Review: Marshall DSL40CR Tube Combo Amplifier

My main amplifier for many years has been a Line 6 Spider III “modeling” unit. It’s served me well both in the studio as well as at gigs, with never a single problem.

Line 6 Spider III Modeling Guitar Amplifier

Notable features:

  • Pushes 75W through a 12” Celestion speaker, custom-made for Line 6.
  • 250 preset effects patterned after famous guitarists, and another 150 based on Classic Rock songs and riffs.
  • 36 memory slots for saving your own settings.
  • FBV Express floorboard with 4 assignable channel switches, combo wah/volume pedal, tuner display.

Over the past six months or so, I’ve gone completely to using outboard effects pedals, so naturally I was running this amp totally clean. Since it has so many built-in effects this defeated its main purpose in life, plus I was more than overdue for an upgrade.

Enter the Marshall DSL40CR 40 Watt 1×12″ Tube Combo Amplifier…

I’ve always wanted a Marshall valve amp, but they were invariably out of reach as far as my bank account was concerned.

Real estate inside my home studio is tighter than a gnat’s ass. Although I would have loved to get a half-stack, a combo amp seemed a much better choice in order to conserve space. But, naturally I didn’t want to sacrifice that awesome Marshall sound in doing so.

So, I did my research and found nothing but rave reviews about this unit. At a nearly unbelievable low price of $799, I could resist no longer… I pulled the trigger, and man am I ever glad I did!

This particular model was available from Sweetwater during a recent sale. In my opinion, they’re the finest on-line company out there for purchasing music gear of any kind. No one else even begins to approach their level of customer service, which as I’m sure you’ll agree is unfortunately becoming a rarity nowadays.

Each customer is assigned a personal “Sales Engineer”. Mine has always called me within a few hours of deliveries to ensure everything had arrived undamaged and performing to my satisfaction, right down to some guitar strings I ordered. (Thanks Aaron!)

DSL40CR Notable Features:

  • Pushes 40W (switchable to 20W) through a 12” G-12 v-type Celestion speaker.
  • Two channels, “Classic Gain” (Clean/Crunch) and “Ultra Gain” (two flavors of Overdrive).
  • Full EQ controls (treble/mid/bass) including a “Tone Shift” push-button, which changes overall tonal characteristics a bit.
  • Presence/Resonance controls.
  • “Classic” and “Ultra” reverb.
  • Five speaker outputs.
  • Send/Return effects loop jacks.
  • “Emulated Out” line-level output jack for connection to A/D converters, mixers, etc. (with or without amplifier enabled).
  • Includes footswitch for channel selection and effects loop bypass.


While I was already aware that Sweetwater performs a 55-point inspection of their guitars prior to customer shipments absolutely free (unheard of, at least by me), I had no idea they also inspected their amplifiers. That was evident by the top repacking tape bearing their logo, along with the inspector’s signature on a shipping card inside the box.

A few included little Sweetwater goodies… Don’t laugh, you’ll soon read
why you’re gonna need that sugar boost to get this beast out of the box!

An initial look within…

As expected, Marshall does an absolutely outstanding job with packing. In addition to the usual plastic bag protection, there were 2″ thick dense foam blocks which completely surrounded every corner.

Okay, high time to get this puppy out of there!

First of all, this amp is surprisingly heavy… It weighs in at over 50 pounds, so it’s time to break out that candy!

Slide for overall front/rear view.
Slide for close-up front/rear view.

Where the rubber meets the road…

Guitar: Fender American HSS Stratocaster, with 2 single-coil pickups and one humbucker.

– Volume: 7
– Tone: 7/7
– Middle and Bridge Pickups selected.

DSL40CR Amplifier:
Identical “middle of the road” settings were used to test both channels in each of their two modes:

– Master Volume, Channel Volume, Channel Gain: All at 12:00 positions.
– All EQ controls: 12:00 positions, “Tone Shift” disengaged.
– Everything else: Zero (off).

“Classic Gain” channel

  • Testing “Clean”

Not much to report here beyond what you’d likely expect: That extremely warm trademark Marshall sound with a signal as clear as a bell.

  • Testing “Crunch

I knew this mode was going to wail, so I first turned the volume pot on my guitar down a hair before switching the channel over to Crunch mode.

That was a trip to Rock and Roll heaven, and its capitol AC/DC city. What simply amazing, down and dirty sound… So gritty, yet not at all overbearing.

Cranking up the channel Volume and Gain to the 03:00 position, I damned near blew the windows out the room, with an additional but regrettable side-effect of totally pissing off my wife.

“Ultra Gain” channel

This channel provides two different types of awesome-sounding overdrive, the second being not only louder but much more “pronounced” than the first, albeit a little noisier with a slight hum. However, in both cases the guitar signal remained clear with no apparent distortion.

Once again, I increased this channel’s Volume and Gain to the 03:00 position. Pointing the guitar’s pickups towards the speaker and performing a long string bend resulted in feedback that I’m certain would have hung in the air forever.

Following that, I had no choice but to take a short break. It felt like my ear drums were leaking out and running down my neck, then landing on my shoulders. So, it’s a good thing I did, since I probably would have ruined my new Jethro Tull t-shirt in the process.

A few more sonic warnings!

  • For a 40 watt amp, this thing is incredibly loud, although as previously mentioned there’s an “Output” switch which can be used for taming it to half-power.
  • Take my advice, be especially careful about cranking that “Ultra Gain” channel!
  • Playing a Les Paul with humbuckers through this amp in just about any mode could possibly lead to irreversible brain damage.

Seriously though, all of this is no exaggeration… This amplifier absolutely fucking roars.

Hail to the King baby!
07/29/1923 – 04/05/2012, RIP

Effects Loop

As I mentioned earlier, I’ve recently gone completely to outboard effects pedals, so this feature was extremely welcome. At the risk of getting too far off-topic regarding the DSL40CR itself, I wanted to discuss that a bit because it can really make your overall tone soar.

No matter your pedal order, sending the entire output of your chain directly into the amplifier’s Line-In jack can muddy up the waters unless all pedals are carefully set to live in harmony with each other (pardon the pun). This is due to the fact that you’re connecting the full chain directly to the pre-amp, which can add undesirable tone coloring and possibly signal attenuation as well.

On the other hand, a basic “Series” effects loop inserts a chain signal between the pre-amp and main amp. The main amp then receives the loop chain signal directly, unmolested by the pre-amp. This results in much greater clarity of the loop’s effects, particularly those which add modulation and time-based sound, for example Chorus and Delay (which are in fact a few of the recommended types of effects suitable for use in an effects loop).

For those unfamiliar, this loop consists of two additional amplifier connections, of course requiring two extra guitar cables or patch cords:

  • Send: Input to chain is fed here after the pre-amp, but before the main amp.
  • Return: Routes the chain output signal back to main amp, totally bypassing the pre-amp.

This may all sound a bit complicated, but is actually very easy to configure. As the old saying goes, a picture is worth a thousand words:

An example Line-In chain (top) and Effects Loop (bottom) combination

I decided to utilize two pedals boards: One for my Line-In effects, and the other for the loop. This is completely optional, but doing so greatly simplifies power and patch cable routing.

That’s not to mention, it also prevents me from going completely insane…

I’m sure that by now you’ve likely come to the conclusion that the DSL40CR has a myriad of features that can’t be beat for the money, and you’d be absolutely right. Instead of writing the Magna Carta covering them all in this post, I instead direct you to the Marshall product page which contains complete specifications. The owner’s manual is also available there as a free download:

DSL40CR on the Marshall web site

Unfortunately, I lack a proper video camera to create a decent demo. No matter, this review from Sweetwater speaks for itself, plus this guy is a slightly better guitarist than me anyway. 😉

In the end, I couldn’t be happier with this rig and highly recommend it…
Without a doubt, it’s Marshall valve amplifiers for me from here on out!

3 thoughts on “Review: Marshall DSL40CR Tube Combo Amplifier

  1. I run a line 6 pod400 pedal with hundreds of effects. Do you have any suggestions on whether to put this before or after the preamp ? I’m figuring I could ditch the modeling and distortion and just use the delay/verb/flange effects through the loop.


    1. Greetings Alex!

      As I’m sure you noticed in the article, before going to this Marshall I was using a Line 6 Spider III. It’s very similar to your POD floorboard, being a multi-effects modeling amp. Both contain circuitry to provide more headroom and avoid muddy sound when what are normally line-in effects (distortion, overdrive, etc) are active along with the time-based/modulation effects you mentioned.

      That said, if things already sound good to your ears I wouldn’t place the POD in your effects loop just for the sake of doing so, although it certainly never hurts to experiment! I went to using outboard pedals since personally I was dissatisfied with the overall sound of combining those two types of effects in the Spider III amp settings.

      In my case, I -can- say without a doubt that placing time-based pedals in my loop resulted in surprisingly improved clarity of those effects. Here’s an example in a cover song I recorded… During the chorus (about 01:35 in) I played my Les Paul through overdrive and distortion pedals line-in, along with a flanger and reverb in the effects loop:

      It can be an expensive proposition, but thankfully there are many budget effects pedals available that sound nearly as good as their much more expensive counterparts. Amazon is a great source, and depending on the product they accept returns for refunds if you’re not satisfied (check the “Return policy” on each product page). I ordered this Vangoa delay pedal a few weeks back for just $27, and its performance is awesome:

      You might also want to take a look at this article for more information and examples. Nearly all my pedals go for less than $50:

      Review: Budget Guitar Effects Gear

      Whew, sorry for all the babbling. Unfortunately, I always get that way when talking shop!


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