DC Mods - Revisited...........Sort of.............

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:mrgreen: That is awesome!!!!
I was going to post a comment on YouTube, but I guess Google bought them and I needed to use my Google password or some such crap. Last thing I need is another freaking account somewhere in imagination land......


Anyway,
Glad you liked the mods!
 
Hi, I'm new to the forum. I have a DC-5A, firts of all I really wanna thank Monsta fot this thread, I had the "blanket removal" and the "volume" mods done and they're great specially the first one, all tho I think it should be renamed to "the uncompress rythm channel mod" .

I do have some questions for Monsta, I remember reading that after the fx loop mod you use the mix knob in there as a "negative feedback" pot. Could you elaborate on the tone capabilities of that, and how could it be done.

Also, for some reason this amp seems to LOVE emgs, or maybe I should say super tight bass pickups, is there a mod that would do something like a the tight switch on Egnater amps, I mean cut some of the bass in the first gain stage to get some of that "emg-love/super chugging" from the amp without having to use the EMGs?.

Greetings from Santiago, Chile
 
Right on, glad they worked for you!

You could easily cut bass in the 1st gain stage. You may not get enough of a result from it though.
The Cathode Bypass capacitor on pin 8 of V1 is a 1 micro farad.
A .68 or .47 micro farad cap there would definitely remove some of the bass.

Another place that you can try (although this may not be a good place for a switch) is the tone stack resistor or Slope Resistor.
Your amp has 2 tone stacks. 1 is fixed and the last one is adjustable.
The Slope Resistor in the 1st one is 56k. You could easily change this for an 82k resistor. This will introduce more treble & upper mids and remove some of the bass.

Try those and see if you like them.

As for the NFB, basically if you remove the NFB or add more resistance in series with it so that the amp sees less NFB in the phase inverter, it will become much louder and will break up much faster.
You will also notice that it feels like the Presence knob is on 200!
 
Monsta-Tone said:
Your amp has 2 tone stacks. 1 is fixed and the last one is adjustable.
The Slope Resistor in the 1st one is 56k. You could easily change this for an 82k resistor. This will introduce more treble & upper mids and remove some of the bass.
!

Ok I think that will be the next mod. Sorry about my ignorance but, Is this the same mod you mentioned here?

Monsta-Tone said:
Lead Channel Mods

Tone Stack Mods:
Right after V3A is the Tone Stack. The DC lead channel has 2 tone stacks, but this is the one that is adjustable with the pots.
1. The stock Tone Stack resistor is 82K. Changing this resistor will change the overall frequency response of the Tone Stack.
Lower value = More Bass
Higher value = Less Bass
I like 56K or even 47K if the speaker is really bright.
This mod really depends on the speakers you are using. I use the C-90 in my DC-5 combo, so I like 56K the best. When I used Vintage 30's, I went down to 47K.
If the amp is too dark for you, then you can go as high as 100K, but you might try the next mod 1st.

Also, about the 500pf silver mica instead of the ceramic cap mod would that be a bad place for a switch?... I'm thinking it would be cool to have switch in the back of the amp to take it from vintage to modern tones.

Thanx in advance!
 
Same mod, only this would be for the 1st tone stack instead of the 2nd one.

You can add a switch for the treble cap.
Remember though that this cap has high voltage on the input side, so the switch will pop unless you place a 10M ohm resistor across it.
I like to add 5-way mid sellector switches so that you can dial in just the right amount of sizzle.
The best way to do this is to place another capacitor in parallel with the existing capacitor.

You can go with these values and see which one you like the most:
250 pf
350 pf
500 pf
750 pf
1000 pf

When you add a capacitor in parallel, it will add to the value of the existing one.
You could easily try this in both tone stacks and see which one has more of an affect on your tone.

Be very careful though, like I said above, the Slope Resistor and the treble cap both have high voltage on them.
Drain the power supply caps and unplug the guitar every time before you reach in there.
It hurts bad if you mess up and forget!
 
oh I get it, so this mod would act before the adjustable tone stack instead of the first one you posted, killer!. This thread just keeps getting better!.
 
This was enjoyable reading. Thank you for that, Andy.

Now let's talk about the bias mod for the DC-3...I've read in other forums where folks have had problems. I just don't get it. It's not like it's simul-class... :?
 
Hey, I thought of another question (sorry to bug you so much). This one is about the Rhythm channel, as you said you have the B version, so hopefully this question is shared with other A version users.

Personally I think I can get a VERY good clean-clean tone outta the rhythm channel. I mean with the gain knob in 1 or 2 and master cranked, but if I try to use it as a mid-gain channel to play something like I don't know, Pearl Jam, Led Zep or something in that ball park, it just doesn't cut it 'cause even tho you have more than enough gain for it once you start to use the gain knob the tone becomes really round and lo-mid oriented kinda like an old marshall with really crapped out tubes.

What would you recommend for me and the other A version users?.

Thanx!
 
Try using the same settings that you use for clean and then pulling the gain pot boost.
Then, try adjusting it to get those tones.

Or....

Try turning the master way down and cranking the gain.
In this way, you are using it like most people use the gain and master on their lead channels.
 
Nop I have tried those things, and I still think I need to either lose some lo mids or pump the hi mid area.

BTW for the people thinking about the "blanket removal" mod , I recorded this last night with my old iphone ( don't expect good sound quality) just to show how the amp became violin-like in the lead channel.

http://www.youtube.com/watch?v=zxc1Rkd39To

Greetings from Santiago, Chile!
 
Yeah, most people just do the volume and fx loop mods, but I think your "blanket removal" mod is killer, and is the main reason why I keep bugging you for more ideas :lol:. Hopefully after watching the video more people will wanna try it.

In the "classic rock" department what I've settle for, is using the lead channel with the gain 1.5. I still wanna be able to use the the gain pot on the rhythm channel with muffling it.

When I use it clean-clean I usually crank the treble and presence pots, so a big pump in the high end won't really hurt, since I can allways back them off afterwards. Could you maybe suggest a starting point?.

I think the treble cap is 250pf, would it be a good idea to go 500pf? , the slope resistor is 150pf, how High would you go?


Cheers!
 
The 1st slope resistor is 56k.
The 2nd one is 82k.
I would make the 1st one 82k and see what happens.

Some vintage Fender amps go as high as 150k, I don't think I would go above 100k.
For most of my amps, I go in the opposite direction and take them both down to 56k, or even 47k.


For the cap, you can go as high as 750pf and still not get too shrill sounding. I like the lead tone with a 1000pf cap across the stock cap, but it's too thin for my rhythm parts.
Remember, with the treble cap mod, you have to have the treble and mids above half way before you will even notice a difference.
 
Hey I still haven't had the time to do any other mods. I wanted to ask you something since you know so much about these amps (I know I ask a lot of stuff).

The amp kinda of has a "spongy" feel to it when your playing in the lead channel, which is nice, I've played other amps with a really percusive feel. So I was wondering where is the spongyness coming from?... is it the fixed bias thing, just the brand of preamp tubes, the tannies?
 
Hey there;

This is truly wonderful stuff.
I just got a DC-5A that was modded by Voodoo Amps already, though I do not know what they did because it was before I took ownership (Volume mod at least).

Quite honestly, I have had several Mesa-Boogie Amps over the years and only kept them for days or even weeks before I sold them 'cause I could NEVER get a decent (Fender) clean sound out of them.

They always sound "boxy", mid-rangey, nasal and compressed to me compared to say, a Black Face Twin Reverb, Deluxe Reverb, Super Reverb or similar classic Fender.
My latest amp is a Hotrod Deluxe that, although it is PC board, ribbon cables and such, still has some nice Fender classic vibe and sound going on.

When I got the DC-5, I thought, well, OK, let's give yet another Boogie a try and see what it is capable of. Setting all the controls to their mid point, I plugged in with a Steinberger L-Series using EMGs and played for a bit.
ARRGH, there was that SAME Boogie compressed, boxey, mid-range squawk with NONE of the sparkle, bottom or brilliance that my Fender Hotrod Deluxe does so well.
I unplugged and prepared to sell yet another Boogie disappointment, and then, several days later, after doing some research on the forums, I was VERY confused and curious.

SO many people seemed to LOVE these little amps, that I figured that I would give it ONE more try. First, I dismantled the amp to inspect the innards and have a look about.
I was impressed with what I saw on the inside (good build quality) and even more confused that this thing would not get at least a little closer to Fender clean tones.

When I plugged it in next, I zeroed EVERY control first, and then began cracking the pots slowly from that zero point. WOW, was I surprised!
With the mid and bass on ZERO, and the presence and treble up above the mid-point, this amp actually sounded kind of glassy and clean in a Fender sort of way!

With a little more playing I dialed in quite a nice sound (clean) and then did the same with the OD channel, again, barely cracking the controls above zero.
Nice sustain at a realistic volume level. Hmmm, pretty good. Then I revisited the forums to find out more AND to see what other mods are available.

Now I am curious if anyone has one "definitive" repository hosting area for DC mods so that I do not have to go looking all through many forums to find them?
I can see that several people here have have done some serious homework and tech work on these amps and I am looking forward to some experimenting.

Thanks for this post and for the groundwork on these cool old amps~!
I am now a Mesa Boogie convert and looking forward to more and more...

AK
 
Hey, so I got the 500 silver mica cap mod with a switch in the back of the amp, it get's it a tiny bit tighter in the low end, more mids, but good mids not honky mids and definetly a better string separation, highly recommend the mod, I really don't think my iphone can record something to notice the difference 'cause is subtle

Also I had a guy do me a "tight" switch based on what the egnater amps do, now that's a killer mod specially if you use low tunnings, he told me he didn't use the mods monsta suggested, he was using some caps at the first gain stage or maybe before, but it really does what my old egnater use to do with the switch.

https://www.youtube.com/watch?v=69UzI1AGcVw <- if you go to about 1:25 the Egnater explains the switch
 
monsta-tone, i´m impressed!
i read both mod-threads and there are a lot of great ideas written down.

GAS is hitting me very hard yesterday as i tested a DC-5b, but there is one thing i was missing compared to my Roadster head:
the solo-level function.

is there any chance of having a switchable solo-level-function on a DC-5 amp?
let´s say i´ll do the FX-loop-mod and solder the cables to the send-jack, could i use the mix pot for adjusting the solo level?
and could i change the reverb-switch-jack to a TRS jack and make the reverb and the solo-level switchable?

would this be possible?
thanks for your advise on this.

and btw. did you found a solution for a switchable FX-loop already?
 
I answered the Solo function question in your PM.
Didn't see the footswitchable loop question, sorry.

If multiple switching functions are needed, I use one of these: https://taweber.powweb.com/store/chansword.htm
I usually get the Optical one, and replace the LDR's with Vactec 5C1's.
You could try this for the footswitchable loop.
Their low power relay board is cool too.

You will most likely have to add a 10M resistor across the item that you are switching to avoid popping.


On a side note, if you're gassing for a DC, mine is up for sale.
 
Monsta-Tone said:
I answered the Solo function question in your PM.
Didn't see the footswitchable loop question, sorry.

If multiple switching functions are needed, I use one of these: https://taweber.powweb.com/store/chansword.htm
I usually get the Optical one, and replace the LDR's with Vactec 5C1's.
You could try this for the footswitchable loop.
Their low power relay board is cool too.

You will most likely have to add a 10M resistor across the item that you are switching to avoid popping.
thanks a lot for this helpful answer!


On a side note, if you're gassing for a DC, mine is up for sale.
thanks for the offer, but i guess you´re located in the US and i live in germany. so i would need a step-down trany and shipping would be very expensive i think.
 

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