I have looked at the "expensive" version and i found it to be a textbook example of what people should never buy! Lots of expensive patches to solve problems that the designer should have never created. Perhaps the most laugh-provoking is the use of a pentium processor as "On screen control for AC line polarity, DC offset detection, Oscillation detection"
AC line polarity... i will quote from memory Douglas Shelf "audio signal is AC, so cables cannot be directional as long as 2 + 2 cannot equal five. Anyone prepared to belive this nonsense will never design an audio amplifier"
DC offset detection... wouldn't it be better to have an amplifier without DC offset?
Oscillation detection: This implies that the amplifier will oscillate. What does the oscillation detector? Show on-screen "The thing you payed 70K$ for is oscillating. Pity." ?
AC line polarity... i will quote from memory Douglas Shelf "audio signal is AC, so cables cannot be directional as long as 2 + 2 cannot equal five. Anyone prepared to belive this nonsense will never design an audio amplifier"
DC offset detection... wouldn't it be better to have an amplifier without DC offset?
Oscillation detection: This implies that the amplifier will oscillate. What does the oscillation detector? Show on-screen "The thing you payed 70K$ for is oscillating. Pity." ?
Re: Re: JOB Circuit?
So no opamp there? I would like to know what's that new thing. I don't expect any sort of bjt to be able to react in picoseconds.
banana said:
I was thinking the same, smd module board underleaf yellow heatsink......... until I opened my old SRA and checked closely.
That's just a cover, on top on some TO92 transistors.
The newer Goldmund 390 uses full SMD parts and no longer have this mysterious heatsink.
So no opamp there? I would like to know what's that new thing. I don't expect any sort of bjt to be able to react in picoseconds.
Hi lumanauw,
Mind is the entry level SRA, bought in year 2000, which only cost USD$1500 at that time. Not a bad deal for the price. Sound is neutral. Modern transistor style, no super warmth tube voice.
It uses the first generation JOB circuit, together with under size power supply, which can only provide 50W 8ohm and 75W 4ohm. Dynamic compression kicks in early in medium loud volume. Good for soft music only. Maybe better match with high efficiency speaker.
I also listened to my friend's JOB150. Dynamic is improved significantly. Treble and clarity is about the same as my SRA.
From a diyer's point of view, the same level of quality can be achieved by a standard non-inverting LM3886. Now I switched to Ucd400, much better in every aspect IMO.
Mind is the entry level SRA, bought in year 2000, which only cost USD$1500 at that time. Not a bad deal for the price. Sound is neutral. Modern transistor style, no super warmth tube voice.
It uses the first generation JOB circuit, together with under size power supply, which can only provide 50W 8ohm and 75W 4ohm. Dynamic compression kicks in early in medium loud volume. Good for soft music only. Maybe better match with high efficiency speaker.
I also listened to my friend's JOB150. Dynamic is improved significantly. Treble and clarity is about the same as my SRA.
From a diyer's point of view, the same level of quality can be achieved by a standard non-inverting LM3886. Now I switched to Ucd400, much better in every aspect IMO.
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