kevinkr said:
FWIW I am in complete agreement with SY, IMNSHO no 12AX7 regardless of provenance has performance that justifies paying that kind of money for it.
That may be very true in Hifi, but I think in guitar amps that might be a different story.
Geetar guys do buy 12AX7's in hordes and the vast majority of tube amps utilize 12A_7's.
Trout said:
While I don't disagree I don't know too many local musicians who can afford that kind of freight. Getting them to replace toasted $10 output tubes is hard enough, I can't imagine them spending hundreds for a couple of 12AX7A.... Maybe the Ted Nugents, and Ian Andersons of the world, but not the average guy doing a once or twice weekly gig at the local bar...😀
kevinkr said:
Oh, I suspect your basically correct, but following the threads on several gear forums, The search for the holy grail of tone is rather surprising, and it is really a surprise how deep the pockets run.
But then again, who would have ever thought a Trainwreck or a Dumble would sell for over $30,000 - $50.000 now.
The math speaks for itself ( IF the advertised data is correct)
$55.00 for a 10 year lifespan tube, Or
$100.00 for enough of the current tubes to last ten years.
(10 tubes x $10)
YMMV of course.
😀
What is really surprising, many of them go to Guitar Center to search for a Holly Grail, then start rolling tubes... It looks like to go to McDonald's in search for an exotic cuisine...
The price I received was a range from 20-30 quid depending on quantity. So still on the pricey side but one must realize that manufacturing new tubes today is very expensive compared to 60 years ago... materials, labor, energy... and don't forget government regulations for chemicals, etc.
Still, many folks burn a lot more than this on NOS tubes of certain brands and used tubes of same... as they're convinced they're getting a holy grail of sorts. At least these will be new and most likely some warranty. The will either make it on their own sonic and electrically compatible parameters or they will fail.
I plan on buying a pair for testing once they're available. Anything beyond that will be based on my personal findings. I also have a reasonable stash of tubes which include all 3 of what they are making plus numerous others.... more than enough to surpass my lifetime.
Regards, KM
Still, many folks burn a lot more than this on NOS tubes of certain brands and used tubes of same... as they're convinced they're getting a holy grail of sorts. At least these will be new and most likely some warranty. The will either make it on their own sonic and electrically compatible parameters or they will fail.
I plan on buying a pair for testing once they're available. Anything beyond that will be based on my personal findings. I also have a reasonable stash of tubes which include all 3 of what they are making plus numerous others.... more than enough to surpass my lifetime.
Regards, KM
Wavebourn said:
Last time I went to a GC was about 15 years ago to buy my daughter a cheapo Strat knowing it would end up in her closet or a garage sale someday 😀
Now there are Best Buy music centers 😱
I bet they will re-define the cheapo market on GC
There is a pretty large boutique instrument and gear market, with a way larger number of really good high end options.
Following a couple gear related forums I see a pretty good number of hobby players dipping deeply into higher end gear from top custom builders.
These are interesting times for sure.
I have my suspicions that they'll be aweful for guitar use, due to bizarre (or non-existent?) grid current characteristics. But it's only a hunch.Trout said:
Merlinb said:
For sure they will sound different, whether or not they work well in a guitar amplifier front end where certain nonlinearities are expected in the dirty channel remains to be answered. I also think they are probably a bit too expensive for the small gig working musician, the ones I know around here aren't that well healed, otherwise probably fine for the week-end warrier with a marketing position at some large local electronics firm I suppose.. 😀
Of course we could well be wrong and these could be a real leap forward, and I think given the effort and investment involved we should probably give them the benefit of the doubt - they could well be doing great things. We'll just have to wait and see.
kevinkr said:
I played several hundred gigs last year... and from that perspective: if the design manages to keep them from going microphonic after banging around in an equipment trailer for a month plus a few 3-foot falls off the top of a 4x12" cab, than I'll buy a set. You don't need the best of the best tone for live stuff, but you do need something that A)will hold up or B) is cheap to replace... and I am sure not going to subject my Mullards or RCAs to THAT abuse. Those go in a little box and only see the daylight when it is studio time!
Same here aletheian,
My main amp uses 2xel84, 1x12ax7, 2x6bm8, ef86, 6ca4...I have nice mullard examples of each of these, which sit in a nice padded box until I really need that little extra thing in a recording setup. Otherwise it's the modern production stuff and some very resilient used GE 12ax7s I have sitting around. I've lost some really nice speakers in live sound setups (never building a cab without a speaker grille again!) and I've had too many tubes go microphonic from being loaded in and out of cars etc. If those EL84 are really as long life as they say, and resistant to microphonics, I would definitely use them...
My main amp uses 2xel84, 1x12ax7, 2x6bm8, ef86, 6ca4...I have nice mullard examples of each of these, which sit in a nice padded box until I really need that little extra thing in a recording setup. Otherwise it's the modern production stuff and some very resilient used GE 12ax7s I have sitting around. I've lost some really nice speakers in live sound setups (never building a cab without a speaker grille again!) and I've had too many tubes go microphonic from being loaded in and out of cars etc. If those EL84 are really as long life as they say, and resistant to microphonics, I would definitely use them...
Not sure about those curves.
The thing about display tubes (CRTs) is that there isn't any great requirement for linearity, whereas for audio...
The thing about display tubes (CRTs) is that there isn't any great requirement for linearity, whereas for audio...
Re: Not sure about those curves.
I'm assuming they're not that clueless.. Let's give them the benefit of the doubt.. 😀 For now...
And actually I'd question that comment (in at least a limited sense) given the small number of convergence adjustments used in modern CRT's, that implies being able to control the position of the electron beam to a relatively high level of precision. Add to that the need to control gray scale and chrominance tracking between guns, some level of accuracy is implied.. CRTs are a lot more complex at the physical level than any of the devices we use in our amplifiers.. hmmm.
Frankly I suspect linearity and other aspects of their performance will be quite good, the cost/performance ratio and overall high cost are a larger concern I think.
EC8010 said:
I'm assuming they're not that clueless.. Let's give them the benefit of the doubt.. 😀 For now...
And actually I'd question that comment (in at least a limited sense) given the small number of convergence adjustments used in modern CRT's, that implies being able to control the position of the electron beam to a relatively high level of precision. Add to that the need to control gray scale and chrominance tracking between guns, some level of accuracy is implied.. CRTs are a lot more complex at the physical level than any of the devices we use in our amplifiers.. hmmm.
Frankly I suspect linearity and other aspects of their performance will be quite good, the cost/performance ratio and overall high cost are a larger concern I think.
Re: Re: Not sure about those curves.
Not to be a pedant, but those CRT dot characteristics (convergence, steering) are controlled by the yoke in a typical electromagnetic deflection CRT, not the grid, which I believe controls only intensity.
That said, in order to get adequate luminance/chrominance control (as you said) requires either a relatively linear tube or a very good understanding of the tube's nonlinearities and driver circuitry capable of compensating. My (admittedly cynical) guess is that it's overwhelmingly easier to deal with the latter.
Will be interested in hearing these, and hearing what others think. They sure look like they're from Mars.
kevinkr said:
Not to be a pedant, but those CRT dot characteristics (convergence, steering) are controlled by the yoke in a typical electromagnetic deflection CRT, not the grid, which I believe controls only intensity.
That said, in order to get adequate luminance/chrominance control (as you said) requires either a relatively linear tube or a very good understanding of the tube's nonlinearities and driver circuitry capable of compensating. My (admittedly cynical) guess is that it's overwhelmingly easier to deal with the latter.
Will be interested in hearing these, and hearing what others think. They sure look like they're from Mars.
Re: Re: Re: Not sure about those curves.
Quite true, however the simplified convergence adjustments I mentioned are due to better internal geometry. IIRC in most CRT the intensity is controlled by varying the beam current(s), and focus is usually controlled by internal electrodes.
koolatron said:
Quite true, however the simplified convergence adjustments I mentioned are due to better internal geometry. IIRC in most CRT the intensity is controlled by varying the beam current(s), and focus is usually controlled by internal electrodes.
The CRT amplify the video signal voltage into beam current variation ( image dot or pixel lighter or darker) like the transconductance in a valve . This characteristic should be liniar . The yoke only move the beam across the screen to form the entire image.
Gamma provides noise reduction
The Vgk to Ia (and therefore brightness) characteristic of a CRT is very definitely not linear; it is exponential and the value of the exponent is the gamma. The UK has generally worked to a gamma of 0.4, whereas Germany tended to assume 0.45. For most broadcast questions, the answer is, "Non-linearity of the display tube." The broadcaster pre-distorts the signal so that the non-linearity of the display tube provides a correct picture. There are lots of advantages to this technique.
The Vgk to Ia (and therefore brightness) characteristic of a CRT is very definitely not linear; it is exponential and the value of the exponent is the gamma. The UK has generally worked to a gamma of 0.4, whereas Germany tended to assume 0.45. For most broadcast questions, the answer is, "Non-linearity of the display tube." The broadcaster pre-distorts the signal so that the non-linearity of the display tube provides a correct picture. There are lots of advantages to this technique.
CRT gun operation and construction is very different from a valve , the question is , can achieve similar or better performance ? I think not .
As a former Philips CRT cathode expert and hobbyist tube amp enthusiast, I am in the lucky situation that I know both technologies well. In reaction to some earlier posts, I would like to point out the obvious that CRT's and audio amps are very different. It doesn't work to take some fragmented knowledge of CRT's, and from that draw a conclusion on how these new tubes will behave in audio applications. This has nothing to do with where some of the parts were originally designed for, but basically comes from the electronic diagram in which they sit.
->CRT's: the purpose is to generate up to a few milliamps of electron beam current, in order to excite light from the phopors on the screen. The current generation takes place in the first parts of the electron gun: cathode, grid 1 and grid 2. The transfer function is Ibeam = Vdrive^2.25 with Vdrive equal to the inverse of the video signal. The later grids are for focussing and acceleration.
->Audio amplifier: purpose is to amplify a voltage, and only power tubes are meant to generate some current worth speaking of. The idealized transfer function is Vout = -const*Vin.
It is really not at all a bad idea to take the cathode and grids 1-2 from a CRT gun and turn these into a planar electron tube. The parts have the same functions and it is mostly the electronic circuits that are different. In CRTs, all voltages except the cathode voltage are static and there is no anode load resistor. In tube amplifiers, there is a load resistor between the anode and B+, which makes the anode voltage follow a load line in the anode characteristic plot.
Harmonic- and intermodulation distortion of the signal occurs if in the anode characteristic plot, the intercepts between this load line and the curves at equal grid voltage, are not evenly spaced. That has very little to do with the gamma factor in CRT applications as is suggested earlier.
Without the technicl stuff: It's almost too obvious to mention this, but just look at the information that is published. Clearly, in an audio amplifier set-up, this tube behaves just like an audio tube and not a like CRT gun.
I don't have any clue how these new tube will sound in practice, so I can't wait for them to become available. So far I haven't read anything from people that visited the show in London last month. Anyone?
->CRT's: the purpose is to generate up to a few milliamps of electron beam current, in order to excite light from the phopors on the screen. The current generation takes place in the first parts of the electron gun: cathode, grid 1 and grid 2. The transfer function is Ibeam = Vdrive^2.25 with Vdrive equal to the inverse of the video signal. The later grids are for focussing and acceleration.
->Audio amplifier: purpose is to amplify a voltage, and only power tubes are meant to generate some current worth speaking of. The idealized transfer function is Vout = -const*Vin.
It is really not at all a bad idea to take the cathode and grids 1-2 from a CRT gun and turn these into a planar electron tube. The parts have the same functions and it is mostly the electronic circuits that are different. In CRTs, all voltages except the cathode voltage are static and there is no anode load resistor. In tube amplifiers, there is a load resistor between the anode and B+, which makes the anode voltage follow a load line in the anode characteristic plot.
Harmonic- and intermodulation distortion of the signal occurs if in the anode characteristic plot, the intercepts between this load line and the curves at equal grid voltage, are not evenly spaced. That has very little to do with the gamma factor in CRT applications as is suggested earlier.
Without the technicl stuff: It's almost too obvious to mention this, but just look at the information that is published. Clearly, in an audio amplifier set-up, this tube behaves just like an audio tube and not a like CRT gun.
I don't have any clue how these new tube will sound in practice, so I can't wait for them to become available. So far I haven't read anything from people that visited the show in London last month. Anyone?
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