I have just purchased a second hand Peavey 5150 Combo 212.
It was shipped to me from England. I was very disappointed when I plugged it in as I know this amp has a reputation for being one of the highest gain amplifiers around. I am wondering if it is working correctly? The hiss from the tubes is unbearable and I could not turn the post gain above or actually anywhere near 1. Also, when the reverb was turned up the gain seemed to distort horribly. Any idea why?
I removed the back panel to access the tubes and noticed that the Power amp 6L6 tubes look black as if they have blown (like a light bulb)? Might this be the case? Can anyone advise as to what the problem might be? If the tubes do need replaced, is this a big (expensive) job?
I am playing this through a 1997 Peavey Wolfgang gloss black #465 (pat pending) and was expecting a similar effect to the start of Back to the Future!. No such joy.
The cost of replacing the tubes depends on what name-brand and condition tubes you use, and how many you need (lotsa amps have 8 tubes, cascaded different ways). I have ordered from this place before: http://www.thetubestore.com/6l65881types.html
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I really dunno nuts about geetah amperage, sorry.
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I cannot offer specifics for that make or model, Aro, but as someone who just got their MESA/Boogie serviced, I strongly suggest that you do the same for your Peavey. Get it checked out - blackened tubes and the inability to dial up gain do appear to suggest that the amp is in need of a once-over…
As for tubes, my EL84’s were about $10 US apiece. The basic servicing was $75 US per hour - and it took about an hour to check it out and put in a new Effects Loop blend pot - total cost for service + new pot + 2 new tubes = about $110 US.
While a Marshall is great if you want to blow the doors off your house, if you want great tone I’d go with a Peavey (as long as we’re talking tubes). I have a Peavey Classic 30 that I love. I don’t have to go above 3 for my level to completely rock out. Actually, the last 3 concerts I have been to, the guitarist has been playing a Classic 30. In answer to the OP, yeah, it sounds like blown tubes to me, especially if you see that tell-tale black.
Replacing tubes outright isn’t necessarily a good idea at this point. “Blackened” tubes sounds suspiciously like a bias problem (negative voltage) in at least that portion of the power supply - a bad capacitor possibly.
Newly manufactured tubes do have quality control issues though, particularly from China. Virtually all tubes today are made at just a few factories. Several companies purchase these tubes, test, match and sort and rebadge them under “premium” labels.
Point being you need to determine the precise nature of the problem before dropping in new tubes.
Is there any way to use the 5150 combo quietly? If it is down to negative voltage would it still be advisable to replace the tubes to get the ultimate sound from the amp? What is the main cure for negative BIAS?
I can’t speak to the negative bias issue - if my amp isn’t working, I take it in to get it serviced…but as for the question about using a tube amp quietly - yes, absolutely there are ways to use big huge amps more quietly:
Take out 1 or more of the tubes in the power stage (NOT the pre-amp stage) of the amp. So if you have a 100w Marshall with 4 6L6 tubes, take out 2 of them and you have a 50w amp. An amp tech recommended this to me once, so I am assuming it will not harm the amp.
If your amp has an effects loop - which means that you can plug your effects into the circuit after the pre-amp but before the power stage - you can get a volume pedal and use that to dial up or dial down the level your power stage, effectively reducing the amps output. Since the effects loop is behind the preamp, you won’t affect your tone (except for the tonal effects of extreme volume). Roland/Boss has a pedal called the FV50H that is great for this - it has a “minimum volume” setting so you can set the floor level of volume and not worry about stepping on the pedal and cutting the volume completely…
Thanks for the advice! I was advised to get a Marshall Powerbrake PB-1 but I believe these are about £249 which is out of my range - is this idea of removing one of the poweramps safe? I have two 6L6’s so I take it they give 50W each? I will try this tonight and pray it don’t blow up? I also have an effects loop at the back - can you recommend any decent volume pedals? I was told however that volume pedals would make the amp thin and that unlike the marshall power brake you wouldn’t really benefit from the amp gain with a volume pedal?
I think I should point out at this stage that the OP (Although actually posted in the first person) was really on behalf of Tim5150, who I know well.
He has only just remembered he is actually a registered member of this forum and so is now posting replies for himself. The amp in question belongs to him.
Sorry for any confusion this may have caused.
Let me start this response by once again stating I am NOT an amp tech, but have spoken to a couple recently as part of getting my tube amp serviced. With that in mind, a few thoughts:
Call an amp tech local to you and ask your questions - in my experience, many are very cool about answering 10 minutes of questions even if they aren’t getting a repair job that minute - good faith help leads to business down the road.
Go to Google and find the Google Group called alt.guitar.amp (here is the link to alt.guitar - go here and at the top of the page you can see links to sub-groups like alt.guitar.amplifier) and either do searches on your questions - I bet there are literally hundreds of threads there dealing with your issues - or post your own query. Some of the folks who post there are clearly engineers and amp techs; they really stand out from the idiots and offer good tips and insights.
In talking with my tech, he showed me a 100w Marshall with 4 6L6s, and we discussed taking out two to make it a 50w. Therefore, I assumed that each 6L6 put out about 25w. However, amps may use the tubes differently to achieve different wattage ratings - that is stuff I do not know - talk to a tech and check the Google group.
The way the tech spoke, it sounded like, yes, you should just be able to take a 6L6 out of the power stage and reduce your volume. Make sure you know that you are taking a 6L6 out of the Power stage and not a different tube out of your pre-amp stage!!
Regarding volume pedals - again, in talking with a working guitarist (who also works in a guitar shop and works on his own amps, although I wouldn’t call him a tech) - his experience (and what I am experimenting with right now with my rig) is to run a volume pedal through the effects loop - since the effects loop comes after the pre-amp, you shouldn’t be affecting your tone - that’s developed more in the pre-amp stage - but instead the volume/output. Therefore, if you dial up the gain on your amp (gain is created in your pre-amp) and use a volume pedal through the effects loop to dial down your overall output/volume (in the power stage of your amp), you should get a gain-y tone at a lower volume. So far, this has been my experience - it has worked - but I have not played at gig volume; that is happening this weekend.
In terms of a volume pedal, apparently Ernie Ball makes a very good one. For me, as I mentioned in my previous posting hear, I got a Roland/Boss FV50H (note: make sure it is an H, for high impedance - required for a guitar - not an L or low impedance). I got it because it has the “volume floor” feature I mentioned in the previous post, and was inexpensive, about $70 US. Plus, it doesn’t use batteries - it is a passive device - so I don’t have to worry about another thing cutting out on me…
Between the two approaches, the volume pedal seems safer/less likely to affect your amp - if you have an effects loop as described above. But do your research and decide for yourself.
Tube bias is inherent to all amplifiers. I’m unfamiliar with your specific amplifier - but tube biasing is analogous to setting the idle on a car. It is critical to obtaining maximum output, tone and longetivity of the output tubes and other components.
As far as your problem, as I stated the last thing you need to do at this point is install new tubes, find out what the problem is first.
What you need to do is test the original tubes for emissions and/or Gm. If the amplifier uses two 6L6 in a push-pull arrangement they’ll need to be matched at least fairly closely to prevent one or the other from hogging current.
It may well be a bad tube that is the source of your problems - the amp might be only running on “one lung” but you either have to know exactly what you’re doing, or find someone who does. Dropping in replacement tubes may well damage the amplifer further as well as the tubes themselves.
One more - Do NOT pull one of the output tubes to reduce the volume, especially if the amp utilizes two in push-pull. Bad Idea.
Take your tubes to a shop to get tested for shorts, emissions and transconductance (Gm); and see if they won’t take a look at the amp to check voltages, particularly B+ and tube bias.
'Should have gotten a Marshall, mate.