yes,call Audio Advisor.I got 1 super low noise Ram 12ax7 for $45.I called Ram and asked them exactly what this 12AX7 was and the customer service dude told me it is actually a NOS Tungsram.It sure was quiet,in fact much quieter than the "quiet" Sovtek it replaced.I ended up returning the tube to audio advisor for a refund after I tried some NOS Telefunkens.My Rogue 99 phono takes 2 12AX7's and 2 12AU7's.I got 2 Tels and 2 Radiotechniques and am very happy with the low noise floor. I do highly recommend the SLN Ram.It isnt far behind the more expensive Telefunken. Don't be afraid to ask Audio Advisor for a discount.They are 'famous' for discounting.Also their 30 day no questions asked return policy is the best in the business,even with tubes!! |
Don't know what specific brand of tubes that RAM relabeled and sold as their own, but when my Dad put them into his preamp, the upper mids became very hard, "glassy" and brittle and the bass turned to a bloated thud. This "tube upgrade" took his pretty decent sounding system and turned it into a mess. Obviously, different components and different tubes might have various effects in various systems. Tubes almost offer TOO many variables sometimes. Sean > |
Thanks to those of you who understand and appreciate what we do at RAM TUBES. We started computer testing in 1981. We are the only premium tube source that tests for real-world conditions. We are the only source that gives you all the data for that particular tube after it has passed out stringent grading system. More importantly, we are the only tube source run by a designer of tube amplifiers and, therefore, know what matters and what does not matter in tubes for amplifiers. The thinking user can see that FFT testing to 100 MHZ is meaningless, cryogenic treatment is foolish, and sandblasting the glass is just plain silly. On the subject of NOS tubes: We have them, we test them, we can provide them, and they are expensive. As they generally yield no more quiet samples than the modern tubes we can buy (at reasonable prices), I caution potential users from buying them untested (for noise) on the open market. Even if these tubes "sound" better, how can you enjoy them if the ones you get are noisy and microphonic? You will likely pay the same price for a Telefunken of unknown performance, have a 2% chance of finding a SLN quality (within 1 dB of theoretical noise limit) and little or no recourse with the seller who couldn't measure the noise in the first place. We have tested 100,000's of tubes since 1981, including nice looking Telefunken gold pin E88CC's and E83CC's. They yield about the same mix of SLN, LN and SG that I find from the new stock that I carefully select from good factories. Since we buy in large batches, we can consistently supply tubes you like. We just sold a customer a replacement 12AX7 Smooth plate Yugo from the same batch he purchased 8 years ago. We stock 5 types (Yugo, Tungsram, Chinese, Sovtek, RCA) + some NOS Telefunken, Bugleboy and whatever else comes our way. We also have matched power tubes, again matched at real world, not Hickok test condition. You cannot match output tubes on a Hickok as the voltages and currents are too far from typical amplifier operating conditions. I am happy to respond to that issue later if there is interest. Please visit our website: ramlabs-musicreference.com for further info. We are updating it in an effort help you with your tube needs and questions. As Audio Advisor and Electron Valve have recently chosen to get out of the tube business, we are offering tubes direct to you and through selected retail stores. Please call 805-687-2236 m-f, 7am-noon, or email: [email protected]. Thanks, Roger A. Modjeski |
Roger, thanks for dropping in. It is a pleasure having someone of your caliber joining the conversation. I hope you don't mind me asking you a few questions and throwing a few comments / observations your way while we have your attention. Even with checking tubes for noise levels, gain matching, etc... how do you account for variables in sonics from tube to tube and brand to brand ? Obviously, not every tube, even though they might have come out of the same batch and production run, will sound or measure the same. That is why i stated that tubes "almost offer TOO many variables", even amongst the same brand. I know that people that work on / design gear for a living tend to look at things like this as kind of a science. I also know that the many years of experience have taught you a LOT of the "in's and out's" of what to look for. None the less, i still think that it is almost impossible to know exactly what tube will work best in a component in a specific system without actually trying them out. Obviously, the work that you do somewhat "pre-qualifies" the tubes in that they are not "junk" or "noisy", but that does not specifically tell anyone what sonics they might possess in a specific piece of gear. As you know, changing just a few of the operating points within the curve can DRASTICALLY alter both the readings and sonics that you get out of a device. This is true of either tube or solid state devices. As such, how do you select the specific settings that you choose to use when testing tubes ? How applicable are those results on a somewhat "universal" basis ? Sean > |
Does not look to me, that the above mentioned article answers Sean's very well founded question. I sincerely hope RM will come back to this thread. He, by the way, was the designer of a wonderful preamp marketed by Beveridge, which a hatchet job review of HP in favour of the SP6 unjustifyably drove off the market and Beveridge into ruin. Cannot remember when that was, must have been in the seventies, It was then, I think, that RM started RAM tubes and his RAM Labs enterprise. |
Sean, Thanks for the question and thanks to Bullwnkl999 for pointing you to my article "Why and Amplifier's sound changes when you change the tubes". I started designing circuits by ear (and my oscilloscope) at a very early age, before I had studied electronics formally. I felt then and still feel now that circuits affect sound more than parts. Yet parts interact with circuits, and that's the rub. As a mature designer, I design so that part variations have the least effect on my circuits. Therefore, you may hear the least variation when you swap tubes in Music Reference products. In the examples given in the article mentioned above, the changes were both audible and measurable and due to circuits which, in my estimation, are too sensitive to tube variations. Now, does a certain tube, say the smooth plate Telefunken always sound the same in every circuit? I don't find it so. Does a tube have frequency response properties of its own? Definitely not. Can a tube change the frequency response of a circuit? Yes it can, but it shouldn't, not in a good circuit. Although we can't fix overly-sensitive circuits, we can screen the tubes for operating parameters such as gain (mu) and plate voltage for a standard bias value. This is better than just a transconductance test in a Hickok as it measures where the tube will "bias up" in a typical circuit. I find that the self-bias point is the most important factor in sound as it affects distortion directly. We have rejected many of the recent 12AX7 variants as they do not "bias up" anywhere near the accepted (RCA, Sylvania, GE, Telefunken) values. As those companies used the same published curves (have a look they are all the same), their tubes biased up to the same point (except for tube to tube variations). So I agree with your last statement wholeheartedly. We keep a tight watch on operating points, and even have customers savvy enough to request tubes from the upper end, lower end or the middle of the range, as they know what they like. Since all the data is on every tube, we can easily pull what they want from stock. With all this information on every tube, why buy random tubes where you dont know anything about the noise, microphonics, gain or operating point. I'll share a little story on noise. When I was visiting the EI factory in Yugoslavia I mentioned to the engineer that the folks at Sylvania (in Altoona) didn't know how to make a low noise 6DJ8, 12AX7 or any preamp triode. It's mostly a function of cathode coating. When I saw how crude the cathode coating technique was, I wondered how a low noise tube gets made anywhere. They just mix this powder up in a bucket with water and spray it on the nickel cathode sleeves. So I asked the engineer at EI how they got such low noise cathodes (theirs are the best I've seen). He said, "Well we dont know for sure, its not a repeatable thing, we have learned to mix the coating a few days before we use it, it may be the water, it may be that the janitor takes a piss in the bucket at night". Well, they say its the water that makes New York bagels the best. Go figure. |
Roger, THANK YOU for responding. You have at the very least acknowledged and answered many of my questions. While i have nowhere near the experience or knowledge that you do, it is good to see that many of my thoughts and findings parallel yours. I see that you find most of the differences in tubes to be due to poor circuit stability. I can see and agree with that ( to a point ). I also noticed that you did mention variances with tubes, especially from manufacturer to manufacturer. Like anything else, I guess that this is to be expected. As to knowing what one likes in a tube or finding out what to look for or request, i guess that this would vary somewhat from component to component. As such, we are still somewhat stuck with doing quite a bit of trial and error. I would think that, and you acknowledged this, everything hinges on one MAJOR variable. That would be the knowledge and understanding level of the engineer that built the product. Once one was able to find out the specifics of what they preferred for that component, the service that you offer should come as a GREAT benefit to the consumer. Do you offer "suggestions" to customers as what you think might work best for them ? I do have some tube gear but am FAR from being knowledgable about various brands, production runs, etc... Having someone that is both a VERY knowledgeable designer and "experienced tube tester" to help us along would make a lot of our lives far more simpler and possibly even less expensive in the long run. Sean > |
