50w Single-Ended BAF2015 Schade Enabled

[vdi_nenna]

How long can the leads be from the board to the mosfets?

For example, I will be using mono-blocks with 12" spacing between heat sinks.
From 6 inch center, if using a 4" PCB board on center, leaves approximately 4" distance to the power mosfets. The rule I remember was to keep the leads under 3 inches.

What's the best way to avoid issues and oscillation?

Thanks,

Vince

 

[Zen Mod]

good to go

you can twist wires slightly , solder gate resistor ditto on gate

you can wrap it in heatshrink (wire , resistor and mosfet pin) , to ensure it mechanically

 

[vdi_nenna]

Cool. Thanks.

 

[2 picoDumbs]

Digikey package arrived.
Still haven't purchased power supply caps but I now have everything I need to build a working prototype. I'll just use a lab power supply to start with.
Hopefully have something complete that plays music within 7 to 10 days.
I won't be able to make a start on it for a week.

 

[2 picoDumbs]

Probably going to build it like this first up, just to satisfy my own curiosity.

 

[Soundhappy]

Digikey package arrived.
Still haven't purchased power supply caps but I now have everything I need to build a working prototype. I'll just use a lab power supply to start with.
Hopefully have something complete that plays music within 7 to 10 days.
I won't be able to make a start on it for a week.

Great Pico !
Please write us your feel & description about music with Schade50
Have a nice day

 

[vdi_nenna]

Digikey package arrived.
Still haven't purchased power supply caps but I now have everything I need to build a working prototype. I'll just use a lab power supply to start with.
Hopefully have something complete that plays music within 7 to 10 days.
I won't be able to make a start on it for a week.

Looking forward to your impressions on sound.

 

[2 picoDumbs]

Couple of notes.
1) With my batch of parts (10 pieces) I am getting values of Vgs between 4.85V and 4.95V for 3.2A (not 4.7V). Room temperature was at 15 C (Winter here), at higher room temperatures Vgs is likely to drop a little bit ( maybe 0.04V as a rough estimate).
Vgs adjustment between 4.65V and 5V would likely cover it for variations in parts coming off the manufacturing line.

2) For Id vs Vgs, I am getting similar values with IRFP250 (steeper than IRFP240 though) which isn't as dramatic as originally thought.

 

[generg]

So you are the first one here in the thread who came over the 2A barrier, congratulations!

 

[2 picoDumbs]

Looks like it.

Edit: Wait a second, that was with Vds of 20V. I'll redo it at 30V

 

[2 picoDumbs]

Testing with Vds of 30V sees Vgs values reduced by roughly 0.12V

 

[Zen Mod]

I presume still stable .

 

[2 picoDumbs]

I presume still stable .

Still stable, but slow to reach equilibrium, somewhere between 30 minutes and 60 minutes from a cold start.
This is just raw Id vs Vgs testing.

I'll start putting together the circuit

 

[Zen Mod]

well , who cares

nature of the beast

who is anal about that , servo is solution

 

[Zen Mod]

Hi Pico,....... but I am afraid It will be autumn since I start the BAF2025 amp.

Autumn of 2026?

or taking warp shots lately ?



(Generg is my man!)

 

[2 picoDumbs]

well , who cares

nature of the beast

who is anal about that , servo is solution

Servo would certainly work. I like caveman circuits though.

 

[Zen Mod]

servo is neat , for tube rolling

 

[2 picoDumbs]

servo is neat , for tube rolling

Yeah that is cool. Hadn't thought of it like that.

 

[2 picoDumbs]

I figure though, if you can bias (set dc offset) your Bablefish J up with 2A using IRFP150 with a simple trimpot where dc offset is critical, then this circuit with output cap should be reasonably straight forward.
Touch wood. Hahahahaha

 

[Zen Mod]

there is (in Babelfish J and pretty much every second amp on planet) inherent servo (input LTP) which is taking care of output offset , via NFB

you don't have that in mumbojumbopuckamp

though, if Papa sez and shows it's doable , no reason for doubts