DC gain structure... more Mark or Recto?

DC-2, 3, 5, 10
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groovebelly
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DC gain structure... more Mark or Recto?

Post by groovebelly » Tue Jan 06, 2015 6:47 pm

I just sold off a DC3, but every time I listen to recordings I made with it, I love the grind in the distortion. My new MkV:25 is great... but, it's different. It doesn't seem to have the grind or edge that the DC had...

Is the DC distorted sound more Rectifier in nature? Does the newer Express series capture that same sound or has it mutated away from the original DC tones? Is the Mark the target tones for the DC?
Stiletto Ace Head
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Widebody closed back C90
Widebody 3/4 back 1x12 C90
mini rec cab stack

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Markedman
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Re: DC gain structure... more Mark or Recto?

Post by Markedman » Tue Jan 06, 2015 10:27 pm

That amp has Mark lV cleans and Rectifier gain, they make a great combo with a 4X12 cabinet. Your guitar of choice will be critical to the final tone, especially the low end chug.
JP2C, Mark llC++ DG, Mark IV-A/B.

Liquids
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Re: DC gain structure... more Mark or Recto?

Post by Liquids » Wed Feb 04, 2015 11:54 am

From the schematics, the lead voicing is probably more in the vein of the Mark series, but with some voicing choices that could be considered a bit Recto like, or entirely it's own thing compared to those two. To the ear--tonally--depending on how one EQs it, or even how one hears it, I'm sure some would swear up and down that it's more Recto, and others would do the same in suggesting it is more Mark style.

To me, the DC series 4x tube-stage lead channel is very Boogie. However, it varies distinctly to the degree that it's hard to feel it is convincingly "just" a Mark series variant or a Recto variant from a circuit standpoint.

Some differences of the DC Lead topology as compared to the Mk lead circuits:

- Obviously the DC only has one gain control, where the Mk type usually has two. In the DC, you could say that compared to a Mk amp, the absent gain/volume control and typical EQing between the 1st and 2nd tube gain stage are set by resistors and capacitors without any external control pot/knobs. The location of the DC's gain pot is fairly unique given that it's the only gain control in that circuit, but it IS right where the Mark series "lead drive" controls are ususally located.

- The passive EQ controls in the Mark amps are usually between the 1st and 2nd tube stage (Mark I's have it between 2nd and 3rd stage in 'lead mode'). In the DC amps, there is fixed component EQ shaping between stage 1 and 2 instead. Then there is an added internal EQ network between the 2nd stage and 3rd stage (like where it would be for a Mark I), but it is not externally controllable. It also seem to function primarily as a gain cut rather than do too much tone shaping, but I'm sure the somewhat subtle EQing it does is an important part of the sound of the DC or it wouldn't be there.

- The passive control panel EQ in the DC is after the 4th stage--at the end--"like a Marshall" and like a Rectifier there. And in the DC, a graphic EQ follows that too, so that part is a bit unique.

- The DC has much lower voltage on the preamp tubes than most amps, especially Mk amp and Recto type amps. This would typically make the gain more compressed, yield a different feel, and different "fidelity" than higher voltage circuits like the Mark series of Recto. The DC-3 has an especially low voltage preamp. The DC-5 suggest 'medium' preamp voltages like a JCM800, still lower than Mark or Rectos.

- The DC lead circuit uses small cathode capacitors in two of the Lead circuit's four tube stages. These caps shape the low frequency gain, or the apparent 'shape,' feel, and tone of the midrange to the ear. So the DC is likely going to be tighter than a Mark series amp on that account. In some ways the DC is a bit more like a Recto circuit in this particular regard, compared to the Mark amps. The Mark amps mix it up a bit, but use significantly larger value cathode bypass caps in at least 2 places for a *different* (less tight) low end feel and midrange grind/fatness/flub(?) than the Mark series amps, all else being equal--though it isn't.

- THE hallmark of a Rectifier and "those" type of lead preamps is a very drastic and distinct way of biasing the 3rd tube (usually), which causes it to distort in a rather drastic and distinct way. The DC lead preamp does NOT follow the Recto here, and since that is one of the Recto's most distinct circuit characteristics, this keeps the DC further from Recto land circuit-wise.

All said, it might be fair to say it borrows from both, and it's fair to say that, circuit-wise, the DC is unique enough in enough ways to be it's own thing, while remaining distinctly Boogie.
Last edited by Liquids on Wed Feb 04, 2015 4:37 pm, edited 1 time in total.

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fusguitar
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Re: DC gain structure... more Mark or Recto?

Post by fusguitar » Wed Feb 04, 2015 3:56 pm

@Liquids
Mate you killing me!!!!
So much info on that one.
I don't have a clue about electronics but i took an idea what's happening inside a dc.
I have the 50w combo and the 100w head and i use to have the Roadster.
I can say that the gain is in between the recto and a mark even if the specs says only recto.
No flubby lows, gain is tight, articulated, organic.
keep on...
:D :D :D :D :D
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Lonestar Classic head v2, DC-5b combo, 50/50 power amp, 2x12 3/4 back cab 180w, Abacus midi foot controller

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Roadster head, Triaxis (x2), DC-5b combo, 2x50 power amp, F50 combo

Liquids
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Re: DC gain structure... more Mark or Recto?

Post by Liquids » Wed Feb 04, 2015 4:29 pm

fusguitar wrote:@Liquids
So much info on that one.
I don't have a clue about electronics but i took an idea what's happening inside a dc.
I have the 50w combo and the 100w head and i use to have the Roadster.
I can say that the gain is in between the recto and a mark even if the specs says only recto.
No flubby lows, gain is tight, articulated, organic.
keep on...
:D :D :D :D :D
I figured the tech types could get the details and the non-techs might get the info about the "results" of the various technical differences noted "between the lines." Sorry. Thanks for reading though.

Landing somewhere unique, somewhere between the recto and the mark is what I expected, given that I've not played a DC-5/DC-10, and only looked at the circuit...hoping that came across in the end. The specs definitely don't "say only recto."

And again, I think with the EQ etc, one could probably make the DC's tone lean further toward Mark or Recto as desired, even if not quite the same.

Specs definitely indicate trying to keep the gain tight. I would imagine that some could feel the gain is "too tight" compared to a Mark series amp by comparing the circuits, but hey, they're just different, and these are all matters of taste!

Cheers.

BlackBoxy
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Re: DC gain structure... more Mark or Recto?

Post by BlackBoxy » Thu Feb 05, 2015 5:24 am

Liquids,

Dc is a 5x tube stage , one triode V1 two triodes V2 two triodes V3!


used to play with my mate who play a MkIV, they are closer overdriven tones than rectifier to our ears!

Liquids
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Re: DC gain structure... more Mark or Recto?

Post by Liquids » Thu Feb 05, 2015 1:20 pm

BlackBoxy wrote:Liquids,
Dc is a 5x tube stage , one triode V1 two triodes V2 two triodes V3!
Well, schematics say the lead stage is V1b-V2a-V2b-V3a, just 4 triode stages, which is all I have for reference.

The V3b triode is effects loop return, and V1a is in the clean channel...

BlackBoxy
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Re: DC gain structure... more Mark or Recto?

Post by BlackBoxy » Fri Feb 06, 2015 5:12 am

Liquids wrote:
BlackBoxy wrote:Liquids,
Dc is a 5x tube stage , one triode V1 two triodes V2 two triodes V3!
Well, schematics say the lead stage is V1b-V2a-V2b-V3a, just 4 triode stages, which is all I have for reference.

The V3b triode is effects loop return, and V1a is in the clean channel...
V3b is comun to each chanel , witch make a 5th stage

groovebelly
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Re: DC gain structure... more Mark or Recto?

Post by groovebelly » Fri Feb 20, 2015 1:44 am

Liquids...

Wow!!!

Everything is suddenly clear!?!

Thanks for the help understanding the gain structures.
I had heard a little about the tone stack and gain placement in the preamp, but nothing to that degree.
Thanks again
Stiletto Ace Head
Mark V25
Widebody closed back C90
Widebody 3/4 back 1x12 C90
mini rec cab stack

PRS Mira

jpistolas
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Re: DC gain structure... more Mark or Recto?

Post by jpistolas » Tue Jun 12, 2018 12:43 pm

Markedman wrote:That amp has Mark lV cleans and Rectifier gain, they make a great combo with a 4X12 cabinet. Your guitar of choice will be critical to the final tone, especially the low end chug.
That's been my impression from the first time I played through one. Some of what I like about both amps but not too much of either. It's own beast for sure.
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