Help!!! with G9 Power transformers

Hey guys, I'm just finishing up my G9 but I'm stuck on how to wire the transformers. Im in the U.S. so I need 110 mains. I have two 110+110:15+15V Toroids I'm just not sure what to do with them. I'm not incredibly savvy with schematics but if someone has a diagram or even a good description it would really be great.
I'm really eager to fire this thing up, but I want to be certain everything is wired properly.

Thanks a bunch! :shock:

warning - very large avatar above

USA = 110volts

first primary is both 110 in parallel ( US boys double check me here)
that gives two 15 Volts secondaries

the first 15 volt secondary is use to light the tubes.

the second is used to drive the SECOND trafo in reverse.
15 volt (usually secondaries) wired in parallel
ZAPPO (usually the primaries) is wired in series to give 2 X 110 = 220 volts.
It also drives the 48volt circuit ... voltage doubler stuff

:roll:
did I get that right ?

If you are worried about the transfomer connection in general, check this diagram:

http://mysite.wanadoo-members.co.uk/deltaharmonic/Technical/Transformer_Connect.gif

Robert[/url]

North American G9 Transformers

First check out just the power section on this page at the bottom of the schematic
www.gyraf.dk/gy_pd/g9/g9_sch.gif
Then download this page and look at it?.for a long time!
www.nrgrecording.de/Gyraf_G9_trafos.pdf right click save as
The PDF File from nrgrecording is for 220V application, North American 110V transformers will have two primaries.
Get your PCB overlay or stuffing guide and map out your intentions for hook up.

*****Note, You must read this first.*****
This reference is using the Hammond 182J15 transformer wire color codes and no other transformer is implied. You must acquire the manufacturer?s color code chart to find out primary secondary match ups.
This is the dangerous part of DIY because power is showing up in you project. We all want success at this point not smoke. Read read and read more on this topic. Keep you hands out for power up.

Both transformers should have two primaries and two secondary windings. Or eight wires. Hammond or Avmeco part numbers listed for the G9 will work. Find out from the manufacturer which wires match up primary to secondary. Then start connecting.


PCB is referenced looking at the board with the two relays at the top left so put it on your bench like that now.

1 . If you are using the common PCB for the G9 the first transformer will be connected with both primaries Blk/Brn together at one terminal and Wht /Orn to the other terminal as mains negative and positive. This must be have a fuse, 1AT is listed on the schematic( I think that is the fuse). Imagine your transformer is now two(2) transformers.

2. The secondary windings will go as follows; one secondary Red and Blu to the 15VAC/1A (above D17) and the other secondary Gry and Yel is connected to the other 15v terminal(beside C23). You now have 15 volts attached to the board in two places.
The first transformer steps 110V down to two(2) 15VAC sources.

Next
3. Then attach the other transformers secondary, yes secondary windings to this same spot below C23 so that you will again have two transformers. So now Gry/Red attached together to one terminal and Blu/Yel attached together on the other. Again you now have two(2) transformers. Just imagine it ok!

4. The Primary windings on the other end must be attached as follows. One black lead to the 220Vac connector above D17, the white and brown wires are tied or soldered or welded or crimped together, Then the orange wire is attached at the terminal point above D17.

Now you have two power input windings pushing one big power output winding. In essence your 15V is now 220 volts.

You are now Dangerous as far as voltage and current are concerned.

I do recommend as you may have seen on other G9 projects the use of a terminal board for your wire attachment points.

Notes I have found on this topic are many from general to specific. Some from Jacob, Kev and question forums with answers. If you want more information PM me with questions. I have not completed this project. I am waiting for a replacement transformer, one winding is open on one primary. So wait a couple of days for my part to come in so I can test and confirm all of this. I have notes from others that reference all I have written but still approach with caution.

If I'm out to lunch on any of this, please correct me.

Hope this makes things more clear. I will draw up an attachment guide as soon as I have more time.

Check this out, this place sells a DIY torroid pwr tranny kit!

http://www.toroid.com/standard_transformers/transformer_kits/transformer_kits.htm

Great post, StrayCat!

:thumb:

Jakob E.

Thank you Jacob,
I posted my transformer problem. I said I had no 15V out from the board. This was not the case. I now know that 15V goes IN at two locations. My one transformer had an open primary on the transformer I connected to the 15V terminal below C23. Well 210K Ohms Open.

I was sent a credit from Digikey after I wrote them about it. They did not require me to send it back so I have a half torroidal transformer to use or try and repair it. Any chance that these are repairable?

I'll check out the DIY pwr transformer kits CJ.

New transformer should be in this morning.

Can't wait to use My G9 for recording.

[quote author="StrayCat"] ..so I have a half torroidal transformer to use or try and repair it. Any chance that these are repairable?
[/quote]

Probably not, as toroid mains power transformers nearly always have their primary windings as the inner layer, and secondaries on top of that.

Jakob E.

New transformer in and D15 Smoked. Any ideas? I am definately getting power there now but something went wrong.
I can't tell on the schematic where D15 is exactly Looks like BR2. I'm certain that the parts are, under the charcoal 4001's from my parts list and stuffing guide. Maybe I have all the diodes in backwards. The line on the diode goes to the line on the silkscreen. Or have I just cofessed my ignorance? Smells bad Too!

Any help on this would be appreciated. My G9 should be tracking by tommorow night, other wise I'm still semi-pro gear wise :sad: .

HELP!

[quote author="StrayCat"] The line on the diode goes to the line on the silkscreen..[/quote]

Yes.

Check for shorts around PSU section. Check for correct component orientations.

Jakob E.

I changed all the diodes, they were 4003's and they were all correctly oriented. My new transformer AMVECO (TE62073-ND from Digikey) has an output of 17.4VAC. My first transformer (Hammond 182J15 was 15.2 or so. both should be 2x117V2x15V
A/C wall measured 118VAC. Is this cause for alarm? I swapped the AMVECO for the Hammond in hopes that this would help. Before this problem the Heaters lit up. After the new transformer the diodes are lighting up. Smells bad. All the caps in the supply area are + and - oriented correctly. the only thing in this run not installed is the panel light. There was nothing out of the ordinary except the burnt diode (D15).
From the schematic there is not much going on in this leg of the power supply and it worked the first time.
I will check again for shorts and fire it up. Thank God I have 86 diodes left.

New smoke test coming up.

Hopefully without smoke.

G9 is up and Running :grin: , pretty dammed quiet I will say. My left channel works well, needed the switches to be tightened to the front panel better. Before I tightened them the unit was micro phonic when I tapped on the switches. Right channel has a wrong resistor in the steps for gain or a short on the switch. As I move up in gain on the input stepped attenuator it drops really low then regains after two more clicks. Other wise it sounds really open. With a few more tweaks no doubt three D open sounds will appear. I 0nly used a Shure 545 unidyne II as a source and it sounded great. On to more experimentation.

Refer to my previous post about transformers if you do not understand this primary secondary stuff.

Transformers used for 15V stepped to 220 had originally shown 105VAC each across each Primary and then as I checked across the two in series they showed 205VAC then collapsed. I switched the other side of the Transformer (the 15V secondary now used as the voltage input) and the 205 VAC stayed. I assume that the two ac voltages cancelled each other out because they must have been exactly out of phase with each other.

Or green wires don't like being with the brown wires, the red and blue wires make purple and the purple wire should be on the primary side like the violet wire which is actually purple and that would cancel out any voltage gain.

Anyway it happened to me so if your using the dual 110V primary this may be a problem for you.

One thing I do have that seems weird, I'll ask before I check. The Caps at the 245 header are DC I take it? So that voltage should be DC? Or have I shown my ignorance yet again?

Anyway I'm done just in time for Christmas which means I have no time to record and my wife will not kill me for spending money on something that up until last night sat on the coffee table or smoked.

Merry Christmas to all that DIY.

Thanks for all the help, support and tolerance.