R2 Mod

[william l stone jr]

I have a Mark III and was wondering if the R2 mod is worth the effort or should I just get an overdrive pedal in the loop.

 

[psmile87]

My III has the mod, and it helps some, but I don't use R2 that much...an OD could work as well..i use one in front of the amp as a boost though

 

[robredo_mattila]

It's definitely worth doing. Easily reversible and will only make the amp more usable as a whole. I plan on using an OD in front of the amp for low gain crunch tones though.

 

[GIG4FUN]

It is the most worthwhile thing you will every do.

I sure hope I have not understated this.

peace

 

[goodwill559]

I have the mod, but I honestly only use the lead channel, so I don't know if it's worth it or not.

Yeah, I know, not very helpful. :wink:

 

[GIG4FUN]

I have the mod, but I honestly only use the lead channel, so I don't know if it's worth it or not.

Yeah, I know, not very helpful. :wink:

well, I will tell you too then! It is a required mod "IF" you plan to use this amp as a three channel amplifier.

 

[Boogie Woogie Man]

I'd love to get the mod done as I do use it as a 3 channel amp.
Does anyone know if it can be done by someone in Scotland ?
I have a great amp tech locally but he would need the schematics etc. to do it.

 

[bloodspoint]

I'd love to get the mod done as I do use it as a 3 channel amp.
Does anyone know if it can be done by someone in Scotland ?
I have a great amp tech locally but he would need the schematics etc. to do it.

He really wouldn't, I don't think. I haven't done mine yet, but I'm no electronics tech, and I have confidence that I can do it. It literally is just cutting a pot in where two resistors are now. I don't have the link, but there is a thread with very clear before and after pics with the components labeled.

 

[CoG]

You really don't need a tech to do it but any tech could and he doesn't need schematics. He's replacing one resistor with a pot.

Unfortunately search seems to be hosed right now. If I have time before rehearsal tonight I will pop the lid on my rackmount and tell you which resistor if someone else can remember the pot value...

And yeah, do it, I really don't know how people use all three channels without it.

 

[Boogie Woogie Man]

Thanks guys. It looks like I will be able to do it myself then. Once I know what to do and what I need to do it, I'll get on to it straight away, man this is going to be a big help.

 

[camsna]

It's way easy to do. Just make sure you discharge the power supply caps so that you don't - y'know - die.

And, in my opinion, the R2 mod is totally necessary. Without it, R2 sounds great but is TOTALLY useless in a live situation. With the mod, my Mk. III is the most versatile amp I've ever played.

You can do eeeeet!

 

[Boogie Woogie Man]

Thanks again guys, the links are invaluable. How do I discharge the caps ?

 

[acorkos]

How do I discharge the caps ?

not like this.... http://www.youtube.com/watch?v=ZA25ghMAyak

do it like this....all you need is an insulated wire with 2 insulated alligator clips - one on each end. looks like this:

make sure your amp is off/unplugged from the wall and flip your standby to "ON"

clip one end onto any one of your big filter capacitors (+ end). carefully clip the other end to pin 1 of V1...the preamp tube closest to your input jacks. pin 1 is the first pin moving clockwise from the gap in the circle of pins.

wait a minute and measure the DC voltage on each of the filter caps with your DMM (you have a DMM, right?). you should read "0" volts...caps successfully discharged. I leave the clip attached while I work, makes me feel safe, like rock climbing with a harness and securely anchored rope