once was
Technics Amps...
mmmm
the old SVI series was based on a higher current handling hybrid IC
such series were SVI200* SVI210* pure output stages w/ overload det.
then they has SVI310* and SVI320* series, these ICS had full onboard operation, had pre amp ic and protect ic inbuilt which prevented overload, DC offset whilst providing thump/dethump prot,
then you had SVI400* series, custom built w/ extra emitter resistors to form the class AA bridge - similar internal layout with different input stage
then Technics got cheap - they skimped out on their heatsinks
then the power hybrid ics themselves hence the RSN series/ i believe the series changeover is due to having the ics developed by a different manufacturing plant or Matsushita knew that the ics werent going to be like the old school SVIs
moreso the big introduction w/ this IC was the class H operation, where its more suited to home cinema use rather than the sheer sound brilliance of the older SVI series (mainly the SVI2 series)
some models are pin compatible, i will add more to this when i explore more RSN ics, - i only own 1 amp w/ these RSN chips, that being a SA-TX50 Pro Logic/THX amp n only then used as the pre amp
i hope this gives you some insight to this
-Baily
Technics Amps...
mmmm
the old SVI series was based on a higher current handling hybrid IC
such series were SVI200* SVI210* pure output stages w/ overload det.
then they has SVI310* and SVI320* series, these ICS had full onboard operation, had pre amp ic and protect ic inbuilt which prevented overload, DC offset whilst providing thump/dethump prot,
then you had SVI400* series, custom built w/ extra emitter resistors to form the class AA bridge - similar internal layout with different input stage
then Technics got cheap - they skimped out on their heatsinks
then the power hybrid ics themselves hence the RSN series/ i believe the series changeover is due to having the ics developed by a different manufacturing plant or Matsushita knew that the ics werent going to be like the old school SVIs
moreso the big introduction w/ this IC was the class H operation, where its more suited to home cinema use rather than the sheer sound brilliance of the older SVI series (mainly the SVI2 series)
some models are pin compatible, i will add more to this when i explore more RSN ics, - i only own 1 amp w/ these RSN chips, that being a SA-TX50 Pro Logic/THX amp n only then used as the pre amp
i hope this gives you some insight to this
-Baily
SVI, I think you are still around.... I'm working on a Technics SA-DX940 which has a overheating RSN313H25 and it is driving me nuts. A replacement part I ordered was worse than the original. Is there perhaps a similar SVI/STK part that I could use to replace the RSN? Or any chance you could point me to the internals of SVI, STK, and or the RSN parts so I can compare for myself?
Ahh the late breed... RSN ... forget SVI equivant for class H series
On the ic what voltages on pin 3,4,5 & 6
This class H ic is kind of like SVI3205 (2 ch V.amp/Pwr amp & protect circuit) with the addition of signal sensing/power supply switching
High rail from pin 1 and 2 is on tap fed to pins 4 and 5 (via power feed transistors internally)
If there’s shorts in that section - you’ll find constant (or imbalanced) high voltages at pins 4 and 5
Pin 20 and 21 (inputs) should be 0V
Pins 4 and 5 should be VL (+/- 24V)
Pins 3 and 6 (outputs) at 0V - this is a good clue to Amplifier health
I have not really delved into this series ic - the larger ch ic (RSN310R37-P) seems to be a MOSFET amp... aren’t sure if they carried this into the 2ch RSH313H25-P
The centre 22 pins appears to be pin compatible - yet to be bench tested.
On the ic what voltages on pin 3,4,5 & 6
This class H ic is kind of like SVI3205 (2 ch V.amp/Pwr amp & protect circuit) with the addition of signal sensing/power supply switching
High rail from pin 1 and 2 is on tap fed to pins 4 and 5 (via power feed transistors internally)
If there’s shorts in that section - you’ll find constant (or imbalanced) high voltages at pins 4 and 5
Pin 20 and 21 (inputs) should be 0V
Pins 4 and 5 should be VL (+/- 24V)
Pins 3 and 6 (outputs) at 0V - this is a good clue to Amplifier health
I have not really delved into this series ic - the larger ch ic (RSN310R37-P) seems to be a MOSFET amp... aren’t sure if they carried this into the 2ch RSH313H25-P
The centre 22 pins appears to be pin compatible - yet to be bench tested.
On my unit, all the static voltages are good. Isolating diodes are good. Module generates quite a bit of heat even with no signal passing through and no speakers connected. Eventually, the module drops the RLY drive to 0, opening the speaker relays, and the DSP pin goes to 0 or +5 telling the processor there is an overload/overheat.
Am currently trying to get a refund on the defective unit I bought from China, and may end up having to try again. Seems like the only reasonably priced units I can find all ship from China, wouldn't mind if it didn't take 3-4 weeks to get them. Was hoping there might have been a more reliable direct replacement, even if the replacement doesn't have the 'protection' outputs and I need to fool the processor.
Am currently trying to get a refund on the defective unit I bought from China, and may end up having to try again. Seems like the only reasonably priced units I can find all ship from China, wouldn't mind if it didn't take 3-4 weeks to get them. Was hoping there might have been a more reliable direct replacement, even if the replacement doesn't have the 'protection' outputs and I need to fool the processor.
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I’d have looked to a reliable seller.... the supplier here still has this in stock.
It’s a case of biting the bullet n getting a new one from a reputable source... may cost a lil more initially but save you time, solder and heatsink compound
Any idea why the 1st one quit?
I’ve had overload errors on a few of the class H receivers- invariably turned out on them to be dry joints on voltage regulator transistors - also bolted to The heatsink (SA-TX50 / SA-TX30)
It’s a case of biting the bullet n getting a new one from a reputable source... may cost a lil more initially but save you time, solder and heatsink compound
Any idea why the 1st one quit?
I’ve had overload errors on a few of the class H receivers- invariably turned out on them to be dry joints on voltage regulator transistors - also bolted to The heatsink (SA-TX50 / SA-TX30)
No idea why the original is overheating. I've got a couple of posts here and AK to see if anyone has the internal schematic of this RSN unit but no replies. As I say, voltages are fine - both the low and high rails are right on the money. None of the electrolytics seem to be leaky, and when working the output offset is very near zero. But it does get hotter than I would expect.
I 'flip' these receivers. The original owner reported that the unit would just go silent on occasion, but initially I could not duplicate. I paid $15 for this receiver, and replaced the high rail power caps as the old ones where slightly bulged. So now I have $30 into it. Was about to sell it when the 'going silent' issue finally emerged. The module I ordered from China (which turned out to be bad) cost me $12.50. Now I'm up to $42.50 without considering any labor or cleaning supply costs. Cosmetically it has a deep scratch across the display bezel - so I don't think I can get more than $40 for it. Really can't justify spending, what, $40? on a US sourced module. If the vendor replaces the bad RSN, I'll try again, but otherwise I may end up removing the RSN and advertising it as having non-operative surround channels and/or keep it for parts.
Thanks for listening to my ramblings.....
I 'flip' these receivers. The original owner reported that the unit would just go silent on occasion, but initially I could not duplicate. I paid $15 for this receiver, and replaced the high rail power caps as the old ones where slightly bulged. So now I have $30 into it. Was about to sell it when the 'going silent' issue finally emerged. The module I ordered from China (which turned out to be bad) cost me $12.50. Now I'm up to $42.50 without considering any labor or cleaning supply costs. Cosmetically it has a deep scratch across the display bezel - so I don't think I can get more than $40 for it. Really can't justify spending, what, $40? on a US sourced module. If the vendor replaces the bad RSN, I'll try again, but otherwise I may end up removing the RSN and advertising it as having non-operative surround channels and/or keep it for parts.
Thanks for listening to my ramblings.....
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