Marshall JCM800 Studio 20W (SC20H) Sound like Sh*t - Solution Fixed - Thanks Me Later!

[rodrigogears]

Let me tell you my Marshall history...I almost gave up on Marshall Heads.

Some years ago I bought the Marshall Studio Head JCM800 20W, on that time I found a Cab with 2x12 70/80 and for my surprise when I tested it, it sounded like Sh*t, treble sharp like a knife on my ears, no matter what treble/presence configs.

I had to save more money over the future months to change the speakers or get new cabs, then I sold the 70/80s and bought 2x12 G12T75s vintage speakers and my JCM800 started to sound good, but despite that, I was still disapointed because I spent money/time and it was not the marshall shound I had in my ears like, Zakk, Slash, etc.

Living in Appartment, I need to play in low volume levels and for this reason the JCM800 sound harsh, thin, too treble, not enough gain... another blocker for me. Studying the possibilities, everybody recommended the Atenuators but I hated the idea to have third party equipment to improve the sound and also I had no money for that.

I almost gave up and was about to sell everything, I knew that Marshall Amps sounds killer with high master volumes but I had no chance to do it because of Neighbours and finally I discorvered something very useful, a JHS LITTLE BLACK AMP BOX Volume pedal and I put that on Looping.

How it works now? With this pedal in the last position of my looping chain, I bring down de volume and Open the master volume of my Marshall JCM 800, doing this I push my POWER AMP section to move more AIR in the speakers but then I control the volume with the JHS on loop.

Basically, I am cheating my marshall head, It thinks my power are exploding in high volumes but in fact, it is not.

This solution IMPROVED A LOT my sound, its a game changer and very cheap. Haters are going to say that it does not work good as a cranked marshall.. but for now, under my scenario, this is all I can do and I have a FAT MARSHALL sound, I boost it with BOSS SD1 and sounds killer, heavy, warm, with a lot of punch, gain and harmonics!

I can~t even tell that it is the same amp.

Next upgrades I am thinking of : Change original Marshall Tubes for JJ Ecc83s (12ax7)! Hopefully it will sound even better!

 

[rodrigogears]

Update: The JHS Little Black Box is a cristal clear volume pedal, it does not change or color your tone at all.

 

[What?]

How I understand it, it's just a volume pot and jacks mounted in an enclosure. I guess it would help in way of letting the master volume be turned up enough so that the bright cap in the amp isn't doing anything (or anything much). You would very likely like the amp just as well with the bright cap removed.

 

[paul-e-mann]

Let me tell you my Marshall history...I almost gave up on Marshall Heads.

Some years ago I bought the Marshall Studio Head JCM800 20W, on that time I found a Cab with 2x12 70/80 and for my surprise when I tested it, it sounded like Sh*t, treble sharp like a knife on my ears, no matter what treble/presence configs.

I had to save more money over the future months to change the speakers or get new cabs, then I sold the 70/80s and bought 2x12 G12T75s vintage speakers and my JCM800 started to sound good, but despite that, I was still disapointed because I spent money/time and it was not the marshall shound I had in my ears like, Zakk, Slash, etc.

Living in Appartment, I need to play in low volume levels and for this reason the JCM800 sound harsh, thin, too treble, not enough gain... another blocker for me. Studying the possibilities, everybody recommended the Atenuators but I hated the idea to have third party equipment to improve the sound and also I had no money for that.

I almost gave up and was about to sell everything, I knew that Marshall Amps sounds killer with high master volumes but I had no chance to do it because of Neighbours and finally I discorvered something very useful, a JHS LITTLE BLACK AMP BOX Volume pedal and I put that on Looping.

How it works now? With this pedal in the last position of my looping chain, I bring down de volume and Open the master volume of my Marshall JCM 800, doing this I push my POWER AMP section to move more AIR in the speakers but then I control the volume with the JHS on loop.

Basically, I am cheating my marshall head, It thinks my power are exploding in high volumes but in fact, it is not.

This solution IMPROVED A LOT my sound, its a game changer and very cheap. Haters are going to say that it does not work good as a cranked marshall.. but for now, under my scenario, this is all I can do and I have a FAT MARSHALL sound, I boost it with BOSS SD1 and sounds killer, heavy, warm, with a lot of punch, gain and harmonics!

I can~t even tell that it is the same amp.

Next upgrades I am thinking of : Change original Marshall Tubes for JJ Ecc83s (12ax7)! Hopefully it will sound even better!

JHS LBB, this is exactly how I run my SV20H, works perfectly and at any volume!

FYI - those are Marshall branded JJ tubes, you dont have to change them out. I'm a fan of Chinese tubes so thats what I have in mine, sounds great!

 

[marshallmellowed]

Let me tell you my Marshall history...I almost gave up on Marshall Heads.

Some years ago I bought the Marshall Studio Head JCM800 20W, on that time I found a Cab with 2x12 70/80 and for my surprise when I tested it, it sounded like Sh*t, treble sharp like a knife on my ears, no matter what treble/presence configs.

I had to save more money over the future months to change the speakers or get new cabs, then I sold the 70/80s and bought 2x12 G12T75s vintage speakers and my JCM800 started to sound good, but despite that, I was still disapointed because I spent money/time and it was not the marshall shound I had in my ears like, Zakk, Slash, etc.

Living in Appartment, I need to play in low volume levels and for this reason the JCM800 sound harsh, thin, too treble, not enough gain... another blocker for me. Studying the possibilities, everybody recommended the Atenuators but I hated the idea to have third party equipment to improve the sound and also I had no money for that.

I almost gave up and was about to sell everything, I knew that Marshall Amps sounds killer with high master volumes but I had no chance to do it because of Neighbours and finally I discorvered something very useful, a JHS LITTLE BLACK AMP BOX Volume pedal and I put that on Looping.

How it works now? With this pedal in the last position of my looping chain, I bring down de volume and Open the master volume of my Marshall JCM 800, doing this I push my POWER AMP section to move more AIR in the speakers but then I control the volume with the JHS on loop.

Basically, I am cheating my marshall head, It thinks my power are exploding in high volumes but in fact, it is not.

This solution IMPROVED A LOT my sound, its a game changer and very cheap. Haters are going to say that it does not work good as a cranked marshall.. but for now, under my scenario, this is all I can do and I have a FAT MARSHALL sound, I boost it with BOSS SD1 and sounds killer, heavy, warm, with a lot of punch, gain and harmonics!

I can~t even tell that it is the same amp.

Next upgrades I am thinking of : Change original Marshall Tubes for JJ Ecc83s (12ax7)! Hopefully it will sound even better!

Glad the volume pot in the loop helps with your situation. This is just for educational purposes, but using that volume pot in the loop does nothing to "push" the power amp. All it accomplishes, is to allow you to turn the amps master volume amp up before it hits the FX loop. Once in the FX loop, you're just turning it back down using the volume pot (black box) "before" it hits the power amp. A change in the position of the amps master volume, and how that interacts with other preamp components is all you're hearing. Regardless, if it's working for your situation, that's a plus.

 

[SloeGin]

Let me tell you my Marshall history...I almost gave up on Marshall Heads.

Some years ago I bought the Marshall Studio Head JCM800 20W, on that time I found a Cab with 2x12 70/80 and for my surprise when I tested it, it sounded like Sh*t, treble sharp like a knife on my ears, no matter what treble/presence configs.

I had to save more money over the future months to change the speakers or get new cabs, then I sold the 70/80s and bought 2x12 G12T75s vintage speakers and my JCM800 started to sound good, but despite that, I was still disapointed because I spent money/time and it was not the marshall shound I had in my ears like, Zakk, Slash, etc.

Living in Appartment, I need to play in low volume levels and for this reason the JCM800 sound harsh, thin, too treble, not enough gain... another blocker for me. Studying the possibilities, everybody recommended the Atenuators but I hated the idea to have third party equipment to improve the sound and also I had no money for that.

I almost gave up and was about to sell everything, I knew that Marshall Amps sounds killer with high master volumes but I had no chance to do it because of Neighbours and finally I discorvered something very useful, a JHS LITTLE BLACK AMP BOX Volume pedal and I put that on Looping.

How it works now? With this pedal in the last position of my looping chain, I bring down de volume and Open the master volume of my Marshall JCM 800, doing this I push my POWER AMP section to move more AIR in the speakers but then I control the volume with the JHS on loop.

Basically, I am cheating my marshall head, It thinks my power are exploding in high volumes but in fact, it is not.

This solution IMPROVED A LOT my sound, its a game changer and very cheap. Haters are going to say that it does not work good as a cranked marshall.. but for now, under my scenario, this is all I can do and I have a FAT MARSHALL sound, I boost it with BOSS SD1 and sounds killer, heavy, warm, with a lot of punch, gain and harmonics!

I can~t even tell that it is the same amp.

Next upgrades I am thinking of : Change original Marshall Tubes for JJ Ecc83s (12ax7)! Hopefully it will sound even better!

Very cool!
I'm in the same situation. I can't play very loud in my house and big fan of Slash, Randy Rhoads and Zakk Wylde.
Maybe gotta go for your setup after all ...
What cab has those 2x12 G12T75s vintage speakers ?

 

[PelliX]

I guess it would help in way of letting the master volume be turned up enough so that the bright cap in the amp isn't doing anything (or anything much). You would very likely like the amp just as well with the bright cap removed.

The "bright cap" is typically at the input, it depends on the Gain setting here (and that *does* have a weird curve to it on the SC, that's true). I've been itching to see if I can't smooth the treble-y low range and bass-heavy upper range of the pot to behave a little more linear...

Glad the volume pot in the loop helps with your situation. This is just for educational purposes, but using that volume pot in the loop does nothing to "push" the power amp. All it accomplishes, is to allow you to turn the amps master volume amp up before it hits the FX loop. Once in the FX loop, you're just turning it back down using the volume pot (black box) "before" it hits the power amp. A change in the position of the amps master volume, and how that interacts with other preamp components is all you're hearing. Regardless, if it's working for your situation, that's a plus.

This 100%.^ Also note that the stock FX loop will drop the volume (or signal level, rather) a bit. The difference tapers out to unity as you turn up the MV.

doing this I push my POWER AMP section to move more AIR in the speakers but then I control the volume with the JHS on loop.

Air is pushed by the speakers. An actual attenuator would allow you to push the power stage harder. I will say that you have turn the SC up a *bit* for it to deliver, but it's not a massive difference IMHO. Typically I don't attenuate mine.

Change original Marshall Tubes for JJ Ecc83s (12ax7)! Hopefully it will sound even better!

Those *are* JJ's. If I could make a single recommendation for "improving" the SC with valves, it would be bigger bottles in the output. I love KT88's in there, but 6550's or 5881's do an excellent job, too. YMMV of course.

 

[rodrigogears]

Very cool!
I'm in the same situation. I can't play very loud in my house and big fan of Slash, Randy Rhoads and Zakk Wylde.
Maybe gotta go for your setup after all ...
What cab has those 2x12 G12T75s vintage speakers ?

The MX212 1936 Marshall Cab

 

[Kutt]

Players have been putting volume pedals / volume devices in their loops for decades, myself included. Welcome to the club.

 

[ken361]

Hated that pedal when I tried it with my combo

 

[TXOldRedRocker]

I'm very glad you like it. Any way to keep and play a Marshall!

I've got one of those JHS volume pedals in a drawer. Tried exactly what the OP described, with several amps, including SC20, and didn't like it at all. I have a JohnH attenuator so I can crank the power tubes with my four Marshall's. I like that solution.

Different strokes for different folks.

 

[scozz]

I tried those little volume pots in the loop, two of them actually, with my Sc20 also through 2-12s. It didn’t do much, it certainly doesn’t drive the power section, it’s really just another volume.

I use an attenuator if I want to crank the master, and make no mistake, blending the overdriven power section, and preamp drive make for some great tones with this amp.

Playing the master around 8 with the preamp around 5 or 6 is gold imo,… but I can’t do that without an attenuator.

 

[PelliX]

Playing the master around 8 with the preamp around 5 or 6 is gold imo,… but I can’t do that without an attenuator.

You can push the preamp further, too - just you have to EQ the low end right down before hitting the front. On the low input, dime the gain anyway unless you're doing something crazy with pedals....

 

[What?]

The "bright cap" is typically at the input, it depends on the Gain setting here (and that *does* have a weird curve to it on the SC, that's true). I've been itching to see if I can't smooth the treble-y low range and bass-heavy upper range of the pot to behave a little more linear...

Oops. I was thinking of a bright cap on non-master amp. Yea, a volume pot in a master-volume amp shouldn't be doing anything other than reducing the volume, same as the master volume knob.

 

[wakjob]

Just gonna parrot what others have said, adding another volume control in the FX Loop does nothing to drive the power output section of an amp.

An alternative would be to put a lower gain tube in the Phase Inverter. Really improves the taper of the amps Master Volume.

.

 

[little_grease]

I use my SC20H in wet/dry setup with 1960A & 1960BV cabs. With preamp around 8-10 and master at 5-7, SD1 in front...it sounds crushing. I've tried the Hotmod and honestly didn't really care for it

Of course using a PS-2A to attenuate the SC20H and another PS-2A to act as the power amp on the wet cab. Using the CE5 to split the signal. TC mini spark for a touch more volume when needed.

w/o attenuating at those settings, it would blow the windows out lol and my ears.

 

[fitz]

With this pedal in the last position of my looping chain, I bring down de volume and Open the master volume of my Marshall JCM 800

I've had one of these for a while and tried it in the loop on some NMV amps with less than desirable results.
Recently started using it in the loop of my JCM800 50w 4210. (moved my John H to the Ceriatone)
I have to say it works great with this amp, but I put it first in the loop, then EQ, then TBE.
It lets me push the pre-amp channel volumes higher and gives back some control at the MV so it doesn't go from whisper quiet to holy $#!+ loud.
And I do think that being able to turn the master up a bit more adds a degree of depth to the tone at lower volumes compared to driving the pre-amp and squashing the signal at the MV.

 

[solarburn]

I use my SC20H in wet/dry setup with 1960A & 1960BV cabs. With preamp around 8-10 and master at 5-7, SD1 in front...it sounds crushing. I've tried the Hotmod and honestly didn't really care for it

Of course using a PS-2A to attenuate the SC20H and another PS-2A to act as the power amp on the wet cab. Using the CE5 to split the signal. TC mini spark for a touch more volume when needed.

w/o attenuating at those settings, it would blow the windows out lol and my ears.

I agree the SD1 will be shelving a lot of that added bass with gain so high. Great sculpting OD.

My windows have survived my 100/120 watters at volume hehe. My ears? Marshallz are ear killerz at volume. Why i use wireless and stand at other end of house. It sounds better too. Only unleash em at home. Can't do that out gigging.

 

[6StringMoFo]

Let me tell you my Marshall history...I almost gave up on Marshall Heads.

Some years ago I bought the Marshall Studio Head JCM800 20W, on that time I found a Cab with 2x12 70/80 and for my surprise when I tested it, it sounded like Sh*t, treble sharp like a knife on my ears, no matter what treble/presence configs.

I had to save more money over the future months to change the speakers or get new cabs, then I sold the 70/80s and bought 2x12 G12T75s vintage speakers and my JCM800 started to sound good, but despite that, I was still disapointed because I spent money/time and it was not the marshall shound I had in my ears like, Zakk, Slash, etc.

Living in Appartment, I need to play in low volume levels and for this reason the JCM800 sound harsh, thin, too treble, not enough gain... another blocker for me. Studying the possibilities, everybody recommended the Atenuators but I hated the idea to have third party equipment to improve the sound and also I had no money for that.

I almost gave up and was about to sell everything, I knew that Marshall Amps sounds killer with high master volumes but I had no chance to do it because of Neighbours and finally I discorvered something very useful, a JHS LITTLE BLACK AMP BOX Volume pedal and I put that on Looping.

How it works now? With this pedal in the last position of my looping chain, I bring down de volume and Open the master volume of my Marshall JCM 800, doing this I push my POWER AMP section to move more AIR in the speakers but then I control the volume with the JHS on loop.

Basically, I am cheating my marshall head, It thinks my power are exploding in high volumes but in fact, it is not.

This solution IMPROVED A LOT my sound, its a game changer and very cheap. Haters are going to say that it does not work good as a cranked marshall.. but for now, under my scenario, this is all I can do and I have a FAT MARSHALL sound, I boost it with BOSS SD1 and sounds killer, heavy, warm, with a lot of punch, gain and harmonics!

I can~t even tell that it is the same amp.

Next upgrades I am thinking of : Change original Marshall Tubes for JJ Ecc83s (12ax7)! Hopefully it will sound even better!

I had an SC, traded it for an SV since I already had a 2203.

Been gigging with my DSL2K for 15 yrs or so and I love my V30s paired with it. I don't know if the 800 is an inheritly mid/high cranked cct but I hated it with the SC for the same reasons you mentioned.

Now, paired with my greenbacks!! The SC and 2203 sound just right!


So far, the SV has paired nice with both and 75Ts. EQ of the SV?

 

[nioclás]

I thought the master volume of that one comes *after* the effects loop, not before, so that it's not a part of the preamp. Apparently I was wrong?...

Myself very happy with an attenuator (and the sleeping kids upstairs are happy with it as well ;-) )