John Heritage <john.heritage@gmail.com> *Sent:* 02 May 2021 12:14 *To:* dave.g4ugm@gmail.com *Cc:* vcf-midatlantic <vcf-midatlantic@lists.vcfed.org>; W2HX < w2hx@w2hx.com> *Subject:* Re: [vcf-midatlantic] OT - 120v to 240v step up recommendations

Thanks Dave, Dave, and everyone - I reality do appreciate the comments and thoughts.

The computer in question is the Commodore Amiga 500 (Rev 5A / NTSC) and is definitely working fine with my other (120VAC@60Hz to DC output) power supply. So I'm assuming the only 'risk' item here for 60 hz input would be the (AC to DC) power supply created by the engineer and not anything on the computer itself.

In this case I'm planning to run here in the US (= 60 hz AC) so worst case it would be a '50 hz transformer running at 60hz'.

Does the frequency of the mains carry over to the DC side somehow? One other option the guy mentioned was wiring a 12V/5A DC power supply directly to the DC to DC converter within the new Amiga power supply, bypassing the AC to DC conversion. This would have the benefit of being a smaller, more power efficient (less conversions) and slightly cheaper solution.

Thanks!

On Sun, May 2, 2021 at 4:38 AM <dave.g4ugm@gmail.com> wrote:

Even if the grid frequency is "not used for anything" it can still matter. Some older, larger computers used resonant transformers and these simply won't work. Going from the UK/EU 50Hz world to the US 60Hz world is not usually a problem. In general transformers are slightly more efficient at 60hz. Going the other way can be a problem and US transformers can run warm and over heat.

Dave G4UGM

...

-----Original Message----- From: vcf-midatlantic <vcf-midatlantic-bounces@lists.vcfed.org> On Behalf Of John Heritage via vcf-midatlantic Sent: 02 May 2021 00:45 To: W2HX <w2hx@w2hx.com> Cc: John Heritage <john.heritage@gmail.com>; vcf-midatlantic <vcf- midatlantic@lists.vcfed.org> Subject: Re: [vcf-midatlantic] OT - 120v to 240v step up recommendations

Per the guy who designed it (iComp.De - he makes tons of amiga/commodore custom electronics) - the input frequency doesn't matter:

does 60 hz / 240V power vs 50 hz / 240V power matter for this power supply if I go the transformer route?

It shouldn't - it's a simple rectifier design where grid frequency is not used for anything.

On Wed, Apr 28, 2021 at 8:13 PM W2HX <w2hx@w2hx.com> wrote:

...

Are you sure the PS in the amiga is expecting 60 Hertz power? It might be expecting 50 Hz depending on where it is from. This is a bigger problem that a transformer won't solve

-----Original Message----- From: vcf-midatlantic <vcf-midatlantic-bounces@lists.vcfed.org> On Behalf Of John Heritage via vcf-midatlantic Sent: Wednesday, April 28, 2021 4:57 PM To: Ethan O'Toole <telmnstr@757.org> Cc: John Heritage <john.heritage@gmail.com>; John Heritage via vcf-midatlantic <vcf-midatlantic@lists.vcfed.org> Subject: Re: [vcf-midatlantic] OT - 120v to 240v step up recommendations

Yep - that's exactly what i'm looking for advice on -- I think transformers are pretty standard/minimalist, but just looking for some links or models of 'ready to use' step up transformers that will plug into my US 120V outlet and give me a 240V UK or EU style plug output..

thanks!

On Wed, Apr 28, 2021 at 4:49 PM Ethan O'Toole <telmnstr@757.org> wrote:

...

...

Hey folks I have a new Amiga PSU coming on from icomp that is 240V only. I'm looking for recommendations for a 120 to 240V step up transformer rated for at least 100W (so it doesnt have to work hard). Preferably silent. Etc. Also what should I avoid in this space ?

I mean you can get a transformer that will take 110 and put out 220 before the Amiga PSU.

The Amiga runs on voltages that you could find on any ATX power supply. You could make a cable that would go from the funky square DIN to a PC motherboard ATX connector and use any old ATX Flex PSU.

- Ethan

Exactly! On Sun, May 2, 2021 at 3:10 PM Ian Primus via vcf-midatlantic < vcf-midatlantic@lists.vcfed.org> wrote:

I see a lot of very complicated explanations and responses, and a lot of very technical "what-if's" attempting to consider every single angle. After all, electronics is the passion of many, myself included.

But at the end of the day, it's a power supply. For a home computer. It's been designed to work with ordinary household power - it's not going to be super picky about tiny differences in voltage, and basically nothing in this entire realm is going to have a problem with a difference in frequency. That really only affects AC synchronous motors like in a record player or something.

A step-up transformer is more than sufficient, just get one that's beefy enough to handle whatever you intend to run. Being that this is an Amiga, it doesn't exactly pull a ton of power, so nearly anything should be fine.

I have a whole bunch of equipment from foreign countries. For operating 240v hardware, I have a couple of step up transformers. One is simply the isolation transformer scavenged from an old arcade machine - one that had multiple input taps. I'm using it backwards, restrapped as 240v, operating it as a step-up. No idea what the wattage is, but it was meant to power an arcade monitor, so probably around 100W or so. Ish. It works fine, I've powered lots of British, Soviet, and other European machines on this thing,

Another step-up I use is actually a travel converter meant to be used as a step-down, to power 120V stuff overseas, converting 240V to 120V. It's an autotransformer, so it does not isolate in any way, and this is likely how most transformers you see on Amazon are built, because it's cheaper. I've rewired it backwards so it converts the 120V up to 240V. This also works just fine and I've powered lots of foreign equipment off of it.

Nearly every product on Amazon has some "scary reviews" thanks to people that simply don't know how to use it. My favorite being from some lithium batteries, two different people complained they caused their devices to catch fire and nearly burn down their house, with photo evidence. One of these photos shows the batteries, burnt and swollen, in the compartment of the device. One of which is installed backwards. So, huh. You take two 10,000mah batteries, and short them out with each other by installing one battery backwards in a device that uses two batteries in parallel, and it catches fire? Who knew? Silly physics. What will it think of next? It should have *known* what this user intended the batteries to do, and not allowed them to explode like that. So, yes. You have to take reviews with a grain of salt. While people may have had horrible experiences, there is a reasonable chance these experiences were self inflicted.

And yes - precise US line voltage is technically 117V, and I'm pretty sure the UK is technically 230V, etc, etc. But the line voltage will vary from area to area, and sag during periods of high usage and on circuits that are heavily loaded. Any device designed for use in the home will be tolerant of these sorts of voltage drifts, and the voltage regulation in the power supply of any given home computer, TV set, or piece of stereo equipment will be able to handle a reasonable amount of deviation.

In the end, it really doesn't matter - close enough is close enough - 220, 221, whatever it takes. It's fine. Any given step-up transformer should have no problem powering an Amiga, and any reasonably designed power supply is going to work just fine on either 50 or 60hz, and within any reasonable deviation of it's intended input voltage. Power in houses is FAR from perfect.

-Ian

On Sun, May 2, 2021 at 8:56 AM John Heritage via vcf-midatlantic <vcf-midatlantic@lists.vcfed.org> wrote:

...

Ok so you recommend just getting a step up transformer and be done with

it ?

...

Any brands you recommend that are UL or similar? (Or anyone else recommend?) . The models on amazon almost all seem to have at least a percentage of very scary reviews..

On Sun, May 2, 2021, 8:03 AM <dave.g4ugm@gmail.com> wrote:

...

John,

I like to keep equipment original so would not be tempted to mess. In addition is the new supply accurate. I run my NTSC CoCo off a

transformer

...

...

and its fine.

The AC does permeate a little past the transformer, so the diodes and smoothing capacitor will usually see 100Hz or 120Hz ripple. (a full wave bridge rectifier acts as a frequency doubler.)

In theory there could be components tuned to this frequency, but even so they would usually not have a high enough “Q” for you to notice or to affect the operation.

Dave

*From:* John Heritage <john.heritage@gmail.com> *Sent:* 02 May 2021 12:14 *To:* dave.g4ugm@gmail.com *Cc:* vcf-midatlantic <vcf-midatlantic@lists.vcfed.org>; W2HX < w2hx@w2hx.com> *Subject:* Re: [vcf-midatlantic] OT - 120v to 240v step up recommendations

Thanks Dave, Dave, and everyone - I reality do appreciate the comments and thoughts.

The computer in question is the Commodore Amiga 500 (Rev 5A / NTSC) and is definitely working fine with my other (120VAC@60Hz to DC output) power supply. So I'm assuming the only 'risk' item here for 60 hz input would be the (AC to DC) power supply created by the engineer and not anything on the computer itself.

In this case I'm planning to run here in the US (= 60 hz AC) so worst case it would be a '50 hz transformer running at 60hz'.

Does the frequency of the mains carry over to the DC side somehow? One other option the guy mentioned was wiring a 12V/5A DC power supply directly to the DC to DC converter within the new Amiga power supply, bypassing the AC to DC conversion. This would have the benefit of being a smaller, more power efficient (less conversions) and slightly cheaper solution.

Thanks!

On Sun, May 2, 2021 at 4:38 AM <dave.g4ugm@gmail.com> wrote:

Even if the grid frequency is "not used for anything" it can still matter. Some older, larger computers used resonant transformers and these simply won't work. Going from the UK/EU 50Hz world to the US 60Hz world is not usually a problem. In general transformers are slightly more efficient at 60hz. Going the other way can be a problem and US transformers can run warm and over heat.

Dave G4UGM

...

-----Original Message----- From: vcf-midatlantic <vcf-midatlantic-bounces@lists.vcfed.org> On Behalf Of John Heritage via vcf-midatlantic Sent: 02 May 2021 00:45 To: W2HX <w2hx@w2hx.com> Cc: John Heritage <john.heritage@gmail.com>; vcf-midatlantic <vcf- midatlantic@lists.vcfed.org> Subject: Re: [vcf-midatlantic] OT - 120v to 240v step up recommendations

Per the guy who designed it (iComp.De - he makes tons of amiga/commodore custom electronics) - the input frequency doesn't matter:

does 60 hz / 240V power vs 50 hz / 240V power matter for this power supply if I go the transformer route?

It shouldn't - it's a simple rectifier design where grid frequency is not used for anything.

On Wed, Apr 28, 2021 at 8:13 PM W2HX <w2hx@w2hx.com> wrote:

...

Are you sure the PS in the amiga is expecting 60 Hertz power? It might be expecting 50 Hz depending on where it is from. This is a bigger problem that a transformer won't solve

-----Original Message----- From: vcf-midatlantic <vcf-midatlantic-bounces@lists.vcfed.org> On Behalf Of John Heritage via vcf-midatlantic Sent: Wednesday, April 28, 2021 4:57 PM To: Ethan O'Toole <telmnstr@757.org> Cc: John Heritage <john.heritage@gmail.com>; John Heritage via vcf-midatlantic <vcf-midatlantic@lists.vcfed.org> Subject: Re: [vcf-midatlantic] OT - 120v to 240v step up recommendations

Yep - that's exactly what i'm looking for advice on -- I think transformers are pretty standard/minimalist, but just looking for some links or models of 'ready to use' step up transformers that will plug into my US 120V outlet and give me a 240V UK or EU style plug output..

thanks!

On Wed, Apr 28, 2021 at 4:49 PM Ethan O'Toole <telmnstr@757.org> wrote:

...

> Hey folks > I have a new Amiga PSU coming on from icomp that is 240V only. > I'm looking > for recommendations for a 120 to 240V step up transformer rated > for at least 100W (so it doesnt have to work hard). Preferably silent. Etc. > Also what should I avoid in this space ?

I mean you can get a transformer that will take 110 and put out 220 before the Amiga PSU.

The Amiga runs on voltages that you could find on any ATX power supply. You could make a cable that would go from the funky square DIN to a PC motherboard ATX connector and use any old ATX Flex PSU.

- Ethan

While a shit in frequency is certainly something that *can* cause problems, it's not going to be something that will be a problem running equipment designed for 50hz on 60hz power, as the higher frequency simply won't saturate the transformer core. Same reason you can use old radios meant for 25hz power just fine on 60hz. The 25hz transformers are absolutely huge to compensate for this and to avoid saturating on such a low frequency - totally unnecessary for 60hz, but they work just fine, and run cool too! The only time a problem might crop up is running 60hz equipment in 50hz countries, but... the difference is fairly minor, and the transformer would have to be really on the ragged edge of saturation to begin with to not function correctly with the change. Definitely something to consider, however. But that's not the problem we're dealing with here, because he's using stuff at a higher frequency than it was designed for, not lower. -Ian On Sun, May 2, 2021 at 8:00 PM W2HX via vcf-midatlantic <vcf-midatlantic@lists.vcfed.org> wrote:

...

basically nothing in this entire realm is going to have a problem with a difference in frequency. That really only affects AC synchronous motors like in a record player or something.

Unfortunately not entirely true, but the power supply gods have smiled upon you. So the op has a switch mode supply and all is well he will not have to worry. In fact, depending on the specs, he may not even need a step up transformer at all if the supply has a broad input range.

The problem with frequency (however small it may be) is that it can cause the core in the main transformer to saturate. This can have various nasty effects like heating and also could induce RFI on the output of the PS. Of course, this all depends on how well the transformer is made. A marginally spec'd unit could exhibit this problem. A better-spec'd unit may not.

So there is something more than a zero percent reason to worry about it, but clearly less than 100%.

73 Eugene W2HX

-----Original Message----- From: vcf-midatlantic <vcf-midatlantic-bounces@lists.vcfed.org> On Behalf Of Chris Fala via vcf-midatlantic Sent: Sunday, May 2, 2021 4:06 PM To: vcf-midatlantic <vcf-midatlantic@lists.vcfed.org> Cc: Chris Fala <chrisjpf33@gmail.com> Subject: Re: [vcf-midatlantic] OT - 120v to 240v step up recommendations

Exactly!

On Sun, May 2, 2021 at 3:10 PM Ian Primus via vcf-midatlantic < vcf-midatlantic@lists.vcfed.org> wrote:

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I see a lot of very complicated explanations and responses, and a lot of very technical "what-if's" attempting to consider every single angle. After all, electronics is the passion of many, myself included.

But at the end of the day, it's a power supply. For a home computer. It's been designed to work with ordinary household power - it's not going to be super picky about tiny differences in voltage, and basically nothing in this entire realm is going to have a problem with a difference in frequency. That really only affects AC synchronous motors like in a record player or something.

A step-up transformer is more than sufficient, just get one that's beefy enough to handle whatever you intend to run. Being that this is an Amiga, it doesn't exactly pull a ton of power, so nearly anything should be fine.

I have a whole bunch of equipment from foreign countries. For operating 240v hardware, I have a couple of step up transformers. One is simply the isolation transformer scavenged from an old arcade machine - one that had multiple input taps. I'm using it backwards, restrapped as 240v, operating it as a step-up. No idea what the wattage is, but it was meant to power an arcade monitor, so probably around 100W or so. Ish. It works fine, I've powered lots of British, Soviet, and other European machines on this thing,

Another step-up I use is actually a travel converter meant to be used as a step-down, to power 120V stuff overseas, converting 240V to 120V. It's an autotransformer, so it does not isolate in any way, and this is likely how most transformers you see on Amazon are built, because it's cheaper. I've rewired it backwards so it converts the 120V up to 240V. This also works just fine and I've powered lots of foreign equipment off of it.

Nearly every product on Amazon has some "scary reviews" thanks to people that simply don't know how to use it. My favorite being from some lithium batteries, two different people complained they caused their devices to catch fire and nearly burn down their house, with photo evidence. One of these photos shows the batteries, burnt and swollen, in the compartment of the device. One of which is installed backwards. So, huh. You take two 10,000mah batteries, and short them out with each other by installing one battery backwards in a device that uses two batteries in parallel, and it catches fire? Who knew? Silly physics. What will it think of next? It should have *known* what this user intended the batteries to do, and not allowed them to explode like that. So, yes. You have to take reviews with a grain of salt. While people may have had horrible experiences, there is a reasonable chance these experiences were self inflicted.

And yes - precise US line voltage is technically 117V, and I'm pretty sure the UK is technically 230V, etc, etc. But the line voltage will vary from area to area, and sag during periods of high usage and on circuits that are heavily loaded. Any device designed for use in the home will be tolerant of these sorts of voltage drifts, and the voltage regulation in the power supply of any given home computer, TV set, or piece of stereo equipment will be able to handle a reasonable amount of deviation.

In the end, it really doesn't matter - close enough is close enough - 220, 221, whatever it takes. It's fine. Any given step-up transformer should have no problem powering an Amiga, and any reasonably designed power supply is going to work just fine on either 50 or 60hz, and within any reasonable deviation of it's intended input voltage. Power in houses is FAR from perfect.

-Ian

On Sun, May 2, 2021 at 8:56 AM John Heritage via vcf-midatlantic <vcf-midatlantic@lists.vcfed.org> wrote:

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Ok so you recommend just getting a step up transformer and be done with

it ?

...

Any brands you recommend that are UL or similar? (Or anyone else recommend?) . The models on amazon almost all seem to have at least a percentage of very scary reviews..

On Sun, May 2, 2021, 8:03 AM <dave.g4ugm@gmail.com> wrote:

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John,

I like to keep equipment original so would not be tempted to mess. In addition is the new supply accurate. I run my NTSC CoCo off a

transformer

...

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and its fine.

The AC does permeate a little past the transformer, so the diodes and smoothing capacitor will usually see 100Hz or 120Hz ripple. (a full wave bridge rectifier acts as a frequency doubler.)

In theory there could be components tuned to this frequency, but even so they would usually not have a high enough “Q” for you to notice or to affect the operation.

Dave

*From:* John Heritage <john.heritage@gmail.com> *Sent:* 02 May 2021 12:14 *To:* dave.g4ugm@gmail.com *Cc:* vcf-midatlantic <vcf-midatlantic@lists.vcfed.org>; W2HX < w2hx@w2hx.com> *Subject:* Re: [vcf-midatlantic] OT - 120v to 240v step up recommendations

Thanks Dave, Dave, and everyone - I reality do appreciate the comments and thoughts.

The computer in question is the Commodore Amiga 500 (Rev 5A / NTSC) and is definitely working fine with my other (120VAC@60Hz to DC output) power supply. So I'm assuming the only 'risk' item here for 60 hz input would be the (AC to DC) power supply created by the engineer and not anything on the computer itself.

In this case I'm planning to run here in the US (= 60 hz AC) so worst case it would be a '50 hz transformer running at 60hz'.

Does the frequency of the mains carry over to the DC side somehow? One other option the guy mentioned was wiring a 12V/5A DC power supply directly to the DC to DC converter within the new Amiga power supply, bypassing the AC to DC conversion. This would have the benefit of being a smaller, more power efficient (less conversions) and slightly cheaper solution.

Thanks!

On Sun, May 2, 2021 at 4:38 AM <dave.g4ugm@gmail.com> wrote:

Even if the grid frequency is "not used for anything" it can still matter. Some older, larger computers used resonant transformers and these simply won't work. Going from the UK/EU 50Hz world to the US 60Hz world is not usually a problem. In general transformers are slightly more efficient at 60hz. Going the other way can be a problem and US transformers can run warm and over heat.

Dave G4UGM

...

-----Original Message----- From: vcf-midatlantic <vcf-midatlantic-bounces@lists.vcfed.org> On Behalf Of John Heritage via vcf-midatlantic Sent: 02 May 2021 00:45 To: W2HX <w2hx@w2hx.com> Cc: John Heritage <john.heritage@gmail.com>; vcf-midatlantic <vcf- midatlantic@lists.vcfed.org> Subject: Re: [vcf-midatlantic] OT - 120v to 240v step up recommendations

Per the guy who designed it (iComp.De - he makes tons of amiga/commodore custom electronics) - the input frequency doesn't matter:

does 60 hz / 240V power vs 50 hz / 240V power matter for this power supply if I go the transformer route?

It shouldn't - it's a simple rectifier design where grid frequency is not used for anything.

On Wed, Apr 28, 2021 at 8:13 PM W2HX <w2hx@w2hx.com> wrote:

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Are you sure the PS in the amiga is expecting 60 Hertz power? It might be expecting 50 Hz depending on where it is from. This is a bigger problem that a transformer won't solve

-----Original Message----- From: vcf-midatlantic <vcf-midatlantic-bounces@lists.vcfed.org> On Behalf Of John Heritage via vcf-midatlantic Sent: Wednesday, April 28, 2021 4:57 PM To: Ethan O'Toole <telmnstr@757.org> Cc: John Heritage <john.heritage@gmail.com>; John Heritage via vcf-midatlantic <vcf-midatlantic@lists.vcfed.org> Subject: Re: [vcf-midatlantic] OT - 120v to 240v step up recommendations

Yep - that's exactly what i'm looking for advice on -- I think transformers are pretty standard/minimalist, but just looking for some links or models of 'ready to use' step up transformers that will plug into my US 120V outlet and give me a 240V UK or EU style plug output..

thanks!

On Wed, Apr 28, 2021 at 4:49 PM Ethan O'Toole <telmnstr@757.org> wrote:

> > Hey folks > > I have a new Amiga PSU coming on from icomp that is 240V only. > > I'm > looking > > for recommendations for a 120 to 240V step up transformer > > rated for at least 100W (so it doesnt have to work hard). > > Preferably silent. Etc. > > Also what should I avoid in this space ? > > I mean you can get a transformer that will take 110 and put > out 220 > before the Amiga PSU. > > The Amiga runs on voltages that you could find on any ATX > power supply. > You could make a cable that would go from the funky square > DIN to a > PC motherboard ATX connector and use any old ATX Flex PSU. > > - Ethan > >