Ciao ragazzi,
Ho letto tutti i tuoi passi per questo amplificatore e ne apprezzo la bontà.
Vorrei chiedervi se secondo voi è possibile realizzare una versione con transistor di potenza senza molti problemi e ottenendo gli stessi risultati?
Grazie
Carlo
Hi guys,
I have read all your treads for this amp and and I appreciate the goodness of it.
I would like to ask you if you think it is possible to make a version with power transistors without many problems and obtaining the same results?
Thank you
Carlo
Sorry. Yeah, I meant BJT. Two nice BJTs, one per channel, also Darlington, of great power and capable of handling that current value.
Of course, I'm talking about the 20W version.
Unfortunately, I am unable to design it but I am certainly able to assemble it.
I think, it is my belief, that BJTs are better suited to handle good powers and have a better sound.
With this I don't want to generate discussions. I repeat, it is my belief.
I currently use a SUMO Nine Plus and would like another lower powered class A to use for tweeters, in biamping.
Thank you all.
Carlo
Thank you Carlo.
Even the experts disagree on bjt vs. mosfets!!
The advantage for Class A is that mosfets are superb in high dissipation areas. They do not suffer from the 'hot spot' issues with bipolars.
You could try simply replacing the mosfets with Sanken darlingtons (2SD2560 npn and 2SB1647 pnp), it will work, but there might need debugging.
These are relatively inexpensive devices and presently available. In principle the replacement would work.......
HD
Even the experts disagree on bjt vs. mosfets!!
The advantage for Class A is that mosfets are superb in high dissipation areas. They do not suffer from the 'hot spot' issues with bipolars.
You could try simply replacing the mosfets with Sanken darlingtons (2SD2560 npn and 2SB1647 pnp), it will work, but there might need debugging.
These are relatively inexpensive devices and presently available. In principle the replacement would work.......
HD
Bene, Axa
Sì, ci sono molte diatribe su argomenti come questi. Ad esempio, sono convinto che, a parità di circuiti di qualità, un amplificatore BJT suoni meglio di uno Mos. Ma sono sicuro che molti saranno pronti a smentirmi.
Credi, tu o altri in grado di farlo (io no, purtroppo) di poter offrire un circuito con un paio di quelli Sanken che sia altrettanto valido, affidabile e senza alcun aggiustamento? Ho anche alcune coppie di TIP 142 - 147, se pensi che possano essere ugualmente valide.
20 W sono sufficienti: ho altoparlanti TL a due vie autocostruiti con una buona sensibilità, ma sarebbe utile solo per i tweeter. Forse potrebbe interessare anche ad altri.
Avrei già a disposizione una custodia adatta e un alimentatore 32+32 DC V.
Grazie per le vostre risposte
Carlo
You could do that, it would be fine.
BUT you are asking me to redesign it with no cost to suit your particular needs.
You could ask me to do redesign it, but I will charge you for it!
The existing design is very good and free, but how much are you prepared to spend for your requirements?
HD
BUT you are asking me to redesign it with no cost to suit your particular needs.
You could ask me to do redesign it, but I will charge you for it!
The existing design is very good and free, but how much are you prepared to spend for your requirements?
HD
Well, Axa
I didn't think it was possible to individually request the development of a circuit. Thank you for this and I'll keep it for good in case I need it.
That was not the point of my request. Mine was intended as an opening to give another face to this amplifier and I thought others might be interested as well. But this opening probably didn't take place. On the other hand, there are already enough proven class A amplifier schemes with BJT to be reproduced.
This could be my first amp with Mos.
Is the power supply of 32 + 32, DC 300W X2 that I already have available perhaps too high for the 20W 8 Ohm version?
Carlo
Carlo,
+/- 32V DC is too high for the ALPHA 20.
If you use a cap multiplier circuit, you will be able to drop 3-4V DC, and that should get you close to +/- 27V, which is suitable for the ALPHA Nirvana amplifier that has an output of 39 watts @ 8 Ohms. However, the AN amplifier will need bigger heat-sinks vs the ALPHA 20. And the ALPHA 20 is also an easier amplifier to build.
Please note that you will require a dual-rail power supply that gives both + and - voltages.
+/- 32V DC is too high for the ALPHA 20.
If you use a cap multiplier circuit, you will be able to drop 3-4V DC, and that should get you close to +/- 27V, which is suitable for the ALPHA Nirvana amplifier that has an output of 39 watts @ 8 Ohms. However, the AN amplifier will need bigger heat-sinks vs the ALPHA 20. And the ALPHA 20 is also an easier amplifier to build.
Please note that you will require a dual-rail power supply that gives both + and - voltages.
Hi, Zman01
A protective multiplier circuit would be an extra complication. I don't think it's worth it and I don't care about the 39W version. At this point, I might decide to built the ALPHA 20 version (20W into 8 Ohm), with its right power supply.
To do this, I only ask for your help in one thing. I have read all your posts and, definitely, after all the improvements, the replacement proposals and more, I have lost the true face of the 20W 8 Ohm version.
Would it be possible to see a final version published that contains all those improvements? I would be grateful.
Carlo
Very good. I thought it was that, but now I'm sure.
I think I will still need help but for now this is enough for me to get started. I think I will have to get a different pcb to adapt it to the case I already have. I hope there are no critical issues in this regard.
Thank you for your help
Carlo
Very good. I thought it was that, but now I'm sure.
I think I will still need help but for now this is enough for me to get started. I think I will have to prepare a different pcb to adapt it to the case I already have. I hope there are no critical issues in this regard.
Thank you for your help
Carlo
Hello, I have build aksalender 20w amplifier. Part list from BOM file. I have big thump when powering amplifier, and small humm. Trafo 250w 2x20V. Psu kbpc3510 15mf-0.2ohm10w 8.2mf 8.2mf 22mf. Maybe psu capacitors capacitance too small, i will buy 22mf per rail tomorrow. ? I tried diode bridge ground braker, shorten inputs,
