Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Misc Schematics and Layouts => Topic started by: sluckey on June 07, 2014, 12:28:15 pm
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The amp is true to the original 1960 Vox AC-15 schematic, but is based on the more reliable Marshall style layout.
It has been successfully built by three forum members (as of 06/07/2014).
The Marshall style, single board layout works well in a 20" x 6.5" x 2.5" chassis.
The amp sounds good, has real pitch shifting vibrato, is quiet, and runs cool.
You can see my project complete with detailed photos on my website.
http://sluckeyamps.com/VAC15/ac15.htm (http://sluckeyamps.com/VAC15/ac15.htm) -- Link updated 07/12/2016
Hoffman makes a very reasonably priced, predrilled board for this amp.
The AC15 turret boards are located on this page
http://hoffmanamps.com/MyStore/catalog/TurretBoard.htm (http://hoffmanamps.com/MyStore/catalog/TurretBoard.htm)
At his price, if I were to ever build another one, I'd just let him do the drilling on his CNC machine. :grin:
Attached is a pdf that contains all my drawings for this project.
Also attached is a compilation of the few mods I've done to my AC-15. IMO
The Brilliance mod and the Vib/Trem mod are huge improvements.
The others are nice to have also.
I also attached the face plates as a PDF file.
None of these mods alter the sound of the original amp.
This is the amp from the main forum thread titled "lego's spin on Sluckey's AC15" (http://el34world.com/Forum/index.php?topic=16874.0).
Edit EL34:
You can use these two documents for my turret boards for assembly tips
https://el34world.com/Hoffman/instructions.htm (https://el34world.com/Hoffman/instructions.htm)
https://el34world.com/Hoffman/files/CommonHookups.pdf (https://el34world.com/Hoffman/files/CommonHookups.pdf)
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The AC15 is a forum members project by Sluckey
I created a turret board based on Sluckeys design
I created a public Parts list for all the AC15 parts I stock
That parts list can be found on this page - Sluckeys AC15 Parts List
http://hoffmanamps.com/MyStore/catalog/PartsListIndex.htm (http://hoffmanamps.com/MyStore/catalog/PartsListIndex.htm)
You can order the boards with wire holes or without wire holes
The AC15 turret boards are on this page
http://hoffmanamps.com/MyStore/catalog/TurretBoard.htm (http://hoffmanamps.com/MyStore/catalog/TurretBoard.htm)
AC15 BOM file with Resistors, Capacitors and Misc parts - Here is the Link for the AC15 BOM
http://el34world.com/Hoffman/files/AC15_BOM.pdf (http://el34world.com/Hoffman/files/AC15_BOM.pdf)
Here is the link for the Hoffman AC15 Layout
http://el34world.com/Hoffman/files/AC15_Layout.png (http://el34world.com/Hoffman/files/AC15_Layout.png)
Here is the link for the AC15 Schematic
http://el34world.com/Hoffman/files/AC15_schematic.png (http://el34world.com/Hoffman/files/AC15_schematic.png)
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Here's the AC15 board I assembled
All went together smoothly, but it is a big board and lots of work so take your time
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Note that I only make the board without wire holes now
They are listed on this page
http://hoffmanamps.com/MyStore/catalog/TurretBoard.htm (http://hoffmanamps.com/MyStore/catalog/TurretBoard.htm)
There are many post in the main board about Steve's AC15
This search link will show a bunch of post you can read up on
http://el34world.com/Forum/index.php?action=search2;params=eJwtzMsKgCAUhOFXiTZtk-h5RI8DXUzjqEXgw3eMdv98izHuMoHg6lDH2lfLrdQkmZZ4a4rH6ZEh2KjYDZR1DP75JXKWYnh8Pz9pt7KwQ6ImMEyL7OQL7Xg6Q2p-AUP8L0Q.
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The AC15 board and AC15 board are shown below
The AC15 is 14 inches long x 3.125 inches high
I can also make the AC15 board as an AC30 board
The AC30 board is 15 inches long x 3.125 inches tall
The only difference between the AC15 and AC30 is the AC30 has two more power tubes
The AC30 has two more 100 ohm screen grid resistors and two more 1.5k input grid resistors
I circled the extra AC30 holes in blue on the diagram below
Make sure your chassis is long enough to fit these boards
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Note that Sluckeys AC15 and AC30 boards are the same layout
There are just two more 1.5k grid resistors and two more 100 ohm cathode resistors on the AC30 layout
Both of those boards are listed on my Turret board catalog page here
https://hoffmanamps.com/MyStore/catalog/TurretBoard.htm (https://hoffmanamps.com/MyStore/catalog/TurretBoard.htm)
A post about Sluckey's AC30 is here
https://el34world.com/Forum/index.php?topic=20313.0 (https://el34world.com/Forum/index.php?topic=20313.0)
Sluckey posted a AC30 pdf file
Here's the link to that
https://el34world.com/Forum/index.php?action=dlattach;topic=20313.0;attach=60775 (https://el34world.com/Forum/index.php?action=dlattach;topic=20313.0;attach=60775)