Hello haiqu,
I’ve quoted your statement and used it as another thread title. It was not right thing to do as some people find it offensive instead of amusing. I sincerely apologize for this and have made edits and request for title change.
For me, your statement is pure humor and meant well.
I’ve quoted your statement and used it as another thread title. It was not right thing to do as some people find it offensive instead of amusing. I sincerely apologize for this and have made edits and request for title change.
For me, your statement is pure humor and meant well.
Actually I wasn't offended in the slightest. It wasn't meant as humour, but nor was it meant to be taken literally for all cases. For this specific amplifier, there's no need to use discrete current sources.
By the way, anyone who is offended by such a statement is too stupid to be bothered with, IMHO.
I am a total noob, but I would really love to build The Magic Amplifier, I have tried to understand what you have written and the great schematic. I have tried to copy the current source attached to the Q3 emitter and think it includes R36 and up, but LTspice gives me strange results, I do also not understand the 10mF shunt cap.
Is there a finished schematic and maybe a photo of the original PCB to be inspired by?
Is there a finished schematic and maybe a photo of the original PCB to be inspired by?
@FriedMule: The best bet would be to build the Blomley Class B which this amp was derived from. PCBs are available for that one.
Hi Haiqu,
Could you please share the Gerber files? I am very much interested in this.
Thank you very much, best regards,
Sorry but there are no gerber files. I have been waiting for the original to be shipped so that I can verify the circuit before making a replica. My friend Peter's son didn't ever get around to shipping it, and Peter himself was in Sydney a few weeks ago on a short visit and didn't send it either. He did send me a photo of the front panel though ...
Hi Haiqu,
Thank you for the picture.
Sorry I should have been more clear: do you have the Gerber file for the Blomley amplifier?
If yes, could you please send me? I am very much interested in it.
By the way, did you build one of this magic amplifier you are discussing here? Does
it have this "presence" or "liveliness" people are talking about?
In your experience, do these 2 implementations have similar sound quality?
Thank you very much, best regards,
Really interesting thread. I had read of the 'Guru' via Allen but any Web Search about the former proved entirely fruitless at the time so it's quite interesting to read the original post, thanks for that.
Oz has many audio(and musical) talents indeed. The Fairlight is legendary if you like the 80's. We owe many of the subsequent, less expensive keyboard samplers to its existence, like the E-Mus and the Ensoniqs of the time. E-Mus became a staple of some of Depeche Mode's most iconic albums, around Black Celebration. I use a Kuzweil K2500XS + KDFX myself.
Hadn't paid much attention to the Magic Amp nor the Blomley, but now these are quite interesting.
Oz has many audio(and musical) talents indeed. The Fairlight is legendary if you like the 80's. We owe many of the subsequent, less expensive keyboard samplers to its existence, like the E-Mus and the Ensoniqs of the time. E-Mus became a staple of some of Depeche Mode's most iconic albums, around Black Celebration. I use a Kuzweil K2500XS + KDFX myself.
Hadn't paid much attention to the Magic Amp nor the Blomley, but now these are quite interesting.
Hi Haiqu,
Thank you. I found the picture in the Blomley Amplifier thread.
By the way, could you please show me how to reduce the gain of your magic amp
from over 40 to 20?
Best regards,
Thanks YashN. These guys were friends of mine so I have a special interest in their history.
That would be interesting. I find Blomley's idea very useful and I've simulated a number of variations with good results (but I'm not very confident in the stability predictions in the sim).
Anyway, looking forward to seeing what's in the "magic box", if you get hold of it! Good luck
BTW, I think it's worth noting that the speaker impedance becomes part of the feedback loop, in that it will determine total loop gain. Impedance dips could be a problem for the amplifier (less loop feedback at that frequency), whereas the impedance peak of a ported speaker will increase feedback at that frequency. Just one more unusual aspect of this topology.
Haiqu, I read your posts carefully. I am playing a lot with this circuit and Blomley's in the sim.
That trim is one of the critical adjustments, if you set it to zero you will have 1.2V between bases of the splitter transistors and that will not give you the separation of the two sub-amplifiers advised by Blomley.
Like you, I was tempted to give the splitters a little bias because of better simulation results, but then I thought more about it and re-read the article, and also Dermot's posts and I have to conclude that the harmonic distortion plots do not tell the whole story.
I think having a trimmer there is a must, the best setting is to be determined experimentally.