Real Jose Modded 1979 Marshall 100 watt head- An in depth Look at the Build and Circuit

T Wilcox · Post by **T Wilcox** » Tue Jun 23, 2020 7:51 pm

Hey guys! Found this awesome video researching Jose mods and such. Figured someone here could find it useful since I spent countless hours looking for something this informative over the last couple months. this would have saved me a ton of time

Goes over every aspect of the amp and then towards the end had an in depth explanation of diode clipping that I found very useful

https://youtu.be/dI1l_uZ0g-k

with respect

Todd

martin manning · Post by **martin manning** » Wed Jun 24, 2020 3:57 pm

Nice video, and interesting take on a MV. FWIW, the "Type 4" MV in TW pages is implemented in the "push" setting of the Jose MV, but he's also added the diode clippers. The pre-tonestack MV is unique, I think.

martin manning · Post by **martin manning** » Wed Jun 24, 2020 4:59 pm

BTW, does anybody know the zener voltage of those unobtainium diodes?

norburybrook · Post by **norburybrook** » Wed Jun 24, 2020 5:42 pm

martin manning wrote: ↑Wed Jun 24, 2020 4:59 pm BTW, does anybody know the zener voltage of those unobtainium diodes?

damn...I did find out the specs recently as I thought about building one.....but I've forgotten....

check this out too, a nice follow on from the last one,

Dave Freidman and Pete thorn with Steve Vai's Jose modded Marshall

https://www.youtube.com/watch?v=TbRJeFYfwjU&t=1343s

M

T Wilcox · Post by **T Wilcox** » Wed Jun 24, 2020 8:10 pm

martin manning wrote: ↑Wed Jun 24, 2020 4:59 pm BTW, does anybody know the zener voltage of those unobtainium diodes?

In the comments below the video he references a 1N4450 but it looks like the cross reference to that obsolete part is a NTE177

1.25v but its not a zener so I think he may be wrong

martin manning · Post by **martin manning** » Wed Jun 24, 2020 9:52 pm

Since the diodes are in series and opposed, one or the other of them will have to go into reverse breakdown to clip the signal. The linked data sheet says minimum 40V reverse breakdown voltage, which sounds about right. A 40V Zener would probably work fine there.

In the comments the author wrote:

"The zener number is my bad- I was reading it off the parts box while doing the narration off the top of my head and transposed the stock number for the actual zener type. Should have been obvious at the time -- since when does a zener designation start with an "a". LOL

The proper number is 1n4450- Sorry about that !"

http://www.digitroncorp.com/Documents/D ... x?ext=.pdf

Tube Amp Archive

Real Jose Modded 1979 Marshall 100 watt head- An in depth Look at the Build and Circuit

Real Jose Modded 1979 Marshall 100 watt head- An in depth Look at the Build and Circuit

Re: Real Jose Modded 1979 Marshall 100 watt head- An in depth Look at the Build and Circuit

Re: Real Jose Modded 1979 Marshall 100 watt head- An in depth Look at the Build and Circuit

Re: Real Jose Modded 1979 Marshall 100 watt head- An in depth Look at the Build and Circuit

Re: Real Jose Modded 1979 Marshall 100 watt head- An in depth Look at the Build and Circuit

Re: Real Jose Modded 1979 Marshall 100 watt head- An in depth Look at the Build and Circuit