Hi
I bought the KA-9100 from the US (120v), but it does not have the switch to select to the appropriated UK/EU (220-240v) voltage. I would prefer not to use it with a step-down transformer (but if it is the case what wattage for an amp that has 90w per channel? 1000watts should that be enough?) the but at the same time, I do not know if a modification is feasible. The model is 'K' for the US market. Here (Cambridge-UK) I don't know any technicians/experts on KA-9100' restoration. Any advice or help will be great.
Thanks
I bought the KA-9100 from the US (120v), but it does not have the switch to select to the appropriated UK/EU (220-240v) voltage. I would prefer not to use it with a step-down transformer (but if it is the case what wattage for an amp that has 90w per channel? 1000watts should that be enough?) the but at the same time, I do not know if a modification is feasible. The model is 'K' for the US market. Here (Cambridge-UK) I don't know any technicians/experts on KA-9100' restoration. Any advice or help will be great.
Thanks
You will find the voltage selector on the power supply board, internally, if it is multi voltage/country.
See page 14 of service information.
See page 14 of service information.
The KA9100 has two mains transformers.
If it turns out the primaries are only for the US market (or likely US/Japan 115/110V), DO NOT GET TEMPTED and tie the primaries in series to get 230VAC!!!
I am sure you understand that I am saying this because I've seen this done and the damage it caused ultimately.
If it turns out the primaries are only for the US market (or likely US/Japan 115/110V), DO NOT GET TEMPTED and tie the primaries in series to get 230VAC!!!
I am sure you understand that I am saying this because I've seen this done and the damage it caused ultimately.
Mine, unfortunately, is the US version (K). The power transformers are two L01-1281-05. I am not attempting to do anything that could damage the amp.
I cannot attach the manual, but it is available online.
KENWOOD KA-9100 SERVICE MANUAL Pdf Download.
I also found two used transformers, that I am thinking to buy, that may be from a unit with a 240v outlet.
I cannot attach the manual, but it is available online.
KENWOOD KA-9100 SERVICE MANUAL Pdf Download.
I also found two used transformers, that I am thinking to buy, that may be from a unit with a 240v outlet.
That seems to be the same manual I posted a snip from above. None of the variations seem to show a single 120 Vac winding although the top left one shows a single 240 Vac version.
I would physically have a look at what wires come out of your transformers and take it from there.
I would physically have a look at what wires come out of your transformers and take it from there.
Attachments
Hard to say for sure seeing that. There do appear to be what just might be unused leads coming from the transformers though.
What you would need to do is note (write down clearly for reference) where all the leads from one of the transformers go.
You would then see if there were one set of windings connected to the incoming mains, or whether there were two sets but connected in parallel. That would suggest that two 120 volt parallel windings could be series connected for 240 volts. Note... this is NOT the same as connecting the two individual transformers in series as ilimzn correctly mentioned. That must never be done.
If neither of those scenarios seem to apply, then is there an unused lead (maybe one, maybe two) that while not connected to anything, are still in electrical continuity with those that connect to the incoming mains supply. If so, that would suggest an extra tapped winding for possibly higher voltages.
This might be a good point to mention safety, and safety is paramount with anything like this 🙂
Never ever connect in hope... you would test first by disconnecting and removing one of transformers completely from the amp and using a low wattage bulb tester (mains filament bulb of perhaps 40watt maximum, in series with the mains) to first test out any possible configurations on the transformer while monitoring the secondary voltages. That is the only surefire way to get connections correct and phased correctly. If anything went wrong then the bulb lights and limits current to a low value.
The pictures unfortunately aren't showing enough detail of what goes where to show what may or may not be possible.
What you would need to do is note (write down clearly for reference) where all the leads from one of the transformers go.
You would then see if there were one set of windings connected to the incoming mains, or whether there were two sets but connected in parallel. That would suggest that two 120 volt parallel windings could be series connected for 240 volts. Note... this is NOT the same as connecting the two individual transformers in series as ilimzn correctly mentioned. That must never be done.
If neither of those scenarios seem to apply, then is there an unused lead (maybe one, maybe two) that while not connected to anything, are still in electrical continuity with those that connect to the incoming mains supply. If so, that would suggest an extra tapped winding for possibly higher voltages.
This might be a good point to mention safety, and safety is paramount with anything like this 🙂
Never ever connect in hope... you would test first by disconnecting and removing one of transformers completely from the amp and using a low wattage bulb tester (mains filament bulb of perhaps 40watt maximum, in series with the mains) to first test out any possible configurations on the transformer while monitoring the secondary voltages. That is the only surefire way to get connections correct and phased correctly. If anything went wrong then the bulb lights and limits current to a low value.
The pictures unfortunately aren't showing enough detail of what goes where to show what may or may not be possible.
Thanks for your explanation! It seems too much for me, but I will ask a friend of mine that is an electrical engineer...He may be able to help me out.
I will keep posting as soon as I get new info/advise
Safety first
I will keep posting as soon as I get new info/advise
Safety first
KA-9100, brings back memories. Bought one in 1978 or 9, was stationed in Australia, picked it up at the US base exchange and kept it for over 20 years until one side died. Always loved that amp, but the chip they used for the power section was no longer available.
Are those part available now?
Are those part available now?
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