DC MOD that is worth looking into!!!!!!

[Monsta-Tone]

Edward turned me onto this link in another thread about a new DC-3 owner.

http://www.thegearpage.net/board/showthread.php?t=229027



I just did it to my DC-10, which needed some footswitching parts replaced anyway. It was slow when switching to the Clean channel after being in the Lead channel for a while.

While I had the amp open, I played it for about 10-20 minutes. Then, I did the mod, which is the easiest mod I have ever done.

WOW!!! What a difference, both in the tonality of the amp at lower volumes and the useability of the Output Volume knob.


If you have doubts about your DC amp, try this mod, you won't be disappointed.

 

[radmo]

Can the be done on an F-30?

 

[Monsta-Tone]

I didn't see a Master Volume for both amps on the drawings.

On the DC amps, it is called "Output Volume."

I don't think that this mod can be done to the F-30. I did see a mod for the power supply attached to the drawings though. It involved changing a 180 Micro farad capacitor to 2 30 Micro farad capacitors in Parallel.

This probably smooths out the tone and makes the amp less punchy.

 

[buckglitter]

Does anyone know why the resister is there in the first place?

 

[Monsta-Tone]

Ed had a good idea, he thought it was a Marketing gimmick. The salesman would be able to say, "See how loud it is on 3."

Of course the salesman would ommit the fact that there was very little volume difference between 5 & 10.

 

[tommyhawk13]

I'll have to check my .50 caliber the next time I clean it, but it has the same drastic change in volume. Could there be any negative effects of cutting the resistor?

 

[Boogiebabies]

Does anyone know why the resister is there in the first place?

In the mid 80's CTS potentiometers move production from the US to China/Taiwan. the American made pots had well defined tapers and would give you a nice, even sweep. The new CTS pots were all over the place.
For instance, dialing in 2 on the Master would be like 4 on the US made pots and the exact opposite was also a probablity. Mesa dediced to use a 22K series resistor before the Master Volume to help ease the wide tangents in sweep. This started in mid 1984. The newer Mesa's, including the MK IV are using CTS or Alpha pots which are both made in Taiwan and still suffer from the lack of exact specifications. Hence, Mesa still uses the series resistors to assist the taper.

 

[Monsta-Tone]

That's completely understandable, but the resistor we are talking about is parrallel to the 1st tab and the wiper of the pot.


This theory might still make sense though, since the parrallel resistor would tame the taper a little.




None the less, it made a huge difference in my DC-10. If the taper from pot to pot is drastically different, I could see where this mod would have more or less affect on different amps.

I can also see, if the pot taper varies, that this mod might make some amps sound worse rather than better.


That's some really good input boogiebabies, thanks.

 

[edward]

Man that Boogiebabies ...sure does know his stuf! Thanks for the insight. Not only makes sense, but is a heck of a lot better than my cheesy guess

Glad you like it monsta-tone. I dig it a lot, as well. Credit does, of course, belong to John on TGP!

Edward

 

[Boogiebabies]

That's completely understandable, but the resistor we are talking about is parrallel to the 1st tab and the wiper of the pot.


This theory might still make sense though, since the parrallel resistor would tame the taper a little.




None the less, it made a huge difference in my DC-10. If the taper from pot to pot is drastically different, I could see where this mod would have more or less affect on different amps.

I can also see, if the pot taper varies, that this mod might make some amps sound worse rather than better.


That's some really good input boogiebabies, thanks.

I am not a DC guy, but I just passed on the beginning of the use of some form of resistance in the Master pot circuit. I totally agree that it can have positive and negative effects. I have a pre 22K resistor IIC+ and it's an amp that needs to be turned up to get the Mojo. The other two have the 22K circuit change and are much easier to get the Mojo at lower volume levels. Go figure.

 

[tommyhawk13]

In that case, I think I'll leave well enough alone.