"Correct" Presence/Density Board (solved)

[jc74868]

Solved See: http://mtsforum.grailtone.com/viewtopic.php?t=15167&postdays=0&postorder=asc&highlight=density&start=0

I recently got a RM50 combo for dirt cheap, converted it to a head and I'm running a KH3 and JF Trilogy. I've ran across articles re: a presence/density issue. How does one tell if an amp has the board with the "correct" value or the wrong one. Also, in terms of tone, what is the difference.

I can't say I'm totally happy with my amp's tone, but not sure if this issue is something worth looking in to. I don't think there's a problem with my cab as I've used that with a variety of heads/power amps and preamps and have pretty much always been able to dial a great tone in quite easily.

 

[eyeball987]

Does the presence knob seem to do anything to the tone before getting it turned up to 3:00? Does the amp seem a bit dark and unclear on the bottom end?

If so, it's probably the old one. Easy fix.

 

[jc74868]

Does the presence knob seem to do anything to the tone before getting it turned up to 3:00? Does the amp seem a bit dark and unclear on the bottom end?

If so, it's probably the old one. Easy fix.

Haven't really experimented with it a lot. It did seem like it doesn't make much difference through most of the knob travel though. And it I felt like it the sound was a bit boomy, almost muddy, even with the density all the way off.

What's the fix?

 

[eyeball987]

Does the presence knob seem to do anything to the tone before getting it turned up to 3:00? Does the amp seem a bit dark and unclear on the bottom end?

If so, it's probably the old one. Easy fix.

Haven't really experimented with it a lot. It did seem like it doesn't make much difference through most of the knob travel though. And it I felt like it the sound was a bit boomy, almost muddy, even with the density all the way off.

What's the fix?

A couple quick value swaps on the board. Jaded Faith probably has an easy fix he can suggest and there is also a post on here about Salvation offering some type of hot rodded replacement as well.

I lack the soldering skills so I have others do the work.

 

[jc74868]

I did a bit more in depth searching on the site and I found the resources you were talking about: http://mtsforum.grailtone.com/viewtopic.php?t=15167&postdays=0&postorder=asc&highlight=density&start=0

I'm going to pull my amp out and check the pot values. I'm not great with a soldering iron, but I think I could manage to swap out the pots. As far as getting in to swapping out the resistors and caps, I might just spend the $40 to have JF do it

 

[Imselln]

I also just bought an RM50 combo and need this done to mine as well. Im interested in exactly what to do. or how much the mod for it costs?

Ed

 

[jc74868]

I also just bought an RM50 combo and need this done to mine as well. Im interested in exactly what to do. or how much the mod for it costs?

Ed

$40, I day turn around. I posted a link above that shows what the incorrect board and correct board pots should look like. Seems really easy to get the board out too.

 

[Imselln]

Yeah, I got it. i must have been typing. my reply when you posted that.Thanks

 

[jc74868]

This is what I discovered when pulling the board out of my RM50C. I believe that all the caps and resistors are correct. The presence pot seems to be the only thing wrong. I checked the values on the components per JF's specs:
Presence Pot: B10K
Density Pot: A1M
Density Cap: 472 (250V)
Presence Cap: 104 (250V)
Electrolytic Cap: 100uF (100V)
Resistor: 56K (1/2W)

And all look correct. The resistor took a moment to figure out, but I googled a green blue orange gold resistor and it is a 56K. Now, I just have to change out the pot. Should be easy, once I obtain one!


Also, on the RM50C. The Master/Effects/Density/Presence are all on the same board

 

[Mike361]

Mine is the old style as well, but I actually kind of like it that way. I guess I like a darker amp. What I would really like is a pic of the headshell you made. Been wanting to make one myself and need dimensions. If possible, would you pm me or post them. Did you copy from a rm head or just measure out what is needed? Thanks for any help.