I'll be receiving my first tube amp in a few days. Please let me know the basics I NEED to know. I really want to know if I should keep a spare set of tubes on hand. I have read the primers I could find on line. I thank all of you excellent Audiogon'r's for your excellent advice and information in advance.
I have afriend of mine who has been in and out of tube amps over the years.
He likes the sound,but lives in fear of a tube meltdown, and he has been known to invest more money in spare tubes than the cost of the amp!
I've owned tube amps over the 40 years I've been at this, and never once had a tube failure or tube blow up.Lucky?
Perhaps, but I don't listen at loud levels either.
At one time ,because of my friend's tube anxiety, I used to think a spare set of tubes was necessary, but not anymore, unless you are into tube rolling, which is a whole other OCD.
My advice is to not worry about spare tubes, but that you do know where to find them if you need them.
And tube life depends a lot on how the amp is made. If it's designed or biased high, you'll need to replace tubes more often.
Tube amps aren't for everyone, especially people with OCD, or neurosis, but in all fairness, they are the one's with the problem, you can't lay the blame on tube amps.
By and large they are a pretty reliable and stable bunch.
Good luck, I hope all your tube experiences will be as rewarding and trouble free as mine have been.
Hi everyone. Thanks for the sage advice. I've been listening to this Baldwin 6L6 tube amp for some time now with the current tube complement and I really do enjoy it. It is matching well with a pair of KEF 103/3 speakers I have. Big improvement in imaging and overall soundstage. I'm getting lots of nice details in various music I've hit the amp with. I think it only ran out of oomph when I was blasting some Blind Guardian.
I'm trying to find out information about the amp now.
Replacements/spares I'm looking into based on my current budget.
3 Matched HP 5963 Large Plate NOS 12AU7 tubes to replace the current trio. That or just 3 new Electro Harmonix 12AU7 tubes.
2 TUNG-SOL 6V6GT Re-Issue tubes to replace the pair of HK 7408s.
2 Russian Military surplus 6Pi3C tubes to replace the 6L6GB amp tubes.
1 ELECTRO HARMONIX 5U4GB to replace the Baldwin 5U4GB tube.
Please let me know what you think. I'm hoping these tubes won't be a step down from what I currently have in the Baldwin amp. Is there a formula to follow with cost of tubes vs. cost of amp?
I will definitely not change the power tubes unless someone can re-bias the amp for me or I can find info onto how to re-bias this amp myself. I was told I could change the 12AU7 tubes without re-biasing the amp. Since I'm happy with the current sound of the tubes in the amp I won't change them out till a tube dies. (I know famous last words.)
I second Usblues, and after you decide how much you like the amp, tell us what tubes it takes. Remember, NOS tubes are a good buy, but must be purchased per Usblues advice.
Jim McShane is really excellent for buying current production tubes well matched. Brent Jesse and Andy at Vintage Tube Services are excellent for NOS - I mean when you get your amp back a decide whether or not you like it.
TVAD, on the resistor-as-fuse amps, it is unfortunate that one of the best sounding amps I have owned and ever heard operates like that - CAT JL2 - the designer thinks fuses screwup the sound - I sold the amp and bought from a fella who thinks that not have an amp fry when a tube fails is important.
Xti16 I couldn't agree more. Running an output tube on a machine for 10-15 mins. is a waste of time. Many output tubes require 24 hrs. for the innards to stabilize. I just got done installing new output EL-34's in a Conrad Johnson Amp. And sure enough with brand new tested tubes one of the Wing C EL-34's started to run away.... You have to be vigilante.
If it's a manual bias you need to know how to bias them first and formost. Only because I have never owned a tube that didn't need biasing after replacement. No matter what tube I 'roll' including input and driver tubes I always start at min bias to let them all warm up first (about 1/2 hr). Then I bias them low and check the bias every 1/2 hr or so. Then I check again on a daily basis for the next few days. I have seen tubes take several days to settle down and stay properly biased.
That being said I will admit that 'factory' matched tubes can be very poorly matched. Something I learned from Jim McShane when I bought some GL KT88's and SED EL34's. I brought my 'factory' matched EL34's to Jim and he showed me how far away they were from a 'good' match.
Is there a priority on what spare tubes to get first or to keep around? I got a modified Baldwin amp that I believe came from an organ. It consists of the following tubes.
I've been listening to it for quite a bit now and I really like the sound it makes. Lots of subtle details have come out in various music I've been listening to. It isn't as forward as some SS amps I have. The previous owner said the tubes that it came with tested well but he didn't know the amount of hours total were on the tubes. I'd like to get the exact same versions of the tubes I currently have on the amp because I'm not exactly sure how to rebias the thing. I've priced out these tubes from Brent Jessee and it is getting bit pricey for me which is why I'm thinking about getting a couple of the necessary spares first.
I don't know how your amp is setup to bias; it maybe a tube at a time or pairs or quads; I would talk to the manufacturer and tell them what you are measuring;then go from there. If this were my amp I would move tubes from left to right channels to see if the measurements move or change;also inspect the pins on the tubes for oxidation;could be some buildup that needs cleaning as well as the tube sockets themselves.
First off did that tube arc? Are their any burned resistors around the output tubes? Was it always drawing this low bias voltage, or did this just happen? If no resistors are burned possibly swapping the outputs might help to diagnose the problem. If the problem moves then you know its the tube and the tube will need to be replaced as it has been damaged. If the problem stays at that tube socket then there is a problem with the voltages being applied to that tube socket or the circuit that supplies that socket. That being said, before trying any of these procedures, I would strongly suggest you contact the manufacturer of this amp as they can help you trouble shoot your problem. I don't have your amplifiers' circuit diagram in front of me. Hope that helps....G
Again, your replies are concise, well reasoned and very much appreciated. I posted under a new thread about a problem(?) I'm having. The bias on my new amp is specified at 1.5 volts. The left side will not bias above 0.5. What should I do and/or not do? Help me, oh help me please.
You have been given great advice mine is don't be afraid of the multimeter(DVM);very easy to use and a very needed tool for manual bias;also checking blown fuses that look good but don't ohm out as a short and read open.
Let us know your thoughts when you receive the amp. I'm assuming you bought it new since you're concerned about burn in. If so, then there probably will be a break in period. However, the good news is there should be some kind of warranty on the tubes, usually around 90 days. This will give you plenty of time for burn in and to decide if you like it or not. It should also give you tube replacement for free should you need it the first 90 days.
The cheapest you'll find a spare set of tubes will be about $110.
One last thing: When you do blow a tube, it's not going to happen when you're running on the treadmill to "Night at the Roxbury". It's going to occur during an ethereal moment of musical epiphany. Be prepared!
Don't buy tubes yet. As long as you are careful and never mess with connections while the amp is on, you shouldn't be blowing tubes so easily. I haven't blown a tube in years. Yes, I have spares but mainly for fun.
By all means, once you've decided the amp is a keeper, follow Tvad's advice. I also recommend that you keep extra output fuses around; when I blow a tube, I blow a fuse. I can replace my tube locally but not the fuse.
THANK YOU! All well reasoned, excellent replies. When you say decide whether I like the amp first, you mean after the break in period? The amp is a relative cheapie. I am almost embarrassed to say it. Please remember this is my first foray into tubes, so I decided to just dip a toe rather than jump into the deep end. It is an Onix SP3, which I have read favorable reviews of. I got a great price on it. It is a manual bias unit. I do know my way around a multimeter.
No harm making sure you like the amp first before investing in spare tubes. Don't try to "fix" the sound by rolling tubes though if you don't like it to start with.
Once you decide to keep it, get a few spare stock tubes though. Again, you can always roll other tubes later as a "tweak" if you are so inclined...or not.
It's also worth noting that some amps require that the set of output tubes per channel be matched, in which case you would need to have spare matching sets of tubes. Other amps are biased for each tube, and don't require matching, so having one or two extras lying around is no problem. Makes a difference in how many "spares" you have to buy.
I agree Grant, buy why buy a spare set of tubes at all if one doesn't like the amp? Example: maybe I decide I don't like the sound of this KT88 amp and want to try a EL34 based amp, or a 300B amp.
Yes, if he likes the amp he should get himself a back up set of tubes.....but let's not put the cart before the horse.
I tend to agree with most here, especially Sogood51's reply. I would caution against buying spare tubes too soon. Make sure you like the amp first. I've made that mistake before, buying NOS tubes before the amp/preamp got here, then finding out that I didn't care for the unit no matter what tubes I put in.
Relax, once you find out if you like the new tube amp, there will be plenty of time to get into 'tube rolling'. Which usually leaves plenty of spares laying around......sometimes many more than you'd like to have lying around.
Hate to be the fly in the ointment but there are some amps that require a resistor replacement before attempting to swap out the bad output tube. This depends on how the tube failed. Some manufacturers use these resistors like fuses. If the resistor fails, like a plate, grid, or cathode resistor, it can minimize damage to other parts of the amplifier. If a new tube is installed and the resistor is not replaced, it can cause damage to your brand new tube. I would probably contact the manufacturer to make sure you can easily swap out output tubes. Small signal tubes like the 12AX7 or 6922 can be easily swapped out as long as the amp has been turned off first. G
Tvad and Mapman are right: have at least one of each type of tube your amp uses available to swap out (in sequence) the amp's tubes in the case of failure. by far most problems you're likely to encounter will be tube failures. you're almost guaranteed to need to replace the odd tube now and then, so you may as well have the spares so you can avoid unnecessary 'down time'.
Whadja get? Is it an autobias amp or one you would have to bias yourself? If you have to do it yourself, you will NEED a multi-meter at some point, and/or a friend to guide you. If it is fully autobiased and the amp doesn't 'eat' tubes, what you really need is time to listen :^)
Extra tubes are OK, but it may be premature. You are better off learning the foibles of the amp with regard to your speakers, your upstream components, and tubes. That takes time, but I expect you won't be overburdened.
Also, the easiest way to determine if a tube has gone bad is to have a replacement available to see if changing a tube fixes the problem when you hear one.
Now I need to follow my own advice and pick up a spare tube or two for my own tube pre.....
Don't start rolling tubes until you have given it enough time to really hear the sound with the tubes the designer intended. Only then will you have a realistic baseline for comparison if/when you try others.
If you are getting it used, make sure you know what tubes are being provided and whether these are standard design issue or custom tubes that a prior user rolled.
Richard, If the amp is new the tubes should last many thousands of hours....do not leave the amp on 24/7 but leave it on the day you listen and turn off when done for the day...try to avoid, on-off, on-off on days you listen...tubes are like light bulbs and on-off can stress them. I would not buy any extra tubes right now. Wait till you get used to the sound and then experiment with tube rolling to change the sound of the amp....not every tube in the design has a sonic effect on a change...you have to know which ones will make an impact. BTW what is the amp?
If you like the amp, and it works well with the rest of your system...you will end up with spare tubes over the course of things :-)......thats just the way it works out.
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