Does your amp have auto biasing? I assume you meant that you did not have them MATCHED when you bought them. |
They're already receiving some bias Voltage, just not the the correct amount (probably).
If they're overbiased, they'll wear out more quickly and maybe even glow red and blow. If they're underbiased they won't sound as good as they should.
Why wouldn't you adjust the bias?
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I'm glad Jjwa asked because I am in the same quandry. I just bought a used tube integrated amp. The second day I had it I blew the fuse. I took the unit in to find out why it blew, and the techie said that the four 6550 tubes were not in the same place the previous owner had them and therefore some of the tubes ran too hot and blew the fuse.
I want to buy a new set of Svetlana KT 88s and will need to bias the new tubes, but my half-a-manual doesn't tell me how to do this... What are my options??? |
Uppermidfi - find out! The info is out there on the net somewhere. If you are going to use this arcane technology, it behooves you to learn its ways. There are some very good discussions of biasing output tubes on the FAQ sections of this and other forums. |
Bias procedures will vary from amp to amp. You guys would do well to list your specific amp including the model, and or do a search (here, google, and AA) using the amp's name and "bias procedure" (or something of that nature). As already indicated, some amps have an auto-biasing circuitry and do not need to be adjusted with tube swaps. Others which require biasing will require a decent digital volt meter and the basic knowledge of how to use it. The actual procedure, as I said, will vary according to the amp.
If you want your manualy biased amp to run properly and not risk tubes, fuses and or very lackluster performance you do indeed have to bias your output tubes. I would furthermore recommend you check the bias at least once a month or so, and more frequently if you are breaking in brand new tubes.
Marco |
The arcane technology john mentioned happens to be the most maturated aspect of high end audio.Study your audio history and you will understand that cd's are still in the thumb SUCKING stage... emphasis on sucking.There are many engineers out there that are slowly realizing that digital cannot offer the many characteristics that a well designed tube stage offer.The young pro audio camp loves digital and that is understandable since they have 30 to 40 less years of analog in their brains than the old fart contingent.Find out the bias #'s that your manufacturer intended for your tubes and if your unit does not autobias then ask the vendor like THE TUBE STORE to bias them for those specs.Good luck |
Find out the bias #'s that your manufacturer intended
for your tubes and if your unit does not autobias then ask the vendor like THE
TUBE STORE to bias them for those specs. HUH?!?! Maybe I'm missing something in what you are suggesting, but how can a vendor "bias your tubes for you?!" How exactly do you bias a tube outside of a circuit? You have to place the tube within a circuit and run current through it in order to bias it, and it has to be the same circuit you are using the tube within. You cannot bias the tube in one place using one circuit, send it to another place, insert it into an entirely different circuit with at different load and expect the bias to be correct. Maybe I've been camping with the wrong campers. I've stayed clear of you old farts as the snoring keeps me up at night. Can't stand those young audio pros either cause they got their music up too loud crankin' tunes I don't click with no more. Maybe you are referring to tube "matching" which a service a good tube vendor can and often does provide. But biasing?! Splain that to me, would ya. Unless you are suggesting he send his entire amplifier, his speakers and speaker cables to a tube vendor to bias it, which really seems rather ridiculous as it's a pretty simple procedure to do yourself. Marco |
I stand corrected...indeed I was thinking of tube matching and of course biasing must occur in the equipment.The issue is what the manufacturer recommends as an operating range and then tweaking the tubes with a voltmeter.Simple enough with my VTL amps. |
Brucegel:
There are good tube designs and bad tube designs. The same goes for SS. Each has its advantages and disadvantages.
As far as digital goes, I feel that CDs are an improvement over vinyl records. It's very hard mechanically to put the signal onto vinyl, and also very hard to retrieve it. CDs don't have those problems, so it's a "less imperfect" medium. The A/D and D/A conversion is where there may be problems, but I feel they're done fairly well, and better than the electrical/mechanical and mechanical/electrical conversion done in vinyl records. The electrical/mechanical and reverse conversion done on CD is less prone to problems because you're simply looking for signal/no signal.
Tape also has electrical/mechanical and the reverse conversions. It's at a smaller scale, but you're still doing it. There are problems with this. Digital tape is more able to ignore those problems because it's easier to do signal/no signal recording and playback. Again, the A/D and D/A conversion could cause problems, but it seems to be quite good.
I'd say that the case is less clear with digital vs. analog tape than with CD vs. vinyl record. Analog tape is probably a better medium than vinyl records. It just costs more to produce which is why it didn't dominate the market.
Getting back to biasing tubes, yes, you definitely want to make sure they're biased correctly. Tube equipment has added hassles that you don't get with SS gear, and that's the price you pay for using tubes. One would hope that the benefit to you outweighs the increased hassle.
Once you figure out how to do it, it's normally quite easy. You shouldn't have any trouble with it. |
Not correctly biasing your tubes is equivalent to buying an expensive 12 cylinder Italian sports machine and not having the engine tuned. It costs you nothing but a little time to bias an amp. I believe it cost $10,000+ to tune a Ferrari. One procedure is clearly a bargain. |
Skrivis writes "I feel that CDs are an improvement over vinyl records"
Whoa!! You are kidding right? |
Lets not forget that an interest in good equipment has nothing to do with ones ability to hear well.An interest serves a myriad of needs,desires and cravings which have nothing whatsoever to do with the sounds we hear.Thats why the pursuit of wonderful sounds is so individual and so unpredictable. |
Judy426>Whoa!! You are kidding right?
Not at all. The built-in distortions of vinyl are so horrible that any slight problems with CDs are rendered meaningless.
The problems with digital are curable, while the problems with vinyl are not. |
Skrivis, I don't know if you've experienced a quality vinyl setup, and i realize that everyone hears something different. Theoretically, and using measureable data, what you are saying may be true, but to my ears, vinyl beats the crap out of cd, i don't even listen to my cd gear that much anymore, and i was a cd man for a long time, i guess i just always get curious when someone prefers cd sound, i just wonder why they can't hear what i'm hearing, but to each his own. |
I could speculate that you've never heard a quality CD setup. :-)
Euphonic distortions sell an awful lot of equipment, usually at very high prices. Vinyl, moving coil cartridges, 8W SET tube amps, very expensive car speakers masquerading as "full-range" speakers...
Then there are the purely psychosomatic effects of fancy wires and parts. Peter Belt is the logical extension of all of this. :-) |
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Skrivis,
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Have you ever had a well put together Viynly system ? If so, what was your set up.
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What is your reference for a CD based system (which CD Player, DAC and or Transport) ?
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Rgds,
Larry
. |
I had an H-K Rabco table at one point, then a newer H-K. My most recent is a Sherwood belt drive table that I've heavily modified for better damping of resonances.
Cartridges have been mostly Grado, but I also had an A-T and a Shure. I prefer Grado. I've also tried the Longhorn mod for the Grado carts, and I, of course, calculate the required load and change my preamp to match.
I carefully setup the cartridge using a Cart-A-Lign, and you can definitely hear the difference. A mistracking cartridge causes noticeable distortion and you can hear it as separate from the music. (Pops and ticks are also perceived as separate, so they're perhaps a bit less nasty than they could be.)
I've also listened to various audiophile turntables and cartridges. None of them did much for me. They're more expensive, but not necessarily better.
Once you do away with unwanted resonances in the table and arm, align the cartridge, and make sure it's electrically loaded properly, you're pretty much at the limitations of the medium.
The CD player or transport is not a big factor. Just choose one that has a digital out and the features you want. I have a Philips player, and it's been working fine.
My DAC is an OmegaStar from Audio by Van Alstine.
I listen to a wide variety of music, and also spend time listening to live music. (I play acoustic guitar too.)
Guitar and piano simply sound more realistic on CD than on vinyl. The dynamics are reproduced better, and there's no smearing of the decay.
The "weight" of large orchestral works also comes across better, the strings sound more realistic, and the brass comes across so much better that it's amazing I ever put up with vinyl.
Reel-to-reel tape is also superior to vinyl. It seems to have some low level problems, and it has noticeable noise. However, as with pops on records, tape noise has a different character than music, and it's fairly easy to listen past it. (It's hard to describe, but tape noise and record pops appear right at the speaker, while the music is not nearly as localized to the speakers.)
Unfortunately, with vinyl, the problems with attack and decay are not so easy to ignore. Perhaps I could best explain it as the problems with dynamics directly affect the reproduction of the instruments and music. Tape noise and pops and things like that affect the background. Does that make any sense to you?
CDs simply provide, to me, a better window to the original performance. Are they perfect? Probably not. But they're good enough that I can safely move on to the speakers and the speaker to ear interface - which is where the real problems lie in most systems.
We have a good handle on the electrical part of things. It's when we interface to mechanical systems that big problems show up. Eliminating vinyl cures on part of it. Mics are quite good. Speakers are not so good. :-)
Then we have issues with how we record a performance, and how the speakers reproduce the electical signal (and how it all reaches your ears). There are some basic flaws to stereo reproduction that are generally ignored. Binaural attempts to deal with this, but it only works if you're close to the generic model they use. Transaural is a better direction to go in.
Non-linearities and distortions in speakers can be a huge problem too.
At any rate, I feel that we now have the chain from microphones to the terminals of the speakers in a state where they're "good enough," and it's time to worry about other things. |
Guitar and piano simply sound more realistic on CD than on vinyl. The dynamics are reproduced better, and there's no smearing of the decay. Hey, who am I to argue? Write me privately, and I'll give you my address so you can send your turntable to me. There is no reason you should have to live with its shortcomings. I'll carry the burden, OK? Oh, and the phono stage too, please. |
