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STK Not Good?

well Jurb, your post is definately not an IC (integrated comment) but a posting containing a lot of discrete characters ! :beerchug:
 
JURB almost convinced me that STK's are worthy. STK's tend to run hot and in some receivers like the Yamaha R-2000, dangerously hot. The plastic form factor and compact all-in-one design work against effective heat disapation and with the exception of Tubes and Class A amps, heat is the enemy. Heat lowers electrical conductivity. This cannot be good for frequency response and output power. I will take an old school metal die T-03 output amp over an STK amp every time.
 
I knew you'd show up here... To 3 is a thing of yesteryear.... I mentioned a few top liners that even flipper would straggle to flip in comparo... Honestly in absolute I get why discrete snobs diss the power hybrid ic.... It's purely on individual component replacibility..... But I have big guns (being monster amps that are discrete) I know amps. And have had pleasure of all their company (except the Yamaha MX 10000 which id love to audition) I do fight for power ic recognition but there's alot of not so good ones under load, and I have a heap that dish out hefty power and sound real good doing it to boot... (I have heard the SVI3206A in flight clocking over 160 watts continuous per side unjaded) but I'm the realm od the power ic invariably you will find the 80 watt <per chan?> darlingtons generally in the STK or SVI based amps you like best. IMHO that power level was where the hybrid ICs really could outdo discrete. Again take note of specific topology and application.... The ruin (especially for Technics) was the cost cutting on heatsinking, but I was also never one for wanting the voltage amp and etc packed in there.... If you care to try, RUN ANY Hyprid IC amp against a Technics SU-V4X.. (1984) it sure is a standard setter in any amp discrete or not.
 
SoCal Sam said:
JURB almost convinced me that STK's are worthy. STK's tend to run hot and in some receivers like the Yamaha R-2000, dangerously hot. The plastic form factor and compact all-in-one design work against effective heat disapation and with the exception of Tubes and Class A amps, heat is the enemy. Heat lowers electrical conductivity. This cannot be good for frequency response and output power. I will take an old school metal die T-03 output amp over an STK amp every time.
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T-O3 is just this side of unavailable. Only a couple of TO-3 audio transistors being made anymore. Rumor has it they will be on consignment soon.

Enjoy,
Rich P
 
I suppose this is kind of off topic but maybe not. Would you guys suggest buying a spare STK (either outright or from a parts unit) or compliment of outputs (or the new equivalent) if you are planning on keeping an amp forever just to beat out obsolescence?

I've got a few pieces I never plan on selling and would be bummed if they became door stops due to unavailable parts.
 
Finding non-fake output transistors is a problem. There is plenty of BPC that could potentially serve as organ donors.
 
Luckily the amps I'm looking to keep long term have current production replacements from On-Semi so I'm in the clear for now.
Looks like it's worth the ~$50 to have piece of mind for a while to come.
 
I have a black faced R300. It sounds wonderful pushing Dahlquist M905's. If I were your kid I would be tickled to take that to school.
 
I think TO-3 will be around for some time still, there is too much pro audio equipment out there using it.

Plus you can usually adapt something. Get it thermally coupled and run wires if necessary.

Who knows though, eventually they might just phase out BJTs period because it takes current to run them. But then at least you do not need an elevated supply like with alot of MOSFETs.
 
It is not snobbery, discrete transistors often run cooler, are more reliable, and can be substituted around. IC output blocks are often proprietary, run hotter often as not, and less margin for safety. I like good sounding, reliable, well built gear, and keep my gear for the long term.
 
The Darlington packs can indeed be rebuilt from discreet components, but often the question is whether or not it is worth it. I suspect that for anyone who isn't able to do it themselves, the answer is quite probably "NO". Even if you were able to roll your own, is the time and parts cost worth what the amplifier is? Might be interesting to do as a technical challenge but I doubt you could do it on something you wished to sell and be able to pay yourself any kind of hourly wage you'd actually be willing to work at for that kind of job.


The only things I deal with that have them are those Ford JBL amps I mentioned. They're not worth the effort. No space to do it besides. If I get into a situation with those where I can't replace the unit, the input and output connectors will come out of them and serve to become adapters to interface with another amplifier that can be easily obtained. THey do have a right nice chunk of aluminum for a heat sink too, would make a lovely dummy load.
 
The single STK-014 powering both channels of my Sansui 331 is still clear as a bell and sounds way better than it has any right to. Just depends though. It's an original that has aged well. I've heard internal particle migration can affect the STK's over time- leading to interference and deteriorated performance within the module.
 
Another thread from the dead! STK bottom line (for me): they run hot, so anything I have with them (currently a Fisher ca-880) gets an external fan. That thing, when pushed, gets DAMN HOT without moving air on it. Keep it cool, keep it hopefully for a long time.
 
z-adamson said:
No...

It is part of the point, but not the whole point.

Reliability and build quality play a big part too. If it sounds great but doesn't last and then can't be repaired, then that's not very "high end"....is it?
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I realize this is an older thread, but just wondering what is it about the R-500 that can't be repaired? Mine just recently lost the STK.
 
infullview said:
I realize this is an older thread, but just wondering what is it about the R-500 that can't be repaired? Mine just recently lost the STK.
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Probably because of the fact that most STK's aren't very trust worthy these days. There are still good one's around but a lot of people say that there are a lot of fakes going around also.

If you want to do the research and the work, there are a few guys around here who replace and build the old STK's with discreet transistors.
 
cademan said:
Probably because of the fact that most STK's aren't very trust worthy these days. There are still good one's around but a lot of people say that there are a lot of fakes going around also.

If you want to do the research and the work, there are a few guys around here who replace and build the old STK's with discreet transistors.
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There at least 3 vendors on e-pay that advertise original Sanyo part, have 100% rating and offer free returns withing 30 days. Can they all be fakes? I'm going to take a chance and try one. Is there a reason the R-500 was so notorious for blowing these things. Are they running above rated specs? Are there parts around the SDK I should look for that might need to be replaced? I checked the emitter resistors and they were all good.
 
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