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First Tube Amp: Advice? Keep spare tubes on hand?

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.

Richard
rhanechak
rhanechak OP
48 posts
 
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.
hifigeek1
770 posts
 
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
rleff
1,065 posts
 
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.
rhanechak OP
48 posts
 
Again, thank you all mucho.
I have spoken to the manufacturer and they are sending me a shipping label to return this one and are sending me another.
jedinite24's avatar
jedinite24
1,503 posts
 
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.

3 12AU7 tubes 1 labeled Baldwin 2 Electro Harmonix
2 Harmon Kardon 7408 tubes
2 Baldwin 6L6GB tubes
1 Baldwin 54UGB tube

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.

Thanks in advance for the advise.
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