rdjones wrote:
These are the "low side" and connect directly to the neutral side of the AC, white color coded lead on a cord, the "N" terminal on the IEC.
The BLK and BRN connect to each other and nothing else, cap this connection off.
The RED/BLK wire is the "hot" and connects to the switch, the switch connects to the OUTSIDE (ring) terminal of the fuse holder, the TIP of the fuse holder goes to the "high side" hot of the AC, which is the black color coded lead of a (properly color coded) AC cord or the "L" terminal of the IEC.
Please follow proper safety guidelines and don't bypass the transformer's cutout, or wire the hot side in any other manner than described above.
Safety codes, guidlines and regulations are there for our protection and that of everyone around us.
SAFETY FIRST !
rd
This is one of the most overlooked items in clone amp building, modern electrical safety wiring.
The New Steve H wrote:It just looked crazy, paralleling the primaries or halves or whatever they're called. My brain could not accept the idea. And I still don't understand why it looks like there's a red/black wire with thermal protection and a black wire without it.
This is a well designed transformer primary, it is the best way to do things on a dual primary PT.
Having the separate wire for the cutout allows the primary to work in the most effecient way for both voltages, instead of just having a tap.
Unfortunately, it also allows the cutout to be bypassed if it's not wired correctly.
The New Steve H wrote:You're right about me enjoying the machining, but machining holes that are neither round nor square is a pain. The inlet or receptacle or whatever I use has a pentagonal shape. Maybe I need to look for a better one. The neat thing about using strain relief is that you can go to Home Depot and buy wire to make a 20 foot cord if it makes you happy.
Thanks for the vote of confidence. The soldering is turning out to be much more aggravation than I thought. I didn't realize that if I used short wires, I would have to solder things to the sockets while the sockets were screwed in. I can't take them out and then put them back after the wires are on. That makes for some serious microsurgery and gymnastics.
Ideally you'd switch both the mains and neutral wires with a dpdt. Your transformer is set up that way on the secondaries just to give you options for what voltages you want to run.
I don't get your socket problem though?
You're not wiring components directly to the pins right? Cut 6 pieces of long wire, strip them, and connect the socket. Then cut the wire after it's soldered on one end.
The New Steve H wrote:You're right about me enjoying the machining, but machining holes that are neither round nor square is a pain. The inlet or receptacle or whatever I use has a pentagonal shape. Maybe I need to look for a better one.
You don't need to match the shape of the IEC inlet unless you really feel the need. SInce you have a mill, just cut a rectangular hole with a 1/4" cutter. The flange covers the difference.
rdjones wrote:...the switch connects to the OUTSIDE (ring) terminal of the fuse holder, the TIP of the fuse holder goes to the "high side" hot of the AC, which is the black color coded lead of a (properly color coded) AC cord or the "L" terminal of the IEC.
RD gives good counsel here. However, I want to add a note of caution.
Examine the fuse holder. These instructions are good for the type of fuse holder where the cap grips the fuse and pulls the fuse when you unscrew it. These are the type we commonly find today.
There is another style of buss type fuse holder that, when you unscrew the cap, the fuse is left loose in the holder still making contact with the tip. This is a potentially dangerous situation if you forgot to unplug the amp. For this type of fuse holder. The tip should connect to the neutral and the sleeve to the hot wire. When you pull the fuse cap, it breaks the connection to the hot wire. This is an older style of fuse holder, but sometimes you will encounter them, possibly as new old stock and certainly in old work.
When I'm capping off wires I don't even bend them back. What I do is cut the wire flush and put a piece of heatshrink over the wire that goes over the wire at least 1/2" and has maybe 1/4" sticking out over the end. All you need to do is after the heatshrink shrinks and you remove the heat, while the heatshrink is still hot and somewhat tacky, pinch the extra 1/4" section closed and it should stick. I usually do two pieces of heatshrink over any wires coming out of the PT as a precaution, sometimes one piece of heatshrink will fall off. The second piece should be more like 3/4" overlap on the wire and just a bit over 1/4" for the overlap (so that it covers the smaller piece completely and then some).
diagrammatiks wrote:Ideally you'd switch both the mains and neutral wires with a dpdt. Your transformer is set up that way on the secondaries just to give you options for what voltages you want to run.
Yes, good idea, but not breaking any codes if not done on US style unbalanced 120V AC.
It's an absolute must on balanced ~240V (EU, etc) mains.
diagrammatiks wrote:Ideally you'd switch both the mains and neutral wires with a dpdt. Your transformer is set up that way on the secondaries just to give you options for what voltages you want to run.
Yes, good idea, but not breaking any codes if not done on US style unbalanced 120V AC.
It's an absolute must on balanced ~240V (EU, etc) mains.
rd
Didn't know that about the EU switches.. Good thing I don't sell anything in the EU!
diagrammatiks wrote:Ideally you'd switch both the mains and neutral wires with a dpdt. Your transformer is set up that way on the secondaries just to give you options for what voltages you want to run.
Yes, good idea, but not breaking any codes if not done on US style unbalanced 120V AC.
It's an absolute must on balanced ~240V (EU, etc) mains.
rd
true, and they also require the use of fused iec mains plugs don't they?
Is this a bad time to point out that I'm using a socket with a built-in fuse? I have no fuse holder, so I'm going to have to adapt the wiring instructions.
Hey guys, I know that this post is almost a year later but I'm in Australia using 240v and just got my transformers for my 5f6a build and I have a few questions about the primary wiring. You should also note, the thermal cutout has been removed from the specs
For 120v the primary wires need to be wired in parallel and for 240v in series, so do I connect the BRN wire to the BLK/WHT wire?
-Then the the BLK wire to the Blue wire coming from the power cord?
-Connect the BRN/WHT wire to the ON/OFF switch?
-For the bias wiring at 50v it says to use RED/GRN-RED/YEL, I only need one 50v so should I
a) use one and ground the other
b) solder both to the connection
c) use one and just cap the other
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steves3972 wrote:Hey guys, I know that this post is almost a year later but I'm in Australia using 240v and just got my transformers for my 5f6a build and I have a few questions about the primary wiring. You should also note, the thermal cutout has been removed from the specs
For 120v the primary wires need to be wired in parallel and for 240v in series, so do I connect the BRN wire to the BLK/WHT wire?
-Then the the BLK wire to the Blue wire coming from the power cord?
-Connect the BRN/WHT wire to the ON/OFF switch?
-For the bias wiring at 50v it says to use RED/GRN-RED/YEL, I only need one 50v so should I
a) use one and ground the other
b) solder both to the connection
c) use one and just cap the other
If you normally wire using the american standard
Pri: 240V = brn + blk/wht
black>hot = switch and fuse side
brn/white>neutral
orange>shield = ground to chassis
Sec: 710= red-red/yel(ct)-red
610= red/wht-red/yel(ct)-red/wht
50V bias tap = red/grn
a) use the red/grn for bias and ground the red/yel to the chassis
TM
Last edited by ToneMerc on Fri May 25, 2012 1:07 pm, edited 1 time in total.
