As some of you know, the Traynor YBA-1 is a very close derivative of the classic Bassman/JTM-45 circuit. I recently picked up a spectacularly clean `67 copy that was all original with the exception of a rather `crappy` fully reversible master volume mod and unfortunately a burnt Power Transformer. This is the version that has the SS rectifier and
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choke and is exactly like the schematic that can be found here: I spent quite a bit of time trying to locate a period correct PT, with no luck. these things were built like tanks and over engineered wrt the power circuits, hence, not many really bite the bullet. I finally ended up using the failed unit as a reference for locating a current production similar sized Hammond PT, which I found in the 278CX. Ironically, the form factor and mounting scheme was exactly alike, so all good there. Except - and this is a pretty big *except* - the secondary is wired for 800V center tapped. My calculations put the B+ at well over 500V. I have no idea what the specs are for the original, Hammond doesn`t have a clue, as these were specially produced for Traynor in the mid-60`s, and emails with Traynor came up short - apparently they don`t keep records that long either. So off I go. The original tube chart calls for 7027A power tubes, which were rated north of 500V on the plates and 450V on the screens. So I bought some of the CP JJ 7027A`s, which are really just larger bottled 6L6GC`s (I have found out), and installed the 278CX. While waiting on the PT to arrive I also did a bit of maintenance, 3-prong power w/death cap removal, cleaning the pots, replacing all the Electrolytics, checking the main coupling caps for DC leakage, installing a variable bias adjust pot/1-ohm 1% resistors off the cathodes, verifying and replacing key resistors...
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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