Welcome to my guestbook, where you can see what previous visitors think about this site and my projects and articles. Many thanks to everyone who has left messages - your feedback really is appreciated!

Guestbook entries from 2012 (13)

    • Michel Desrosiers
    • Joliette, Qc. Canada
    • 1 December, 2012

    Thank you Mark.

    Very useful. I own a A1 since 1989. I have a problem actually, i don't know exactly what it is, but with your drawing i will find the trouble more easily.

    Thank you to take the time to build this website!


    • Constantiu Soare
    • Bucharest, Romania
    • 29 October, 2012

    Hello Mark,

    Congratulations for your web site!
    After successfully building a DIY air bearing tonearm for my turntable, the next step was to build a decent power amplifier.
    Your Micro-Amp seemed to me the best choice. And indeed it was!
    I used your schematic (except the mute/thermal protection). For the power-on mute I used the simple circuit from the TI LM4780 data sheet which works fine.
    The amplifier worked fine from the first power-on attempt: no oscillation, no hum, just MUSIC


    • Laurence Gibbs
    • UK
    • 24 October, 2012

    Hi really enjoyed the info on the Musical Fidelity A1. I had one from new and had a diode in the bridge rec fail when it was a few years old. Can't remember what i replaced the diodes with now but it was for something a little better quality (i worked for the now defunct Mastercare as a TV & Radio engineer at the time, just out of my apprentiship). Sadly i sold the A1 (big mistake). So I keep looking for one on Ebay at "the right price".
    Thanks for the interesting read.

    • Tim Lim
    • Georgetown, Penang
    • 30 September, 2012

    Hi Mark,

    Great work. I stumbled upon your site when I goggled for BBC LS3/5A. It is a shame the other models of BBC are not as well known outside of the UK. The current owners of Rogers, whom incidentally is based in my country, should really revive those other models.

    Best regards,

    • cyrille
    • arnhem, netherlands
    • 27 September, 2012

    great site!!! thank you!

    got a pair of p-20's, got a brochure pdf if you want to.

    groetjes Cyrille

    • john
    • Marietta, GA
    • 10 September, 2012

    Thanks for the editor tip! I've been using metapad which is useful and I like it but not especially designed for code. So far I like ConTEXT and its loaded with options and customization features.
    You may be curious about some of my work, if so, here's a sample:
    Enjoyed your site.

    • Graham Tait
    • Edinburgh
    • 11 August, 2012

    I wish I could organise my garage like yours! Much admiration.

    • Norman Jackson W7NRJ
    • Near Seattle, WA, USA
    • 6 July, 2012

    Electronics hobbyist, ham radio operator, just getting in to PIC's, found your site. Your writing style makes it easy to understand, minimum mumbo-jumbo techie talk. I appreciate your effort to help others understand PIC's.

    • John
    • New Zealand
    • 1 June, 2012

    Thank you for the write up on the differences between non-inverting and inverting gainclone and the value recommendations for the resistors, it has been of great help. Kudos on writing it up in such a clear and simple way that's easy to understand.

    • ranulfo ymbong
    • philippines
    • 7 April, 2012

    Hi, i'm happy that you shares your knowledge about pic micro-controller to us, i find it very useful. thank you very much.

    • Paco
    • Spain
    • 14 March, 2012

    Hola amigo:

    El blog web es excelente. Multitud de informes y bien redactado.

    Gracias por ayudarnos.

    • mauricio marotta
    • BRASIL
    • 14 March, 2012

    Dear Mark.
    Thank you.
    G b y.

    • Kelvin Turner
    • Oxford
    • 26 February, 2012

    Hi Mark! Great site. I want to thank you for all the info. and tips you have here. They helped me enormously. Here's what I just posted on the DIY audio site..."Hi all! I have just completed a replacement programme of all the electrolytic capacitors in my MA50 monoblocs and WOW what amazing amplifiers these things are! I remembered them being praised to the skies in the days when they were available new (mid eighties) in magazines like HiFi Answers. At that time I could not afford such luxuries, but when I found a pair of these on ebay I bought them. I listened and thought I had made a mistake, but then I found Mark Hennessy's site and followed his advice about swapping the electrolytic capacitors as a first step to rejuvenating the amps. I have never done anything like this before, but i managed to work out how to make the changes and executed the soldering with great care (the circuit boards are old and the track has a tendency to come away some times). The results are FANTASTIC! I will post a list of the capacitors I used on Mark's brilliant site in a kind of homage to all he has done to help me. Good luck!"

    I would like to send you a list of the capacitors I used in case it helps anybody else to make the improvements I have. Could you let me know how? Cheers. Kelvin.