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Quite a few clients of ours, who purchased one or more of our practical DIY tube amp DVD programs, expressed interest in a more fundamental program that would explain basic terms and issues regarding vacuum tube operation and construction, and their use in guitar and hi-fi amplifiers. Most audiophiles and guitar players using tube amps have a limited knowledge of valves (tubes) and would benefit from a deeper understanding of many issues that are often ignored, misunderstood, misused or perpetuated as myths.
2 DVD programs in one set. 4 DVDs, approx. 5 hours total length! Each of these programs sells for AU$69.- separately, here both for AU$109.- Save AU$29!
Color, in English, region-free discs, PAL or NTSC standard
PROGRAM 1: SECRETS OF VACUUM TUBES Brand new, 2 DVD set (approx. 2 hours and 20 minutes), produced and recorded in 2007 in Australia, by ValveMark founders
Learn:
- Two types of tubes: directly-heated and indirectly-heated
- Physical operation and internal construction of a diode
- Progression from diode to triode, tetrode and pentode
- Electrodes - cathode, grids, anode (plate)
- Control grid, screen grid, suppressor grid
- Different types of grid geometries
- Ideal diode
- Diode as a rectifier
- Dual rectifier tubes - parameters and limiting values
- Full wave rectification using tubes
- Internal construction of a few common triodes and beam tetrodes
- Triode limitations - Miller's effect and capacitances between electrodes
- Beam tetrode compared to pentode
- Dual triodes - 12AU7, 12AT7, 12AX7 (Ecc82, Ecc81, Ecc83)
- Triode as a voltage amplifier
- 3 tube parameters explained - gm, Rp and u (mju) - mutual conductance, plate resistance & amplification factor
- Tube curves and parameters - plate curves, transfer characteristics
- Linearity and distortion
- Ideal versus real triode
- Ideal versus real pentode
- Load lines and operating point Q
- Reactive loads (loudspeakers) and load ellipse
- Loudspeaker behaviour - impedance vs. frequency curve
- Odd and even harmonics
- Choosing plate load - the impact on power and distortion
- Classes of operation - A, AB1, AB2, B
- Biasing
- + much, much more ....
PROGRAM2: SECRETS OF VACUUM TUBE AMPLIFIERS Brand new, 2 DVD set ( approx. 2 hours and 40 minutes), produced and recorded in Australia in 2007, by ValveMark founders
This DVD program covers the use of vacuum tubes in hi-fi (audiophile) amplifiers with some coverage of their use in guitar amps. It will help you deepen your understanding of vacuum tube technology as used in the hi-end audio and will serve as a foundation for your further learning and the mastery of tube audio technology.
Learn:
- Power supply - mains transformer, heating voltages, bias voltage, anode and other high voltages
- Full wave and half-wave rectification
- Power supply filtering - CRC and CLC
- Solid state versus tube rectifiers - lessons from Mesa Boogie amps
- Common cathode amplification stage
- Cathode follower (common anode) stage
- Direct and capacitive coupling between stages
- NFB - Negative feedback: pros and cons
- How to find NFB on a circuit diagram
- Linearity and distortion, fidelity of reproduction
- Triode, ultralinear and pentode operation of the output stage
- Single-ended output stage
- Push-pull output stage
- Fixed bias versus cathode or self-bias
- Classes of operation - A, AB1, AB2, B
- Biasing
- Frequency range (bandwidth) of an amplifier
- Measuring the bandwidth -3 dB points
- Square wave testing of amps - how to tell amp's quality just by looking at the shape of the output signal
- Output impedance and damping factor
- Fully balanced topology - triple differential circuit
- Internal construction of a few commercial amps with 300B, EL34 and 2A3 and other valves
- Detailed discussion of two ValveMark circuits: single-ended, class A triode amp with 300B or 2A3 and a push-pull triode amp with 2A3
- + much, much more ....
The amplifiers pictured are for illustration purposes only, not included in the sale.
REGARDING CHEPSKATES AND LOW-BALLERS:
I have been receiving low-ball offers on some of our DVD programs (those with a "Best offer" option), $12, $40 and so on. These are insulting. Try making such offers to a plummer, car dealer or your doctor or dentist! Some people even commented on internet forums that $100+ for 3 or 4 DVDs is too expensive. Maybe they are too cheap ...
Here is how I see it:
1. These DVD programs are the only ones of this kind in the world, unique. Therefore no price is too high, since you have no other option - you cannot buy a competing from anybody else. I think that AU$109 or AU$119 per set is actually too cheap. That is the cost of a mediocre 3-course dinner and drinks for one in an ordinary restaurant in Australia!
2. You are not getting just a DVD set but a full color-laser printed book to go with it, and with some programs, a colour laminated sign.
3. Each of our DVD programs took months to script, film and edit. Booklets took weeks to design, edit, print and bind. The investment in filming equipment only was more than $3,000, not counting computers, professional video editing software, multiple disk burners, colour laser and inkjet printers and so on. The there is a high investment in amplifiers fetured, test & measuring equipment, parts and components and the like. All those expenses have to be costed and recouped from the modest price of our DVD workshops.
4. Ultimately, you are not buying DVDs, you are buying knowledge! This knowledge comes from more than 80 years of combined professional experience in physics, tube and solid-state electronics, audio manufacturing & retailing, and teaching and training business (Dr Bob since 1950's and Igor since 1980's).
5. This is how I make my living - selling these DVD programs is my only source of income. Igor and Bob provide their assistance and their valuable time for free. I cannot wish for a better husband or nicer father-in-law.
6. Although ongoing technical support and advice is, stricctly speaking, NOT included in the cost of a program, Igor and Bob are happy to answer any reasonable question you may have, free of charge. They cannot spend two hours guiding you through your DIY project for free, but a question or two that take 10-15 minutes to answer via email, we are happy to oblige. That is additional value you get for the modest price of our DVD programs.
7. Most importantly, I have never had one unhappy or unsatisfied buyer, someone who wanted to return a DVD program he or she bought. That tells you something. We ship on the same day of the payment and you get your stuff within 3 days in Australia and within 8-14 days world-wide. Although airmail (untraceable) postage is at buyer's risk, in a few very rare cases where the package does not arrive, we replace it at our expense - we don't want undeserved negative feedback, we want you to be happy! In other words, I try to make your experience with us a real pleasure.
So, if you still think our DVD prorgams are not the best value-for-money around, feel free to spend hundreds of hours searching the web for this information (most of it you'll never find since it isn't there), and then a few more hundreds of hours trying to make sense out if it all, reconcilling often contradictory claims and false information from amateurs, Good luck!
Thank you for your trust and your purchases! Best wishes, Elena
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