SEWA - Seven Watt Amplifier

[marc brown]

I'd definitely like to start with a kit. I've looked at a few nice kits and that seems like the way to go. I saw one project on eBay where guy had all the pieces for a Nelson Pass son of Ampzilla (I believe). I almost bought that but the price went too high.

 

[djk]

Were is the fan going?

Unless you saw that thing up into several pieces and stand them on end, you're going to need a fan (unless it's a really low power amp).

 

[meanman1964]

Were is the fan going?

Unless you saw that thing up into several pieces and stand them on end, you're going to need a fan (unless it's a really low power amp).

Do you mean my amp?About the heat that's covered.The amp is working at a voltage of 14,5 DC.We'll see how hot the sinks can get.

 

[Tyimo]

Hi Meanman1964!

You will not need so big heatshinks. You will see.....

Greets:

Tyimo

 

[meanman1964]

Hi Meanman1964!

You will not need so big heatshinks. You will see.....

Greets:

Tyimo

What about these ones?

 

[meanman1964]

Another picture

 

[Tyimo]

What is your plate's material? Alu?
You should try with the first big heatsink, but without fun. I think it will be enough.

Tyimo

 

[meanman1964]

It's an iron plate not alu..
I prefer the big sink,it looks nicer more body.That's my opinion.

 

[meanman1964]

Hi Tyimo,
I have a question for you.The output cap (10000µF) can it be changed by 6800µF or 8200µF?

 

[Tyimo]

I have a question for you.The output cap (10000µF) can it be changed by 6800µF or 8200µF?

Yes. 4700 is the minimum.
2x4.7000 would be a very clever solution. May be the sound would be a bit"faster".

I prefer the big sink,it looks nicer more body.That's my opinion.

Yes, but you will not need the electric fan. (sorry, in my last post I wrote "fun" )

Tyimo

 

[Tyimo]

Mads!

Would it be possible to modificate your original SEWA (the resistore loaded) to operate with dual rail supply? Also to operate without output cap?
Personaly I like output caps, but there are some people who not and I would like to show them the "differences".

Greets:

Tyimo

 

[meanman1964]

Another layout for the Choke Loded Sewa

 

[Tyimo]

This one looks good!

When will you ready?!?

Greets:

Tyimo

 

[meanman1964]

This one looks good!

When will you ready?!?

Greets:

Tyimo

I don't have my toroid yet,I mean the 2x12VAC;I do have one of 1x14VAC without load.I also was thinking to make a regulated supply with modules of Thel Audio.By this way I could use my 2x30VAC toroids.Do I need only 1 toroid?

 

[Tyimo]

Do not use regulated supply!!

When will you get your toroid?

Tyimo

 

[Tyimo]

Do I need only 1 toroid?

What do you mean???

You can use one toroid with dual secondary 12V for "kvazi" dualmono" PSU, but toroid with only one 12V secondary is also enough.

Important: You need 150-200VA

Tyimo

 

[meanman1964]

Do not use regulated supply!!

When will you get your toroid?

Tyimo

I've ordered them from Schuro in Germany.They didn't has them in stock,I've to wait 3-4 weeks?Why shouldn't I use regulated supply? www.thel.de

 

[Ryssen]

Important: You need 150-200VA

I used a 300VA and it gets kind of hot..

 

[meanman1964]

I used a 300VA and it gets kind of hot..

Did you build the original Sewa and what voltage has your toroid?

 

[Ryssen]

Yes it´s the original,I get 22,5v DC so it must be 18v AC x 2.
I have a relay to shift to higher bias,then it gets even hotter..

I would also like to know why "not regulator"?