#1
As some of you may know, I recently bought a Mark IV. I played it at the sellers house with a recto 2x12 cab at about 1.5 volume (still LOUD!)

Everything sounded good, a little bit noisy with active pickups but nothing insane.


Today I played with a drummer so I got to crank it a little louder. This thing was PERFECTLY clean while playing. NO noise what so ever, very tight sound. However, as soon as I stop it screams with feedback and noise. The direction I face or the distance did not seem to really make a difference. This is pretty much ONLY on the lead channel.
The only time I have experienced this was a 5150III lead channel with the gain cranked to 10.


So my question:

Is this typical of a Mark IV and do I need a noisegate? Or is something wrong with my tubes.

I may add the seller said the amp was just re-tubed, but obviously that is just his word. The power tubes are 6L6 tubes.

EDIT: I have not checked the instrument cable
And now its too late to crank it.. Hopefully thats it.
Last edited by mespinos at Aug 23, 2009,
#2
It might be your cables/pickups are not shileded. I get horrid feedback when i use my flying V so i always keep a noise gate handy. But when i use my RG's no feedback or noise. The amp itself shouldnt be that noisy.
I traded in my Real Books for Robbins and Cotran Pathology Textbooks
#3
Quote by mexican_shred
It might be your cables/pickups are not shileded. I get horrid feedback when i use my flying V so i always keep a noise gate handy. But when i use my RG's no feedback or noise. The amp itself shouldnt be that noisy.


Interesting, I tried with 2 guitars today, but both have active EMGs. Didn't think about the shielding in the pups, I will have to play with that.
#5
And like your edit says it might be the cable. but it might not. Or maybe a pedal you might be running with it. I know as soon as my ts-9 comes in the chain(even off) i get more noise

If its the tubes it would be the preamp tubes going microphonic.

Or you were near a source of radio waves like a tv or computer with those pups.

I've never had troubles with emgs before with the mark IV
I traded in my Real Books for Robbins and Cotran Pathology Textbooks
#6
Hmmm, okay. Well I think tomorrow I will try with different guitars, cables, ect.

Not running any pedals with it, just the head itself. I guess I need to do some playing around tomorrow and I'll come back and report lol
#7
It might also be the power supply/socket you are plugging everything into. I was running my amp up in my room in a socket with like 5 other things and it had quite a bit of hum, then I took outside to play and crank it and the outlet I used had absolutely no hum what so ever. So you may be getting bad current from the house or possibly interference from other electronics.
#8
Your amp could have a microphonic preamp tube.

I cranked my Mark IV constantly and that amp was dead silent, no feedback at all. Even the one time I turned it to 8, that was scary.
Quote by Dave_Mc
I've had tube amps for a while now, but never actually had any go down on me
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maybe you're not saying the right things? an amp likes to know you care.





www.SanctityStudios.com
#9
Today I tried it with a new cable and different guitars. It seemed to be slightly better with a new cable and the same guitar. It was GREATLY improved with my Jackson RR3 with passive pickups.. but those pups just have WAY less gain so that could be why.

My final question.. There is a VERY clean hum on the lead channel when the volume on my guitar is all the way down. Would a noise gate help with this? Will it also help with feedback? I have been looking at a Rocktron Super C. It seems to have good reviews and several professional musicians use it.

http://guitars.musiciansfriend.com/product/Rocktron-Hush-Super-C-Guitar-Noise-Reducer?sku=180605

Any thoughts? I don't think I can shell out $400 for a ISP rack
#10
The isp decimator G is a nice 200 buck alternative to the isp rack. On ebay they sell for 179 usd.

Itll help a little bit if you can run it through the fx loop and in front of the chain


And your pickups or some electronics in the emg guitar must not be shielded right
I traded in my Real Books for Robbins and Cotran Pathology Textbooks
#11
When you describe a "clean hum", it sounds like the power in your house could be dirty...

A noise gate would help but you might wanna look into a power conditioner as well.
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What the hell is a G&L.



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Gay & Lesbian I think, the box smelled funny
Greg what did you send me??
#12
Quote by mexican_shred
The isp decimator G is a nice 200 buck alternative to the isp rack. On ebay they sell for 179 usd.

Itll help a little bit if you can run it through the fx loop and in front of the chain


And your pickups or some electronics in the emg guitar must not be shielded right



Hmm, Can they be shielded with copper or aluminum tape?

Quote by Raijouta
When you describe a "clean hum", it sounds like the power in your house could be dirty...

A noise gate would help but you might wanna look into a power conditioner as well.


Its not really a hum, its just noise from the gain on the lead channel. I think its normal, I may just be describing it wrong. Though I am getting a power conditioner

I'm tired of pedals though I wanna have everything rackmounted

I don't run anything pedal or effect wise and don't really plan to. Just a power conditioners, tuner, and noise suppressor. People here don't seem to like the rocktron, but reviews online seem good. Anyone have personal experience with one?
Last edited by mespinos at Aug 24, 2009,
#13
The rocktron is by no means bad. very useable and a lot nicer than others i've tried. I use one with one of my amps. But for the price i paid for it and side by side comparison i liked the decimator more.


You could always try ebay for a rackmount isp but that still might be a little expensive

You'll have to ask the guys in GB&C forum to see what they say about the problem, to see if its really shielding and how to shield properly.
I traded in my Real Books for Robbins and Cotran Pathology Textbooks
Last edited by mexican_shred at Aug 24, 2009,
#14
Quote by mexican_shred
The rocktron is by no means bad. very useable and a lot nicer than others i've tries I use one with one of my amps. But for the price i paid for it and side by side comparison i liked the decimator more.


You could always try ebay for a rackmount isp but that still might be a little expensive

You'll have to ask the guys in GB&C forum to see what they say about the problem, to see if its really shielding and how to shield properly.



Thanks man I really appreciate it
#16
the 129usd one and the g string one differ in that the g string one can be runned(grammer?) in the fx loop and in front at the same time. normal can only be used in one space. Check ebay if you want to buy a decimator. The stores are usually reliable and cheaper than retail for both versions
I traded in my Real Books for Robbins and Cotran Pathology Textbooks
#17
depending on the space you are jamming, the lights could have some affects too
#18
So I'm assuming I want the G string decimator. So the G string will clean up the sound like running 2 of the normal kind? One in the FX and one in front?
#19
Yup. Thats the low down of it.
I traded in my Real Books for Robbins and Cotran Pathology Textbooks
#20
double post

You could try the ns-2 for way cheaper. Supposedly if you run it the correct way (x pattern) it doesnt suck tone and works really nicely. But i've never had luck with it. MikeyElite and IbanezPsycho have though

The x pattern is still a way you can run the decimator
I traded in my Real Books for Robbins and Cotran Pathology Textbooks
#21
I had an NS-2 with my old rig and I can't find it

I think I'll try the decimator g string though. If I put it in a rack drawer it will make me feel better about no pedals
#22
Try to find it to see if it works setting it up like this


I traded in my Real Books for Robbins and Cotran Pathology Textbooks
#23
Quote by mexican_shred
Try to find it to see if it works setting it up like this




Hm thanks, now I'll have to go dig through my stuff to find it :P

Really appreciate it