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Greg Hanks BA660

5.300,00  4.995,00  + 21% IVA

Whither Tubes

…Smooth,…Fat,…Warm,…Silky,…Analog.

                   These are just some of the terms used to describe the sound of vacuum tubes. A technology in resurrection. A boon for the listener and a bane for the designer. From an engineering standpoint there are many difficulties with tubes;

  •  Low gain
  • High electrical noise
  • High distortion
  • Thermal instability
  • Low mechanical stress thresholds
  • HIGH VOLTAGE!…(DANGER)
  • High output impedance
  • Low drive capability

            Faced with the question of why use tubes, aside from the obvious marketing advantages, we have to look at what a tube offers that semiconductors don’t….. Headroom! (a by-product of above item 6).

A little background is in order. Of the five senses, hearing has the widest dynamic range. On the order of 7 decades (140db), our ears rival the sciences to accommodate with fidelity the capturing of perceptible acoustic phenomenon. Because of this, I have set out to produce the world’s finest Microphone Pre-amp with the widest dynamic range possible within practicable means (154 db) and couple it to the best limiter that I can build. This device can present to standard studio equipment a signal of exceptional purity within the confines of our current digital dynamic range window of 96db(16bit), [or 120db(20bit)].

How do we do it?

            When  examining ‘classic’ tube designs, the trade-offs made at the time of the design must be examined and the logic behind them explored. In the ’50’s and ’60’s the cost of components, (Caps, Precision resistors and tubes) was considerable. Most engineering effort went to squeezing the last ounce of performance out of every part used, then using less parts, at a subsequently lower cost. A four stage design was extravagant indeed! The audio benefits of such an approach are those of minimal signal path, but at the expense of stability, linearity, distortion and circuit flexibility.

Manufacturing and automation technology has brought about enormous economies of scale. Mass assembly methods have reduced the expense of discrete transistors, resistors, capacitors and sockets. The cost of components has thus plummeted to a level where the sheer number of devices is no longer the primary bounding element in circuit topology.

            Exploiting technology in the production of our tube Mic Pre/limiter line we have capitalized on the benefits of tubes by utilizing semiconductors for the stabilization and bias of the tube elements without the necessary sonic trade-trade-offs, (Audio passes only through the tubes) and without the concurrent trade-offs of noise, distortion, thermal instability and high output/low load impedance that have previously plagued tube design. With careful attention to parts selection and biasing choices, the Mic preamp has a noise figure that is set by the losses of the input transformer.  We  achieve the exceptional noise performance of the limiter by utilizing the wide headroom margin internal to the Mic-Pre/comp-lim (+40db), instead of requiring 25 to 40db of attenuation of the input signal to provide operating range.

            The most significant tradeoff necessary in this implementation is that I have not used global feedback and have kept local feedback limited to DC bias. This means that the measured distortion figures are high (<.3%). The use of  feedback (which is how all low distortion figures are achieved) brings a new set of problems which have adverse sonic effects. The dichotomy is  that equipment with low distortion figures achieved via large amounts of feedback don’t sound as good as gear that has high(er) distortion numbers but achieves fidelity through careful balance and bias.

            Our patent pending methods of tube control yield performance heretofore unachievable and provide pleasing sounding equipment capable of handling any signal that current transducer technology can source, now and into the foreseeable future. Have a listen.

Descripción del Producto

Manual de Usuario

BA-660 Motherboard Build of April 2012

BA-660 Motherboard Build of April 2012

Birth and growth of BA-660 Motherboard
BA-660 stereo coupling 1

BA-660 stereo coupling 1

Demonstrating tracking of gain cells of two BA-660’s
BA-660 stereo coupling part two

BA-660 stereo coupling part two

Illustration of unit to unit tracking Without being coupled
BA-660 Gain control parameters illustrated and explained

BA-660 Gain control parameters illustrated and explained

Attack and release times and shapes
Limiting vs control voltage

Limiting vs control voltage

Top trace is plate voltage of gain cell Control voltage is superimposed on input signal
nbs 101

nbs 101

Work in Progress! First look at NBS (No Bull Shit) modular series. Mic Pre with remote control volume. Solidworks by Bernie Daraz…. Mechanical Genius!
BA meter in use

BA meter in use