DSL 50 C12 mod advice please

Mike_j · 10-20-2009, 01:54 PM

Hi,
I been reading a fair bit about the C12 mod on DSL 50 heads and have 2 questions:
1. Does it add more "body" to the red channel bringing it a bit closer to the fullness of the green channel, and take out some of the thin high end fizz?

2. Realistically, how hard is it for a complete beginner to do? Is it just a case of unsoldering the capaciter?

Any help/comments appreciated. Thanks.

Wilder Amplification · 10-20-2009, 02:31 PM

Quote:

Originally Posted by Mike_j

Hi,
I been reading a fair bit about the C12 mod on DSL 50 heads and have 2 questions:
1. Does it add more "body" to the red channel bringing it a bit closer to the fullness of the green channel, and take out some of the thin high end fizz?

2. Realistically, how hard is it for a complete beginner to do? Is it just a case of unsoldering the capaciter?

Any help/comments appreciated. Thanks.

Unless you have a solid grasp on basic electronics, I advise against attempting anything inside of a valve amp simply due to the high voltages that exist inside of them (up around 400-500 volts...much higher than what comes out of your wall). I suggest you take it to a reputable tech who's familiar with valve amps.

As far as the mod, I have no idea since I've never played much through a DSL amp other than to test one out after fixing it.

Mike_j · 10-22-2009, 05:10 AM

Awesome. Thanks for that.

jcmjmp · 10-22-2009, 08:44 AM

C12 is a relative to a specific given set of board revision/issue numbers. It should be pretty simple to do but unless you know what the cap is supposed to do, it will be hard to determine if you're removing the correct component.

what is it that you're trying to fix? You want more bass on the Red Channel? Beware - too much bass on a high gain channel can lead to flubbyness.

Mike_j · 10-22-2009, 12:50 PM

jcmjmp

I'm finding the red channel too "thin". I'd like to get it a bit more full sounding.
I'm taking it to my tech guy tonite but I'd like to be able to offer up some suggestions to him.

jcmjmp · 10-22-2009, 12:55 PM

Quote:

Originally Posted by Mike_j

jcmjmp

I'm finding the red channel too "thin". I'd like to get it a bit more full sounding.
I'm taking it to my tech guy tonite but I'd like to be able to offer up some suggestions to him.

Maybe your tubes need changing?

I can't describe the lead channel as "thin". Do you have an eq pedal or rack mount? If so, experiment with it in the loop and try to figure out which frequencies fill the sound up and take it from there.

"Thin" sounding is highly subjective.

Wilder Amplification · 10-22-2009, 01:49 PM

Not knowing much about the DSLs having never owned one, according to the schematic for the DSL50, from what I can see C12 is a 470pF cap in the reverb recovery stage. If that's the case, I doubt a mod having anything to do with that cap will help you.

jcmjmp · 10-22-2009, 02:06 PM

Quote:

Originally Posted by Wilder Amplification

Not knowing much about the DSLs having never owned one, according to the schematic for the DSL50, from what I can see C12 is a 470pF cap in the reverb recovery stage. If that's the case, I doubt a mod having anything to do with that cap will help you.

Wilder: As I've already stated in an earlier post, C12's location and function is different depending on the board you're looking at and the issue/rev you have...

He's probably referring to the treble bleed cap on VR3, on the control board.

Wilder Amplification · 10-22-2009, 02:18 PM

Quote:

Originally Posted by jcmjmp

Wilder: As I've already stated in an earlier post, C12's location and function is different depending on the board you're looking at and the issue/rev you have...

He's probably referring to the treble bleed cap on VR3, on the control board.

Based on this, am I to assume the component IDs on the master schematics mean nothing due to the few board revisions they've had on these amps over the years?

Or do they come up with updated schematics with revised component IDs everytime they revise a board?

jcmjmp · 10-22-2009, 04:52 PM

1) There's the HW board rev - JCM2-60-00 where the "00" is the rev number. This is a different physical board and layout, which also means different component IDs.
2) There's the Issue number. This is a "soft" change where certain component values might change, but its essentially the same board.

Schematics for the DSL specify which HW board and issue number they are for.

I'm actually working on a DSL info page that will contain some of this info, along with upgrade components and tips/tricks.

www.lydian.ca

If just have to get over my chronic insomnia and get some energy back before I can start putting some real time on the page. I also want to get my PT/OT protos tested.

Mike_j · 10-22-2009, 05:03 PM

Quote:

Originally Posted by jcmjmp

Maybe your tubes need changing?

I can't describe the lead channel as "thin". Do you have an eq pedal or rack mount? If so, experiment with it in the loop and try to figure out which frequencies fill the sound up and take it from there.

"Thin" sounding is highly subjective.

Thin, fizzy, no body of fullness to the tone. I want the red channel a little closer to the tone of the green but still retain some overdrive. Sorry, I can't be any clearer.

jcmjmp · 10-22-2009, 05:32 PM

Quote:

Originally Posted by Mike_j

Thin, fizzy, no body of fullness to the tone. I want the red channel a little closer to the tone of the green but still retain some overdrive. Sorry, I can't be any clearer.

A bad tube could cause that, which is why I suggested a tube swap.

Looking for more bass? Low Mids? High Mids? Does it sound like you want with the deep switch in?

Mike_j · 10-22-2009, 06:01 PM

Quote:

Originally Posted by jcmjmp

Does it sound like you want with the deep switch in?

No. The red channel still sounds pretty gutless. Yes, the tubes probably do need changing and I'll get tech guy to do that. I'm not sure that would explain the tone disparity between the 2 channels. Either my amp is fucked or it is the way the amp is designed.

Buggs.Crosby · 10-23-2009, 03:58 PM

Read this whole thread....there is lots of info and i'm sure you will find what your looking for in it....15 pages though
The Marshall Amp Forum: • View topic - DSL100 too bright compared to my 401, any ideas on modding?

Mike_j · 10-24-2009, 04:13 AM

Got it sorted. Thanks all for the help.
Took it to my tech guy who suggested changing the capacitors (that he felt were low quality), test it out in a band and recording situation BEFORE deciding to start pulling things out.
I felt it was good advice so I'll go with that. He also thought the power transformer was pretty shitty too and that could be in for a change a bit further down the track.

jcmjmp · 10-24-2009, 10:58 AM

Quote:

Originally Posted by Mike_j

Got it sorted. Thanks all for the help.
Took it to my tech guy who suggested changing the capacitors (that he felt were low quality), test it out in a band and recording situation BEFORE deciding to start pulling things out.
I felt it was good advice so I'll go with that. He also thought the power transformer was pretty shitty too and that could be in for a change a bit further down the track.

Good Idea.

MaidenStrat02 · 10-24-2009, 10:54 PM

The C12 mod is pretty much automatic these days. Some people swap out different values, I clipped it. Cuts down on that harsh treble in the Ultra channel

Ken · 10-29-2009, 01:22 PM

Hmm...on my DSL 50 the ultra channel is noticable brighter than the green channel like everyone talks about but it's not "harsh" at all. With the added distortion I like that brightness; to my ears it enhances the tone just right. I wouldn't change it.

Frankly I don't see the point on having both channels sound the same except for overdrive; I've read complaints about the shared EQ meaning you can't make them similar and I have no problem with it. It IS a TWO channel amp after all, not a one channel with a massive gain knob. Both channels SHOULD sound different!

Ken

10-20-2009, 01:54 PM	#1 (permalink)
Mike_j Senior Member Join Date: Mar 2009 Location: Melbourne, Australia Posts: 125	DSL 50 C12 mod advice please Hi, I been reading a fair bit about the C12 mod on DSL 50 heads and have 2 questions: 1. Does it add more "body" to the red channel bringing it a bit closer to the fullness of the green channel, and take out some of the thin high end fizz? 2. Realistically, how hard is it for a complete beginner to do? Is it just a case of unsoldering the capaciter? Any help/comments appreciated. Thanks. __________________ "...the world is your oyster but your future's a clam..."

10-22-2009, 05:10 AM	#3 (permalink)
Mike_j Senior Member Join Date: Mar 2009 Location: Melbourne, Australia Posts: 125	Re: DSL 50 C12 mod advice please Awesome. Thanks for that. __________________ "...the world is your oyster but your future's a clam..."

10-22-2009, 08:44 AM	#4 (permalink)
jcmjmp Senior Member Join Date: Nov 2008 Posts: 1,341	Re: DSL 50 C12 mod advice please C12 is a relative to a specific given set of board revision/issue numbers. It should be pretty simple to do but unless you know what the cap is supposed to do, it will be hard to determine if you're removing the correct component. what is it that you're trying to fix? You want more bass on the Red Channel? Beware - too much bass on a high gain channel can lead to flubbyness.

10-22-2009, 12:50 PM	#5 (permalink)
Mike_j Senior Member Join Date: Mar 2009 Location: Melbourne, Australia Posts: 125	Re: DSL 50 C12 mod advice please jcmjmp I'm finding the red channel too "thin". I'd like to get it a bit more full sounding. I'm taking it to my tech guy tonite but I'd like to be able to offer up some suggestions to him. __________________ "...the world is your oyster but your future's a clam..."

10-22-2009, 04:52 PM	#10 (permalink)
jcmjmp Senior Member Join Date: Nov 2008 Posts: 1,341	Re: DSL 50 C12 mod advice please 1) There's the HW board rev - JCM2-60-00 where the "00" is the rev number. This is a different physical board and layout, which also means different component IDs. 2) There's the Issue number. This is a "soft" change where certain component values might change, but its essentially the same board. Schematics for the DSL specify which HW board and issue number they are for. I'm actually working on a DSL info page that will contain some of this info, along with upgrade components and tips/tricks. www.lydian.ca If just have to get over my chronic insomnia and get some energy back before I can start putting some real time on the page. I also want to get my PT/OT protos tested.

10-23-2009, 03:58 PM	#14 (permalink)
Buggs.Crosby Member Join Date: May 2009 Posts: 90	Re: DSL 50 C12 mod advice please Read this whole thread....there is lots of info and i'm sure you will find what your looking for in it....15 pages though The Marshall Amp Forum: • View topic - DSL100 too bright compared to my 401, any ideas on modding?

10-24-2009, 04:13 AM	#15 (permalink)
Mike_j Senior Member Join Date: Mar 2009 Location: Melbourne, Australia Posts: 125	Re: DSL 50 C12 mod advice please Got it sorted. Thanks all for the help. Took it to my tech guy who suggested changing the capacitors (that he felt were low quality), test it out in a band and recording situation BEFORE deciding to start pulling things out. I felt it was good advice so I'll go with that. He also thought the power transformer was pretty shitty too and that could be in for a change a bit further down the track. __________________ "...the world is your oyster but your future's a clam..."

10-24-2009, 10:54 PM	#17 (permalink)
MaidenStrat02 Senior Member Join Date: Nov 2008 Location: The Rue Morgue Posts: 147	Re: DSL 50 C12 mod advice please The C12 mod is pretty much automatic these days. Some people swap out different values, I clipped it. Cuts down on that harsh treble in the Ultra channel __________________ Gibson '07 SG 2 Customized Fender Strats Modded DSL50 MM choke,PT&OT Carvin 2x12 V30's Pitchblack-LPB-1-Budda Wah-TS808. Loop= 108EQ-Modded Phase 90-Carbon Copy-George L cables-Voodoo Pedal Power 2 Plus-Pedaltrain board Contact for Facebook request

10-29-2009, 01:22 PM	#18 (permalink)
Ken Senior Member Join Date: Feb 2009 Location: Arlington Heights, IL Posts: 607	Re: DSL 50 C12 mod advice please Hmm...on my DSL 50 the ultra channel is noticable brighter than the green channel like everyone talks about but it's not "harsh" at all. With the added distortion I like that brightness; to my ears it enhances the tone just right. I wouldn't change it. Frankly I don't see the point on having both channels sound the same except for overdrive; I've read complaints about the shared EQ meaning you can't make them similar and I have no problem with it. It IS a TWO channel amp after all, not a one channel with a massive gain knob. Both channels SHOULD sound different! Ken

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