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Chip Amps Amplifiers based on integrated circuits

80s Amps: Technics New Class A, SU-V2X
80s Amps: Technics New Class A, SU-V2X
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Old 1st February 2008, 01:57 AM   #1
arki is offline arki  Australia
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Join Date: Jan 2008
Default 80s Amps: Technics New Class A, SU-V2X

Bare with me guys im new here and not that literate when it comes to Hifi, but here it goes..

Just picked up a nice old 80s Technics amp on ebay. It's a New Class A SU-V2X.

^(pics not my amp)

Does anyone have any experience of this or similar Technics amps of the era? For some reason the Amp always indicates its operating in "Safety Operation" (orange) mode and never in "Auto > Computer Drive"(green). The New Class A lamp has not illuminated either.

Can't find any "Free" manuals anywhere and was wondering if anyone knew where to find some info on these things?

The amp sounds OK (Im pretty sure) but this will bug me till i figure it out / get some info. If someone could also confirm whether the above info indicates that the unit is faulty? Thanks in adv.
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Old 1st February 2008, 02:25 AM   #2
tiltedhalo is offline tiltedhalo  United States
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Join Date: Sep 2005
Location: Melbourne Florida
Default New Class A

Ok somebody more familiar with Technics correct me if I am wrong.
I do not have direct experience with the SU-V2X, they use a IC output that is biased class A at low levels then runs AB at outputs above a few watts. The computer drive is no more then the circuit that tracks the class A bias, it also will shut down the class A operation of the chip if the load is to great, ie low impedance speakers. If thats the case the amp will not light the class A, but the comp drive light should be active.
Does the amp run hot when idle??
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Old 1st February 2008, 03:51 AM   #3
arki is offline arki  Australia
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Join Date: Jan 2008
Thanks for the quick reply. Appreciated, as I'm trying to confirm to the seller that the item(ebay) has "faults"

"If thats the case the amp will not light the class A, but the comp drive light should be active."

re: the above Comp light is inactive & I have not seen it active since i received the amp and began using / evaluating it.
I turn the amp on, safety light flashes 3-4 seconds then remains active. The amp then "functions" in this state.The amp gets pretty warm. When you say idle do you mean "on" and no source input?
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Old 1st February 2008, 04:02 AM   #4
paulb is offline paulb  Canada
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Join Date: Jun 2001
Location: Calgary
I have an SE-A5 that I'm servicing, by replacing the power amps with ESP P101 boards. The owner gave it to me; it's been repaired at least twice and wasn't working when I got it. Maybe same problem as yours, I don't remember the details.
But take a look at this, it may help
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Old 1st February 2008, 07:26 AM   #5
arki is offline arki  Australia
diyAudio Member
Join Date: Jan 2008
thanx paulb: I had a read and I must admit a lot of that ref. went over my head.

I did however find this post in one of the threads here in re V2K/V4K series:

"the V4X, i know like the back of my hand
- not cos they break down, simply because theyre my fave amp.

the biggest prob w/ V4X amps are Q501-Q504 Pre Drive / Current Stabilizer 2SA1123/2SC2631 - Replace these w/ 2SA1124/2SC2632 - the faults these transistors can cause are usually ongoing safety operation/intermittent safety operation / safety operation after a certain time/ whistling (soft) / distortion & in the WORST CASE take out IC502 - SVI2004A by both goin short and applying both +&- to their respective input pins at the same time

Save the IC - its no longer Available and what for? the sake of replacing aprrox $7USD in transistors???

*** the abovementioned transistors account for a staggering 90% of the faults in V2X/V4X Amps.

^ Does this sound like what I'm experiencing to you guys?
And yes Ive done an idle test and it does run "reasonably warm" to the touch...
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Old 27th November 2010, 03:50 PM   #6
tmmitzzie is offline tmmitzzie
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Join Date: Nov 2010
Default suv2x

Hi guys. I was looking around for info on the technics suv2x new class A amp, one of which I have a chance to purchase. Not sure if I'm in the right place to ask this question, please bear with me and hopefully somebody can help. My question is, on the suv2x back panel there are links labelled 'ext out'
and 'ext in'. can I connect a graphic equaliser to these connections ? has anyone ever done this? any info greatly appreciated.
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Old 7th December 2010, 12:57 PM   #7
JanErik is offline JanErik  Finland
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Join Date: Aug 2010
Location: Vasa
I have an SU-610, also "New Class A", nothing special, basic consumer chipamp that doesn't weigh nearly as much as 2*75W should.
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Old 31st October 2013, 02:21 AM   #8
freespiritw is offline freespiritw  United Kingdom
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Join Date: Oct 2013
Location: UK
I have an SU-V2X User Manual and Service Manual if anyone is still interested... just PM and i will email them. cheers
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