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

DC-2, 3, 5, 10
50 Caliber

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Monsta-Tone
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Re: DC Mods - Revisited...........Sort of.............

Post by Monsta-Tone » Mon Nov 26, 2012 10:00 am

Maybe re-read the whole thing. I was talking about adding an LDR to the amp so that people could install the Solo function that is on most of the newer amps.

I was trying to help people.
Elvis said.......
Amp techs do get shocked. :shock:

BlackBoxy
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Re: DC Mods - Revisited...........Sort of.............

Post by BlackBoxy » Mon Nov 26, 2012 10:50 am

mismatched stuffs, never mind!

solo function? i use eq to boost, and a pre amp!

a solo through the output via a LDR could be usefull , right , with a pot bleeding some power to the ground,
wouldn't it change the 6l6 attack tone?

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Re: DC Mods - Revisited...........Sort of.............

Post by Monsta-Tone » Mon Nov 26, 2012 11:00 am

I didn't really like it all that much. Seemed to work great on the Heartbreaker and a few Rectos that I added it to, but on the DC I think you need as much juice going to the power tubes as you can get.
Elvis said.......
Amp techs do get shocked. :shock:

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Re: DC Mods - Revisited...........Sort of.............

Post by BlackBoxy » Tue Nov 27, 2012 5:08 am

i look for less OD in the rythm channel without changing the tone, at 4 on gain it gets crunch, what would be better, increasing 150k that ground tone stack (near boost gate) or reducing 470k on V4a pin 2 divider?

i got the dc5a ..

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Re: DC Mods - Revisited...........Sort of.............

Post by Monsta-Tone » Tue Nov 27, 2012 10:04 am

Take a look at the DC-5b drawing. If you look closely, there are only a few parts that are different. The B has much more headroom.
One of the things I did a lot for people was convert the A to the B clean channel.
Elvis said.......
Amp techs do get shocked. :shock:

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Re: DC Mods - Revisited...........Sort of.............

Post by BlackBoxy » Thu Nov 29, 2012 12:03 pm

Monsta-Tone wrote:Take a look at the DC-5b drawing. If you look closely, there are only a few parts that are different. The B has much more headroom.
One of the things I did a lot for people was convert the A to the B clean channel.

V4 pin 2 voltage divider 220k-470k for the A and /10 3.3M-33k for the B and pin 8 15uf for the B ?


thanx Monsta

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Re: DC Mods - Revisited...........Sort of.............

Post by Monsta-Tone » Thu Nov 29, 2012 11:03 pm

To change DC version A clean channel to Version B:

V1a - Pin 1
- Add .001mf cap across grid resistor
- Change grid resistor from 100k to 150k

V1a - Pin 2
- Remove 500pf cap to ground

V1a - Pin 3
- change 3.3mf cap to 1mf cap (I usually use electrolytic here, make sure you watch polarity)

Gain Pot
Change "Bright Cap" from 120pf to 75pf

V4b - Pin 7 (just after Gain Pot)
- Remove 82pf cap to ground

V4b - Pin 8
- Change .47mf cap to 15mf

V4a - Pin 2
- Change 220k resistor to 3.3M resistor w/39pf cap across it
- Change 470k resistor (to ground) to a 330k resistor

Resistor just before Channel Master Volume
- Change from 680k to 330k resistor

These changes make the clean channel have much more headroom than the A version. To my ears, they sound much more like a Fender.
Sometimes I experiment and only make some of the changes, or make them 1 at a time to see exactly what effect each one has.
Some of them (especially the V1a Pin 1) will add gain if you do not do some of the ones at the end, like changing the 220k after V4a Pin 2 to a 3.3M.
Experiment, have fun, it's great mad scientist stuff!
Elvis said.......
Amp techs do get shocked. :shock:

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Re: DC Mods - Revisited...........Sort of.............

Post by BlackBoxy » Fri Nov 30, 2012 1:24 pm

i think i'll go for a 80k on v1 to the place of 100k , and look at master pot resistor, most of the headroom is made by the weakier (inpedance) just before Master pot which with the 680k makes a voltage divider , i'll look at this because i really love my clean tone, got two sylviania black long plates D getter on V1 and V4 , its just i got crunch too early for my taste !

thx Monsta!

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Re: DC Mods - Revisited...........Sort of.............

Post by BlackBoxy » Mon Dec 03, 2012 11:28 am

Well, i just finished upgrading/mods of my dc5!

all electrolytics caps been changed , all optocouplers optoisolators and relays are brand new ones, all 9pins and octo tubes sockets changed too!
most of Monsta great mods been done +first lead filter stack before gain pot with orange drop 500p/0.1/0.047, great mod, last one replaced 680k by a 330k more headroom, changed presence ceramic cap with a mustard tad 150nf, and changed 220R 5w blue voltage 50v, beware this resistor it burn on and drys the pcb, especially after 20 years , i modded chan footswitch to work in the place of reverb on stereo jack 2 switch FTsw !

got old Winged "S" 6l6gc plugged in, with v1/v4 sylvania black plates D getters NOS, V2 mullard cv4004 NOS V3 RCA long black plates NOS, V5 grey long plates sylvania, V6 mullard NOS cv4024!

i really like my tone, its a tone i was looking for, at bedroom or club's volume!

Would like to thanks all pundits bringing knowledges about this amp!

regards

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Re: DC Mods - Revisited...........Sort of.............

Post by motormenace » Thu Jan 24, 2013 5:44 pm

Picking up a DC-10 head in trade for my Rectoverb combo. These mods will defiantly be done to it.

Also, I was noticing the reverb mod and was wondering if it will get me close to a Twin Reverb sound?

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Re: DC Mods - Revisited...........Sort of.............

Post by BlackBoxy » Fri Jan 25, 2013 3:52 am

motormenace wrote:Picking up a DC-10 head in trade for my Rectoverb combo. These mods will defiantly be done to it.

Also, I was noticing the reverb mod and was wondering if it will get me close to a Twin Reverb sound?
absolutly, very close!

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Re: DC Mods - Revisited...........Sort of.............

Post by motormenace » Fri Jan 25, 2013 9:55 am

Very cool! Thanks! Now I defiantly can't wait to dig into the amp! :D

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Re: DC Mods - Revisited...........Sort of.............

Post by crguti » Wed Jan 30, 2013 8:26 am

BlackBoxy wrote:i really like my tone, its a tone i was looking for, at bedroom or club's volume!
clips or you don't have a good tone. :roll:

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Re: DC Mods - Revisited...........Sort of.............

Post by BlackBoxy » Wed Jan 30, 2013 1:59 pm

crguti wrote:
BlackBoxy wrote:i really like my tone, its a tone i was looking for, at bedroom or club's volume!
clips or you don't have a good tone. :roll:
well shakespeare was right "Something is rotten in the state of Denmark"

:D

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Re: DC Mods - Revisited...........Sort of.............

Post by crguti » Fri May 24, 2013 7:19 am

Monsta-Tone wrote:Lead Channel Mods
More or Less Gain:
Between V1B & V2A there is a Voltage Divider (page 5 of the drawing).
You will see a 150K resistor going from the signal path to ground. Change this resistor.
Lower value = Lower gain
Higher value = More gain
I like 220K. 330K is really nice too, but starts to get a little bit mushy.
Any more than this and it gets really mushy but has gobs of gain.
What is the appropiate power rating of the resistor?

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