Help with Marshall amp

[IBZRG470]

I have a marshall VS100 amp and I wouldnt trade it for anything, BUT it has a hum problem. I know its not feed back or just normal noise, this thing hums real loud in the low frequency range especially after its warmed up. It only happens in OverDrive with the Reverb turned up, at first I thought it was feed back, so I tried turning up the reverb and standing back ~20ft from the amp...... no good, it still hums. I thought it might be noisy pickups, but it hums with any guitar. It also tends to drop volume by about 1/2 and loose gain, almost like its shorting out somewhere, but its totally random and will recover itself. I have taken my amp to 4 places now, and they all treat me like Im stupid, One guy even tried to explain to me what a pickup is and how it works, well until i hooked up their prized 4,000.00 les Paul to it and the amp recreated the problem without fail, and it usually takes a while for this to happen, but this time it did it right away. At that point i told him i wanted my money back for the "cleaning" he did on the connections and pots. So im stuck, does ANYONE know what this is?? Grounding problem maybe???

[ESP_Viper]

Well, how old is the amp. Has it always done this? Or was it more recently. I would be willing to bet that the tube in it needs changed. The valvestates use the tube on the overdrive channels, and it only makes this hum on the overdrive channel. Try changing the tube. I don't know if it will solve the problem, but it may help your tone a bit. www.thetubestore.com I would say get the electro-harmonix 12AX7 (12AX7EH) it is the highest gain tube that I can find. It also has sweet tone. If it still does the hum after you change the tube, take it to a marshall certified tech. Show him what the amp does, they will believe you if they witness it for themselves right in front of you. And what you did was good, taking that piece les paul that they love and show them that the amp hummed with it plugged in. Guitar salesmen LOVE les pauls... they get them lots of commission. Even though they suck. :)

[Plastique Jam]

On my Epiphone amp, you usually have to turn the presence or treble knob down a bit. Or, if you have all the knobs at full, turn them to halfway, except the volume one, of course.

[Krieselman13]

I have to agree with the person before me, and ESP_Viper. It is eoither the presence, which I use a LOT; or the tubes which need to be changed.

[PRS One]

I like alot of high gain, would I notice the difference if I switched the stock 12AX7 (ECC83) in the AVT50 w/ the 12AXEH?

[ESP_Viper]

Possibly you would. The 12AX7EH is a sweet tube. I don't know how marshall designed their amps with the tube. But it should give you a little more gain. I have played with different tubes in the old valvestates, it didn't change the tone just the ammount of gain that I got. Now the AVTs may get different tone from tube to tube, I would have to experiment. But a 12AX7EH would be a good purchase, they are only like 10 bucks a piece. I am thinking of putting some in my ADA MP-1 to get more gain. I have a friend that put some in his 5150 head, and he says they are so sweet sounding. He's the one that turned me on to the 12AX7EH actually.

[PRS One]

so you feel www.thetubestore.com is a pretty reliable site to order from? I'm just hesitant about having a delicate item like a tube sent to my apartment over ground mail.....

[ESP_Viper]

My friend who has the 5150s, he buys his tubes only off tubestore. He has bought from them in the past, and will definately do so in the future. I haven't yet, as I have recently just got an all tube setup. But when I do retube, I will go with tubestore. I also have heard great things about eurotubes.com The guy they swears by JJ tubes. I am going to retube my power amp with JJs, and my preamp with the electro-harmonix. JJ power tubes are very good, but their preamp tubes aren't as high gain as EH. THe eurotubes guy also has them for dirt cheap. So if you have get an amp that is 100% tube, go with JJ power tubes.

[PRS One]

anyone know of any promotional codes for samash or marsmusic? or does anyone know of a site that will sell the AVT50 cheaper than most? I'm trying to get the cost down.... anyone's help will be appreciated.....

[ESP_Viper]

Well, it's hard to say. Some little stores online have the best prices, you have to search around. You might try ebay. I've gotten a preamp off there. If you use paypal, it's safe. Don't buy it unless they have pictures, and email them w/ questions to see if they're bull ****ting.

[PRS One]

ok, i just got the AVT50. I'm gonna replace the preamp tube w/ a 12AX7EH, I know it may improve the distortion, but I was wondering if it will make more hiss on the clean channel. Or how DOES it affect the clean channel? ESP Viper, maybe you can help me on this one......

[ESP_Viper]

I really don't know. The old valvestates wouldn't have any difference in the clean channel with a tube change. The AVTs maybe different. The best way to know is right when you turn the amp on put it on the clean channel and see if you can play. If you can RIGHT when you turn it on, the tube is not used. This is because the tube isn't warmed up so it wouldn't be operative. If the clean channel uses the tube you won't hear anything with the clean channel on right at power up.

If you don't like the 12AX7EH you may like JJs. www.eurotubes.com

[PRS One]

the 12AX7EH kicks mutha freakin ass.... yes, the clean channel does use the tube (takes about 30 seconds to warm up) but it still sounds sweet, and the distortion is like no other, how do JJ's compare i'm curious?

[ESP_Viper]

Well the JJ guy says that it has better tone and that it is smooth. He's going to say that JJs are better than everything since he sells them and is pretty much the only JJ dealer like that. He's really honest, I've asked him a few questions and he was quite frank with me.

Here's some of that he said:

Now for some facts. The sovtek 12AX7WA's are a standard 12AX7 and are not a high gain tube. They are very bland with a weak low end, a big harsh and cardboard like mid and a piercing brittle high end. The EH 12AX7's are a little better but are still made by sovtek and are nothing more than the newer shorter plate sovtek LPS. They still have a non linear frequency response with big bump in the mid range. The only high gain 12AX7 made is the sovtek 12AX7WXT+ and if you can stand the scratchy, nasally and altogether ugly tone from this tube it will give you the highest gain.

Another fact is that preamp tubes like power tubes vary from side to side ( they are dual triodes ) and in efficiency. The only way to get the highest gain tubes or balanced tubes is to test them on a machine that will test for plate current and transconductance like a Hick**** TV2. As of this month I acquired one and even though I have not added this info to my website yet ( you are the first to know ) I am now able to offer the ECC83S, ECC81 and ECC82's in a premium grade for either high gain or balance. The charge will be 2.00 per tube which is about one third the cost of my closest competitor.

Now for that 100% honest answer to your question "for GAIN do the 12AX7EH do the job better than the JJs?" No. The JJ's in general are not higher gain than either the WA's or WB's but the JJ's are however a much more linear tube in frequency response with a deep, tight low end, a very natural and harmonically rich mid and a sweet high end that is not brittle. The JJ's are more dynamic and touch responsive with a greater definition even in high gain applications.




When you retube, try a JJ in place of that EH you bought. Then compare what you think between the two. I may just go all JJ for everything I have when it comes time to retube. Since he sells JJs DIRT CHEAP. I still can't believe he makes profit selling his tubes that cheap... but he has them at that price so he must make profit.

I am glad you like the EH though. Hope it performs the way you like.

[PRS One]

Quote: I am now able to offer the ECC83S, ECC81 and ECC82's in a premium grade for either high gain or balance.

What does he mean high gain or balance? He can gear a tube for high gain? If so, then what's "balance"?

[ESP_Viper]

Balance would mean it gives you a linear response. The tube will be more predictable and it will also be a smoother tone. If you want more balance you sacrifice in gain, if you want gain you sacrifice in balance. I would personally go for gain. I may get a high gain tube and a balanced tube for my preamp; I'll have to ask that dude what he'd think of that, then get all balanced tubes for my power amp's pre section.

[PRS One]

my curiosity's got the better of me. I ordered a high gain ECC83S from JJ's and am gonna compare the 2 tubes. Hope it makes a difference. I figure, for $10, I'll eat the cost if I like the tone.....

[ESP_Viper]

That's cool. Doin your own testing to see differences between tubes. Let me know which you think is better, or the differences in sound you have with them.

[chicken_polo]

just so everyone knows, if youve got one of the vs100 amps that have the dmall, 1 cm x .3 cm power button, the second generation, it DOES use the preamp tube on the clean channel.