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Roland Cube 40XL hiss


Jazzer2020

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I bought a used 40XL not too long ago.

It came with nice overall sounds, a missing input jack nut and a hiss.

 

I have asked two Kijiji sellers in my area if their 40XL's have a hiss (they said no) and have read on various sites that users

have/don't have hiss on their 40XL amps.

 

I also have a Cube 30. My Cube 30 has a 3-prong plug and my Cube 40XL has a 2-prong plug.

 

Question. Anyone knowledgeable with these amps here?

Can I easily get rid of the hiss or do I just have to live with it?

 

My Cube 30 does not have any hiss (had it for more than 15 years).

TIA

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There are a bunch of others who complain about the hiss so I'm guessing its an inherent design flaw.

 

His is caused by the solid state transistors and op amps. The sound comes from the silicone in those components having impurities and when the electrons try to flow through them in a straight line and when they strike the impurities, they bounce around like balls on a billiard table which is what causes the hiss.

 

The only fix is to either redesign the circuit or use higher quality components that make less noise. Both would be ridiculously expensive to accomplish and you could simply buy a better amp using quiet Mosfets for the cost.

 

They may have had a prototype when they first built it that did sound quiet, but companies often cut corners to maintain profits. I wouldn't doubt they found a cheaper source for the parts from some sweat shop in China that saved then ten cents a transistor and its why the amps wound up sounding hissy. It may be a design flaw too.

 

I haven't looked at the schematics but they likely borrowed the designs of a previous amp, like that 30 you mentioned, tweaked the gain up to get 40W out of it and as a result the his level went way up. Again, I'm just guessing but its something all these companies do so I don't doubt your answer lies there some place.

 

The only fixes I can think of are these. If this is an amp with preamp gain and a master volume, you'd need to check and see if the hiss if coming from the preamp or power amp. If you turn the preamp/input volumes up and the his increases, and the amp has an effects loop, buy a hush pedals and stick it in the effects loop and adjust its attack so when you hit the strings the gate opens and you hear the sound. When you stop playing, the gate closes and turns the preamp off from making noise.

 

If the amp hisses with the master volume turned down, then there ain't nothin you can do to fix it besides sell it and get something else.

 

 

Since there are so many posts on it hissing, this would have been something you could have easily found Googling before you bought it.

I buy allot of used gear because I am an electronic tech and I can repair most of what I buy. I still dig around and find whatever poop I can on the gear before I buy it however because at least 1 out of 5 times I find something that will bring the thought of purchasing it to a grinding halt. It may be inherent problems, issues finding replacement parts, performance issues, and I may even come across none of that and simply find another for half the cost, so be sure to read the positive sides and the negative sides before you pull the trigger on buying anything and you'll have less chances of getting stuck with something that doesn't perform the way you want it too.

 

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The only fixes I can think of are these. If this is an amp with preamp gain and a master volume, you'd need to check and see if the hiss if coming from the preamp or power amp. If you turn the preamp/input volumes up and the his increases, and the amp has an effects loop, buy a hush pedals and stick it in the effects loop and adjust its attack so when you hit the strings the gate opens and you hear the sound. When you stop playing, the gate closes and turns the preamp off from making noise.

 

If the amp hisses with the master volume turned down, then there ain't nothin you can do to fix it besides sell it and get something else.

 

Thanks for your reply WRG.

I just tested with the master volume turned right down. The hiss stayed exactly the same. :(

 

I did Google the amp before buying and did read about the hiss complaints.

But I thought I might get lucky. Wasn't listening for it when I tried it at the seller's apt.

Also the newer version 40GX dropped the looper which I really wanted (the 40LX has it).

 

I wonder if those selling the amp on Kijiji locally who claim there is no hiss really have hiss-free units or they just are partially deaf?

 

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If the amp hisses with the master volume turned down' date=' then there ain't nothin you can do to fix it besides sell it and get something else.[/quote']

 

The problem with a lot of modern amplifiers is that the "Master" Volume occurs too early in the circuit. In fact, the Master has become part of the preamp circuit and there are several noise generating stages that follow.

 

I like what Yamaha did with their DG series of modelling amplifiers. Although they are capable of producing a lot of gain, these amps do not require a noise gate. The so-called Master control is still part of the preamp but there is a separate Output level control that determines how loud the power amp section is. The Master control can be turned up to get and emulation of power amp overdrive then everything (including any noise) can be turned down with the Output control. The DG amps also have a separate independent Level control for the speaker emulated balanced line out which comes in handy for recording sessions.

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Hiss has been an issue with solid state amps ever since they started including them in amp builds. Tubes can have a certain amount of hiss too depending on the design and components used but matched and well balanced tubes can null allot of it.

 

This Rolland has Composite Object Sound Modeling (COSM) and digital amp modeling. I'd guess that's where some of the noise is coming from.

Its one thing to use a multieffects pedal board that will do that in front of an amp. You can use the amps EQ to dial out the offending hiss. When you sandwich that in between the preamp and power amp, the power amp is wide open and amplifies any noise that circuit makes.

 

I get the same kind of hiss when I stick a rack unit effects unit in an effects loop. Depending on the quality of the effects unit, it can change the otherwise quiet amp into a hissy beast. But I can attenuate the input and output gains to minimize the noise.

 

 

Since the amp is still new to you. I would investigate setting all the effects back to the factory defaults. Maybe the previous owner has everything maxed out which is causing an abnormal amount of hiss. Check the manual too. Sometimes there's a method of setting everything back to default.

This would explain why some people say the amp is fairly quiet and others complain of it being noisy. Maybe they just maxed out gains in the amp selections or effects settings and those extreme setting are amplifying the max noise levels.

 

The only other fixes I can think of for you situation would be to use a different speaker or possibly a speaker attenuator.

I know my buddies Rolland twin chorus uses aluminum domed speakers and they have and extended frequency range, mainly because its more of a jazz guitar amp. You'd have to do some research, but a speaker with a lower high frequency cutoff will roll that hiss off naturally because the speaker just wont produce those frequencies.

 

Of course this will change what your amps EQ settings are going to sound like too. The trick is to use a speaker that cuts the hiss but impacts the EQ response minimally. If you have access to other speakers where you could try some out and see which ones would work best would be your best option. His is better then sticking something in there that will mute the crap out of your tone.

 

The only other trick I can think of is to use a power brake type speaker attenuator. I don't favor them myself but you may even be able to get away with using a strictly resistor based rheostat type attenuator to cut down the wattage to the speaker, then turn the amp up. since the ambient noise is at a fixed level you would reduce that ambiance when you attenuate the speaker. Then you'd get the instrument volume back by turning the signal up at the pre and power amp levels. It is a solid state amp and it is a lower 40W head so I don't think an speaker attenuator would harm the circuit so long as it can easily dissipate generated by the wattage.

 

If course you could do the same thing by using a lower SPL speaker in an extension cab. You'd run that speaker and disconnect the internal speaker when you want low noise, say for recording purposes, then use the internal speaker when you need to play loud.

 

Not the ideal solutions I know but there just aren't allot of options. Of course you'd probably never hear that white noise playing with a drummer in a band which is when you'd actually need that extra wattage, but quiet is a good thing to have. Most of the SS heads I have are Mosfets which work like tubes. I have some that are 100 & 200W and even my PA heads which rate 500 to 3000W they are as quiet as a mouse. Of course if you feed them a noisy pedal or preamp they can be annoying as the worst SS amps but at least you can shut those off when not in use or gate them down between notes.

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Since the amp is still new to you. I would investigate setting all the effects back to the factory defaults. Maybe the previous owner has everything maxed out which is causing an abnormal amount of hiss. Check the manual too. Sometimes there's a method of setting everything back to default.

This would explain why some people say the amp is fairly quiet and others complain of it being noisy. Maybe they just maxed out gains in the amp selections or effects settings and those extreme setting are amplifying the max noise levels.

 

Thanks, there is no factory default setting/reset.

There are two channels. The JC clean jazz channel that I use 99% of the time and the other channel with all the modeling amp stuff.

One would think that using the clean channel would stop all the hissing but it doesn't. It's exactly the same as the modeling side, hiss-wise.

 

An interesting note on the hiss. When you start up this amp (as compared to my Cube 30) the amp runs through a series of checks/procedures.

It starts out with no hiss. Then after it has finished its tests (lights and effects are tested) and the settings are returned to their last settings use, the hiss begins. This startup takes a couple of seconds.

 

A couple more things that might add to the hiss noise picture.

 

Yesterday I did some recordings with the amp. I plugged in a cord to the record out jack at the back of the amp and fed that to my Edirol UA-25EX audio box.

Two things stood out immediately. As soon as the cord was plugged into the record jack the hiss stopped (as would be expected).

As soon as I put on my headphones there was the hiss once again in all its glory.

 

I twiddled with the Sens switch on the Edirol and was able to get rid of almost all the hiss while retaining most of the good tone.

So I managed to make a decent recording this way.

 

 

 

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From what I understand, those particular amplifiers are inherently noisy.

 

You can get a better signal to noise ratio by turning the amp up. Unfortunately, this can result in the amplifier being way too loud when the speaker is engaged. For recording, however, with the speaker disabled you can turn the amp up and turn down the input level on your interface.

 

I use a Boss ME-25 for practice and some recording. Like the Roland Cube, it uses COSM amplifier emulation and has a combination headphone/line output. For regular practice, I run the line out into a Yamaha mixer and into a pair of studio monitors. Perhaps you can do something similar with your amplifier so, again, you will be able to turn the amp up and keep the room volume down with the mixer.

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Thanks, there is no factory default setting/reset.

There are two channels. The JC clean jazz channel that I use 99% of the time and the other channel with all the modeling amp stuff.

One would think that using the clean channel would stop all the hissing but it doesn't. It's exactly the same as the modeling side, hiss-wise.

 

An interesting note on the hiss. When you start up this amp (as compared to my Cube 30) the amp runs through a series of checks/procedures.

It starts out with no hiss. Then after it has finished its tests (lights and effects are tested) and the settings are returned to their last settings use, the hiss begins. This startup takes a couple of seconds.

 

A couple more things that might add to the hiss noise picture.

 

Yesterday I did some recordings with the amp. I plugged in a cord to the record out jack at the back of the amp and fed that to my Edirol UA-25EX audio box.

Two things stood out immediately. As soon as the cord was plugged into the record jack the hiss stopped (as would be expected).

As soon as I put on my headphones there was the hiss once again in all its glory.

 

I twiddled with the Sens switch on the Edirol and was able to get rid of almost all the hiss while retaining most of the good tone.

So I managed to make a decent recording this way.

 

 

 

The amp being quiet when booting is normal. Nearly all digital effects units do that. Its essentially a mini computer booting and the sound doesn't pass till the circuit has finished loading its parameters from memory.

 

You may be turning the input down on the digital channel when you use the clean channel preamp only, but that doesn't attenuate the output of the digital channel that feeds the power amp so the noise is still there.

 

Having hiss using the headphone/line out seems to confirm the hiss is coming from that digital circuit in the preamp section of the amp. The circuits is after the input and before the power amp so its always active feeding that noise to the power amp. The headphone jack probably disconnects the power amp, that's why it goes quiet. I don't think it would disconnect the speaker itself and any use an attenuator type DI. I'd have to find the schematic to know for sure, but I suppose its possible.

 

The key with recording is like Onelife mentions. You want to get the signal going coming from the headphone jack to be louder so the noise level appears to be lower compared to the signal. You have to attenuate the interface input more to accomplish this. The Interface may have a guitar level input and the amp output is line levels so you have to turn the interface input way down. You may even want to try a DI that has a pad switch which drops the signal gain down -10 to -20db. An amp emulated DI would be even better because it filters a good deal of the hiss by rolling off some top end.

 

You could accomplish the filtering, by connecting a .005uf cap and 22K resistor in parallel across the tip and ground of the cord you use to connect the amp to the interface. This should kill the high end noise and let the guitar frequencies come through mostly untouched. Its a very simple mod to a cord and you can do it by unscrewing the end of the plug and soldering the cap and resistor across the two connections. You can test it by just wrapping the component leads around the connections just to see if it works. If it helps then just sacrifice a cord for that purpose and solder them on permanently. You wont be able to get the cap back over them of course.

 

If you want keep the cord intact you could buy a metal box and a couple of jacks and mount it in a box.

 

You would use this diagram for it. You would not use the 470 ohms resistor, just use a bare piece of wire in its place. This is a diagram for a DI for connecting to a speaker output. You could include the 470 ohm resistor and try that too if you wanted but since you already have the line level/headphone jack, I'd just use that and skip using the unneeded resistor.

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