class A Line level buffer

[Bonsai]

Hi, I've just posted a class A line level buffer design up on my website.

Also just added is an article on RIAA Equalizers.

[Ken Newton]

Andrew,

As far as I'm concerned, you win the trophy for the most professionally presented and documented diy project I can recall having ever seen. That goes for the design of your hifisonix website as well. I have some sense of the time and effort it must have taken. I'm extremely impressed.

[Bonsai]

Hi Ken - appreciate the positive comments!

[PMA]

Very nice, Bonsai. Are the plots, like FFT Figure 3, measured or a result of LTSpice?

[Bonsai]

Hello Pavel. LT Spice at this stage. This weekend I am assembling a proto on veroboard and will measure it next week on the AP at work. Article will be updated then.

[Bonsai]

Hello, I've just posted up the final article on my website below on the buffer. I was able to get some measurements done this week on the prototype I assembled last weekend. The actual measurements are now included along with minor corrections to the original article.

[diegomj1973]

Hola a todos!. Soy nuevo en el foro. Soy de Argentina. Vivo en Marcos Juárez, provincia de Córdoba. Quiero compartir con ustedes un diseño de circuito de mi propiedad que consiste en un power follower (drain común) capáz de desarrollar hasta 1,25W rms (por canal) sobre una carga de 6 ohmios mínimo y con niveles de distorsión más que aceptables. Dispongo de toda su especificación técnica para quien lo desée armar.

Actualmente lo utilizo conectado a la salida de un CD player (2V rms), con lo que obtengo potencias de hasta 0,66W rms sobre 6 ohmios.

Saludos

PD: excuse me for my english!!!

translated by moderation


Hi everyone!. I am new to the forum. I'm from Argentina. I live in Marcos Juárez, Córdoba province. I want to share a circuit design of mine which is a power follower (common drain) capable of developing up to 1.25 W rms (per channel) with a load of 6 ohms minimum and more than acceptable distortion levels. I have all the technical specifications for those who wish to build it.

Currently I use it connected to the output of a CD player (2V rms), with which I get power of 0.66 W rms at 6 ohms.

Greetings

[tinitus]

hi, diego

please post in english


moderation

[AndrewT]

Hi,
just had a read through you pdf.
Well done.
It looks so simple and yet performs so well.
I'm thinking it might just be ideal as a headphone amp.
I happen to have 3 soic8 samples of the 4562
One chip and a few discretes and I'm done !

[Bonsai]

Thank you Andrew.

I also want to measure (maybe next week) for reference an NE5532 and a TL072 in the same proto board. I susepct (and hope) the 5532 will also measure well - maybe 10-15ppm, and TL072 at maybe 20-30ppm.

My 'high end' pre-amp I am working on at the moment uses LME4900 buffers (cost a fortune . . . ). Next time round, I'll go for this buffer - less expensive, class A and performanc is not bad.

For a h/phone amp, if you use a dual op-amp, the unused part can be used to do a 2x or 3x amp to feed the buffer stage, since coming straight out of a pre-amp line stage (c. 1V RMS) you need a bit of extra gain I've found. To keep the whole thing class A, you will need to preload the first amplifer stage as well. I might draw something and put it up in the next few days - very busy at the moment.

I'd be interested to hear about your results.