C+ Bright Reduction - De-mod?

[#2121313]

I have heard that this can be done rather easily - but how would one perform this?

I have a DRG that I have been told (actually by Boogiebabies) that has the Bright Reduction Mod done on it. I'd like to reverse this mod if possible, if this is something I can do?


















I uploaded a few pics, I'm not a tech so I don't even know where to look lol. But with the right direction I should be good to go, I do work on guitars a bit (my own) and am in the telecommunications/audio video trades...

Anyone able to assist in providing direction?

 

[Boogiebabies]

1. If cap is labeled 10pf, change to 20pf.
2. Clip one leg of the cap and lift it up and out of the way.

 

[DaveP]

Hi Mike, I wasn't aware this one had the bright mod. Sorry. I would have disclosed that but I didn't know. I am interested in this reversal also. I purchased the C+ Miguel had for sale here and he mentioned it had the mod done.
BB, shouldn't the cap be discharged before clipping it? Always error on the side of caution, less surprises that way. ( :shock: )

 

[Boogiebabies]

I looked the photo's over before he bought it and explained the bright mod.
I knew this amp well as I have it's identical twin. I think the serial numbers are
1 or 2 digits apart.

The caps discharge to 9V about 40 seconds after you turn them off. There are two 150K resistors
on the power board between the caps that bleed the voltage to ground. After this time you can safely work
inside the amp. If you are feeling any anxiety, wait another minute and you will be fine.

 

[#2121313]

Hi Mike, I wasn't aware this one had the bright mod. Sorry. I would have disclosed that but I didn't know. I am interested in this reversal also. I purchased the C+ Miguel had for sale here and he mentioned it had the mod done.
BB, shouldn't the cap be discharged before clipping it? Always error on the side of caution, less surprises that way. ( :shock: )

No prob Dave, I knew it was a legitimate mistake, that's why I never brought it up - it's totally cool, here!

BTW - Dave's a hell of a packer, heavily padded, nice thick box, tubes separately wrapped and tucked away, even put little pads between the PT and bottom of shell to keep things as snug as possible. Not a scratch or ding arrived as mint as in the photo's!

1. If cap is labeled 10pf, change to 20pf.

The one circled?

2. Clip one leg of the cap and lift it up and out of the way.

The larger orange one?
(btw is it a Sprague?)

Yeah Boogiebabies, which of the two circled caps should I clip? And what do you mean by "If cap is labeled 10pf, change to 20pf."?

 

[JOEY B.]

They are both small, brown ceramic disc capacitors in the photos.

Some food for thought:

I have two original DRG IIC+ amp heads, one with the mod and one without. When I had them tubed the same, I could use the pull bright(Vol 1) on the one with the mod as well as a slightly higher Volume 1 setting to get them to sound very similar. Just sayin' this before you break out the iron. 8)

 

[#2121313]

They are both small, brown ceramic disc capacitors in the photos.

Some food for thought:

I have two original DRG IIC+ amp heads, one with the mod and one without. When I had them tubed the same, I could use the pull bright(Vol 1) on the one with the mod as well as a slightly higher Volume 1 setting to get them to sound very similar. Just sayin' this before you break out the iron. 8)

Funny, cause that's what I'm experimenting with right now, I keep the Treble, Master 1 & Lead Drive always pulled. I'm just now experimenting with pulling the Lead Master & the Vol1 to try and achieve a brighter tone...Not sure which of the two I prefer to pull...I'm also running my presence at 4.5...Good point tho, thanks Joey B.

I really dig the brightness tho so I may ultimately opt for the de-mod, I just wanna get a complete handle on what needs to be done first, then pull out the chassis and see if I can do it without messing things up! That's what's ultimately important! lol

 

[DaveP]

BTW - Dave's a hell of a packer, heavily padded, nice thick box, tubes separately wrapped and tucked away, even put little pads between the PT and bottom of shell to keep things as snug as possible. Not a scratch or ding arrived as mint as in the photo's!

You welcome. I believe if you take that extra step in packing it right it really avoids the hassle of filing claims and the disappointment the buyer feels when they open an expensive purchase only to find it busted up. Some people haven't figured out the packing peanuts turn to dust and your amp becomes a bouncing ball in the box. Pack it tight and it arrives in the same condition. (I hope) LOL

 

[Boogiebabies]

1. If cap is labeled 10pf, change to 20pf.

The one circled?

2. Clip one leg of the cap and lift it up and out of the way.

The larger orange one?
(btw is it a Sprague?)

Clip the leg of the circled #2 brown .001 cap on the side facing the power amp.
It has a pad for those willing to desolder, but you will need to bend the 270K resistor to the
left and the .02 Orange Drop to the right to get at the backside solder pad.
Happy Wire Burning....

 

[Boogiebabies]

They are both small, brown ceramic disc capacitors in the photos.

Some food for thought:

I have two original DRG IIC+ amp heads, one with the mod and one without. When I had them tubed the same, I could use the pull bright(Vol 1) on the one with the mod as well as a slightly higher Volume 1 setting to get them to sound very similar. Just sayin' this before you break out the iron. 8)

Funny, cause that's what I'm experimenting with right now, I keep the Treble, Master 1 & Lead Drive always pulled. I'm just now experimenting with pulling the Lead Master & the Vol1 to try and achieve a brighter tone...Not sure which of the two I prefer to pull...I'm also running my presence at 4.5...Good point tho, thanks Joey B.

I really dig the brightness tho so I may ultimately opt for the de-mod, I just wanna get a complete handle on what needs to be done first, then pull out the chassis and see if I can do it without messing things up! That's what's ultimately important! lol

This amp may benefit from the removal of the .001 cap. It only has one of those IIC's with all harsh Green Ceramic disc caps, so it does not fall into
the heinous crunch category. If the cap # 1 is 10pf, it won't make a mind altering difference.

 

[av8or3]

Hey Ed,
Who has "Most Heinous" in the heinous crunch category? :wink: :wink:
Just wonderin'
Jim

 

[#2121313]

This amp may benefit from the removal of the .001 cap. It only has one of those IIC's with all harsh Green Ceramic disc caps, so it does not fall into
the heinous crunch category. If the cap # 1 is 10pf, it won't make a mind altering difference.

Thanks Ed.

Lemme better understand...If I remove the .001 cap, your saying this will then put me into heinous crunch territory?

Is that advised to do instead of the bright de-mod or in conjunction with to achieve the additional crunch/gain?

MERRY CHRISTMAS!

 

[Boogiebabies]

This amp may benefit from the removal of the .001 cap. It only has one of those IIC's with all harsh Green Ceramic disc caps, so it does not fall into
the heinous crunch category. If the cap # 1 is 10pf, it won't make a mind altering difference.

Thanks Ed.

Lemme better understand...If I remove the .001 cap, your saying this will then put me into heinous crunch territory?

Is that advised to do instead of the bright de-mod or in conjunction with to achieve the additional crunch/gain?

MERRY CHRISTMAS!

Removing the .001 cap will give a bit more brightness and gain perception. You should not be in the heinous crunch area.

 

[Boogiebabies]

Hey Ed,
Who has "Most Heinous" in the heinous crunch category? :wink: :wink:
Just wonderin'
Jim

Not you !!! :mrgreen:

 

[JOEY B.]

Hey Ed,
Who has "Most Heinous" in the heinous crunch category? :wink: :wink:
Just wonderin'
Jim

Not you !!! :mrgreen:

How about the "hy-anus" crunch? :lol: :lol: :lol: Get it. (sounds like ass)
:wink:

 

[#2121313]

Here is another picture that shows the cap (it's easy to recognize from this angle it has a big glob of glue on it) that I need to clip to do the bright reduction, de-mod, am I clipping the leg that is on the side facing the front face of the amp (Vol1, Treb, Bass, Mid etc knobs...) or the leg facing the rear of the amp?



CAP#1 (Extra Shred) - This reads 10J 1KU, should I remove entirely?

CAP#2 (Bright De-Mod) - Which leg do I clip?

 

[chipaudette]

I found that the 0.001u cap (the one labeled "2" in Boogiebabies's photos) has a very strong effect on the sizzle/harshness of the lead channel.

My amp is a IIC upgraded to a IIC+ by MikeB at Mesa. It came with the 0.001u (aka 1000pF) from Mesa. While I like its smoothness, there are times when I want more sizzle. Like you, I wanted to make my amp a little brighter.

But, instead of just clipping the 1000pF cap out of the circuit, I decided to put a switch in the back of my amp. I put the swtich in place of the Slave Out jack. The switch lets me bring the 1000pF cap into or out of the circuit as I desire. Therefore, I can have either the stock (1000pF) sound or the more sizzly sound (no cap).

It turns out that I didn't like the no-cap sound at all. It was too harsh for me. So, instead of no cap, I wired in a small cap that gets me an intermediate value( 350pF). Now, my switch goes between the original 1000pF and the new 350 pF. The 350pF setting is currently my favorite. I like it a lot better than no-cap and I like it for many situations better than 1000pF.

For reference, the schematics that I've seen for the Mark IV show a 500 pF cap in this location. I haven't yet tried 500pF. It should sound slightly smoother (less sizzle) than my 350 pF setting. I'm thinking that 500 pF might be very nice indeed.

So, as you do this experiment yourself, be aware that your choices are NOT just 1000pF or nothing. You can try intermediate values to get you a sound in between. Also, by just cutting the cap out of the circuit, you can't actually do an A/B comparison to really decide which you like better. If you have any skills with electronics at all, you should consider adding a switch. You can always pull it out and hardwire your favorite choice once you've made your decision.

Chip

 

[#2121313]

Many good points Chip. Thanks for your input. Truth is, I'm not quite that great with a soldering iron, I'm decent in guitar wiring and in other similar areas but not so much in electronics and circuit boards, the space is a bit tight for my skill set.

But I do however appreciate your advise, it sound very logical to me. I definitely want to maintain the smoothness of my tone but at the same time I'd also like that extra brightness..

I'd still like to go ahead with the bright de-mod.

If anyone else has any info on the other cap, labeled "#1" in Boogiebabies pic, I'd be interested in feedback on tone with that cap and without, maybe also mention what model C+ you have and whether it has the bright mod done....

Thanks.

I still need clarification on:

Which leg to clip for the de-mod?

 

[#2121313]

Many good points Chip. Thanks for your input. Truth is, I'm not quite that great with a soldering iron, I'm decent in guitar wiring and in other similar areas but not so much in electronics and circuit boards, the space is a bit tight for my skill set.

But I do however appreciate your advise, it sound very logical to me. I definitely want to maintain the smoothness of my tone but at the same time I'd also like that extra brightness..

I'd still like to go ahead with the bright de-mod.

If anyone else has any info on the other cap, labeled "#1" in Boogiebabies pic, I'd be interested in feedback on tone with that cap and without, maybe also mention what model C+ you have and whether it has the bright mod done....

Thanks.

I still need clarification on:

Which leg to clip for the bright de-mod?

 

[#2121313]

I still need clarification on:

Which leg to clip for the de-mod?

I don't think it matters. Clipping either one will take it out of the circuit.

The reason I ask is because Boogiebabies mentioned:

Clip the leg of the circled #2 brown .001 cap on the side facing the power amp.

But I do not now where the power amp is to reference?