Solid State vintage Integrated Amplifier and Stereo Receiver close to Class A like Musical Fidelity A1

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tiefbassuebertr

tiefbassuebertr

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Joined 2005
tiefbassuebertragung.de
#1
long time ago I start this threads:
https://www.diyaudio.com/community/...ntegrated-and-power-amplifier-devices.146528/
https://www.diyaudio.com/community/...dels-quasi-complementary-power-output.157430/

Now I am looking for an overview of vintage stereo receivers and integrated amplifiers with much more quiescent current through the output stage than the typical class B value between 20-50mA for quasi - and true complementary BjT power devices and 100mA for both only N- and N-/P-channel power MOSFET's.

A good known example is Tim de Paravicini's design for Musical Fidelity (A1, A100 etc.) - go to
https://www.markhennessy.co.uk/mf_a1/technical.htm
The Designer:
http://www.ear-usa.com/tim-de-paravicini
(Hiraga's "Le Classe A" and Pioneer's M22 unfortunately are power amplifiers without attenuation (volume control) and input selector).

Probably there are many more models in this kind.
Thanks for some advice.
 
#5
tiefbassuebertr said:
long time ago I start this threads:
https://www.diyaudio.com/community/...ntegrated-and-power-amplifier-devices.146528/
https://www.diyaudio.com/community/...dels-quasi-complementary-power-output.157430/

Now I am looking for an overview of vintage stereo receivers and integrated amplifiers with much more quiescent current through the output stage than the typical class B value between 20-50mA for quasi - and true complementary BjT power devices and 100mA for both only N- and N-/P-channel power MOSFET's.

A good known example is Tim de Paravicini's design for Musical Fidelity (A1, A100 etc.) - go to
https://www.markhennessy.co.uk/mf_a1/technical.htm
The Designer:
http://www.ear-usa.com/tim-de-paravicini
(Hiraga's "Le Classe A" and Pioneer's M22 unfortunately are power amplifiers without attenuation (volume control) and input selector).

Probably there are many more models in this kind.
Thanks for some advice.
Click to expand...

The late 1980s integrated A220 is as bad as a A1 for heat dissipation and gets as hot (the only difference is the heatsink is inside but the vented case top still gets too hot). It's AB but basically biased so heavily it's almost class A - to make things more interesting the BUZ90x series (so that's complementary lateral mosfet output devices) are stuck to the undersized heatsink. Thermal equilibrium is about an hour or so. Preamp stage is simply a quad opamp.
If you want true BJT power devices then the 308 for example (a later design) has true BJT power output devices.
 
#6
MF A1 should be on lists of old and unreliable devices. What is it with making lists and be busy with old stuff almost only found in pawn shops that also need overhauling and repair with parts that are nowhere to be found? First the search in shady shops, then pay too much, then discover it is of course broken, then replace everything defective and worn out. For what purpose? Exceptions confirm the rule, 2 years ago a man I know bought a mint/unused A1X for 25 Euro...

A newly built (DIY) device will cost less effort and money and will give enjoyment for years to come. An A1 made with current transistors, adequate PSU with rightly rated caps, overdimensioned heatsink and normal volume control will outperform the original one and live longer. One can have the design of then without the design errors and cost cutting, pay the right attention to thermal issues, add loudspeaker protection (a MUST with A1) and have longevity as bonus.

Recently I reluctantly did such an overhaul of an old class A amplifier as a special request. It was strange to notice even PCB material had become brittle, film caps had cracks in the casings etc.
 
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#7

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#13
A21se yes but years ago before covid. Tried to find an affordable one but eventually abandoned class A alltogether. Small power amplifiers are way easier to make them perform exemplary IMHO. In fact it takes less money, less effort and their silent operation, less heat, longer longevity, smaller size, lower weight and lower power consumption are all welcome.
 
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#19
jean-paul said:
Yes and class D. We live today not in the past.
Click to expand...
Especially with regard to the last generation Class-D, many guys claim that the Purifi Eigentakt 1ET400A module - go to
https://purifi-audio.com/wp-content/uploads/2020/01/1ET400A-Data-Sheet-1.00.pdf
https://purifi-audio.com/eigentakt/
clearly blown away all analog classics amps in all respects of sound quality at all loudspeakers and that one finally say goodbye to yesterday's analog amplifier stuff once you've heard it - even Class-A and even best known tube amps.
Whether this guys are right in their opinions ??
 
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