A quick one, just making sure I'm not an idiot.
Ordered some R-core transformers for DAC kits and they all buzz very loudly when powered up, this is without load or anything connected to secondaries. Once connected they seem to buzz a bit louder.
The secondaries give output AC voltage although they are all off the requested spec voltages.
Why would an R-core buzz loudly without load, is this a manufacturing error?
Ordered some R-core transformers for DAC kits and they all buzz very loudly when powered up, this is without load or anything connected to secondaries. Once connected they seem to buzz a bit louder.
The secondaries give output AC voltage although they are all off the requested spec voltages.
Why would an R-core buzz loudly without load, is this a manufacturing error?
I would say it is either a mounting issue; (Eddy currents set up due to mounting bolts acting like a shorted turn) or they are not built correctly and have not been sealed.
Thanks Jon, I feared as much. Hopefully James will replace or refund. These are unusable for high quality audio.
To anyone reading - James transformers have been very good in the past, this incident is very unfortunate. No way these were checked before dispatch.
If ordering from James, clearly ask for testing before shipping.
To anyone reading - James transformers have been very good in the past, this incident is very unfortunate. No way these were checked before dispatch.
If ordering from James, clearly ask for testing before shipping.
If transformer buzz then the U/N (input voltage to number of primary turns ratio) is too high.
It is either the transformer is design improperly, or your transf. is 100...120 V in the 220V grid.
The first guess: maybe the transf. primaries need to be connected in series with the proper phasing.
If not this, then it is the wrong primaries voltage, or too low number of prim. turns.
Also, it can be shorts between the adjacent turns.
The usual recommendation to impregnate the defective transf. with some stuff to reduce the buzz
is a bad advice - it's like sweeping the dirt under the rug.
It is either the transformer is design improperly, or your transf. is 100...120 V in the 220V grid.
The first guess: maybe the transf. primaries need to be connected in series with the proper phasing.
If not this, then it is the wrong primaries voltage, or too low number of prim. turns.
Also, it can be shorts between the adjacent turns.
The usual recommendation to impregnate the defective transf. with some stuff to reduce the buzz
is a bad advice - it's like sweeping the dirt under the rug.
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I have yet to see any R-core transformer with regulatory approvals such as UL, CSA etc. That in itself is troubling and risky imo. There are good reasons for these approvals.
Unlike toroids none of my R-cores buzz. Still, my first course of business would be to try the effect a DC mains filter has on the buzzing.
Yes it could be dirty AC , try a DC blocker before blaming James.
All my R cores have been silent. I have a CSA high pot tester and check them all, they’ve all been fine.
All my R cores have been silent. I have a CSA high pot tester and check them all, they’ve all been fine.
No one outside the USA needs UL and US issued certifications. What we do need is good transformers made by trustworthy companies. One will also not find all the US stamps on Japanese transformers for tube amplifiers etc. either. None of my R-core transformers have issues, not even the cheap Indian ones. Never had or have seen any by James.
Either these James made transformers are not wound correctly or there is a user error at play.
1. Are they labelled with the primary and secondary voltages?
2. Are you sure you wired them up correctly?
3. Or ... did the manufacturer mix up wiring colors? As they are off the specified voltages there is something wrong.
4. Can you post a picture?
Either these James made transformers are not wound correctly or there is a user error at play.
1. Are they labelled with the primary and secondary voltages?
2. Are you sure you wired them up correctly?
3. Or ... did the manufacturer mix up wiring colors? As they are off the specified voltages there is something wrong.
4. Can you post a picture?
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