I used CREE shottky barrier diodes 20 years ago.....................shocking !!!!! BUT they reveal also the shortcommings of a system..............so they are GOOD tools................they were very expensive twenty years ago ....... UF is exellent for the money and make a difference !!! And there others .....BYV xx etc......... As Peter Walker said half a century ago........................the MORE you open the window the more dust comes in................( but the clearer the view on the beauty of nature when you can get rid of the dust ) Rectifiers is a whole other story ................so often miss - UNDERSTOOD ! ( restart the subject of ALNICO versus CERAMIC on another level ) Have a nice day every one...................
Thank you Frank! Indeed, that's a danger of very good rectification - shortcomings of the rest of the amplifier will be more audible. That's good because it will incentivize to fix the shortcomings... yet, as you said, there's no such thing as simply the best - as a very good one will unmask errors elsewhere.... ;)
Nice to listen to electronical engineering basics, but as usual, I'm far away to follow those kind of AMP DIY. Would greatly appreciate to put it in a DIY series, else I'm a bit lost to follow your different videos. Unfortunately I'm not the bro some of your followers are, just the guy to follow HiFi mentoring fundementials. Never reaching the goal, to build something seriously by myself. Thanks a lot for your passion, love it!!!
I learned emipirically through a point to point kit.. then reading up a bit (start with Aikenamps and Tubecad webpages, then Pete Millet’s online library) you get to understand it slowly.. I suck at math and have no engiineering background so it is harder for me..
There is a book that helped me finally get started. This book is available and is easy to understand. You will build an amp. Look up "Vacuum Tube Amplifier Basics by EJ Jurich"
Hi Janos, Kia Ora from New Zealand! We visited Hawaii just before Covid-19 hit the world and hope to revisit again. I recently purchased a home made 2A3 SET amplifier (2 parallel channels with one power transformer in one chassis) from the estate of an experienced tube radio restorer who had branched out to make his own power amplifier. The driver tubes are 6SL7GTs and it has a hum trim nob. It appears to have 3 chokes (I am not a tech so could be wrong). I bought it to power my Klipsch La Scala speakers. The amp has a tube rectifier and is I had my local tech guy look it over and apart from fitting an off/off switch, said it was well built. The mains hum is acceptable when no inputs are connected but more than I would like after inputs are connected. Any ideas on how to reduce the hum? Cheers David
Hi David, it seems that the problem is with the connected source, the interconnects picking up hum, or there is a ground loop between the source and the amplifier. You can try to ease the ground issue between the amp and source by plugging them in to the same AC outlet. If that's not enough, try adding an extra ground wire between source and amplifier if possible. Could try different interconnect.... but it is all for naught if your source is noisy. Most gear are not designed to be quiet enough for efficient horns. Good luck!!!
@@realworldaudio Hi Janos, thanks for the detailed reply, much appreciated. If I connect each source to the amplifier directly there is not as much hum. I run an earth wire from the turntable to my Ballari phonostage and then direct to the amplifier without much issue. But when the TV, turntable and CD player are all connected via the Ballari passive preamp the hum is too much. I have tried connecting all from the same wall socket via a multiblock outlet, and also connecting them via different wall sockets. I have tried different interconnects. The Klipsch La Scala speakers are simply too heavy to move up and down between floors. I have a pair of Altec Lansing Model 19 in the main lounge (downstairs) that are also too heavy to move up a floor. I am not experiencing the same problem with the sources connected to the Altecs via the Bellari passive preamp. The Klipsch speakers are more sensitive than the Altecs, but I think not sufficiently more sensitive to cause the amount of increased hum I am experiencing. I wondered whether there is a hum on the mains wall socket outlets upstairs but my electrician said that was above his paygrade! So I am at a loss. BTW - where did you acquire all your knowledge? Would you consider hosting a basic training series. I would love to build an amplifier but haven't plucked up the courage. Before choosing which amp, an explanation of what to do, what tools and equipment to have to hand, and how to build an amp be marvellous. Keep up the great work :)
YES Janos..................sometimes forget that people has to begin................One must learn to walk before to RUN................... Words and literature are good but they are not the same as the REAL experience..................a proffesional Guide book for cooking does not make you a great cook after reading and passing an examen...... BAHHHHHH, 12 volt DC is nothing to worry about .................OH YEAH ????? Short a 12 volt car batterie with an English key and look what happens ( at a distance )..........
I mean if you are building tube amp getting zapped is inevitable, i have been zapped many times ,sometimes even after days of any use ,the caps store current and give a nasty shock , what's a good way of avoiding that without isolating your whole work bech which will be a big task in itself , people say to keep one hand in pocket but i cant work with one hand i need both
@@IDontExist14 Hello 29 , put a bleeder resistor on the HV rail..........and or build a stick with a resistor and at the other end a crocodile clamp to connect to the earth/chassis mass to discharge the capacitor banks ! ANYWAY...................HV should NOT be present after the filaments of the tubes are cold............NEVER leave voltage on the anode when gthe amp is shut off..............to preserve your precious tubes. You can also install a bleed with a switch to activate it when shut down and to be inactive when you're listening.
@@frankgeeraerts6243 good advice im in the process of figuring out the bleeder resistors , frank can you contact me through email so i can share pics with you as well are you on facebook
How about soft recovery rectifiers? Aren't they supposed to be lower noise? How do we calculate voltage headroom, for the drop across the valve, for a GZ34 full wave rectifier with CLC filter?
For voltage calculations I always use Duncan amps PSUD software, it gives quite good approximations. (As the voltages will depend on so many things - from power transformer impedance through current draw, turn-on draw is different from steady state, etc...) Yes, soft recovery keeps the switching noise soft - not hard. They are very good. Voltage headroom: look at the datasheet to the rectifier tube, and they have ratings listed. The maximum voltage also depends on the current draw and input capacitance. (Lowered current and lowered input capacitance can handle higher voltages.)
