For best PSRR input/output difference should be 5 Volts. Same with LM317/337 regulators.
Hello,
I am in agreement.
A little more voltage at the input helps clean up the noise floor on FFT plots.
DT
Depends on the regulator, it is not the same for all. Some it's simply excess heat produced.
But i agree, as i said in this case, more Vin will be easily dissipated due to larger heatsinks and low current consumption.
It's a simple and straightforward experiment to set up. Just install a variac between the AC mains and your Pearl 3 power cord. Dial it down until you've got only 17 volts applied to the input of the LM7815 voltage regulator ICs. Then listen or measure, and evaluate Pearl 3 when the regulator's Vin-Vout is 2 volts. Now dial the variac up until you've got 21 volts applied to the input of the LM7815 voltage regulator ICs. Listen and/or measure again, and evaluate Pearl 3 when the regulator's Vin-Vout is 6 volts.
Easy!
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Easy!
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Attachments
Five Volts minimum is the safe value for all regulators without using additional equipment to measure or listen which is tedious process. Jung Super regulator works even with 2.5Volts difference, but Jan Didden measured best results with 5Volts minimum.
Some old National app. Instruction for 78.. and lm 337 /337 rec. 5Volts.
Some old National app. Instruction for 78.. and lm 337 /337 rec. 5Volts.
It is mentioned 5V because it is a quite a safe margin for unregulated supply to the regulator itself. You can use most (i say most as there are differences between batches) onsemi 7815 and measure. 2.5V and above on 1A won't provide almost any measurable results (sub 100mA, it will go with reasonable results up to 1.6V). And you can see many equipent made with 78xx 79xx regs won't have more than +3Vin. Hence what i said it depends on the regulator itself. One can simply make tests on ear if no equipment is available with what Mark said. And again in this case to repeat myself, there is enough sized heatsink to go above and not worry about it.
Why should one insist on small input/output difference? In this case mains voltage fluctuation will reduce input voltage to useless level. Pearl 3 regulators are not LDO types.
I am going to build Pearl 3 with Jung Super regulators and lm337/317 preregulators. First stage will be built on Pass Xono pcb which I have from that project, they are similar, and second stage with bass boost part of eq. wil be gain block from Vendetta phono . On home made pcbs in the real DIY spirit.
John Curl made masterpiece with Vendetta phono stage.
He was very active on this forum. What happened with him?
I am going to build Pearl 3 with Jung Super regulators and lm337/317 preregulators. First stage will be built on Pass Xono pcb which I have from that project, they are similar, and second stage with bass boost part of eq. wil be gain block from Vendetta phono . On home made pcbs in the real DIY spirit.
John Curl made masterpiece with Vendetta phono stage.
He was very active on this forum. What happened with him?
"Ask"... not "insist".
I asked about minimizing heat and/or if that was even necessary in a particular, speculative configuration.
I appreciate the discussion to this point.
One could provide an optimal, minimal target input voltage with a pre-regulator in the PSU.
I'm still left with the question of how to heatsink a vertically-oriented board or if it's necessary to do anything different.
Every Diy assembler should have digital thermometer with thermocouple probe to
measure heatsink temperature. They are not expensive. Target heatsink temp. Is about 45 degrees Celsius max. Put a blob of thermal paste on probe tip before measuring.
Simulate desired load with resistors on power rails. I think that safe pearl 3 raw voltage is 30 Volts.max. If necessary , put a bigger heatsink or reduce voltage with power resistor in series.
measure heatsink temperature. They are not expensive. Target heatsink temp. Is about 45 degrees Celsius max. Put a blob of thermal paste on probe tip before measuring.
Simulate desired load with resistors on power rails. I think that safe pearl 3 raw voltage is 30 Volts.max. If necessary , put a bigger heatsink or reduce voltage with power resistor in series.
It's not showing me smd ones with the same query. Can you screenshot me the rest of what it filtered out for you?
I did consider it, @mhenschel! I have a couple of slope front, vented chassis boxes for instrumentation builds, so I can temporarily mount them inside one.
No, that would reward laziness.
Why don't you create a little table for yourself, containing the values of those five parameters (post 653), for original non-SMD transistors that Wayne selected? There are only four to look up; the fifth one ("Manufacturer") is already given: Dont-show-me-any-transistors-except-Toshiba.
Now ask DigiKey to show you you surface mount transistors whose parameters are as good, or better than, the parameters of Wayne's non-SMD transistors.
When you've got those part-numbers safely copied into your engineering notebook, you can start to wonder: which parameter values do YOU think are important? Maybe you don't fully agree with my choices, which is perfectly fine. Pick your own parameters-of-great-importance, look them up on the datasheets of Wayne's non-SMD devices, then ask DigiKey for transistors as good or better, on YOUR parameters.
You will feel a great deal of satisfaction from knowing that the transistors were chosen for good reasons and not just because Somebody Typed Something On The Internet. It's especially satisfying when they are chosen for YOUR good reasons.