Equipment

Cibalba Stage And Studio Special Studio Problem & Solution Focus

We have a long history of not only providing a service, but of innovation and engineering great sound.   Our expertise falls into these general subject areas:
1) JBL speaker modification (see our Djumble.com for midrange and kennedyaudio.com for our 18 inch modifications.    We believe you need speakers running while recording voice for realistic reverb and sound reinforcement. 2) It is typical that vocal microphone pickups need some kind of thickening - either realtime or post processing. 3) Microphonic noise and dealing with it. Feed back loop and resulting resonances.    Our unique solutions incorporates new simiconductors physics where the old electrolytics based tech used to fail, given enough time. And time has taught one golden rule: That knowing may not be needed today, but not knowing makes life much harder for the next person who wants to be involved and use the same methods instead of inventing it from trial and error to succeed!    A) We still have and use a 50K ohm high impedance system and mics. While this type of system is an older design from the days when sensitivity of a microphone was much lower and used magnetic low voltage, these systems mix many microphones better, achieve better stereo stage presence and left/right location information and sound better. The lower voltage older standard allows more current amplitude variation as well and makes it hard for anyone who does not know enough science history to make mixing fool proof, hence it was abandoned for a more narrow milliamp standard, and then digital standard. This happened when newer main board attached volume pots and sockets came into fashion, and the standard volume control now yields a rolloff that allows only less than 2500 hertz at low volume (full 64k ohm) setting and if that wasn't bad enough, the AES made in Mexico thing exchanged the microphone pins 2 and 3. A few quick fixes bubbled up; such as replacing the 12AX7 with half the gain or 1/3 the gain substitutable triode dual 6 volt preamp tubes, but this still requires rewiring all inputs and output panel jacks even if the volume can then be turned higher and not destroy the compression or next processing unit in the microphone chain. Harry Olsen, and engineer at RCA, invented two types of wave capture, to which the Germans of World War II vintage added a third non-magnetic impulse generating polarized diaphragm. So, today we also now have to check every microphone for pin exchange proglems and its intended interface standard's variable compliance level. This is the stuff we do at Cibalba Stage and Studio. We are not a retail operation by ANY means, but we do have retail chain parts channeling capability we use for quality improvements like djumble.com's innovation efforts.    B) The problem is more than that MOST microphones are balanced these days and almost all instrument systems are unbalanced, which requires a lot more special equipment because the two systems are completely incompatable for low noise studio purposes. Conversion is done in our studio by special converters that maintain phase relationship.    C) Many pickup or diaphragm types with different sensitivitys interface with preamps with different noise generation to signal pre-gain (line level) to power amp gain profiles. We designed unique amplification with very high sensitivity - down to one millionth of a volt - to deal with high noise solid state and expose the hidden sources of problems that come up in post processing or conversion into digital format when desired. We sell / build our amplifier. 4) Bass frequency instruments require exponentially more power. Sometimes tube amplifiers with special tubes and/or transformers can make this combination sound smooth, but the quick easy way is to use solid state power amplification. Tubes become liquid when operating. The metal plates are partly melted and the vibration of the tube causes ringing and wears out the bass tubes in this application quickly. This microphonic ringing also makes microphone applications with specialized bass tube amplifiers very difficult. However the distortion can be very pleasing to the ears. At one time the 6L6 (before the 'C' version) used interstage transformers. The purpose was to put capacitors into the grid control (-) and plate (+) voltages to regulate the output spectrum and not rely solely on the output transformer because the coils in the transformer (inductors) and the tube itself (switches current based on change in volts) favored the lower frequencies and did not allow as much throughput after 2500 hertz. However, if the interstage transformer burned its sensitive primary coil (it was exposed to high DC which could only be filtered by large 500 volt electrolytic capacitors that can dry out when stored) then the entire circuitry was destroyed - output transformer (expensive) and all the tube - with smoke! 5) Good midrange and treble requires a Class-A amplifier, to which we add field coil amplifiers and speackers of the type that modulate the magnetic field through the tubes. We also use compression drivers extensively but they need matched midrange speakers to get clear tone as well as intentional distortions and intermodulation (musical Chords) to resonate well. We use the 10 inch JBL extensivly in our recordings and believe it to be the best sounding speaker that exists, as well as using many modified 15 inch with an 18 inch voice coil, which you will hear us call a 2228, for best midbass. Such issues as even harmonics (much better with tube amps than solid state) and how the tubes are operated (class A versus wired for class B) are addressed here. 6) Guitars and their pickups. These vary widely. We have in stock a wide range of vintage guitars, fretless bass, 1950's, Fender 1970's, Rickenbacher as well as guitars for leads with build in resonation chambers and elements such as a 1960's Nobel thinline, Dana Alvarez scoop, Electra, Victoria, Harmony Meteor, and acoustic guitars. Frankly sometimes there is nothing better than a cheap souding guitar. It depends upon the song. 7) We can get 'high end' analog (soundcraft) or digital mixers (Tascam 16) but our standard mixer is a british made analog 16 channel which we believe gives better stero sound stage. The initial recording can be on 1 inch or half inch (Tascam 16 channel) which goes into our high reliability Tascam 44 mixdown unit in half inch four channel before it is either burned to CD format or put into some other final recording by various methods. We have video capable of 60p, a resolution so high that it has to be sent to specialized studios in Canada or California just to convert in to final commercial format.





Studio Equipment



Matching Mic Transformer




Tradeoff table of Target Load's 'input' impedance
AWG of Wire 200 ohm rated Z 600 ohm rated Z
14 AWG, std 110v 450 Feet Max 1 mile Max
20 AWG, std 12v 100 Feet Max 1500 Feet Max
28 AWG, std mic 10 Feet Max 50 Feet Max

As wire size gets large, the dB of loss increases and more source voltage is required. But as the table shows, Large wire is capable of doing the job. So, the wire for stages and for studios is vastly different. On studio time, bridge impedance, not match impedances are used. The bridge impedance is relative to skin effect and electron spin variables, not high Z versus low Z. Cibalba Stage and Studio does solutions AND standards. AND we can demo every common preamp tube and GT version of it using our transformer matching expertise as well. At Cibalba S&S we sometimes wind our own transformers (with great success) for better control of mic to preamplifier, perfect transducer resistive coupled response. As much as consumers want it, digital STILL does not show any listening test improvements at higher sample rates, and even then they are listening to a two dollar microchip in a $450 box. While we have TI brand encoding and glass cable, the black magic is in effects of speaker cable, preamps, tubes, low bias even harmonic distortion, 50:1 transformer bridges and even solid state preamps running at their full power with attenuator plates. We believe in exhaustive reading and interpretation as a beginning point to golden audio. Do onto others... There is NO intrinsic value in high priced audio interfaces. It is too often done for the sake of saving time and political disagreement. With processing such as compression, our stanard is the Waves L2 type units. It unlikely however that this would ever concern one who wants to start from zero and develop a relationship with a good vintage mic or transfomer or hijacked from power tube preamp signal. Leave that to us. It can be dangerous anyway and certainly has it's share of headaches and putz part R&D costs. Vintage audio studios are spattered around many states, But few offer drive in, drive up and walk in services (in summer only). Custom Mic Transformers wound Gold Audio Mic Sound









Speaker Reactive Loading Science in Audio Applications For the more technically aggressive customer

Cibalba Stage And Studio Special Studio Problem & Solution Focus

For any one out there in the great golden sphere that is interested in doing math that is aligned with the science of magnetics, We can offer some guidance about what topics we consider relevant to our continuing improvement efforts and R&D. One area of profitable study would be the development of attenuation devices for solid state amplification. This basically allows them to compete with tube amplifiers. The problem is that solid state transistors are designed to supply current that takes advantage of holes in electron state transfer rather than what a tube amplifier design does. A tube is magnetically coupled while solid state eliminates transformers, and the magnetic field generation. Normally AC signal has essentially three components, somethink akin to 3 phase electricity versus one phase, but not the same thing. The three components are 1) The Reactive (Magnetic field or capacitor ) Power Q= E*I*Sin(Phi) and is in VAR(Reactive Volt Amperes} or KVAR 2) Real Power P= E*I*cos(Phi) where the angle (Phi) is the Power Factor and after Q and P is 3) The apparent Power S=E *( I Conjugate ) or S=(E conjugate) * I . S is in VA or in KVA. When a transistor is capacitively coupled, it acts with Q, but Plus Q is instantly available whenever changes on the opposite plate of a capacitor is due to plus voltage which instantaniously induces a negtive Q on the plus terminal capcitor plate side) The same transistor if inductively coupled, acts with Q but Plus Q is available after plus voltage reverses the momentum in the coil from the previous cycle and with that voltage being selectively absorbed and dropped at different resonant frequencies and extinguished gradually as frequencies get higher opposite of the capacitor coupled reactive load. Putting both onto a load line in parallel therefore causes circulating voltages and current and distorts the signal far beyond desired levels. That is because while voltage tends to act instantly, inductance requires time factor compensations. That is, the MAGNETIC part of the three parts has vastly different reactive properties depending on how current flows. Only the current flow causes motor action in the speaker but only voltage changes that change plate charge and then move current toward a capacitor plate which had been otherwise charged and is now acting like a reversed charged magnet or coil can move the motor. Furthermore, the magnet in the speaker requires the entire magnetic field to collapse to a center line like in a zero point energy generator in order to pull the cone back into full retract position. The process must be controlled or at least adjusted, hence a difficult to read discussion of variables comes up in discussions about reactive loads and solid state amplifiers. Design Solution: While such design is still in infancy stages, one approach is to eliminate iron cores and other metal cores materials and use air cores only (no metal core). Another approach has been to simply use tube amplifiers for low frequency applications. That fart sound you hear at your friend's home theater is the subwoofer doing just what this article is all about! This air coil method is just one transformer design technique that is well known to assist in reducing the reactive component that adds complex loading and excessive draw for solid state devices. Negative feedback and stabilizing designs become more narrow in their scope of application whenever such design is attempted. Progress is a evolution and structural standard dependant decision process. We have yet to embark on that journey. Even with computer math and models, it is thus far been left to clever innovators by trial and error methods to prove it can be done. The most progress has been made in subwoofer cables and ribbon microphones that twist their ribbons stretched between reversed magnetic horseshoe sets. This at last, with the help of the internet, is becomming widely written about and accepted as a valid area of research which yields results, even if it is not the easy low hanging fruit that digital processing technology is.

A bit of myth debunking is in order about negative feedback. The tube amplifiers use positive feedback in their power output transformers ( to the plus grid G2 or screen / grid). Tube amplifiers use a lot of feedback in their preamps (12A?7, just like solid state amplifiers. However, a few designs used interstage transformers instead. Because both solid state (servo impedance load feedback - called chopper in digital or differential in discrete transistors) and tube amplifiers (reflected impedance load feedback) favor the midrange frequencies where there is less resistance to signal coupling due to average matching impedances, these interstage designs are the vocalist's prefered system. But an even better system is to bypass retailing, bypass computer blogging, bypass the academic bias of the 1970'2 that viewed puritanical midrange as the only part of the spectrum that was stage and studio worthy and go see somebody in a recreational home with your chosen familiar SS or tube amplifier. In other words, modify the old, don't follow what's sold. We believe in combining SS and tubes. Neither one actually needs positive or negative feedback to work, it is used because of the wide range of loudness settings that most people use. You can turn any $200 amplifier into a $2000 preamp and $3000 power amp with a little love. And Those new digital sound computer systems are pretty much like the phone system. They will transmit to you a signal and give you one knob plus on button, but that's all they ever will do.

This may at first seem a very radical solution, especially to those reading advertising tauting 'hot' speaker deals.

A good example is the very low sensitivity speakers sold for automobile system, typically 86dB or 12 times less sensitive than DJ speakers are. These are attenuators that allow the current amplifier to run near it's full potiential thus eliminating differential feedback that destroys harmonics, especially even ones. The extra even harmonics in turn make the car stereo sound more like a tube amplifier would sound, with less risk of heat causing the already complex impedance of a voice coil in a magnetic field to draw too much power. Extra air space for voice coil gap is part of this design system as well. The designer gets more cooling and avoids adding attenuators which are probablyl going to be vacuum tubes. And Vacuum tubes are expensive and breakable when removed by the glass envelope, and bent pins are constantly popping out. This, excessive power output, is the designer's secret danger in solid state transistor discrete amplifiers, and so volume is controlled as near the small signal preamp origination point as possible. Even a tube amplifier does change its voltage when a speaker gets hot but because the power tube is always running near its maximum voltage, there is an upper limit on voltage draw. The current must have voltage to draw it, but voltage does not need current to respond to it. Current reacts to voltage and there is another major difference. Some articles on audio like to say that both systems favor midranges because of the fact that ohm's law acts backward from the speaker the same way. However, these over simplified discussions are very unproductive for decision purposes. They are not for the advanced audio readers but often are dressed up to look like they are very professionally selective text on the subject. When a DJ speaker on a big solid state amplifier feedback control system gets hot, its gets a more compressed sound due to the suppression of current by the feedback safety electronic loop. In a 12 volt current automobile, that does not happen and in a high fidelity tube amplifier, a center tap may be used to cause the ground to float so it's called positive feedback. The positive feedback is just one simple form of power amplifier feedback. The more complex systems are called ultralinear due to their leveling effect. But all of them tend to increase and skew the phase relationship of several important ratios when they are active, including the heater voltage to plate sag ratio and the more desired lower ratio of matching impedance to inductive reactance type impedance in the transformer. As a result, simple very low power single ended mono amplifiers with low gain single element set (unbalanced type) have had very real advantages in sound quality without any extra added safety overrun controls systems or balanced load signal path.

At Cibalba, one thing you get is a heavy reliance on the old designs from the days of pre-feedback or no feedback systems. The 6SK7, 6J5, 6SL7, and for solid state 12SK7 preamp interstage and attenuation technologys. We even work on the newest recreation effort of single ended non-feedback low power system - the high power 2A3 running at 420 volts. While the old tube construction could take more power, they were intended to last as long as possible, not produce finest audio spectrum sonic profiles. One article even states that 1963 designers of monolithic (transistor) amplification had better performance than one of today's third generation chopper stabilized feedback digital amplifiers. the ATT 300b brother tube, the 2A3 is from China, but today the typical Chinese audio student is replacing the Research & Development that once was so common in America, and doing a pretty fair job at advancing the art while not falling into the same cost quak-mires that AM radio made in the rest of the world, making solid state sound like a blanket was thrown over the speaker when it does bass lines and musical intermodulations.

Without giving away years of research and development in tube amplifiers and microphone reconstruction, we would like to conclude this article with a brief look at how we achieve better studio and stage sound.The two are quite different. Usually. Not at Cibalba however. First, the ribbon elements of very high quality microphones are thinner, more delicate.Those ribbons can not be moved about like a stage that gets reconstructed between acts or a tour bus would do. Thicker ribbons in the same microphone can do that job, but at a cost of response quality and bandwidth.

Second, tube amplifiers have their similar sensitivity problems. We are stong on design for frequency modulation for upper high tones and harmonic resonance effects, but we use a different approach, amplitude modulation for bass frequencies. The ideas are our American innovation that is similar to but not the same as recent European modifications to the existing tube sets that eliminate feedback and volumen pots and focus on matching resistances, interstage watt usage and a full balanced design. Just a balanced design far exceeds ordinary tube power amplifier stability and clarity and helps us add the exponentially greater exaggerated tone needed in speech and vocal recordings. While stereo amplifiers tend to limit the tone and harmonics added to preserve clarity and soundstage, our work is more like an old movie director's design to maximize the actor or actress as a brand by achieving brand recognition. We plan to continue our work, expensive and tough to manage, with common off the shelf lower cost components and allow our users to compare to the expensive approach as well.