Pre amp wire up__new

[orm0003]

so i have finished soldering my diy kit from ebay,
was hoping u guys could check i have the transformers wired up right?
( the bread board is so i can check the direction of the leds, they is no polarity on the board and there not in the schematic.. so yer) View attachment 6N3 SRPP schematic.pdf

 

[Jsixis]

You need a transformer for the 230 volt, you can't wire that directly off mains.
It is not safe and can kill someone.

you need to twist those wires to offset hum.
Earth ground needs to go to each transformer.

 

[artosalo]

Do you plan to take the 230 VAC without a transformer ??
Don't do that. You absolutely need a transformer.

According to the schematic there are two separate 6,3 V heater voltages.
The polarity of these is not critical.

 

[orm0003]

The power in Australia is 230v so what transformer do I put in for the 230 volt impute then?

The transformers supply two seperate 6.3 volt to the what I assume to be the heaters.
And thank you yes, I'll grab some better cable and twist it all for the full install this is just for test/show u guys for help purpose.
Cheer guys the replys ? What extra transformer do I need ?

 

[dovla]

Are the LEDs under the sockets (just to artificially light the tubes up)? If so, you're better without them.
You can determine polarity by checking DC voltage on J12 (according to the schematic + is on J7 pin1 that likely goes to J12) or pins 1&9 of the tubes.

 

[orm0003]

I think the LEDs might just be for show as they are not on the schematic, so I was jut going to flip the around till te light up and then solder,

I'm still not sure on the 230v wire up.
Someone suggested another transformer, but I don't under stand what I'll need ? ( Australian 230v 60hz mains )

 

[Regenpak]

The power in Australia is 230v so what transformer do I put in for the 230 volt impute then?

You need one with a 230V primary and a 460V (2x230V) secondary with a center tap as it's a two-phase rectifier circuit. Basic stuff. If you're tired of life and want to run it directly off mains power you need a bridge rectifier with four silicon diodes because it's single phase.

 

[IanS1]

Looking at the schematic you need a centre tapped transformer with a 230v AC primary and 230-0-230 secondary. This then feeds the 6Z4 rectifier valve. Is the 6Z4 mounted on the PCB?

 

[orm0003]

Looking at the schematic you need a centre tapped transformer with a 230v AC primary and 230-0-230 secondary. This then feeds the 6Z4 rectifier valve. Is the 6Z4 mounted on the PCB?

from what i can tell the 6z4 is the tube on the power supply board, the the bridge for the 6.3 volt stuff is the little black package.
could u link me the transformer u are talking about? ( i have read about them but jaycar ( local aus supplier) doesnt advertise them )
thanks for all ur help guys, i really want to get it wired and running,

 

[IanS1]

Locally (Aus), I have no idea where you'll get one from. But you could try Hammond here: Power Transformer and Choke Prices

 

[orm0003]

Can I just take 230v in to a bridge rectifyer and then take the neg and plus instead of getting a transformor, as I am not actually tansformin volage. ?

 

[lordearl]

I generally use Tortech for transformers in Australia - they do custom designed ones, but price is up there, around $100 or so. You could try Farnell (Element 14), the search function allows you to filter by secondaries. High voltage transformers are never cheap. Perhaps simply order an R-CORE from ebay, even though it's most likely for 220V primary, it will still work....

 

[DF96]

NO!!!!!

Sorry for shouting, but this is a vitally important safety issue. Never, ever, connect a circuit directly to the mains. Always use an isolating transformer.

If you don't understand what a mains transformer does, should you be building something which requires you to use one?

As several other people have said, you must find a mains transformer which takes 230V on the primary and provides 230-0-230V on the secondary. In most caes this will also provide you with one or more 6.3V secondaries too.

 

[Regenpak]

Can I just take 230v in to a bridge rectifyer and then take the neg and plus instead of getting a transformor, as I am not actually tansformin volage?

Of course you can. If you're tired of life, that is. If you want to live longer than after plugging in your amp do follow DF96's advice and use a transformer. It isolates you from mains power which, as any fule knows, can be deadly. <kzert>

 

[00940]

If you can't find transformers with 230-0-230 secondaries, an option might be to search for isolation transformers (230vac to 230vac). You'll need to adapt a bit the preamp:

- remove the rectifier tube (6Z4);
- connect the transformer secondaries to a diode bridge with a suitable rating;
- connect the positive output of the bridge in between pin 5 of the rectifier socket and R1 and the negative output to ground.;
- adapt R1 and R2 to get 280V (you might have quite a lot more voltage), putting higher values resistors (able to sustain the increased heat too).

An example (you don't need that much power though): Mains Electrostatic Screen 225VA Isolation Transformer | eBay

Another example: http://au.element14.com/schneider-electric/abl6ts02u/transformer-25va-1-x-230v/dp/2070176

 

[SY]

Of course you can. If you're tired of life, that is.

The issue is not only your own safety, but that of others. It is FAR too easy for a circuit like this to deliver a DEADLY voltage to other places. Do you really want to kill someone who accidentally touches your power amp or speaker cables or...?

Seriously, don't even THINK about doing what you're trying to do. An isolation transformer is mandatory.

 

[kevinkr]

You must use a power transformer, this is NOT optional, and is required by forum safety rules.

 

[orm0003]

Okay I guess it's a few weeks waiting for eBay then. Thank you heaps for ur impute. I'll report back when I get a isolation transformer.
Again. Thank you!

 

[orm0003]

Been doing heaps of research in to transformers and I see where u are coming from. I appreciate the concern. Getting an appropriate transformer now. Thankyou