2N Bipolar Transistors – BJT are available at Mouser Electronics. Mouser offers inventory, pricing, & datasheets for 2N Bipolar Transistors – BJT. 2N Microsemi Bipolar Transistors – BJT Power BJT datasheet, inventory, & pricing. Electrical Rating, Symbol, Min, Typ, Max, Unit. DC Current Gain, HFE, 40, Turn Off Time (nS), toff, , ns. Maximum Electrical Rating, Symbol, Min, Typ.

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This value has been changed due to the power rating considerations. This is a very basic regulator circuit, without any additional features such as foldback current limiting, and does not have the same performance as an ic regulator. There is also a significant improvement in the quality of the treble where there is greater transparency.


2N697 Datasheet, Equivalent, Cross Reference Search

Anyway, thanks again for the suggestion of these transistors, they are a big step up from the 2Ns and I wouldn’t go back now. It took me several weeks to find out that the sound of the amplifier changed just because of this removal of the resistor. Since the supply voltages and output currents involved lead to dissipations in the order of 17 watts in each output transistor, and since it is undesirable for component longevity to permit high operating temperatures, adequate heat sink area must be provided for each transistor.

This may not have an audible effect, but it ensures a low esr at high frequencies.

2ninfo: Semiconductors, Stock Items

Tr5 is 2N on heatsink or alternative type. However, they can be replaced by the more robust 2N Geoff Moss 2n679 me to write this article. The other results are summarized in Table 2. Reluctantly, they were removed from the circuit due to a faint hum which was not present with the 2Ns.

2N Datasheet, Equivalent, Cross Reference Search. Transistor Catalog

Silicon planar transistors are used throughout, and this gives good thermal stability and a low noise level. The performance criteria of better than 0. I suppose that the final proof of my satisfaction with the class A transistor amplifier was that, a year or so later, I gave my old Williamson to a friend. The result of this change was a more open and natural treble with an increased sense of fluidity, depth and ease.

Some thought, in discussions with interested friends, has been given to the implications of this unlookedfor discovery, and a tentative theory has been evolved which is offered for what it is worth.


This addition is shown in Fig. On seeing these results, Datazheet built a tidied-up stereo version as a Christmas present to myself in The 2Ns were replaced with MJ Since the amplifier ratasheet a straight-forward class A circuit, the distortion decreases linearly with output voltage.

I cannot believe the improvement over my old JLH.

NPN Transistor

At that time,silicon p-n-p transistors were not very good, so the design used only n-p-n power devices. This seemed to be worth investigation, to discover whether there was any foundation for this allegation. The MJ gave a noticeable improvement in sound quality, but introduced a low frequency hum, the cause of which has yet to be determined.

I introduced one ‘new’ thing into the design. Subsequent high-quality transistor power amplifiers have largely tended to follow the design principles outlined in this article. The following list of substitutes has been prepared to assist those who are having difficulties in finding the specified devices. The performance of this simple circuit in terms of ripple voltage reduction is not as good as the previous circuits, but it is still more than adequate to reduce any hum to inaudible levels unless you have extremely sensitive speakers.

I had received reports that the circuit modified to dual supply rails sounded better than the version, but I could not be sure that there were no other variables involved. Before Tim first contacted me, he had built a kit version of the design, which he had subsequently upgraded with higher quality components. The transparency was all right though. However, one of the main benefits of the ccs is that the output dc offset variation as the amp warms up is greatly reduced.

If any user cares to experiment with an alternative and somewhat more elegant form of quiescent-current control another regulation circuit is shown in Fig. Recordings that were previously hard and bright are now sumptuous with crystal clarity, while recordings that were dull are now alive with a new sense of vibrancy. In comparison with these the 2Ns sound grey and rather diffused with less sense of authority, less detail and a more prominent treble quality.

Some obscurity arose, inadvertently, in the original diagram concerning the reason for the different values of input decoupling resistor quoted for mono and stereo use. This increases the harmonic distortion to about 0.

At this point, D. This amplifier did not sound like a transistor amplifier at all, it sounded so round and full and gave an immense depth into the music. But two of my friends urged me to do so. It now appears that the mains transformers used in the development of the prototype of this amplifier were not as efficient in respect of apparent secondary circuit resistance or secondary leakage reactance as some of those which have been supplied for this purpose since the publication of the article.


My amp is singing at this very moment, it sounds just so much better. Most MP3’s sound terrible with this amp. This led to an improvement in both bass firmness and in detail, treble sounded less bright. An additional characteristic of the class B output stage is that the current demand of the output transistors increases with the output signal, and this may reduce the output voltage and worsen the smoothing of the power supply, unless this is well designed.

With the values of the reservoir capacitor shown in Table 3, the ripple level will be less than 10mV at the rated output current, provided that the current gain of the series transistors is greater than The open loop gain of the circuit is approximately with typical transistors.

To this end, I built or borrowed six well thought-of audio amplifiers, my own Williamson, a Quad 2, two dissimilar but recently published class AB transistor amplifiers, a commercial 30W solid-state unit, and a simple Class-A unit of my own design. Alternative method of quiescent-current control. Fig 2 — The Final Circuit Removal of the feedback capacitor I had received emails from a couple of constructors reporting on the beneficial effects of removing the feedback capacitor C4.

I have resolved that this probably has a lot to do with music choice – they listen to a lot of female cabaret stuff which is fairly light in musical texture, not too much outside the midrange and not a lot going on at the same time – avoiding intermodulation and bass problems that test equipment out on rock and classic.

The MJ is more expensive than the 2N, but not by much. Every capacitor sounded different and the one that really made the amplifier sing was the Roederstein other capacitors made the amplifier sound more ‘mundane’, more clinical, more sterile.

There are several cures for this problem. If the old design could sound that good, there clearly is not much wrong with the design itself. Low gain output devices such as the 2N should only be used with a high gain driver transistor, for example the 2N or 2N or a suitable alternative – perhaps a specially selected BD