I was curious about what the actual resistance of these NTE wirewounds were...I didn’t bother measuring before I plopped the 4.7 one in.
These come in 2 packs marked 5% tolerance. The second one from the pack measured 5.1 Ohms.
With a 47 Ohm Panasonic 3 Watt piggybacked I measured about 4.5 Ohms cold. They appear to drift upwards once they heat up.
So I got 2.46V across this set up. Should have nudged the current up to about 550mA?
It functions pretty much the same during the TOC process. Maybe the LEDs are a little more of a flicker now. Still dipping to about 5.6V I think.
I noticed that the voltage dips are a symptom of the TOC read process and also appear to a lesser degree if you skip to tracks further across the disc before hitting play. So the process of having to scan and shift the mechanism at the same time is drawing a lot of current.
Of course I didn’t feel the need to buy a 3.9 Ohm 5 Watt. I skipped to 3.3 and then 2.2.
I did buy a large variety of lower resistance 2 Watt just in case.
These come in 2 packs marked 5% tolerance. The second one from the pack measured 5.1 Ohms.
With a 47 Ohm Panasonic 3 Watt piggybacked I measured about 4.5 Ohms cold. They appear to drift upwards once they heat up.
So I got 2.46V across this set up. Should have nudged the current up to about 550mA?
It functions pretty much the same during the TOC process. Maybe the LEDs are a little more of a flicker now. Still dipping to about 5.6V I think.
I noticed that the voltage dips are a symptom of the TOC read process and also appear to a lesser degree if you skip to tracks further across the disc before hitting play. So the process of having to scan and shift the mechanism at the same time is drawing a lot of current.
Of course I didn’t feel the need to buy a 3.9 Ohm 5 Watt. I skipped to 3.3 and then 2.2.
I did buy a large variety of lower resistance 2 Watt just in case.
When on edge of just enough current limit, heating up to +R is no good. Enough extra R to start hiccups.
Got the 3.3 Ohm 5 Watt in place after another soldering session. The board still seems to be holding up well.
The voltage across R301 is at about 2.25-2.35. The actual resistance of this wirewound was about 3.5 Ohms. So it should be in the 650mA ballpark.
I fired the transport up and it went through the TOC without a problem.
I tried it several more times and observed no flickering or dimming of the red LEDs in the voltage reference section.
There is a slight dip in voltage measured going into the transport circuit...perhaps down to 7.6V during the TOC read process.
I would think that this might just be reasonable and expected at this point since it doesn’t appear that the SSLV is struggling to deliver current?
I let the transport play several tracks so I could monitor the temperature of R301, Q301 and Q306.
After about 10 minutes of play I got concerned as the temps seemed to just continue to climb and they were approaching 70 degrees C. I shut it down.
I’m not sure what temps are acceptable and at this point I’m wondering how I will handle the heat in a smaller enclosure that would fit on a shelf with the transport.
The voltage across R301 is at about 2.25-2.35. The actual resistance of this wirewound was about 3.5 Ohms. So it should be in the 650mA ballpark.
I fired the transport up and it went through the TOC without a problem.
I tried it several more times and observed no flickering or dimming of the red LEDs in the voltage reference section.
There is a slight dip in voltage measured going into the transport circuit...perhaps down to 7.6V during the TOC read process.
I would think that this might just be reasonable and expected at this point since it doesn’t appear that the SSLV is struggling to deliver current?
I let the transport play several tracks so I could monitor the temperature of R301, Q301 and Q306.
After about 10 minutes of play I got concerned as the temps seemed to just continue to climb and they were approaching 70 degrees C. I shut it down.
I’m not sure what temps are acceptable and at this point I’m wondering how I will handle the heat in a smaller enclosure that would fit on a shelf with the transport.
Losing 0.4V from 8V nominal rail during peak current demand seems tolerable by the transport and if it was my system I wouldn't attempt even more current overhead to be paid in dissipation at this point.
You surely need bigger sinks to lose 10-20C. Your transport is not benign at all for consumption peaks as it proved. Maybe devoting a high idle shunt reg to cover its needs is not a good idea unless you will like the sound quality much (if affected).
But ok you already had a board. A much more efficient solution would be opting for the L-Adapter. L-A Link
P.S.
Can a part of the 0.4V peak loss be attributed to the output cable? Because if only due to marginal current limiting also means momentary starving of Vref and led blinks would still be seen? Measure for voltage drop on that cable's send side end to end to know.
You surely need bigger sinks to lose 10-20C. Your transport is not benign at all for consumption peaks as it proved. Maybe devoting a high idle shunt reg to cover its needs is not a good idea unless you will like the sound quality much (if affected).
But ok you already had a board. A much more efficient solution would be opting for the L-Adapter. L-A Link
P.S.
Can a part of the 0.4V peak loss be attributed to the output cable? Because if only due to marginal current limiting also means momentary starving of Vref and led blinks would still be seen? Measure for voltage drop on that cable's send side end to end to know.
Hi Salas
Given the heat dissipation issues already present, more current doesn’t seem like an option.
I’m glad I built the SSLV regardless as to whether I use it to power the transport. It is something I wanted to learn more about for a while.
I can easily reset this board to use for a 5V supply in my DAC project which is waiting in line after this transport. I think it will require much less current and create less heat if that is the case.
I haven’t given up yet. I’ve come this far and would like to at least try using this supply with the transport.
I think you already planted the seed in my mind that the wiring could limit current in a previous post. It is definitely something I will look at.
My intention was to figure out a way to wire the SSLV to the transport in 4 wire mode using one of the 4 pin aerospace connectors I just picked up.
I suppose if I wanted the sensing wiring separated until it reached the transport board I’d have to use a DPDT switch for the + wires?
On the topic of heat dissipation...I do have some larger TO220 heat sinks I could try using or incorporating into a case.
My original intention was to use a 1/4” thick plate for the bottom of my transport power supply enclosure which would be big enough to house the SSLV, transformer etc and attach the transistors to that.
I have a 1/4” thick scrap about 3” X 8” I was thinking of using so the scale of the supply would be similar to the transport. Figure a 3” X 3” X 8” enclosure. I do have plenty of other aluminum plate that I could cut or machine as well.
I’m wondering how to figure out if the 3” X 8” piece will dissipate well enough once everything is enclosed ...even if I vent the enclosure.
I could invert the board in the case so the plate would become the cover and vent the sides to hopefully dissipate heat better rather than trapping it in the bottom of the case.
I’m going to see if I can find a resource to help me calculate the approximate dissipation of the 1/4” plate based on dimensions.
Given the heat dissipation issues already present, more current doesn’t seem like an option.
I’m glad I built the SSLV regardless as to whether I use it to power the transport. It is something I wanted to learn more about for a while.
I can easily reset this board to use for a 5V supply in my DAC project which is waiting in line after this transport. I think it will require much less current and create less heat if that is the case.
I haven’t given up yet. I’ve come this far and would like to at least try using this supply with the transport.
I think you already planted the seed in my mind that the wiring could limit current in a previous post. It is definitely something I will look at.
My intention was to figure out a way to wire the SSLV to the transport in 4 wire mode using one of the 4 pin aerospace connectors I just picked up.
I suppose if I wanted the sensing wiring separated until it reached the transport board I’d have to use a DPDT switch for the + wires?
On the topic of heat dissipation...I do have some larger TO220 heat sinks I could try using or incorporating into a case.
My original intention was to use a 1/4” thick plate for the bottom of my transport power supply enclosure which would be big enough to house the SSLV, transformer etc and attach the transistors to that.
I have a 1/4” thick scrap about 3” X 8” I was thinking of using so the scale of the supply would be similar to the transport. Figure a 3” X 3” X 8” enclosure. I do have plenty of other aluminum plate that I could cut or machine as well.
I’m wondering how to figure out if the 3” X 8” piece will dissipate well enough once everything is enclosed ...even if I vent the enclosure.
I could invert the board in the case so the plate would become the cover and vent the sides to hopefully dissipate heat better rather than trapping it in the bottom of the case.
I’m going to see if I can find a resource to help me calculate the approximate dissipation of the 1/4” plate based on dimensions.
Attachments
We will be happy to know how your efforts will play out. Keep us posted.
*I wouldn't recommend a switch for Kelvin/standard wiring. The moment you switch there's no Vref control for a split second. Bad voltage peak and damages are possible. Not only to the load. Even for switching it when off-line only, contacts wear with time. Especially on DC. Compare Kelvin or not to Kelvin your app the hardwired way IMO.
After long listening sessions I changed & now I like more the Reflektor-D for the Chronus re-clocker.
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Its always the true CCS result what voltage you measure on a setting resistor divided by the resistor. If its enough for the particular heater spec (deduct 100mA spare) then look elsewhere for the not reaching Vh problem. An oscillation or a small part not adequate or broken, like needing a higher value trimmer, or a TO-92 is broken.