Hi,
I am moving from a 110V to a 220V country
Can you help me with an indication of the wattage the 220v-110V converter should have for a 50 wat tube amp?
Melody i880 amplifier
StereoTimes --
Thank you,
Jock
I am moving from a 110V to a 220V country
Can you help me with an indication of the wattage the 220v-110V converter should have for a 50 wat tube amp?
Melody i880 amplifier
StereoTimes --
Thank you,
Jock
it is possible that your amp can be changed to 220 / 230v.
ask the question directly to melody.
Melody HiFi
ask the question directly to melody.
Melody HiFi
if you look closely, it seems that your Melody is a Mingda clone, so it is quite possible that your power transformer is 110 / 220v at a time.
for that, just look behind the manufacturer's plate, it can be marked on 110 / 220v and if not, it must open and look in the power transformer
for that, just look behind the manufacturer's plate, it can be marked on 110 / 220v and if not, it must open and look in the power transformer
Its class AB1 (supposedly), two channels, 8 tubes plus some sexed up looking balldongle in the middle that presumably does something and uses some power. There is about 70w in heaters alone, and guessing around 66% efficiency in AB1 so a wet finger in the air tells us around 75w of power per channel is required by the audio path when its balls to the wall.
250w of 220/110 transformer just gets you there. I'd aim at a 500w unit.
250w of 220/110 transformer just gets you there. I'd aim at a 500w unit.
Check the fuse value for 110V, multiply your fuse value by 110, add 50% to 100% for safety margin and for the ability to blow the fuse, there you go.
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Most modern power transformers have dual 110V primary windings. They are connected in series for 220V or in parallel for 110V. Open your amplifier and check if you can switch the primary connections.
If you truly need a transformer, the "wattage" is dependent on were you source it. On popular web sites of china parts, I would look for 2000W models. The 2000 stamped on the converter is probably the model designation number, because by size, weight and price I belive they have a 500VA to maybe 800VA transformer inside. The one I once tried, quickly became worringly hot at half load. It also had a noticeable hum. I replaced it with a toroidal insulation transformer with dual 115V primary windings and dual 115V secundary windings; primary in series, secundary in parallel, slow-blow fuse as protection. Same price, way higher quality and safety. If you go on this do-it-yourself route, buy the 110V sockets were you live now. They are unobtainum in EU, I had to use the Amazon Global shipping service to get good quality UL listed USA wall sockets to mount on the converter front panel.
Be aware that most 220V countries are also 50Hz countries. Due to 60Hz to 50Hz difference, you need to derate your amplifier transformer maximum power. Theoretically, to avoid core saturation it is necessary to keep maximum flux density constant. You do this by maintaining V/f constant. In other words, you apply only 83% of the voltage that you would have applied if it were a 60 Hz system (5/6 = 0.833). This is obviously not possible, so you will derate the current instead, and still get a temperature increase. Quality vintage equipments may tolerate this, modern parts not so much.
If you truly need a transformer, the "wattage" is dependent on were you source it. On popular web sites of china parts, I would look for 2000W models. The 2000 stamped on the converter is probably the model designation number, because by size, weight and price I belive they have a 500VA to maybe 800VA transformer inside. The one I once tried, quickly became worringly hot at half load. It also had a noticeable hum. I replaced it with a toroidal insulation transformer with dual 115V primary windings and dual 115V secundary windings; primary in series, secundary in parallel, slow-blow fuse as protection. Same price, way higher quality and safety. If you go on this do-it-yourself route, buy the 110V sockets were you live now. They are unobtainum in EU, I had to use the Amazon Global shipping service to get good quality UL listed USA wall sockets to mount on the converter front panel.
Be aware that most 220V countries are also 50Hz countries. Due to 60Hz to 50Hz difference, you need to derate your amplifier transformer maximum power. Theoretically, to avoid core saturation it is necessary to keep maximum flux density constant. You do this by maintaining V/f constant. In other words, you apply only 83% of the voltage that you would have applied if it were a 60 Hz system (5/6 = 0.833). This is obviously not possible, so you will derate the current instead, and still get a temperature increase. Quality vintage equipments may tolerate this, modern parts not so much.
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