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Post by brucew268 on Mar 17, 2021 12:48:38 GMT
OK, now some questions about transformers. For my balanced power 1.5KVA a few years ago I went with Canterbury Windings. But on another order I exceeded his patience and decided to fish elsewhere next time.
Toroidy has been a good source in my limited experience and was considering that but saw Oliver's recommendation of James Transformers... ooh, O-core!!
I notice James has an Order sheet with lot's of details that can be bespoke. But wasn't sure about several:
For example, if I am ordering an 800VA transformer, why specify input Amps? Isn't that redundant, as I am putting 10A for each secondary.
Do you to specify 230VAC and decrease the secondary rating, as we do for Toroidy, or do you put exactly the primary/dsecondary voltage you want? My mains tend to be 247VAC and want 25V, so for Toroidy which is 230VAC primary, I put 24V secondaries or could even go with 23V possibly.
Colours: if you don't care, leave them blank and he'll choose?
Do you specify any changes from defaults for the performance you want? I notice James lists insulation at 100 MOhm but Toroidy lists a 4 kVA, so I've no idea how those apples and oranges compare.
Does James include the fixing hardware, or I source?
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Bigman80
Grandmaster
The HiFi Bear/Audioaddicts/Bigbottle Owner
Posts: 16,399
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Post by Bigman80 on Mar 17, 2021 13:04:56 GMT
OK, now some questions about transformers. For my balanced power 1.5KVA a few years ago I went with Canterbury Windings. But on another order I exceeded his patience and decided to fish elsewhere next time.
Toroidy has been a good source in my limited experience and was considering that but saw Oliver's recommendation of James Transformers... ooh, O-core!!
I notice James has an Order sheet with lot's of details that can be bespoke. But wasn't sure about several:
For example, if I am ordering an 800VA transformer, why specify input Amps? Isn't that redundant, as I am putting 10A for each secondary.
Do you to specify 230VAC and decrease the secondary rating, as we do for Toroidy, or do you put exactly the primary/dsecondary voltage you want? My mains tend to be 247VAC and want 25V, so for Toroidy which is 230VAC primary, I put 24V secondaries or could even go with 23V possibly.
Colours: if you don't care, leave them blank and he'll choose?
Do you specify any changes from defaults for the performance you want? I notice James lists insulation at 100 MOhm but Toroidy lists a 4 kVA, so I've no idea how those apples and oranges compare.
Does James include the fixing hardware, or I source? I usually drop them an email as their website is a bit uninformative at times. Just drop them a message with your requirements. I have all of mine shielded and potted these days too. He's very reasonable about everything and I have not had a single thing to complain about and I've had about 25x O-Cores from him.
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Post by brucew268 on Mar 17, 2021 14:40:09 GMT
I'll contact him.
Here's a random question: an electrostatic screen is often between primary and secondary windings. If doing 4x25V as a dual monoblock, I wonder if a screen can also be added to good effect between the secondaries as in: Primary/screen/A/B/screen/C/D.
Or are multiple secondaries not wound over the top of each other so much as interspersed beside each other? I can't find an exploded anatomy that makes it clear.
Worth a cheeky ask?
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Post by electronumpty on Mar 17, 2021 15:51:49 GMT
I used him for my bb3, he's very quick to respknd in my experience. No harm in asking.
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Post by misterc on Mar 17, 2021 15:58:01 GMT
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Post by brucew268 on Mar 17, 2021 17:14:24 GMT
Interesting article, though I can’t keep up. Do I understand then that for sensitive hifi electronics fed by a linear power supply:
Have you A/B tested this in real world listening and found consistent identifiable results?
Would this be affected at all when mains is fed through a balanced transformer?
....Numpty questions.
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Post by misterc on Mar 17, 2021 19:15:04 GMT
We wind our own transformers that we use in our ultra quiet power supplies, we use a stat shields between the P & S windings we do this on all of our toroidal, although we do not use the 'o' cores we use our cores different materials and more of a pancake with rounded edges, quality reduction in emi and rfi in both conducted and radiated emissions. The James Tx's are good imho a step up from the Toroidys. With soft start modules I would recommend the use of one with a Tx over 500Va and or a total storage of 70K uf. We are just in the final throws of testing our SSB with full dual differential ac filtration, dc blocker and programmable soft start with up to 20 different turn of current in rush arb's. It is something that is overlooked. (Les W Avondale Audio) does a nice little SS for £62 works well for those watching the bank balance Avondale SS module information
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Post by brucew268 on Mar 23, 2021 14:03:33 GMT
I usually drop them an email as their website is a bit uninformative at times. Just drop them a message with your requirements. I have all of mine shielded and potted these days too. He's very reasonable about everything and I have not had a single thing to complain about and I've had about 25x O-Cores from him. OK, I'm having some communication issues, using plain english and clarifying a couple times. So let me ask you Oli about your experience with James transformer, Everywhere I've lived has been 245VAC, not the supposed 230VAC national standard. So, I behave as if it's the old 240VAC from years back. When I have ordered from Toroidy a 230v/10v transformer, what I got was a 12v secondary @245v, not a 10.6v secondary that I'd expect. - Have you generally specified 240v or 230v and lowered the secondary specs to compensate?
- Do James' secondaries tend to come in with higher voltage than you specified?
- How long is his build time usually (1 wk, 4 wks, 8 wks)? I can't get him to answer that.
I always specify 240v for anything i built for the UK, as anything below would be a mistake IMO. Voltage at my house often is above 245v. Send him the spec you want. tell him it needs to be as close to spec as possible and usually they are spot on. I had one that was 181v instead on 175v on the secondary. i told them, they got it right next time and have been right since. But i do tell them every time i order. Times are around 2 weeks.
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Post by macca on Mar 23, 2021 14:20:53 GMT
230v is only a notional European standard because uk is on 240 and the rest of Europe on 220v, we didn't drop down to 230v and they didn't come up to 230V, nothing at all chanegd.
Whilst I know next to F#ck all about this I have seen this issue raised many times over the years and the answer is always that it doesn't matter.
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Post by electronumpty on Mar 23, 2021 14:28:20 GMT
I usually drop them an email as their website is a bit uninformative at times. Just drop them a message with your requirements. I have all of mine shielded and potted these days too. He's very reasonable about everything and I have not had a single thing to complain about and I've had about 25x O-Cores from him. OK, I'm having some communication issues, using plain english and clarifying a couple times. So let me ask you Oli about your experience with James transformer, Everywhere I've lived has been 245VAC, not the supposed 230VAC national standard. So, I behave as if it's the old 240VAC from years back. When I have ordered from Toroidy a 230v/10v transformer, what I got was a 12v secondary @245v, not a 10.6v secondary that I'd expect. - Have you generally specified 240v or 230v and lowered the secondary specs to compensate?
- Do James' secondaries tend to come in with higher voltage than you specified?
- How long is his build time usually (1 wk, 4 wks, 8 wks)? I can't get him to answer that.
I always specify 240v for anything i built for the UK, as anything below would be a mistake IMO. Voltage at my house often is above 245v. Send him the spec you want. tell him it needs to be as close to spec as possible and usually they are spot on. I had one that was 181v instead on 175v on the secondary. i told them, they got it right next time and have been right since. But i do tell them every time i order. Times are around 2 weeks. Without a load the secondaries will be a higher voltage , can't remember the exact % more but that will be why the secondaries are over the 10v rating, nearer 12. Measure it under load to be sure. I had the same question on my 1st bb build a while ago.
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Post by brucew268 on Mar 23, 2021 15:09:30 GMT
OK, I'm having some communication issues, using plain english and clarifying a couple times. So let me ask you Oli about your experience with James transformer, Everywhere I've lived has been 245VAC, not the supposed 230VAC national standard. So, I behave as if it's the old 240VAC from years back. When I have ordered from Toroidy a 230v/10v transformer, what I got was a 12v secondary @245v, not a 10.6v secondary that I'd expect. - Have you generally specified 240v or 230v and lowered the secondary specs to compensate?
- Do James' secondaries tend to come in with higher voltage than you specified?
- How long is his build time usually (1 wk, 4 wks, 8 wks)? I can't get him to answer that.
I always specify 240v for anything i built for the UK, as anything below would be a mistake IMO. Voltage at my house often is above 245v. Send him the spec you want. tell him it needs to be as close to spec as possible and usually they are spot on. I had one that was 181v instead on 175v on the secondary. i told them, they got it right next time and have been right since. But i do tell them every time i order. Times are around 2 weeks. Without a load the secondaries will be a higher voltage , can't remember the exact % more but that will be why the secondaries are over the 10v rating, nearer 12. Measure it under load to be sure. I had the same question on my 1st bb build a while ago. Raw was 12.67v. Connecting leads to power supply and power supply to DAC, gave 12v, still 20% over. Is that sufficient load or does it need to be playing music?
James Transformers estimated 5% difference between load/no-load.
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Bigman80
Grandmaster
The HiFi Bear/Audioaddicts/Bigbottle Owner
Posts: 16,399
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Post by Bigman80 on Mar 23, 2021 15:14:31 GMT
230v is only a notional European standard because uk is on 240 and the rest of Europe on 220v, we didn't drop down to 230v and they didn't come up to 230V, nothing at all chanegd. Whilst I know next to F#ck all about this I have seen this issue raised many times over the years and the answer is always that it doesn't matter. The Voltage here is always above 230v and in most places I've checked, it's above 240v. As such I have experienced transformers humming like mad (mechanically) due to being over saturated. This Includes custom made ones that stopped vibrating when we turned the Variac down to around 233v No DC blocker will fix that problem. UK equipment should have a 240v transformer in it as far as I'm concerned.
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Post by brucew268 on Mar 23, 2021 15:16:21 GMT
I always specify 240v for anything i built for the UK, as anything below would be a mistake IMO. Voltage at my house often is above 245v. Send him the spec you want. tell him it needs to be as close to spec as possible and usually they are spot on. I had one that was 181v instead on 175v on the secondary. i told them, they got it right next time and have been right since. But i do tell them every time i order. Times are around 2 weeks. Thank you, that helps. The BBCode was off a bit so I almost missed the answer. I've bodged it to show clearly your separate answer.
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Post by misterc on Mar 23, 2021 15:42:38 GMT
UK spec is 230vac +5% -10% so 217 to 241.5Vac Here today is 239vac, last Friday it was 243Vac. Having a genuine 240vac core is preferable imho
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Post by misterc on Mar 23, 2021 15:44:39 GMT
The Voltage here is always above 230v and in most places I've checked, it's above 240v. As such I have experienced transformers humming like mad (mechanically) due to being over saturated. This Includes custom made ones that stopped vibrating when we turned the Variac down to around 233v No DC blocker will fix that problem. UK equipment should have a 240v transformer in it as far as I'm concerned. Would like to say that not all DC blockers are created equally
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Deleted
Deleted Member
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Post by Deleted on Mar 23, 2021 16:39:16 GMT
230v is only a notional European standard because uk is on 240 and the rest of Europe on 220v, we didn't drop down to 230v and they didn't come up to 230V, nothing at all chanegd. Whilst I know next to F#ck all about this I have seen this issue raised many times over the years and the answer is always that it doesn't matter. We are on 230V here.
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Post by macca on Mar 23, 2021 16:43:11 GMT
In reality or in theory?
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Post by macca on Mar 23, 2021 16:47:00 GMT
230v is only a notional European standard because uk is on 240 and the rest of Europe on 220v, we didn't drop down to 230v and they didn't come up to 230V, nothing at all chanegd. Whilst I know next to F#ck all about this I have seen this issue raised many times over the years and the answer is always that it doesn't matter. The Voltage here is always above 230v and in most places I've checked, it's above 240v. As such I have experienced transformers humming like mad (mechanically) due to being over saturated. This Includes custom made ones that stopped vibrating when we turned the Variac down to around 233v No DC blocker will fix that problem. UK equipment should have a 240v transformer in it as far as I'm concerned. Ideally yes. Can't say I have ever had a problem with humming or buzzing traffos anywhere I have lived or regardless of the voltage spec of the traffo. No idea what the variance is here as I've no way to monitor it. used to a lot of heavy industry round here, most has gone now though.
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Deleted
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Post by Deleted on Mar 23, 2021 20:00:39 GMT
Theoretically 230, reality about 231 when I last measured it.
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