MA50H - Hiss problem

[Aleph76]

Hi everybody!

About a week I got my Marshall MA50H and was very excited about it. I tried it in the store and compared against an MG100HCFX. The MA sounded a lot more alive than the MG to me so I went for it. I noticed some hiss coming out of the MA but I thought it was normal in a tube amp (this is my very first experience with a tube amp) and I also thought that the noise was coming from the guitar and with some nice shielded cables and maybe a NS it would be ok.

I’ve been testing to find my sweet spot but found some issues instead.

Hiss is coming out of the amp even on clean channel with volume zeroed (both in the amp and in the guitar). The guitar is connected to the input of the amp, no effects are used and guitar volume pot is zeroed. When changing to the OD Ch hiss increases a bit but the real issue comes when switching to boost. The hiss is much louder and noticeable. (Remember, I have my guitar vol pot zeroed so no signal is input to the amp so the hiss is coming from within the amp I think)

Next I tried increasing amp’s volume on both channels (clean and OD) including OD + boost still with guitar vol zeroed. The result is more hiss as the volume increases.

I’m concerned as I know there should be almost no hiss if the amp’s volume is zeroed specially on Clean Ch. Am I right?

Next, I tried to put some effects on the loop and tried to connect a DS-2 through it with dist = 0 to make it work as an attenuator (I’ve no OD pedal so I used this instead). Didn’t work and the only thing I got was even more hiss on all channels when pressing in the fx-loop switch button on the back of the amp. I’m also connecting a GT10 through the loop to use the effects in it as stomp boxes (no modeling). This also increases the hiss.

I could use some expert advice since I don’t know whether the hiss is normal or not.

Could something be happening in the preamp section or in the fx-loop?

Thanks!!

Cheers!

Aleph

* Gear: MA50H + MA412 cab, Ibanez RG w/dimarzio crunchlab & liquifire, Epiphone Les Paul w/dimarzio Airclassic neck and bridge, PRS Torero, GT10, BOSS CH-1, BOSS DS-2, Dunlop Cry Baby wah.

[jagermike66]

Hi Aleph

Sounds strange as both me and the other guitarist in my band have MA50H', both of which run very quietly. I would get the bias and power tubes checked straight away. If too much current is going through the amp it will cause hiss regardless of the volume on your guitar/pedals, though I doubt it will be too high straight from the factory. Also check your power tubes aren't redplating. They should be glowing a healthy yellowy colour, if you see any red/purple then you have a dying power tube.

Sounds like a dumb question but have you checked all the cables including the speaker cable and mains plug? Also try a different guitar if you can just to check!

Mike

[Aleph76]

Thanks Mike!

I’m plugging the amp through my UPS. Tubes are glowing more like an orange colour but not red. It’s hard to tell because of the red light inside the head but they aren’t purple for sure.

I’ve tried with my three guitars and it’s the same. I’ll try to plug another one as you suggest.

Speaker and mains cables are the ones supplied with the amp and cab. Should I try with different ones? The manual says that the speaker cable shoud not be shielded but I don't know the reason why, so I haven't tried that.

--- update: March 24th, 12:32pm
So I just came back from the store where the guy that sold me the MA said that I can take it to service to determine if this is a faulty amp or not. I was offered to exchange MA for a JMD1 (for a difference)... Do you think JMD1 is a better choice than MA?

Cheers!

[jagermike66]

Ah I would try different cables before you pay for anything drastic, you'd be surprised how much hiss can be caused by a cable!

hmmm I'd say if you use more stomp boxes and you need 1 or 2 basic sounds from an amp, stick with the MA as I think its a great work-horse. If you need a bigger variety of sounds, and dont use many pedals, then go for the JMD :)

[Aleph76]

OK, I'll give it a try with different speaker cables. A normal guitar cable (unshielded) would do?

Regarding the JMD... I suppose that I can use my GT10 to model through the MA but in fact I was considering the JMD because of the hiss issue and also for that kind of 'break' that is heard when you switch between channels (a little bit annoying). Is this normal on tube amps? If so... is there a workaround to this? or it's just in the MA series? (why?)

It sounds like I'm just complaining about the MA bur I'm not. I really like it but I just want things to sound good. I know neither of these amps are like a DSL, JCM or JVM and if I weren't on a budget I would get one of those. someday maybe, jeje

Thanks!
Aleph

[jagermike66]

Hey sorry for the late reply!

Don't use a normal cable to test the speaker cab if you can help it. Theyre designed for the tiny level between the guitar and amp, not the massive level between the amp and speaker! It will probably be ok at low volumes but dont turn the volume up!

The break between channel changes is common on most amplifiers which have a simple switching circuit (IE not midi). The break in signal is there on purpose to hide the loud pop that you would hear without the break.

It really depends how many sounds you need from the amp I think. For me, I need 2 sounds, clean and OD, and I use pedals too. I also like amps that are as simple as possible. The MA fits this perfectly and I would happily run it next to any other marshall. It totally rips through relentlessly when you use it at gigging volumes. I have melted many faces with my MA :)

[Aleph76]

I finally decided to take back my MA to the shop and they are supposedly going to check/fix it but It has been more than a week and still no news. So in the meantime I tested a few more amps: Vintage Modern 2266, JVM205H and DSL50. I just loved the sound of the three amps but they cost twice the price. I am seriously considering to make an extra effort to get one of those three. I'm not sure if I'm going a little bit nuts here but I think it's worth it

I Haven't decided though.

Any suggestions or recomendations?

Cheers!
Aleph

[SteveD]

Welcome to the forum Aleph76.

It's always been good advice to get the best you can afford, so if you can stretch a little further I would say you won't regret it!

[Aleph76]

Thanks Steve!

I must say that you gave me the final push towards going for the next step. Although I like more the thick tone on the VM (which I also tried at the local store and what a sound! Someday I’m getting one) I finally made up my mind for a JVM205H for its versatility and its incredible amount of gain for heavy stuff. The DSL sounded great as well but I went more for the modes on each channel on the JVM, the MIDI capability and the silent recording. Haven’t used them though.

Don’t get me wrong, the MA sounded very cool on the clean channel but to my ears the gain channel wasn't what I was looking for so I traded it for the JVM. I’m pretty sure that with a good OD or distortion pedal it can deliver, it’s just that I wanted the pure sound of the driven tubes.

Mike… thanks for your replies and helpful advice. Hope you melt more faces with the MA and hope to read you guys around

Rock on!