I have the a power transformer with a 6.3v 5A non center tapped winding I was planning on using on a TSE-II board with 45 tubes.
Can I use it or do I need a center tap? If so, can I create a virtual center tap?
Right now I am getting 0v on pin 4 of the power tubes, with T1-GRN-1 and T1-GRN-2 receiving 6.3v.
Thanks!
Can I use it or do I need a center tap? If so, can I create a virtual center tap?
Right now I am getting 0v on pin 4 of the power tubes, with T1-GRN-1 and T1-GRN-2 receiving 6.3v.
Thanks!
I am unsure about the answer to your question, but based on what is written on the Tubelab.com website as it relates transformer requirements for the TSE with a 45 tube, it appears that you do:
http://tubelab.com/designs/tubelab-se/applications/
"Possible power transformers are the Hammond 270FX, the Allied 5K56VG (made by Hammond). You need 540 or 550 VCT at 125mA, 5 volts at 2 amps, and 6.3 volts CENTER TAPPED at 3 amps." (It is BOLD CAPPED on the site, which suggests it is important.)
I have a. Allied 5K56VG which I purchased and will not be using. It was installed, but never used. PM me if you are interested in it.
Good luck with your amp.
Jacques
http://tubelab.com/designs/tubelab-se/applications/
"Possible power transformers are the Hammond 270FX, the Allied 5K56VG (made by Hammond). You need 540 or 550 VCT at 125mA, 5 volts at 2 amps, and 6.3 volts CENTER TAPPED at 3 amps." (It is BOLD CAPPED on the site, which suggests it is important.)
I have a. Allied 5K56VG which I purchased and will not be using. It was installed, but never used. PM me if you are interested in it.
Good luck with your amp.
Jacques
Oh I see! Thank you for the information and the offer. I actually have a spare transformer or two with 6.3v center tapped. I'm going to try use them and see if I get voltage on pin 4 of the power tube then.
I wonder if I can create a virtual center tap on the transformer in the picture above by adding two 100ohm resistor between each 6.3v winding an ground...
I wonder if I can create a virtual center tap on the transformer in the picture above by adding two 100ohm resistor between each 6.3v winding an ground...
The 6.3 volt winding is used in a full wave center tap configuration for 2.5 volt tubes. This is similar to the high voltage secondary where the center tap is grounded and each 3.15 volt green wire goes to its own diode to produce about 3.5 VDC that feeds the regulator to make 2.5 volts. The CT must be present, and a resistor based virtual tap will not work.
The 6.3 volt winding is used in a full wave bridge configuration for 5 volt tubes. 4 diodes are used to make about 6.5 VDC that feeds the regulator to make 5 volts. The CT is not connected in this configuration, and therefore not needed.
It is possible to configure the transformer jumper for 5 volts in order to use a non CT transformer, then configure the regulator for 2.5 volts. This will make the regulator dissipate about 15 watts, so a BIG heat sink would be needed. A second 6.3V 3A filament transformer would be smaller than the heat sink, make far less heat, and be more reliable, so this option is NOT recommended.
Your old transformer was made when our line voltage was 110 volts (stated on the transformer). On today's 120 to 125 volts you are going to get secondary voltages at least 10% higher than what's written on the transformer.
Whatever you do, measure the filament voltage at the tube socket BEFORE installing any 45's. They aren't cheap anymore. I found out the hard way many years ago that they last one ohnosecond on 5 volts.....and that's when good used 45's were $10 each.
The 6.3 volt winding is used in a full wave bridge configuration for 5 volt tubes. 4 diodes are used to make about 6.5 VDC that feeds the regulator to make 5 volts. The CT is not connected in this configuration, and therefore not needed.
It is possible to configure the transformer jumper for 5 volts in order to use a non CT transformer, then configure the regulator for 2.5 volts. This will make the regulator dissipate about 15 watts, so a BIG heat sink would be needed. A second 6.3V 3A filament transformer would be smaller than the heat sink, make far less heat, and be more reliable, so this option is NOT recommended.
Your old transformer was made when our line voltage was 110 volts (stated on the transformer). On today's 120 to 125 volts you are going to get secondary voltages at least 10% higher than what's written on the transformer.
Whatever you do, measure the filament voltage at the tube socket BEFORE installing any 45's. They aren't cheap anymore. I found out the hard way many years ago that they last one ohnosecond on 5 volts.....and that's when good used 45's were $10 each.
Ouch! Ok! Thank you for the informations. I guess I'll have to find a different transformer then...