This is common in SS amps. They use snubbers (RC networks) that pass more current than in other amplifiers. This makes the resistors run very hot. This has nothing to do with the rail voltage.
You have to remember that resistors are made of materials that can withstand very high temperatures. Ceramic wire-wound resistors can withstand 500+ degrees (F).
There could be a problem that's causing excessive ringing or noise on the power supply but it's more likely that this is normal.
You have to remember that resistors are made of materials that can withstand very high temperatures. Ceramic wire-wound resistors can withstand 500+ degrees (F).
There could be a problem that's causing excessive ringing or noise on the power supply but it's more likely that this is normal.
Javan is asking you here on forum and me in private mail. he wants to replace the resistors with higher wattage ones, which is possible but to no real advantage except maybe some durability gains.
His rails supply appears to be in high power mode and my prints only shows high current mode voltages, hence his voltage concerns. My concerns were with all the foreign parts in the amps possibly causing the supply to not function properly so he has replaced everything as close to original as possible, but the resistors still get excessively to his IR meter....
His rails supply appears to be in high power mode and my prints only shows high current mode voltages, hence his voltage concerns. My concerns were with all the foreign parts in the amps possibly causing the supply to not function properly so he has replaced everything as close to original as possible, but the resistors still get excessively to his IR meter....
It seems to me a poor design choice to have something so damn hot in such a tight & cramped space without any means of dissipating that heat, but you two both know far more than I so if you say its not an issue then Ill give it some hell on the test bench & see what happens. Could very well be they have a peak temp just over 200* & ive just been too cautious to let it actually reach that point. Ill save the 10w resistors just in case these decide to give up the ghost.
If its common for these to get hot, is there a known operating temp range for this application?
If its common for these to get hot, is there a known operating temp range for this application?
On Ref's I worked on they got hot. Too hot to touch without causing pain so yes I say the get hot. Since this has always been common to these amps when ever I saw them I never paid much attention to them as they read in spec every-time I checked them. And yes I do check them, as they serve a very important purpose in the circuitry or they would not be there.
I have seen older PPI amps have similar temp issues on their filters like this. Most amps use some form of this around the toroid so to protect the mosfets and to prevent RF and noise transmission from the power supply.
It's all part of a typical accepted design's many amp manufacturers use. In this case they run very hot to the touch, and if they had been too hot the resistors would have opened up or raised in value before you got the amp for repair....hope this helps some.
I have seen older PPI amps have similar temp issues on their filters like this. Most amps use some form of this around the toroid so to protect the mosfets and to prevent RF and noise transmission from the power supply.
It's all part of a typical accepted design's many amp manufacturers use. In this case they run very hot to the touch, and if they had been too hot the resistors would have opened up or raised in value before you got the amp for repair....hope this helps some.
The amp seems to be in great working order, I guess I am just a little overly cautious of things heating up that quickly.
Powered up & sat back to watch for potential fireworks, and the temp finally peaked around 260*F at idle.
Interestingly enough the more load I put on the amp the lower the temp would get. Bridged to a 4 ohm load and cranked up I got the temp back down to almost 200*F.
I had it running for several hours, and sitting idle for almost an hour, and everything seems to check out just fine.
Powered up & sat back to watch for potential fireworks, and the temp finally peaked around 260*F at idle.
Interestingly enough the more load I put on the amp the lower the temp would get. Bridged to a 4 ohm load and cranked up I got the temp back down to almost 200*F.
I had it running for several hours, and sitting idle for almost an hour, and everything seems to check out just fine.
Glad to hear its working for you...That is what we try to do here for folks...
& thats why Im here, to tap this insane resource of knowledge.
Just imagine if they had not included that snubber in the amps design at all ??? With all the heat its making its doing and protecting something very well don't you think?
Indeed, and something I'll appreciate more once I understand just how it works Im sure. lol
soundstream R1000
Hi Audiophile 247. I was wondering if you got your R1000 fixed. I designed and built the old Reference amps. the first thing I noticed is that the transistors shown in the blowup look like there the wrong ones. Those transistors are the Mosfet drivers and they are high current. The 2N2222 and the 2SA1562 are the correct ones. If you can't find them I have some. R124 is a 15 ohm 1/2 watt resistor. You can check the values by looking at the the drive components for the upper 4 f=mosfets. There are a set of drivers on each side of the input filter caps. (The ones mounted on the top of the PC Board) One set near the edge of the board and one by the power input connectors.
If you need any more info or some transistors let me know at:
wade@stewartelectronicscorp.com
Hi Audiophile 247. I was wondering if you got your R1000 fixed. I designed and built the old Reference amps. the first thing I noticed is that the transistors shown in the blowup look like there the wrong ones. Those transistors are the Mosfet drivers and they are high current. The 2N2222 and the 2SA1562 are the correct ones. If you can't find them I have some. R124 is a 15 ohm 1/2 watt resistor. You can check the values by looking at the the drive components for the upper 4 f=mosfets. There are a set of drivers on each side of the input filter caps. (The ones mounted on the top of the PC Board) One set near the edge of the board and one by the power input connectors.
If you need any more info or some transistors let me know at:
wade@stewartelectronicscorp.com
audiophyle247, I don't know if this is too late but the 1ohm 5 watt resistors in the Reference 1000s was eventually replaced with a ten watt resistor. i originally designed the 1000s but during it'sv final design I was not thgere. The resistors Are snubbers on the switching Mosfets. there was a large spike across the Fets. I have included a schematic for the 1000s.
wadest
wadest
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