Build This MoFo!

[PRR]

Thank you very much for the elect-tech fiction(?).

I believe it may be a useful genre. I have not got as far as sketching one. I will note that Gus' Garage in Popular Science gave good (car) tech lessons in story form. Also I believe POWER magazine around 1910 published some extensive explanations of hydrodynamics in the form of un-edjucated dialect between the Old Guy and the New Kid.

I object that it has no Dames, no Guns, and no Murders. Unless the "beginners" end up murdering MOSFETs by not understanding the bias instructions. What is "P1 minimum setting"? Left? Right? Facing which way? I could see wrong-way leading to 4 Amps and 60 Watts dissipation-- quick death. _I_ think it should self-adjust, but resistor is wasteful and when I added a NPN servo it complicated the plot.

 

[xrk971]

Thanks for the great story, and the tip on where to get big fat Hammond inductors for a reasonable price. This is much more compact and less expensive than the spool of wire.

193V Hammond Manufacturing | Mouser

 

[dimkasta]

IRFP240 is the horse not IRFP250.

It could be because of the increased Ciss on the 250s
A buffer in front of it should make the comparison fairer 🙂

 

[dimkasta]

FABs can also use 195R10 or even 195R20 to match their plutonium-powered PSUs 😛

195R20 Hammond Manufacturing | Mouser Greece

 

[Ralph G]

I'm no expert, but if do some quick calculations, I don't think a lot of inductance is needed. Won't a Hammond 159ZE be a good and cheap solution?

28mH should have a -3dB at 5Hz. And this one can take upto 3A. Only 19 euro's.

Edit: or use two of these in parallel. Or the 159ZC in parallel. A lot of inductance and current capacity....

 

[Puffin]

Are there any boards available for this yet?

 

[Soundhappy]

It could be because of the increased Ciss on the 250sA buffer in front of it should make the comparison fair🙂

Good point Dimkasta yes, I do need to try with IRFP250 to understand why is optimal for MOFO.
Maybe Santa brings me some gift from Mouser in December

FABs can also use 195R10 or even 195R20 to match their plutonium-powered PSUs 😛

Haha yes for Super Dude Ultimate MOFO

193T is 4 times less heavy and 2 times less pricey if compared with 193V
193T Hammond Manufacturing | Mouser France
http://www.mouser.com/ds/2/177/5c0033-71126.pdf

 

[Ralph G]

I have read the post 27 of Soundhappy an hour ago. And I just posted my post (10 minutes ago). But for some reason my "new" post is 25, and the "old" Soundhappy post is 27.

And my post has a 9 AM time stamp (it is 11 AM over here).

Edit: partly answer from the bottom of the page: All times are GMT. That explains the time stamp. But not the post numbering. Never mind.

 

[Soundhappy]

I have read the post 27 of Soundhappy an hour ago. And I just posted my post (10 minutes ago). But for some reason my "new" post is 25, and the "old" Soundhappy post is 27.

And my post has a 9 AM time stamp (it is 11 AM over here).

All OK edited my post for additional commentaire naturally number is changed. Have a nice day 🙂

 

[Ralph G]

Are there any boards available for this yet?

😕 You want a PCB for this design 😕

I've made an inverted-mini-aleph without one 😀

I always use proto boards with 3 connected islands. These are brilliant. Roth RE310 for instance.

 

[Soundhappy]

Are there any boards available for this yet?

Yes see on page No18 in MoFo pdf article

 

[Puffin]

😕 You want a PCB for this design 😕

I've made an inverted-mini-aleph without one 😀

I always use proto boards with 3 connected islands. These are brilliant. Roth RE310 for instance.

No not really, I just think stuff looks neater if you use one and the PDF mentioned that there would be some. Rob.

 

[Ralph G]

True. I didn't see this. 😱

But still: why need a PCB for this? Yes, it looks profi, but you can use a proto board that is way faster and way cheaper. And way more flexible. 😕

Maybe I'm not used to PCB's enough to appreciate them. And I'm Dutch, so a cheapskate. 😎

 

[Michael Rothacher]

Before I start going through the posts and answering questions and stuff, just wanted to say sincere thanks for the encouraging comments. That means a lot. I'm proud to be a member of the international FAB brotherhood. 🙂

 

[Ralph G]

I really like the simplicity of this design. 🙂

Class A SE, with only 1 active part AND a half decent efficiency. Also not to difficult to drive (high input impedance) AND good damping.

I use a SRPP 6N6P preamp, that can swing close to 100V RMS if needed. But at 1000 ohms or something. So I was already thinking of building a power follower (such as the F4 or F6 with different input transformers).

A huge heatsink and 4 powertransformers are already available. Now I only need to source a couple of chokes (159ZE looks most promising).

Thank you for this inspiration.

 

[Vix]

Wow, I just had a look on my own post, which I wrote yesterday, BEFORE I had read MoFo article! 😱

http://www.diyaudio.com/forums/vend...rg-nutube-available-online-9.html#post5216603

looks like some some dreams are interconnected...

By the way, I am listening to a Mofet Follower, mildly different (lightbulb instead of a choke)...

Thanks for a great article 🙂

 

[dimkasta]

Well yes if you've read the l'amp series articles, it was a matter of time to connect the dots to the follower equivalent 🙂

 

[dimkasta]

Double post

 

[xrk971]

If one replaces the Hammond with the big 110mH spool of copper wire, would the distortion go down? As these are power line mains filtering inductors, they may not react as well at higher frequencies.

 

[Soundhappy]

Maybe I'm not used in PCB's enough to appreciate them.

Classic Point to Point are the best for MoFo experiments and modifications.
PCB for final build is elegant I agree