@jean-paul,
did you ever find out what really caused the failure, the defect? And let's leave out the mundane stories such as dried-out capacitors or a rectifier diode that has become low-resistance (alloyed through) when answering this question.
☕
Coffee?
No I am into mundane stories (also called reality) and I have seen this device and other unreliable MF stuff a lot and practically always broken. I don’t see the point of a 2024 root cause analysis of decades old consumer grade devices that had failure by design written all over them. Heat was both the main landmark and the culprit and efficient/fastest was complete overhaul. This is all not very interesting to readers and you yourself pointed several times to wanting to discuss only the 2023 version.
This is not PM or chat either. My totally non relevant opinion is that both the old and the 2023 versions have so many points against them combined with an absurd price tag that they are surpassed by many other more affordable devices that usually still work after 5 years. I would feel cheated if I had forked out 1599 for one. It is a connaisseur category device and not for high price/quality ratio aficionados.
This is not PM or chat either. My totally non relevant opinion is that both the old and the 2023 versions have so many points against them combined with an absurd price tag that they are surpassed by many other more affordable devices that usually still work after 5 years. I would feel cheated if I had forked out 1599 for one. It is a connaisseur category device and not for high price/quality ratio aficionados.
Last edited:
For those who are interested in the current Musical Fidelity A1 Class A Amplifier (?)
THD
Output resistance (steady-state at 3kHz) is
Ri= 0,475 Ohm
Damping factor is now
8,421__4Ohm and 16,842__8Ohm
Note:
Above 9.5Wrms_4Ohm (only one channel operated), there is a very noticeable crossover distortion, which is already clearly visible on the oscilloscope. In other words, from load currents of 1.6A RMS (only one channel operated) the oven is off ---> 4.53App.
THD
| 100Hz | 1000Hz | 3000Hz | 10000Hz |
0,5W | 0,005 | 0,012 | 0,011 | 0,001 |
1W | 0,003 | 0,018 | 0,017 | 0,009 |
5W | 0,045 | 0,071 | 0,068 | 0,066 |
10W | 0,142 | 0,169 | 0,164 | 0,165 |
15W | 0,216 | 0,244 | 0,248 | 0,243 |
20W | 0,321 | 0,348 | 0,346 | 0,311 |
Ri= 0,475 Ohm
Damping factor is now
8,421__4Ohm and 16,842__8Ohm
Note:
Above 9.5Wrms_4Ohm (only one channel operated), there is a very noticeable crossover distortion, which is already clearly visible on the oscilloscope. In other words, from load currents of 1.6A RMS (only one channel operated) the oven is off ---> 4.53App.
Thank you very much for your comments - I am completely in the picture.
On the topic:
when you were still repairing countless of these devices, you never thought about the cause and you are not really interested in the A1 (old or new edition) in the discussion thread you opened about the Musical Fidelity A1 model. That is incomprehensible to me.
That is very revealing. By the way, the current model differs only marginally from the 1980s classic - in my opinion, the new edition is the great stroke of genius of Heinz Lichtenegger MF-CEO.
Greetings,
HBt.
(all the A1s that I have repaired for my circle of friends have never broken down again)
A side note:
Between1.3kHz and 1.9kHz the internal components of the A1 sing a song! You can clearly hear the excitation frequency
Could be piezo effect from ceramic capacitors used in the signal path where high voltage excursions are taking place. A good place to start looking would be comp caps or Zobel network if fitted. I learnt this on my Ovation 250 watt amp back in 2006/7.
Between1.3kHz and 1.9kHz the internal components of the A1 sing a song! You can clearly hear the excitation frequency
Could be piezo effect from ceramic capacitors used in the signal path where high voltage excursions are taking place. A good place to start looking would be comp caps or Zobel network if fitted. I learnt this on my Ovation 250 watt amp back in 2006/7.
From 18 volts peak to peak upwards with further signal deformations in the peaks (i.e. the amplitude) itself.
For pure information and self-reflection (only),
HBt.
yep, being personal and trolling in my thread (first post):
is revealing. And you are the best, you know that don't you?
I like the little Englishman very much, despite all his well-known weaknesses.
I don't believe that the problems that often occurred in the past (1985 to perhaps 1996) will occur to the same extent with the device that is professionally manufactured in Taiwan today (2024) - the temperature development must of course still be viewed critically.
The
Musical Fidelity's specifications for the technical data of the new A1 differ insignificantly from the values I determined, whereby I left out the phono branch for measurement purposes (the MC sound is outstanding).
In terms of performance or audiophile, the A1 is still worth a gamble, the sales price, which has now dropped to up to 1300€, is all in all (in the current situation) expensive compared to the current Yamaha amplifiers (for the same money), but it doesn't get much cheaper than that. The quantities produced will not allow a sales price of €360 to a maximum of €720, no matter how much we would like that (as now retired students 😉 ).
During the winter months, my A1 will certainly bring me a few hours of musical pleasure.
Bye,
HBt.
Psst
Well, yes,
you /we can rebuild it yourself /ourself at any time - perhaps a user will start their own thread and report on their experiences.
#
Dampingfactor at significant low frequency is approx 27 (8Ohm) and 13 (4Ohm) - not better, but sufficient.
I don't believe that the problems that often occurred in the past (1985 to perhaps 1996) will occur to the same extent with the device that is professionally manufactured in Taiwan today (2024) - the temperature development must of course still be viewed critically.
The
- sound is great, the external appearance (even with the plastic knobs and plastic feets) is of high quality
- connection options are practical in every sense, but the minimum speaker impedance should not fall below 4 ohms /never.
Musical Fidelity's specifications for the technical data of the new A1 differ insignificantly from the values I determined, whereby I left out the phono branch for measurement purposes (the MC sound is outstanding).
In terms of performance or audiophile, the A1 is still worth a gamble, the sales price, which has now dropped to up to 1300€, is all in all (in the current situation) expensive compared to the current Yamaha amplifiers (for the same money), but it doesn't get much cheaper than that. The quantities produced will not allow a sales price of €360 to a maximum of €720, no matter how much we would like that (as now retired students 😉 ).
During the winter months, my A1 will certainly bring me a few hours of musical pleasure.
Bye,
HBt.
Psst
Well, yes,
you /we can rebuild it yourself /ourself at any time - perhaps a user will start their own thread and report on their experiences.
#
Dampingfactor at significant low frequency is approx 27 (8Ohm) and 13 (4Ohm) - not better, but sufficient.
I am not responsible for questions of faith, the only thing I can contribute is: the state of affairs - to Musical Fidelity's A1 Class A Amplifier.
#
Below 5 watts removed, he is a true magician whose charm is impossible to resist. A clear recommendation for those who are not stingy and can get over 1300€ - otherwise the do-it-yourself construction calls and rewards the hobbyist with a dream.
kind regards,
HBt.
A1 secrets
The secret has been out since Mark Hennessy at the latest.
Two independent single-ended circuits that work against each other, while in DC terms they are equivalent to a voltage regulator. Our reference, the DC zero, is modulated by the input signal - everything else logically results from this approach to a somewhat unusual amplifier (definitely in operating class A), which can be considered 2 * 20Wrms_8Ohm within a small time interval. However, in a truly steady state it is not, and in a single consideration of the individual single-ended amplifier only >2.5 real watts remain.
That's how it is with this strange class A representative, which does everything differently from a JLH or J. Hiraga approach.
However, how a Musical Fidelity A1 Representative reacts to a complex load and the EMF of a three or four-way loudspeaker -> with regard to its 3D distortion behavior at a load present in practice, has never been published to my knowledge.
This would be a challenge that could generate profound knowledge in fundamental contexts.
HBt.
The secret has been out since Mark Hennessy at the latest.
Two independent single-ended circuits that work against each other, while in DC terms they are equivalent to a voltage regulator. Our reference, the DC zero, is modulated by the input signal - everything else logically results from this approach to a somewhat unusual amplifier (definitely in operating class A), which can be considered 2 * 20Wrms_8Ohm within a small time interval. However, in a truly steady state it is not, and in a single consideration of the individual single-ended amplifier only >2.5 real watts remain.
That's how it is with this strange class A representative, which does everything differently from a JLH or J. Hiraga approach.
However, how a Musical Fidelity A1 Representative reacts to a complex load and the EMF of a three or four-way loudspeaker -> with regard to its 3D distortion behavior at a load present in practice, has never been published to my knowledge.
This would be a challenge that could generate profound knowledge in fundamental contexts.
HBt.
means dynamically that they act in parallel, Mr. de Paravincini was also exactly correct in his comments
Yes,
an original A1 is a small, adorable horror store - but not a haunting horror movie.
A small practical test:
As
a result, the THD (n=9) remains below 0.01% in the entire audio frequency range - generously rounded up, the lowest point of the well-known bathtub is 0.001% between 0.3kHz & 3kHz !
The
🙂.
If you don't yet have an A1, you should seriously consider building one yourself.
Two monoblocks, each with a 100VA toroidal transformer and 2*18Vac secondary windings, C-L-C power supply of course.
As
- a load, I simply connected two Visaton W170S4 woofers in series, free air
- Input voltage 2Vrms
- Output voltage as well, 1 & 2 Vrms
a result, the THD (n=9) remains below 0.01% in the entire audio frequency range - generously rounded up, the lowest point of the well-known bathtub is 0.001% between 0.3kHz & 3kHz !
The
- famous first watt, or let's say a higher, already loud room volume, is without fault
- A1 is a hot tip for cold winter days.
🙂.
If you don't yet have an A1, you should seriously consider building one yourself.
Two monoblocks, each with a 100VA toroidal transformer and 2*18Vac secondary windings, C-L-C power supply of course.
I would like to add something interesting,
with this MF-A1 you /we can calculate the distortion factor and approximate it fairly accurately with a power function.
THD(%) as a function of P(W_rms) at Rload=8Ohm
= 1.285386*10^-2 * P^1.043256
THD(%) as a function of I(mA_rms) - loadcurrent
= 6.155162*10^-8 * I^2.087275
Note:
The power supply unit is only capable of delivering a maximum of approx. 1.6Arms loadcurrent in steady state.
with this MF-A1 you /we can calculate the distortion factor and approximate it fairly accurately with a power function.
THD(%) as a function of P(W_rms) at Rload=8Ohm
= 1.285386*10^-2 * P^1.043256
THD(%) as a function of I(mA_rms) - loadcurrent
= 6.155162*10^-8 * I^2.087275
Note:
The power supply unit is only capable of delivering a maximum of approx. 1.6Arms loadcurrent in steady state.