I am looking at the A1 manual 2023 ver and the marketing materials. It mentions “Pure Class A 25W @ 8 Ohm”. Thus, it is designed to work in pure Class A. That alone solves a lot of issues. As the distortion is very low at Class A. No mod is necessary.
https://www.musicalfidelity.com/uploads/catalogerfiles/a1-2/5_MF-A1-EN.pdf
In the manual, thd+N 0.05%. You are not going to notice.
https://www.musicalfidelity.com/uploads/catalogerfiles/a1-2/4_A1_Integrated_2023_manual_issue_4.pdf
Question
Can older versions deliver class A 25W?
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I am sorry to say your feedback approach is still not quite right. At the audio frequency, the ltp still see signal from the sensing resistors (by the ratio of 2.2k vs 59k).
Try this approach.
Are you really and absolutely sure about this?
1 + (59k||59k||2k) / 270
= 8.583
global CLG is 18.67dB !
This is and remains my suggestion for one of the possible modifications, it is fully functional and therefore correct.
#
Your suggestion doesn't hurt, of course, it also works - but it won't (further) improve @Zen Mod's interpretation in the least. Right?
HBt.
The quiescent current is about 800mA -> the class A operation definitely ends at the beginning of the 5Wrms mark.
You can see this wonderfully by measuring.
All old models share a common power supply and the rails drop to +/-21Vdc. The old model can also only claim 5W or 10Wpeak in true A mode - but then there is the mirror, the active mirror image, the active SE load. In push-pull mode we like to say (2*0.8A)^2 * 8Ohm = 20.48 Watt.
And this is also true for sinusoidal time functions in a steady state with a static load. The explanatory addition “peak” is missing.
20Wpeak
current MF-A1 distortion
Interestingly, you can directly calculate the conditions under which the THD specification of MF results.
#
The user manual specification is totally worthless, all the necessary parameters are missing ... the way the <0.05% is written there, it's just there - and we have to guess that it's supposed to be THD_1k at 1Wpeak, right?
The 25A peak to peak also refers more to the TIP xx C pair used than to anything useful. The poor mains transformer (which incidentally gets scaldingly hot) can never deliver more than 4.8App anyway.
It is better to record the real specifications ourself.
Bye,
HBt.
Interestingly, you can directly calculate the conditions under which the THD specification of MF results.
#
The user manual specification is totally worthless, all the necessary parameters are missing ... the way the <0.05% is written there, it's just there - and we have to guess that it's supposed to be THD_1k at 1Wpeak, right?
The 25A peak to peak also refers more to the TIP xx C pair used than to anything useful. The poor mains transformer (which incidentally gets scaldingly hot) can never deliver more than 4.8App anyway.
It is better to record the real specifications ourself.
Bye,
HBt.
In full bloom, with a figure of light, the CEO. But I like him, he stands behind his products.
The current A1 is perfectly fine --> but we are building an interpretation, a better tribute to a legend. If @m0rten is kind enough to give the forum a PCB again.
Should @wahab reveal his (simple but ultimate) forum suggestion (a really good one that I also like, and is not an A1), then I will gladly implement it - simply for the joy of audio amplifiers.
Bye,
HBt.
🙂
Because this thread should be solely about Musical Fidelity's A1, that's why.
Even if I myself actually like the compound final stage, i.e. the CFP (or however you want to abbreviate it), the concept is only comparable to an A1 as a Lego brick with very good will and an extremely wide arc. For me as an archaeologist and forensic scientist, comparable to Doctor Quincy, M.E., these are all just Lego bricks.
Incidentally, the Goodman 90 receiver is simply too bad and ugly on the outside. It's not worth it.
To be honest:
I have no idea where the journey is going.
So I'm very excited to test the preliminary final circuit from posting #98 extensively in the real world -> MC12 promises a lot here.
I also warmly recommend it to the Asian kit faction.
regards,
HBt.
I also warmly recommend it to the Asian kit faction.
regards,
HBt.
I can't speak for everyone here, but I have to admit that I don't really see where this thread is going either.
No one but the reader himself can know what individual benefit he will derive from this or other threads.
For my part, I find the A1 interpretation of the user Zen Mod delightful; it has given me the idea of questioning the actual parameters /screws of the concept, which I have known for almost four decades, once again.
The basic intention behind this thread is to strive for improvements in detail. Linked to this is of course the desire to arouse interest. It could also be understood as a call to build an amplifier yourself, which at first glance seems very unusual (for beginners).
The users who write here could do this immediately - but that's not the point.
It is a suggestion and homage at the same time. It is an easy task for us writers to improve the existing suggestions or iterations a little. We can always push it further and improve even the smallest part. No problem.
But the practical test and the relevance remain outside until it is a successful replica project, a kit that can be purchased. Our countless threads cannot be more than suggestions for thinking and trying things out for yourself.
I don't assume that Heinz Lichtenegger is reading along here and will soon have a forum edition created and produced.
#
My question( to myself) about the itinerary refers to wahab s question about the next corpse or assembled dinosaur skeleton I exhumed. So no longer about Master Tim's aged A1.
greetings,
HBt.
If
Good night for today or tomorrow!
🧛♂️
- there are no further questions, I'll close my coffin lid and go to sleep - I already feel very anemic
- anyone would like to try a new interpretation of the 20 watt class A theme in the style of the classic MF-A1, please refer to posting #28 and keep it in mind.
Good night for today or tomorrow!
🧛♂️
Hi @hbtaudio ,
Do you hear any artifacts (distortion) with A1 comparing to other amps? Once distortion is low enough let’s say 0.3%, it really doesn’t matter much. I own couple tube amps. Despite relatively high distortion, as long as the noise floor is good, I can’t really tell those apart from my daily driver, Quad 405.
Do you hear any artifacts (distortion) with A1 comparing to other amps? Once distortion is low enough let’s say 0.3%, it really doesn’t matter much. I own couple tube amps. Despite relatively high distortion, as long as the noise floor is good, I can’t really tell those apart from my daily driver, Quad 405.
Just give me something to work with... 😎
Which schematic is "current"?
I have made this one so far...
I don’t see how this amp can deliver 26 amps as stated in the spec given the 2 output devices and the small PSU.
25 A ok to ok is 12 A peak and about 8 A RMS.
Am I reading it correctly?
25 A ok to ok is 12 A peak and about 8 A RMS.
Am I reading it correctly?
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My last sketch /step or iteration is located in posting #98.
thx M0rton, thats great
🙂
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The official technical data with the heading specification are not really correct.
However, the 2*12.5A_peak specification could be regarded as a short-term, maximum possible discharge current of the power supply unit, with R_load in the order of 2Ohm. This is probably the solution to the official puzzle, a burst measurement below 2 Ohm.
Incidentally, the specification of the amplification factor is also incorrect.
A superficial glance at the technical specifications reveals an excellent thd, imax and a fabulous damping factor. So what catches your eye is a new A1 of the year 2023, a design wonder, a healthy, great A1.
But of course this is just a dazzle, window-dressing or rather a fairground trick.
HBt.
thx M0rton, thats great
🙂
__________________________________________________________________________________________________________________________________________________________________
The official technical data with the heading specification are not really correct.
However, the 2*12.5A_peak specification could be regarded as a short-term, maximum possible discharge current of the power supply unit, with R_load in the order of 2Ohm. This is probably the solution to the official puzzle, a burst measurement below 2 Ohm.
Incidentally, the specification of the amplification factor is also incorrect.
A superficial glance at the technical specifications reveals an excellent thd, imax and a fabulous damping factor. So what catches your eye is a new A1 of the year 2023, a design wonder, a healthy, great A1.
But of course this is just a dazzle, window-dressing or rather a fairground trick.
HBt.
Attachments
Recently they updated the design, so those numbers are not for the previous version, but anyway let s be honnest,
this amp has no musical fidelity whatsoever, that s just yet another prove that when you have a name you can sell
whatever garbage all while praising the thing s alleged qualities.
To summarize they took a 1302 Beettle, clothed it as a Porsche 911 and equipped it with a motorcycle 2 strokes engine,
last was to set a 1600€ price tag to instillate the idea that it was forcibly good given such a hefty price for a 2 x 25W,
and apparently it did work since this caricature of an amp is still produced and sold nowadays.
Dear jxdking,
Your question is very difficult to answer, I would like to say that the current A1 has a kind of watermark, but it's easy to imagine something like that ... I would also like to be able to claim that I can identify every amplifier in my household by its sound - but in a double blind test I would definitely fall flat on my face.
Artifacts? No, absolutely not.
Differences in sound? Basically yes. But these are all just nuances. The differences between various loudspeakers can be described more clearly.
However, it seems to be a fact that the current A1 can work out tiny details of a sound recording. It works them out.
Artifacts, such as those created by our countless (digital) optimization algorithms, are something it doesn't do.
The A1 is definitely lively and bright.
Quite different from how Bernhard, for example, would describe it from memory.
greetings,
HBt.
Psst
The 2*TL072 preamplifier is also in the game! Inseparable, i.e. a fully integrated amp.
☕
Dear wahab,
I have already written about this in Jean-Paul's thread, perhaps we should use his thread to write positive or negative things about the current device.
Here, in this thread, we should try to focus only on comparisons of possible modifications or reinterpretations of the topic,
don't you think?
We could of course send a petition to Vienna to persuade Heinz L. to give the order to finally catapult the A1 into the two-thirties.
kindly,
HBt.
I have already written about this in Jean-Paul's thread, perhaps we should use his thread to write positive or negative things about the current device.
Here, in this thread, we should try to focus only on comparisons of possible modifications or reinterpretations of the topic,
don't you think?
We could of course send a petition to Vienna to persuade Heinz L. to give the order to finally catapult the A1 into the two-thirties.
kindly,
HBt.