20th Ann. Shiva mod?

  • Thread starter Thread starter tcrash
  • Start date Start date
T

tcrash

Member
I've read about the mod for the Shiva alllowing you
To foot switch between the 2 modes.
Can anyone explain this to me?
Is there a schematic out there?
I REALLY want this on mine.
 
Sommatone will do it for you, but its a very straightforward mod that you could likely do yourself if you have a moderate level of comfort dealing with a tube amp and a soldering iron. My understanding is no parts other than a 5" piece of wire are required. Unfortunately, I can't say for sure how its done, but I'm sure someone else will chime in shortly.

What I am interested to know is whether or not there is a noticeable dip in volume when you switch between the two modes on Channel 2? I have to think there is, as when the front panel button is depressed, compression increases and I would expect you would become "lost in the mix" without compensating by increasing Channel 2's volume a little bit as well. What I wonder is: given there are 2 reverb jacks on the rear of the amp, could you wire the mod to use one reverb jack as the footswitch input, and the other as a volume knob dedicated to adjusting the volume of Channel 2 when the heavier (i.e., more compressed) mode is selected?

Oh, if you haven't figured it out from the above, you need to have the non-reverb model if you wish to do this mod without having to drill a new hole on the amp's rear panel.
 
Thanks for te info.
I have a Reverb model, but, Im gonna try to find a way to do it.
 
I had this mod made to my 20th Anniversary Shiva. My amp has the reverb and (I was told) the reverb jack is already a TRS jack (just like the channel/boost jack is). So, all that had to be done was a run a short wire from the reverb jack to somewhere on the board and that was it. It took about 10 minutes for the tech to do (after he called Bogner for direction) and it works perfect - it's also completely reversible.

I had RJM make me an Amp Gizmo custom interface cable with (2) TRS plugs on it and now I can footswitch the following: channels, boost, mode and reverb. This allows me to set the gain relatively low (less than 1/2 way up) and have low gain and high gain channels via the mode switch and further gain on each channel as needed via the boost.

I have not notices a loss of volume as you switch the mode in and out - it seems pretty consistent to me. I do notice there is a considerable drop in volume when the shift button is engaged, but this button is not footswitchable.
 
psmith68":o83xjmez said:
I had this mod made to my 20th Anniversary Shiva. I have not noticed a loss of volume as you switch the mode in and out - it seems pretty consistent to me.
Click to expand...
Good to hear. Thanks! :thumbsup:


psmith68":o83xjmez said:
I do notice there is a considerable drop in volume when the shift button is engaged, but this button is not footswitchable.
Click to expand...
That's to be expected, as it's cutting mids.
 
psmith68":35m4p4h6 said:
I had this mod made to my 20th Anniversary Shiva. My amp has the reverb and (I was told) the reverb jack is already a TRS jack (just like the channel/boost jack is). So, all that had to be done was a run a short wire from the reverb jack to somewhere on the board and that was it. It took about 10 minutes for the tech to do (after he called Bogner for direction) and it works perfect - it's also completely reversible.

I had RJM make me an Amp Gizmo custom interface cable with (2) TRS plugs on it and now I can footswitch the following: channels, boost, mode and reverb. This allows me to set the gain relatively low (less than 1/2 way up) and have low gain and high gain channels via the mode switch and further gain on each channel as needed via the boost.

I have not notices a loss of volume as you switch the mode in and out - it seems pretty consistent to me. I do notice there is a considerable drop in volume when the shift button is engaged, but this button is not footswitchable.
Click to expand...
Do you have any pics of this?
Would love to see it
 
I just picked up one of these amps also. With the reverb. I would really like to see the pics of this procedure as well.
 
Mine is done, works great.
The reverb jack is a tip/ ring/ sleeve jack.
So you just solder the wire to the ring connection on the back of the mini pc board
I need a 4 button foot switch, to use all the features. After the mod the front panel switch doesn't work.
 
tcrash":357nt4ye said:
Mine is done, works great.
The reverb jack is a tip/ ring/ sleeve jack.
So you just solder the wire to the ring connection on the back of the mini pc board
I need a 4 button foot switch, to use all the features. After the mod the front panel switch doesn't work.
Click to expand...

If the switch on the amp doesn't work, is it permanently "on" or "off"? (in or out)?
 
It is "in" ( the higher gain mode)
Unless you have a TRS cable connected to the reverb jack
 
I don't mind just walking over to the amp to flip the switch, but it would be cool to make use of my reverb switch. Even better, I would love to be able to turn on or off my effects loop.
 
You must log in or register to reply here.
Back
Top