Member
Joined 2002
Has any one built the nelson pass Voltage regulator's. ? Im thinking about bulding two of them 1 per amplifier i have 2 1kva toroidal transformers 35-0-35 and would use a regulator to bring it down to 15-0-15 V Any one have any idea's or what they used ?
Certainly loads of them have been built.
Why would you rather burn off all that energy as heat instead of unwinding or rewinding the transformer? This seems like a bad idea, unless you live in a VERY cold climate.
Why would you rather burn off all that energy as heat instead of unwinding or rewinding the transformer? This seems like a bad idea, unless you live in a VERY cold climate.
Are the transformers identical? If so, you could wire the primaries in series and use the secondaries, one for each of a stereo amplifier. The load on each transformer has to be the same.
Or you could parallel the secondaries, using low value resistors in series to help share the load.
I agree with the previous caller, that's a LOT of heat to waste. However, I'd be leery of unwinding the secondaries. Sounds like a lot of work.
Or you could parallel the secondaries, using low value resistors in series to help share the load.
I agree with the previous caller, that's a LOT of heat to waste. However, I'd be leery of unwinding the secondaries. Sounds like a lot of work.
Member
Joined 2002
I could look at the transformer and see if it has dual primarys and see if i can change it.. if so ill do that. if not then maybe i should just sell them. BUT having a regulated psu would be better 😀
Given that it is for a class A amplifier, you could also do a choke input filter... this would give you a raw DC of about 30V after diode drop, and more current delivery... still a lot of juice to burn off... this might be best done with a shunt reg.
dave
dave
Member
Joined 2002
I could do that but i need to get it down to 15V so 15-0-15
35-0-35 ac is 40-0-40 35vac * 1.41 = 39.9 rounded ^ 40V rails - 15 = 25V that i need to remove 😀
35-0-35 ac is 40-0-40 35vac * 1.41 = 39.9 rounded ^ 40V rails - 15 = 25V that i need to remove 😀
jleaman said:35-0-35 ac is 40-0-40 35vac * 1.41 = 39.9 rounded ^ 40V rails - 15 = 25V that i need to remove 😀
no. 35-0-35 vac is +/-50 vdc, so that's 35v you need to remove 🙂
Member
Joined 2002
xplod1236 said:
no. 35-0-35 vac is +/-50 vdc, so that's 35v you need to remove 🙂
heh i'll re-type this..
35-0-35 ac is 50-0-50 35vac * 1.41 = 49.9 rounded ^ 50V rails - 15 = 35V that i need to remove
Member
Joined 2002
Brain fart..
This transformer is..
2 blue wires measure 35v AC
2 brown wires measure 35v Ac
one green one. I presume GND
a set of white and black ac in.
on the blue / brown set they both have one wire that has a shield plastic on it. I wonder if i just use one set of blue wires / brown and use that as the ac in on the boards i could split 35v in half and get 17V i could use that for my aleph mini's could i parallel the Secondary.. ?
Maybe i should post a picture of what I’m talking about ?
This transformer is..
2 blue wires measure 35v AC
2 brown wires measure 35v Ac
one green one. I presume GND
a set of white and black ac in.
on the blue / brown set they both have one wire that has a shield plastic on it. I wonder if i just use one set of blue wires / brown and use that as the ac in on the boards i could split 35v in half and get 17V i could use that for my aleph mini's could i parallel the Secondary.. ?
Maybe i should post a picture of what I’m talking about ?
If that one wire with a plastic shield is a center-tap, then it could be (roughly) 17-0-17 which is much more reasonable for regulating to +/-15. If not, it really is not all that much work to unwind a toroid...usually
Hi,
Instead of unwinding the whole secondary windings just break into each of the secondaries and create a 17 0, 0 17, 17 0, 0 17.
You can see where the tappings come out from the core.
The midpoint of the windings will be about diametrically opposite.
Unwrap the outer insulation to expose the secondaries. Scrape a little enamel from a two adjacent secondary wires and find which one connects to which ends.
CAREFULLY power up the transformer and measure the voltage at the two exposed patches on the windings. If these voltages are well away from the midpoints try to work out which direction to move around and try again ( with the power off). If you do go wrong here a little varnish & new insulation wrap will save the tranny.
Once you have found the winding midpoits cut the two windings at these points and unwind the extra turns to achieve your desired voltage. You will probably only have to remove a maximum of 2 or 3 turns. Solder in some new flexible wires to the 4 new ends to create a 4 secondary output from your tranny. Insulate it with black insulating tape using a 55% overlap on the turns, self amalgamating would be better but quite difficult to get off later.
You now have a choice; parallel two windings to double the amp capacity or create a close approach to dual mono.
good luck.
Instead of unwinding the whole secondary windings just break into each of the secondaries and create a 17 0, 0 17, 17 0, 0 17.
You can see where the tappings come out from the core.
The midpoint of the windings will be about diametrically opposite.
Unwrap the outer insulation to expose the secondaries. Scrape a little enamel from a two adjacent secondary wires and find which one connects to which ends.
CAREFULLY power up the transformer and measure the voltage at the two exposed patches on the windings. If these voltages are well away from the midpoints try to work out which direction to move around and try again ( with the power off). If you do go wrong here a little varnish & new insulation wrap will save the tranny.
Once you have found the winding midpoits cut the two windings at these points and unwind the extra turns to achieve your desired voltage. You will probably only have to remove a maximum of 2 or 3 turns. Solder in some new flexible wires to the 4 new ends to create a 4 secondary output from your tranny. Insulate it with black insulating tape using a 55% overlap on the turns, self amalgamating would be better but quite difficult to get off later.
You now have a choice; parallel two windings to double the amp capacity or create a close approach to dual mono.
good luck.
Member
Joined 2002
- Status
- Not open for further replies.
- Home
- Amplifiers
- Power Supplies
- Voltage Regulator !