Aum Acoustics Triode Buffer
Replaces An Active Preamp With About 5-6db of Gain
Incredible Sound Quality Using the Most Linear Portion Of The Triode Tube
The Tube Is Operated At 30 Volts Instead of the Normal 300 Volts
One Of The Best Buffers Available Today (Maybe The Best)
I'm building and selling a very unique "high level" audio component. It's a single tube buffer that is an excellent replacement for a 20k+ active preamp. The tube is operated only at 30 volts where it's sonic curve is most linear. The two power supplies are some of the best available using two Belleson regulators. The buffer board uses only naked Vishay resistors and the toroidal power transformer is a custom design done by an engineer at toroid.com. I shared the schematic and operational points with the engineer and he designed the absolute best transformer for the two power supplies plus included an electrostatic shield to lower any background noise.
This buffer is as transparent and clean as is possible using one single 9 pin triode tube. The buffer circuit was originally designed for a 6H30p tube but that tube doesn't sound that great (in my opinion). It's got way too much gain and provides too much boost to the midrange area plus it doesn't provide a delicacy that I require when placing a tube in my audio circuit. I've spent almost 9 full time months working on and perfecting this buffer circuit. It's finally "there". I've listened to every single connection point and have modeled many different wire metalurgies and gauges. In the end, I feel that I've perfected this circuit as much as is possible and I now know how to tune it to perfection.
I also spent a huge amount of time and money finding the absolute best sounding and most linear tube. The tube I eventually discovered to be the best is the 1975 Reflector SWGP silver shield tube. There's nothing that touches the sound quality of this tube. The closest competitor is the exotic and uber expensive Siemens CCA tube but it is even dwarfed by the sonics of this particular tube. No other year, manufacturer, or alternative works anywhere near as well. Even other tubes made during 1975 don't compete. It has to be this tube and they're getting extremely rare and difficult to find. I've purchased a stash of these tubes and will include one with the purchase of any buffer that I build and sell. Because I'm running this tube at 30V instead of the usual 300V, it should last for a very long time. I'm expecting at least 10 years of use before needing replacement.
The key to the beauty of the sonics of this tube buffer (an uber expensive preamp alternative) is the coupling capacitors. Everything in this circuit is about providing linearity and transparency. The only body and textural tone included comes from the coupling caps. They are key to creating the sound quality and are most important element for gaining the incredible sound quality this circuit is capable of. I've spent a huge amount of money and time modeling Jupiter copper foil, Jantzen foil and other high-end capacitors. They all sounded weak and uninteresting (suprisingly). The coupling caps that provide the "uber" sound quality that I'm now getting is a pair of V-Cap CuTF copper foil teflon coupling caps. Unfortunately, this cap costs $1,151.96 a pair. I've tried lower cost V-Caps (OIMP and ODAM and there is no comparison - not even close). The only caps that sound superb are the CuTF copper foil caps. Their inclusion really adds to the total parts cost but in all honesty, they are what create the sound quality that will competes with 20k+ active preamps. Volume control is provided by a Tortuga based LDR unit (that I also customize and build with superb parts to gain another level of transparency). These two units are absolutely breathtaking when combined with a great DAC, a great power amp, and superb speakers.
This volume control solution sounds relatively "flat" and "uninteresting" until it's combined with the triode tube circuit. This circuit adds the most beautiful and linear 2nd order harmonics using the best tube I've found. The 3D spacial-ness and sound quality provided by this single small triode 9 pin tube is huge, beautiful, and does the least harm to the sound quality. Bass has slam, midrange is textured and full with body, and the treble remains super transparent and incredibly beautiful. I'm really impressed by the sound quality this buffer and LDR volume control add to my system. If I wasn't, I would have abandoned it during my lengthy and costly fine tuning process.
Parts cost for the buffer is $2,900. I can't lower that any more (without giving up substantial sound quality) and this price does not include the cost of the single exotic 9 pin triode tube ($150) or my time and research costs (easily over 5k). I'm willing to build several of these units and sell them for parts cost only without markup for my time (considerable) or the R&D costs involved. As payment for my work, however, I'm asking that whoever buys one of these unique buffers provides an honest review that I can include on my website. I'll enter your review on my new website (when it's built) and this will help others understand how good this component actually is. I will build one of these units at a time and then offer it for sale online. I won't accept orders in advance.
Meanwhile, I do have one single ended, single triode (6922 tube family) unit available for sale. It provides about 6db of gain and is the most linear tube component I've ever heard. It should be connected between your volume control (RCA inputs) and then connect to your power amp (via RCA outputs). If you need a volume control, I build a single input or 2 input small LDR based unit that I'll be glad to discuss your needs with you. Two alternative volume controls that work well (but don't have the features of the LDR unit) are the Slagle autoformers and the Stevens and Billington transformers. However, the OLED display that is designed for the Tortuga based LDR and the Apple Remote is so much better plus it has 100 attenuation steps (not 24 or 48) and the ability to change output impedance. Sound quality for all three volume control methods is excellent and all three would work well as a "front end" volume control for this triode buffer. The lowest cost unit and most flexible and fun unit to use? The Tortuga.
Let me know if you have any questions. Meanwhile, I'm now focusing on making my move and will soon be purchasing a new home in the Boston, MA area. When my move is complete, I'll expand this website considerably and will provide more information about this custom buffer, custom volume control, Metrum DACs, and a few other items that I'll be introducing.
Thanks for checking out my website,