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January 26, 2020, 04:58:55 PM

Author Topic: Noob question re wiring 6.3-0-6.3 secondaries for nominal 12.6V output  (Read 125 times)

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Offline Deke609

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All - Just want to double check my thinking here.

In the hopes of bumping up my supply voltage to the BeePre filament heater circuit I am playing around with dedicated filament heater transformers - specifically the Hammond 166L12B - which is spec'd as 25VA and 12.6V (C.T.).  I plan to try one 166L12B for each filament.

Am I right that I should just cap the center tap (leave it disconnected) and wire the remaining two secondary wires into a 4-diode bridge?

Or is another method of wiring recommended - e.g., one that makes use of the center-tap?

many thanks, Derek
Derek
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Roon Intel NUC ->  Yggdrasil DAC -> BeePre (w/ BeeQuiet and EML 300B)  -> Kaiju (w/ DCFil and EML 300B) or Stereomour II (2A3 [EML Mesh] and 45 Conversion [EML 45B])  -> Audeze LCD4

Offline Paul Birkeland

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Re: Noob question re wiring 6.3-0-6.3 secondaries for nominal 12.6V output
« Reply #1 on: November 15, 2019, 07:26:56 AM »
I'd leave the CT disconnected.  Is your line voltage 115V?
Paul "PB" Birkeland

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Offline Deke609

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Re: Noob question re wiring 6.3-0-6.3 secondaries for nominal 12.6V output
« Reply #2 on: November 15, 2019, 07:34:35 AM »
Thanks PB. Yes, mains power is now 115V but I will be bumping it to 120V +/- 1.5V with the autoformer and buck/boost setup (which I have yet to build - will use the variac in the interim to test).

cheers and thanks, Derek
Derek
______

Roon Intel NUC ->  Yggdrasil DAC -> BeePre (w/ BeeQuiet and EML 300B)  -> Kaiju (w/ DCFil and EML 300B) or Stereomour II (2A3 [EML Mesh] and 45 Conversion [EML 45B])  -> Audeze LCD4

Offline Paul Birkeland

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Re: Noob question re wiring 6.3-0-6.3 secondaries for nominal 12.6V output
« Reply #3 on: November 15, 2019, 07:36:26 AM »
Well, that transformer is for 115V.  I don't recommend giving Hammond transformers more than they say they'll handle.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline Deke609

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Re: Noob question re wiring 6.3-0-6.3 secondaries for nominal 12.6V output
« Reply #4 on: November 15, 2019, 07:42:37 AM »
OK. I may have to check with Hammond about this - I think they only make 115V and 117V variants - which seems odd for North America where wall voltage can be as much as 125V or more.

I figured than since I'll be drawing a max of 1.35A and the trafo is rated for 2A I'd be ok and not overtax the primary winding. But maybe my thinking about this is wrong?

thanks, Derek
Derek
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Roon Intel NUC ->  Yggdrasil DAC -> BeePre (w/ BeeQuiet and EML 300B)  -> Kaiju (w/ DCFil and EML 300B) or Stereomour II (2A3 [EML Mesh] and 45 Conversion [EML 45B])  -> Audeze LCD4

Offline Paul Birkeland

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Paul "PB" Birkeland

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Offline Deke609

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Re: Noob question re wiring 6.3-0-6.3 secondaries for nominal 12.6V output
« Reply #6 on: November 15, 2019, 07:56:38 AM »
Thanks for that, PB. I am going to email Hammond and if they say anything over is 115V is a no go, I will get the Edcors.

Is this is an issue of the dielectric strength of the primary magnet wire coating?

cheers and thanks, Derek
Derek
______

Roon Intel NUC ->  Yggdrasil DAC -> BeePre (w/ BeeQuiet and EML 300B)  -> Kaiju (w/ DCFil and EML 300B) or Stereomour II (2A3 [EML Mesh] and 45 Conversion [EML 45B])  -> Audeze LCD4

Offline Paul Birkeland

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Re: Noob question re wiring 6.3-0-6.3 secondaries for nominal 12.6V output
« Reply #7 on: November 15, 2019, 07:59:51 AM »
No, when you put 120V on the 115V primary, you won't get 12V out.  The transformer may also saturate. 
Paul "PB" Birkeland

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Offline Deke609

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Re: Noob question re wiring 6.3-0-6.3 secondaries for nominal 12.6V output
« Reply #8 on: November 15, 2019, 08:04:11 AM »
Many thanks PB. I was prepared to deal with over voltage output, but hadn't considered saturation. I put in an inquiry with Hammond.
Derek
______

Roon Intel NUC ->  Yggdrasil DAC -> BeePre (w/ BeeQuiet and EML 300B)  -> Kaiju (w/ DCFil and EML 300B) or Stereomour II (2A3 [EML Mesh] and 45 Conversion [EML 45B])  -> Audeze LCD4

Offline Deke609

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Re: Noob question re wiring 6.3-0-6.3 secondaries for nominal 12.6V output
« Reply #9 on: November 18, 2019, 03:51:06 PM »
Hammond reports that 120V mains with 1.35A draw from the secondaries is no problem for the transformer.  It just bumps up raw output from 12.6V to 13.2V - something I've already addressed with a 15W dropping resistor. So all good!

cheers, Derek
Derek
______

Roon Intel NUC ->  Yggdrasil DAC -> BeePre (w/ BeeQuiet and EML 300B)  -> Kaiju (w/ DCFil and EML 300B) or Stereomour II (2A3 [EML Mesh] and 45 Conversion [EML 45B])  -> Audeze LCD4