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Technics "New Class A"

Theophilus Punoval

Theophilus Punoval

The Queen says it's OK...
Here we go again. I have an old Technics receiver that has a logo stating it's a "New Class A Amplifier".

The unit has a wood case and is very heavy. It has a digital tuner so I figure it's 1980s era unit. It has a nice sound but I'll be darned if I can get any info on the unit.

What's a "class A" amplifier and why did they need a new one? Does anyone have any information on the model, SA 450, or Technics in general?

Thanks. I'm so confused!
 
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I'm pretty sure Class A amps were invented for folks who wanted to move from toobz to sand, but wanted to be sure to retain the amp's ability to serve as a room heater. If you are blessed with "golden ears", you will be able to smugly proclaim that you can actually hear the difference between the Class A's 0.001% distortion and a Class AB's 0.005%, while your less-endowed friends will notice no difference at all. You will definitely notice a difference in your electric bill, though.
 
http://www.vintagetechnics.info/receivers.htm

Some searching around here at AK sould find you some very comprehensive threads/explanations of the difference between the Technics sliding bias, and a true class A amplifier.

When everything is up to spec the Technics scheme works fairly well, but really shouldn't be confused with or compared to a genuine class A amplifier section.
 
As Bowtie says, the "sliding Class A" scheme is designed to allow for closer to class A sonics without the heat dissipation caused by actually running in Class A all the time. Back in the day, this was a big deal with many of the hifi manufacturers. Sony, for example, called their sliding bias scheme "Legato Linear."

Class A amplifiers definitely have a different sonic character than say, Class B amps. Crossover distortion is different from harmonic distortion. Some folks are very sensitive to this type of distortion, and others are not.

The 450 is a decent product. I'd go ahead and enjoy it!
 
Crossover distortion is usually observed as high order harmonic or intermodulation products. However, harmonic/intermodulation measurements do not indicate the source of the distortion.
Crossover distortion in class-AB amplifiers generally consists of short spikes on the distortion waveform where the amplifier output current passes through zero. On virtually all properly functioning audio grade amplifiers, notch distortion is negligible and totally inaudible.
 
LouStools said:
Jeez, when I told the future former Mrs. Stools that, she dlaimed she's never met anyone less-endowed than I. Sheesh.
Click to expand...

could have been worse... my friend was told by his ex that he was smaller than distortion in MY stereo (TIM = unmeasurably small)

thats gottah hurt even tho she wasnt attractive... i have seen better heads in video recorders
 
NewClassA.jpg


I found this diagram as a comparison
 
Hi
NewClassA has NOTHING to do with "class a" imho .
And old? It's mid eighties, if I recall right, even late eighties. I have had 2 of those SU-V6/8... wouldn't call them neither classic nor old.


LouStools said:
Here we go again. I have an old Technics receiver that has a logo stating it's a "New Class A Amplifier".

The unit has a wood case and is very heavy. It has a digital tuner so I figure it's 1980s era unit. It has a nice sound but I'll be darned if I can get any info on the unit.

What's a "class A" amplifier and why did they need a new one? Does anyone have any information on the model, SA 450, or Technics in general?

Thanks. I'm so confused!
Click to expand...
 
Last edited:
new class A started in the late 70s (77-78)

refer to technical outlines posted above (diode / resistor config)

in the late `80s they still used the decal (`88 on) though the synchro bias had vanished... class AA come across as a successor but, it too lacked synchro bias.

whilst not a power chewing class A setup, the outputs do not turn off.

the results speak for themselves, im not talking paper and figures here, listen to one.

try SU-V4X SU-V8X SE-A3MK2 SU-V8 SU-V9 SU-V909 all of these amps are sure yo please the ears...
 
I have a TOTL Technics SU-V9 integrated amp in the rock room, and it's excellent. I picked it up for practically nothing, and it delivers clear, rich sound with none of the aforementioned heat issues. IMO, a winner! :thmbsp:
 
Can't Find Info

The unit really sounds great and it weighs a ton. I guessed the 80s because it has a digital tuner. It also uses AA batteries to hold stations in the memory, and that looks 80s as well.

It's wired for American jizz so I don't think it's an overseas unit. Maybe it's Canadian. The case is wood with a wire grille on the top rear for heat.

I've never seen specs or other information on this model. It definitely says SA 425 on the faceplate, not 424. Could it have been a previous model # or a successor? For now I'm in the dark.
 
Mixed feelings about Technics SU-V75

I am listening to the V75 now. Well, it certainly has power in that little all grill box. Feels more like 110 watts than the 85 in its specs. And it it very clean at high volume. Speakers well controlled. Jazz band sounds great. But strings a little harsh. Just put on old Capitol Sinatra, No One Cares. Well, that's a disapointment. Sounds grainy and HOLLOW. Why? Rolled back bass. Rolled bach treble. Worse. Increased both modestly. Sounds better. Odd. Compared to Sansui AU 5500. The Sansui much more detailed and natural, clearer. Lots less power of course. Compared to Yamaha HTR-5280. Yamaha has more punch in the trombones. More power. Smoother sound. Suave. Stereo imaging better. So the Technics is not bad, but not as good as I expected. I am guessing that with a diet of pure rock played loud it would shine. But not subtle enough even to get lounge vocals right. And I have no desire to hear it shred chamber music. Still for $8 from Diversity Thrift I do have a kickass little rock and roller.
 
The latter years yeah I see your point... Imo I don't think they ever shoulda chucked the voltage amp into the output stage... But, it's less of an issue.... Key issues are cutbacks in heatsinking, power supply and most noticed by you the whole front end that feeds the power amp. Overall they're great at Rock music/ sound of its generation. Want to see more stellar sonics you should look at 1978-1985... Bout 87 the cost cuts really surfaced.

Interestingly I've heard similar claims of their better lines of that had similar tonal traits... But the power amp direct function has been said to totally bring the stellar sound that should have always been..
 
I've been looking for a Class AA unit for quite a long time as I liked the concept behind it much more than the one of the New Class A topology. However, as things turned out I now actually own a New Class A unit instead of a Class AA amp (I do have a Class AA CD player though), and I immediately fell in love with it. Differences are inaudible anyways, and all the mentioned rest does not depend on the amplifier class but much more on its circuit itself.
 
I have a pair of SU-V4X integrateds. Both silver, not that this is of any consequence. One is my daily driver the other is my backup. I have yet to break the daily. The V4X was a well kept secret during 84-85, many still prefer them over the discrete output and considerably more expensive V6X -V10X.
 
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