SEWA - Seven Watt Amplifier

[Mad_K]

Are you talking about the PCB screendump i attached in post #15 in this thread?

[Tyimo]

Yes!

[Frank40]

Sorry for the late replay. I have been tryingen to make a better sch. of my amp. But my screen cap is not verry god.

So here is a link for down load of the sch.:

http://rapidshare.de/files/14371438/Cap128.jpg.html (550Kb)

If anyone is welling to helpe my, please poste the pic. So it can seen on this forum.

The amp is one stange whit voltages gain, low output imp. and no feedback. It has a real nice sound, much like a single ended tube amp.


I hope you can use it.

Regards
Frank

[Mad_K]

Originally posted by Tyimo
Yes!

That one never made it, sorry. But the circuit is so simple, it can easily be done p2p. A pcb is really superflous. If you want to make the switch between OTA 3,5 Rev.0 and SEWA Rev.1 as easy as possible (and plan on using the pcb layout provided) you can simply print the layout and use it as a guide to drill the heatsink. Then do OTA3,5r0 p2p, later you can swap without having to redrill the heatsink. However, if you insist, I do have a pcb layout for OT3,5r0 that fits in the same holes, as seen on the pictures in the OTA thread

[Mad_K]

Frank, I think you might get more help with that design if you make a new thread for it

[lineup]

Originally posted by Frank40

I have been trying to make a better schematic of my amp.
If anyone is welling to help my, please post the pic.
So it can be seen on this forum.

The amp is one stage with voltages gain, low output imp.
No feedback.
It has a real nice sound, much like a single ended tube amp.

Here is your MOSFET amplifier.
In attachment.
I had to do some image work

Maybe you can use schematic, if you start a new topic about your amplifier.

This topic is about Mad_K amplifier SEWA.

[Tyimo]

Thanks Mad!

One more question:

What is the situation with the phase in your SEWA V1?
I mean: source-follower circuits doesn't change the phase, but if I use the BOZ preamp that change the phase need I invert the speaker + and - connections in the SEWA output?
With my BOZ+ZenLite it is not problem because both amp are phase shifter.

Greets:

Tyimo

[Frank40]

Sorry Mad_k for bargeing in to you topic, It seems that I can not delete my postes in here.

To Lineup, thanks for you helpe whit the pic.

Frank

[Mad_K]

Tyimo; you are right. SEWA/source followers are non inverting, so you will have to invert the speaker terminals to have absolute phase correct when driven from BOZ.

Frank; it's ok, but I think it is better to stay on topic, or else things may get very confusing (as I've already managed by shifting names on my designs)

[Tyimo]

Hi Mad!

One more question: should I use different Mosfets for Q1 and Q2?
I mean for Q1=IRFP044 and for Q2= IRFP240?

Greets:

Tyimo