Tweed BluezMeister with 5879 OD

[VacuumVoodoo]

And you don't hear a difference between a DC Mosfet CF vs a tube one?

That is correct. I can NOT hear a difference.
With respect, 10thtx

The tone difference between AC and DC coupled cathode follower is due to the DC coupled grid drawing current from the triode driving it. AC coupled CF doesn't do this.
Mosfet's gate draw hardly any current at all, so it won't make any difference whether it's AC or DC coupled. As long as MOSFET's gate is tied to a polarizing potential it's happy. Mosfet is shot if gate draws current.

[surfsup]

My experience with the 5879 tube is that it greatly benefits from a CF when used in the OD position (not so in the V1 position like on the HoSo56).

I have used tube and mosfet cathode followers. I truly can not hear any difference between the two of them tone wise.

The mosfet CF behind the 5879 significantly smooths the 5879 overdrive tone. Whatever slight high end "hash" in the tone is eliminated with the CF behind the 5879 (in the OD position only).

I personally have experienced the same thing though I feel it is more attributable to the 56k rather than the CF, itself. If you swapped that for 100k I think you'll get more raw from it. On a 4 gainstage build I used a switch to parallal two 100ks or just one and the 50k setting is noticeably more smooth and I left it in that way. Merlin has a nice write on this in his preamp book as well (in the cathode follower chapter).

This was using a triode CF, not a mosfet.

[Jack Hester]

Here's the latest revision. The same schematic, but I've completed a layout. When I have the chance, I will draw a schematic that conforms more to convention. In the meantime, take a look and comment please.

Jack

12Jan14 - Note: See below for update to rev-D.

[Jack Hester]

I updated the drawing, and left it as the same revision. The major change was to correct the component labeling to have sequential numbers.

I found an error where I had a ground in the wrong place on the Tone Stack.

I had to add a missing capacitor to the Volume pot, giving it the next highest number (C29), rather than shifting them all.

I also added a missing resistor (R35) to the PI.

Other than these changes, I believe that it can be considered ready for construction. Please look it over and comment with errors found, or improvements. Every time that I think that I'm done, I seem to find one more thing. Hopefully, that's not the case now.

Jack

12Jan14 - Note: See below for rev-E.

[Jack Hester]

I'm thinking that this will be the last update, before a build. I managed to put together something of a standard schematic. It's still not entirely like most, but it's a start.

So with this revision, I have included the layout, the new schematic, my original format schematic, a Bill of Materials, and a complete sheet of the entire drawing. I only drew the power supply once, as it's simple enough, as is.

Somehow, I still managed to leave C29 off of the BOM, but it's on my original schematic, and on the layout (on Vol pot R14).

I plan to start putting something together in a couple weeks, when long work hours are behind me. I'll post my progress.

Jack

[Jack Hester]

Note: C29 is now on the BOM and the new schematic (Vol pot R14). Also, added the Hum Balance Pot to the Layout.