Goldmund Mods, Improvements, Stability

[keantoken]

KSA1381, not KSC1845.

I have one sitting right in front of me.

- keantoken

 

[Krisfr]

I have searched Google and I can not find the pin-outs or ANY information on the 2 driver transistors.

The Q2SC4793_x

or

Q2SA1837_x

any substitutes? or am I looking up the wrong part?

I found them, there is NO Q...

Thanks😕

 

[keantoken]

The models were named funny so I can tell them apart from the mediocre models...

http://www.toshiba.com/taec/components2/Datasheet_Sync//66/7846.pdf

http://www.toshiba.com/taec/components2/Datasheet_Sync//66/7632.pdf

- keantoken

 

[Salas]

Take the ''Q'' and ''_x'' out when you google. Its just a part of the spice model designation.

 

[keantoken]

My dinner. Hopefully the finished amplifier will be so fine.

- keantoken

 

[Salas]

Don't fork a nearby semiconductor too by accident.😀 Bon appetit!

 

[keantoken]

Shoot, I have the perfect book for this occasion.

Mmmmmm. Rosemary Jfets.

http://www.amazon.com/Teach-Yourself-Electricity-Electronics-Gibilisco/dp/0071377301

- keantoken

 

[Salas]

You had it in mind all along! There was a French guy who could eat a color TV on a live show. He had a house eaten at his leisure as a world record. DON'T follow that route. Make the amp is better.

 

[keantoken]

Wasn't there another guy that ate motorcycles? I think some major detoxing is in order... And stricter diet standards.

Isn't the C4793/A1837 pair a little slow by modern standards? 70MHz...

- keantoken

 

[Salas]

You could say slow depending on your goals. Slower means controllable also on the other hand. There are the Sanyo FBET 2SA1538,2SC3953 but they are 120V 200mA.

 

[Krisfr]

Please do not shoot at this too much...😉

Thanks🙂

 

[keantoken]

Where are the 100R base stoppers on the drivers?

Also shouldn't the base leads to the drivers be longer and the drivers next to the FETs?

Not that I know much, I'm on the learning end here.

Also, the 1k feedback resistor will have to be a 10W type or something horrendous like that. That's why I increased it to 10k and the 33R to 330R. This way we can use a 2W resistor.

Also the drivers don't have rail filtering. Which schematic are you using?

- keantoken

 

[Krisfr]

We can talk about the closeness to the FETs. I am just trying to do whatever I can to get something built and into testing, if only on a plus and minus 15 supply or something...When ever you finishup the shunts will be fine. I just want to fire up the circuit by building a pc board with in the next day or two.

You are talking about the OUTPUT Fets Right😕

Thanks

 

[Krisfr]

Is this going to be close enough?😕

 

[keantoken]

Turn the drivers 180degrees, so the emitters are right next to the first pair of FETs.

- keantoken

 

[Krisfr]

Flipped

 

[keantoken]

I would also make the traces on the frontend wider by at least twice as much. A trace's inductance is directly related to it's width.

- keantoken

 

[Krisfr]

Justa little wider now...😀

Looks like you are ready to SHUNT...

Thanks🙂

 

[MJL21193]

Hi Krisfr,
I don't know the layout program you are using but you might want to try to redraw the footprint of the TO-92's to spread the pads out a bit. This will give you more clearance for traces and be much easier to solder.

These are 1.5mm traces and 2.2mm pads:

 

[Krisfr]

That is a great IDEA... I am just getting back into doing this. So forgive my short comings...I started out doing black, blue and red tape... 🙁

I will make a plug in for the input FETS, that should help 2.

So all this fancy stuff is part of climbing up the curve...😉

We are a long way from where I want to be with this board, but we are getting there.

I am going to rest my eyes for the night...

Give me some thoughts on this overnight and I will put them in Manana...

Thanks🙂