some joe davisson circuits and circuit salad mosfet comp

[MaheshSK]

Who doesn't like some joe davisson circuitry.. Found these on my pc while cleaning up. here goes.

[Silver Blues]

These are pretty cool. I like the Dual MOS and the compressor especially.

[MaheshSK]

Yeah The Compressor looks exciting so does the obsidian.

[Frank_NH]

I like that MOS overdrive.  Just wondering how that T-notch filter in the feedback loop of the op amp works.  I haven't seen that before...

[MaheshSK]

He sure did some things very different.. Pretty unique.

[doomkraft89]

Don´t know if someone really asked for a layout.
But here is the Obsidian. I think it´s okey!

[MaheshSK]

 doomkraft89

[doomkraft89]

[doomkraft89]

[MaheshSK]

Thanks doomkraft..running low on mosfets need to buy some . will get building soon..

[doomkraft89]

I Don´t know if I´m capable of doing the compressor.. Should the resistors marked with "threshold level" and "decay setting" replaces with pots? or is it set-and-forget?

[Silver Blues]

I think it's up to you. As I understand it, just using the values marked on the schematic are good for general-purpose use.

[doomkraft89]

Tought I will try and it came out okey. Easy to mod for threshold and decay pots if wanted..
I got the flu and is a bit dizzy. So I´m not 100% confident with this one. Will go thru all the layouts and maybe build some of them in the week.

[Frank_NH]

I built the Dual/MOS over the weekend using my own vero layout (before DoomKraft89 posted his great layouts - thanks!).  I found it to be very bright and over-the-top gainy.  Not that it's a bad thing, but...  So, I decide to try redesigning it with just a single MOSFET gain stage, and a tone control tacked on at the end.  I'm still playing around with it, and will post the new layout if it comes to something.

I'm still trying to get a handle on MOSFET biasing.  It seems that these circuits bias the MOSFETs differently, and I want to understand how that impacts the gain.   An opportunity for learning something new...

[MaheshSK]

Get well soon doomkraft.. thanks for the layouts.. inputs much appreciated frank.. care to post the layout.

[doomkraft89]

Find some other "Joe-citcuit-layouts" on my computer. if someone don´t like FETS etc..  But who don´t?!

[Frank_NH]

MaheshSK wrote

Get well soon doomkraft.. thanks for the layouts.. inputs much appreciated frank.. care to post the layout.

Yes, I'll post it when I'm done with the redesign.  I'm adding some filtering to tame the brightness, and may also redo the mosfet bias using something a little more conventional.

[Frank_NH]

By the way, go ahead and place these layouts in separate threads at the "Unverified" side of the "Contributions" section of the blog.  Once they're verified, they can go on the "Verified" side.

[doomkraft89]

Yeah. I´l do that!