I liked the idea of distributed active RIAA correction and also the concept of using negative feedback to linearize the input stage. Now, the original Collin design has a few significant flaws (openly admitted by the author in the same article), one of them being the very poor PSRR in the input stage. To avoid hum and other noise artifacts to enter the signal chain, this design calls for
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a solid power supply, much better than the original. So I decided to add a Jung regulator on the same board. The plan was to feed HPS 1. 0 from a 24V wall wart, so some extra circuitry is required to split the power supply. I decided for a TLE2426 rail splitter. This little circuit works great and it`s ideal for balanced rails current; any imbalance flows straight through the virtual ground created by this circuit, so I would advise to be careful in your applications. The HPS 1. 0 currents are already imbalanced by the input stage JFETs, dragging current from the positive supply only. The TLE2426 gets a little hot, but nothing to worry about. However, further extending the same concept to more paralleled JFETs may create some serious power dissipation issues. There`s not much to tell about construction; just use good quality components (polypropylene caps, metal film resistors) and low noise opamps (AD797 or LT1115, LT1128, LME49710, OPA211 on a SMD adaptor) and the good results are guaranteed. The relays are DIP case 12V models. It is a good idea to mute the preamps before powering up/down or switching the gain to avoid a large thump into the speakers. For this build, the dynamic range (aka the headroom) is around 22dB at 1KHz, for the max gain of 64dB and +/-17V supplies. This is not bad, but has a certain audible as you`ll find later on this page. As you will find in the Measurement sections, the equivalent input noise...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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