PCB Heatsinks
Hi
A local metal shop told me that it is realtively easy the make the PCB heatsinks. If there is enougth interest I can explore this possibility of having some made for the group members.
For this of project I prefer to have the PCB look at neat as possible versus using any piece of scrap for heatsinks.
Interested parties can mail me for a quick headcount.
Jozua
Hi
A local metal shop told me that it is realtively easy the make the PCB heatsinks. If there is enougth interest I can explore this possibility of having some made for the group members.
For this of project I prefer to have the PCB look at neat as possible versus using any piece of scrap for heatsinks.
Interested parties can mail me for a quick headcount.
Jozua
36D is the old series(and i mean really old), replaced by the 36DE code.
The DE version is 85C max and the DX type good for 95C max temperature.
105C types are common nowadays, used to be only a couple of manufacturers who made them.
Big computer grade cans also came in 85C only.
(ps: the DY types are nice capacitors, high surge values, designed for freq.converters)
The DE version is 85C max and the DX type good for 95C max temperature.
105C types are common nowadays, used to be only a couple of manufacturers who made them.
Big computer grade cans also came in 85C only.
(ps: the DY types are nice capacitors, high surge values, designed for freq.converters)
Hi,
I have been experimenting with PMA's CCS + Shunt regulator.
By adding a Zener to the TL431 tail I got a fairly good 52V out of it.
Noise on the basic 15V version is about 0.3mVpp on the scope.
This 52V version has quite a bit more noise at 1.5mVpp.
Might be worth putting an extra cap on the Zener and maybe a small one across the electro on the output.
Output drifts from 51.80V @ start-up (cold) to 52.14V when hot.
Very simple and cheap components.
The Klone requires about 32mA for the front end, excluding the drivers, and Pwatts arranged for the PCB power to be split to just suit this short circuit proof low current supply.
I've seen the stacked Zenners + Follower.
Any other suggestions for a low current regulated supply?
I have been experimenting with PMA's CCS + Shunt regulator.
By adding a Zener to the TL431 tail I got a fairly good 52V out of it.
Noise on the basic 15V version is about 0.3mVpp on the scope.
This 52V version has quite a bit more noise at 1.5mVpp.
Might be worth putting an extra cap on the Zener and maybe a small one across the electro on the output.
Output drifts from 51.80V @ start-up (cold) to 52.14V when hot.
Very simple and cheap components.
The Klone requires about 32mA for the front end, excluding the drivers, and Pwatts arranged for the PCB power to be split to just suit this short circuit proof low current supply.
I've seen the stacked Zenners + Follower.
Any other suggestions for a low current regulated supply?
Attachments
A cap in parallel with the zener will help a lot. Try 100uF and upward. A small resistor in series with the zeners also help, with the cap still in parallel with the combo.
I had very good results with the stacked zeners (two drops the noise very low) but its regulation is not ideal due to its lack of feedback. Much better than just using the main supply though, and Krell regulated its KMA's supplies rather nicely with a single zener follower for the drivers and front-end.
Just building it for the 39V supplies instead, i.e. replacing the 39V zener and 1k resistor on the board will also help and be easier due to the lower power dissipation.
For the 39V supplies though, an excellent method is a high-precision voltage reference, a low-power opamp (for inverting purposes) and one OPA547 per rail. The positive rail adds the necessary gain for 39V from the reference in non-inverting mode, the opamp inverts the reference and the other OPA547 adds gain for the -39V. With the small opamp it allows the negative OPA547's to only use its negative terminal powered since their maximum rail difference is 60V. TI has a high-voltage low-power opamp capable of +-39V rails so it's not necessary to subregulate its supplies. Only pity is that TI has recently taken the OPA547 off the sample programme and they're quite pricey.
The same method can be used for the front-end and drivers too, but then the OPA548 or OPA549 would be necessary. For the 39V supplies it also isn't necessary (although still recommended) for a separate power supply; the opamps good regulation and high PSRR makes it suitable to be driven from the output stage.
I had very good results with the stacked zeners (two drops the noise very low) but its regulation is not ideal due to its lack of feedback. Much better than just using the main supply though, and Krell regulated its KMA's supplies rather nicely with a single zener follower for the drivers and front-end.
Just building it for the 39V supplies instead, i.e. replacing the 39V zener and 1k resistor on the board will also help and be easier due to the lower power dissipation.
For the 39V supplies though, an excellent method is a high-precision voltage reference, a low-power opamp (for inverting purposes) and one OPA547 per rail. The positive rail adds the necessary gain for 39V from the reference in non-inverting mode, the opamp inverts the reference and the other OPA547 adds gain for the -39V. With the small opamp it allows the negative OPA547's to only use its negative terminal powered since their maximum rail difference is 60V. TI has a high-voltage low-power opamp capable of +-39V rails so it's not necessary to subregulate its supplies. Only pity is that TI has recently taken the OPA547 off the sample programme and they're quite pricey.
The same method can be used for the front-end and drivers too, but then the OPA548 or OPA549 would be necessary. For the 39V supplies it also isn't necessary (although still recommended) for a separate power supply; the opamps good regulation and high PSRR makes it suitable to be driven from the output stage.
Capacitor
Hi
Thanks Jacco for the info.
This weekend I replaced my 100.2 main capacitors (which are possibly 18 years old) with the exact Sprague replacements except that these were DX version compared to the old DE versions.
If there ever has been a cheap upgrade, this is it. The midrange and bass improved dramatically. If ordinary Spague caps can make such a difference I wonder what a high end eletrolyctic Mundorf can do ?
Does anybody have a idea how long these Sprague's require to burn-in ?
Regards
Jozua
Hi
Thanks Jacco for the info.
This weekend I replaced my 100.2 main capacitors (which are possibly 18 years old) with the exact Sprague replacements except that these were DX version compared to the old DE versions.
If there ever has been a cheap upgrade, this is it. The midrange and bass improved dramatically. If ordinary Spague caps can make such a difference I wonder what a high end eletrolyctic Mundorf can do ?
Does anybody have a idea how long these Sprague's require to burn-in ?
Regards
Jozua
Hi,
I don't believe in burn in.
Once the electrolytic has reformed after it's storage period it is working to full spec. After that it deteriorates (as you found out).
The question you could ask is "what will it sound like if all the electrolytics were replaced with an equal value of film capacitors" (and damn the cost/space constraints)?
I don't believe in burn in.
Once the electrolytic has reformed after it's storage period it is working to full spec. After that it deteriorates (as you found out).
The question you could ask is "what will it sound like if all the electrolytics were replaced with an equal value of film capacitors" (and damn the cost/space constraints)?
Well, I finally had a small breather today and got three shipments on the way...
Austrailia, Arlington Hts.,IL, and Finland. Yous guys know who you are
I should have some more time this Saturday to get at least several more on the way. Thanks for everyone's patience... Work has been hell lately. Two more lengthy road trips and one 6 screen multiplex to install before things get back to normal.
I will be glad when I have some time to get back to this forum as well.... lots to digest and spit back out!
Thanks,
Mark
Austrailia, Arlington Hts.,IL, and Finland. Yous guys know who you are
I should have some more time this Saturday to get at least several more on the way. Thanks for everyone's patience... Work has been hell lately. Two more lengthy road trips and one 6 screen multiplex to install before things get back to normal.
I will be glad when I have some time to get back to this forum as well.... lots to digest and spit back out!
Thanks,
Mark
You guys are all still on the list. I've found out that shipping diodes is alot easier to just ship by first class mail in a small envelope. It might actually be alot faster too. But for boards and diodes it all still has to go by priority mail.
Yea, just being married and traveling is not that easy even though I enjoy my customers and the traveling!! I am in Sun Valley/Ketchum, Idaho this week and the weather is beautiful up here. Occasionally I bring the wife and our dog Dakota along on some of the trips when she can sneak away from her work long enough. Dakota loves to swim every chance he gets and its good for his hind legs. The good part about all this is that I've been doing this type of work for a very long time and the work is easy for me today... almost second nature if you know what I mean. That also makes it more enjoyable and easier to put up with day in and day out. At any rate I'l be glad to get back into this thread in the near future too. For now a photo of Dakota dripping wet...
Mark
Yea, just being married and traveling is not that easy even though I enjoy my customers and the traveling!! I am in Sun Valley/Ketchum, Idaho this week and the weather is beautiful up here. Occasionally I bring the wife and our dog Dakota along on some of the trips when she can sneak away from her work long enough. Dakota loves to swim every chance he gets and its good for his hind legs. The good part about all this is that I've been doing this type of work for a very long time and the work is easy for me today... almost second nature if you know what I mean. That also makes it more enjoyable and easier to put up with day in and day out. At any rate I'l be glad to get back into this thread in the near future too. For now a photo of Dakota dripping wet...
Mark
