Hello,

I am building a 5W tube amp (Octal Fatness)

Now my question is what kind of transformer i would need for this amplifier (i live in the netherlands so primary is 230vac)

And where would i purchace this transformer?

Thanks in advance!

Nick

 

Looks to me like you would want about 357V on the secondary, considering the point after the diodes is 356V.

Regardless, I don't know where in your country to buy transformers, but they typically are specified by secondary voltage rating and current. You need to figure out how much current it will require.

 

seems like a strange place for the switch.

 

Yeah the switch is in a strangr place, ill probably place it in front of the transformer.

But im looking for a model of transformer that will suffice (if possible), or maybe even a webshop where to acquire the transformer

Thanks!

 

There is a valve transformer company in UK, they do a 230/350-0-350v, and a 410v. Website

 

Are you sure about those resistor values? If the 238V was shorted to ground you would be drawing less than 1 watt.

 

Hello,

I've decided to build my own transformer because i cant find one with the right specifications for a reasonable price.

Now my question is:

Where can I order a transformer kit?
or
Where can I order the parts I need to build the transformer?

Thanks in advance!

Nick

 

I was working in a company that was specialized in design and manufacture of transformers. If you provide some specification I can give my man there a call and ask him how much would it cost. I am not sure I am allowed to provide the site of the company. If you want to know it write me a PM and check it yourself.

 

I've never heard of a transformer kit. There are two approaches you could take.

1. Locate a suitable torroid core
2. Fabricate a core from multiple pieces of sheet steel

Once you have a suitable core you use enameled magnet wire to wind the transformer. Then comes testing and finishing.

 

There are transformers and there are transformers.

Tell us what you want to transform with numbers, voltages, currents, wattage, frequency.

 

I need a transformer P230V S350-400V about 10-20W

but I have a hard time finding a suitable transformer to do the job

 

Are you in USA?

Shouldn't be hard to find something. Or use two.

One time use?

 

I live in Europe, One time use in Tube amplifier

 

Saying in which country would be helpful. There are a lot of companies that will make it for you, and a 20W should be pretty cheap.

 

Hello,

I've decided to build my own transformer because i cant find one with the right specifications for a reasonable price.

If in N.A. you could pick up a Toroid from Antek (Jonango on ebay) that has the closest specs, this will already have the primary and you can either add to or remove a secondary winding to increase the particular voltage you need.
Also small aux windings can be added if needed.
I see you are in Europe so look for a Toroid manuf there.
Max.

 

Sorry, I live in the Netherlands

 

checkout "control transformers" I am not too sure of the european standards, but here we can get control transformers for industrial use pretty reasonable and from 5 to 5000 watts or more.

 

I can't find any listed in Europe.
The closest I can find is Antek AN-1T350

http://www.antekinc.com/as-1t350-100va-350v-transformer/

http://electrontubestore.com/index.php?main_page=product_info&cPath=19_174&products_id=1031

 

For example http://www.trafo.cz/cms/index.php makes custom transformers in Czech republic, the shipping costs to netherlands shouldnt be too much.

 

RS components used to do a transformer kit with a pre-wound primary I think. They come up from time to time on e-bay, otherwise you can canibalise an existing transformer. google diy transformers for info....

HTH Steve.

http://lmgtfy.com/?q=diy+transformers