Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => PC Express and JSchem - Schematics and Layout diagrams => Topic started by: tubenit on September 18, 2008, 10:16:26 am

Title: Studio 15 (4001 with mods)
Post by: tubenit on September 18, 2008, 10:16:26 am

I changed numerous things from the Studio 15:

This one uses a GZ34 instead of solid state.
It has a dpdt center off on V1a for cathode caps being paralleled
It has a negative feedback switch
It has the attentuation cathode bypass switch
It has just cathode bias and not cathode plus fixed bias both
It does not use DC on the heaters

I have NOT built this. Check for errors and compare to original Studio 15/ Marshall 4001

with respect, Tubenit

Title: Re: Studio 15 (4001 with mods)
Post by: tubenit on September 18, 2008, 01:16:22 pm

I have NOT built this.  I have only glanced over it to CHECK for ERRORS.  If you see any, please leave a post and I'll work to get it corrected.

Any discrepency between layout and schematic .................. refer to the schematic as "correct".

With respect, Tubenit

Title: Re: Studio 15 (4001 with mods)
Post by: dbtk44 on October 12, 2008, 05:05:54 pm

Just curious, has anybody built or worked with this one? I'd like to take a crack at it, but since it seems to be preliminary I wonder if the schematic and layout are both workable?

Oh, And thank you for sharing this Tubenit!

Title: Re: Studio 15 (4001 with mods)
Post by: equinox on March 24, 2012, 10:07:55 am

Ditto! It seems like someone did some work and the Studio 15 w/ 6V6 was a great base.  I'd like to know how this turned up and hear some clips if possible.  Please let us know.  Thanks in advance.

Equinox