I need t00bz info

[TheWinterSnow]

just got my 5150 in today and found that the power tubes are bad/going bad. eh whatever, no big deal but i need some recommendations for good power tubes. I am looking at TAD and JJ/Eurotubes, which are looking around the same price. anyone want so stray me away at their reliability or tone or praise them as well as any recommendations.

I also noticed that the actual saturation is really low, even with an OD pedal in the high input jack i have to set the gain to 7 to get anything usable, and there isn't a different in gain from the two input jacks, I don't know how to tell if bad pre tubes are the problem. Im thinking either the V1 or V2 is bad, but then again i am not sure.

EDIT: I took the thing apart and did a once over, only thing that seems fishy is the screen grid resistor is going bad. Moved the pre tubes around and nothing changed. But not i find that the fx loop doesn't work period, place an eq in the loop, (i tried two) and both times when they are in, the sound goes to as if the post gain is all the way down and no matter how high you crank it, the volume will not change. Both meters on the eq's were not registering anything from the send and only a faint signal from the pre out.

seems like the whole pre section doesn't have enough gain period, no matter which tube is where. Unless all the pre tubes have gone out evenly or for some reason the tubes are not getting enough power to them to function correctly. Its near impossible to get a probe in the sockets so i can test.

help?

 

[TheWinterSnow]

bump

 

[lolzgreg]

If you're having this many problems, I suggest bringing it to a good amp tech.

Ask the tech what tubes they've used in previous 5150's that they've liked best. I've actually tried a variety in mine (the amp tech's I deal with have sets of tubes that they use/throw out monthly simply for testing. I still find that the Sovtek 6L6GC is THE MOST RELIABLE and most even sounding tube. I use the Sovtek 12AX7LPS in my preamp as well. I don't really like the sound of JJ's in the preamp (which run at slightly different voltages than normal 12ax7's) or really in the power amp.

I would ask if whoever retubes your amp can give you a blind test between the two tubes.

 

[TheWinterSnow]

so i am figuring that they FX loops is dirty, i cleaned it haven't tested it yet. I was swapping around the pre tubes again and found that they are all 12AT7 which explains the low gain. So really i just have to find out what is up with the FX loop if it still doesn't work.

But i still need some recommendations for tubes, i hear that JJ are the best bang for the buck and are a typical fav for 5150 MkI users. bottom line i actually want to put some good grade tubes in, so that means i prefer to stay away from chinese and low grade russian tubes, which doesn't leave me very many options outside NOS.

right now it is running GT for the pres and Sovtek 6L6WXT+. The combination sounds dull, no definition and like cardboard. My spider II has more definition but that leads me to believe that either the tubes suck really bad, or are extremely old and are bad. between that and the fact that 5150s are naturally biased so low its ridiculous. But once i get some new tubes that work good and i have the FX loop working i will be doing a bias mod to get it running hotter. Should be golden then.

 

[lolzgreg]

12AT7s in the preamp>> Whoever had the amp before you is retarded, the 5150 wasn't meant for low gain. A 12AT7 may be nice, but ONLY in the "rhythm channel" position to clean it up.

NOS tubes are generally darker than most new tubes. They also may be very reliable, or not reliable at all. You always are taking somewhat of a chance. I would recommend NOS tubes for an NOS sound... if you have an old Fender and need old KT88's and things of that sort, go for it.

My opinion, I would go with the Sovteks. If anyone wants to stand up against my opinion, post your 5150 clips with NOS tubes vs New Sovteks and do a double blind test.

-Greg

 

[TheWinterSnow]

I have everything working clena and clear now, the GT 12AT7's are little on the dark and loose side. So I am really looking for a brighter and tighter tube. I will definitely be throwing a Tungsol in V1, probably V2 as well. I need a balance of screaming edgy high gain and a fair amount of warmth. None of that round, sweet or dark shit, i play metal, not blues.