my transformer output has a center tap: what do I do with this?

jarthel · 7th February 2010, 12:09 PM

the transformer outputs are rated:
main output: 260-230-0-230-260V
heater output: 2.5-0-2.5

I seemed to recall that this is needs to be connected to power supply ground or maybe mains ground? maybe not connected at all?

thank you

Eli Duttman · 7th February 2010, 12:18 PM

That trafo is set up for use with a directly heated rectifier, like a 5Y3 or 5R4. Connect the plates to either set of HT taps and ground the HT winding's CT. You take the "raw" B+ from the CT of filament winding.

If you use a rectifier with a cathode sleeve, like a 5V4 or 5AR4, tie the filament winding's CT off and take the "raw" B+ from pin 8 of the tube socket.

jarthel · 7th February 2010, 12:39 PM

Quote:

Originally Posted by Eli Duttman

That trafo is set up for use with a directly heated rectifier, like a 5Y3 or 5R4. Connect the plates to either set of HT taps and ground the HT winding's CT. You take the "raw" B+ from the CT of filament winding.

just want to clarify:

I am using a 5u4g. I am using an LCLC circuit. One of the leads of the 1st choke is connected to the CT of the main output. The CT of the heater winding is grounded (connected to supply ground).

Is this correct?

thanks again

Eli Duttman · 7th February 2010, 02:51 PM

Quote:

Originally Posted by jarthel

just want to clarify:

I am using a 5u4g. I am using an LCLC circuit. One of the leads of the 1st choke is connected to the CT of the main output. The CT of the heater winding is grounded (connected to supply ground).

Is this correct?

thanks again

You have the CT's reversed. The CT of the rectifier winding gets grounded. You connect the CT of the filament winding to the PSU filter.

kevinkr · 7th February 2010, 07:09 PM

Quote:

Originally Posted by jarthel

just want to clarify:

I am using a 5u4g. I am using an LCLC circuit. One of the leads of the 1st choke is connected to the CT of the main output. The CT of the heater winding is grounded (connected to supply ground).

Is this correct?

thanks again

Only if you want a negative supply relative to ground, (observe cap polarity in such a case) otherwise do what Eli says!

jarthel · 8th February 2010, 10:02 AM

thanks everyone

7th February 2010, 12:09 PM	#1
jarthel diyAudio Member Join Date: Jan 2002 Location: somewhere in Australia	my transformer output has a center tap: what do I do with this? the transformer outputs are rated: main output: 260-230-0-230-260V heater output: 2.5-0-2.5 I seemed to recall that this is needs to be connected to power supply ground or maybe mains ground? maybe not connected at all? thank you

7th February 2010, 12:18 PM	#2
Eli Duttman diyAudio Member Join Date: Apr 2004 Location: Plainsboro, NJ	That trafo is set up for use with a directly heated rectifier, like a 5Y3 or 5R4. Connect the plates to either set of HT taps and ground the HT winding's CT. You take the "raw" B+ from the CT of filament winding. If you use a rectifier with a cathode sleeve, like a 5V4 or 5AR4, tie the filament winding's CT off and take the "raw" B+ from pin 8 of the tube socket. __________________ Eli D.

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8th February 2010, 10:02 AM	#6
jarthel diyAudio Member Join Date: Jan 2002 Location: somewhere in Australia	thanks everyone

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