Doug Self Preamp from Linear Audio #5

Great!

Let's start a group buy list. I'll leave it up for 30 days or so. Expect delivery to be mid to late November

georgebrooke - 1kit
Halauhula - 1 kit
hfxrzw - 2 kits
PJN - 1 kit
kiroje - 1 kit
still4given - 1kit
GlennW - 1kit
erik777 - 1 kit
arthur - 1 kit
zrxshack - 1 kit
rock12 - 1 kit

If you have asked to be added to the list but don't see your name be sure to let me know!
 
This preamplifier draws a bit of current, upwards of 650 milliamps steady state. It deserves to be fed by a quality & quiet power supply. Anybody here have a tested favorite? To this point I have been using my dev lab power supply.

This project requires a +/-15 volt supply that can sink 1 amp (allows for project addons). Bring out your power supplies!

Anybody here have a 'tried and true' low parts count series pass dual regulator using a MOSFET as the pass element??

That would be interesting ...
 
Last edited:
Power Supplies

This preamplifier draws a bit of current, upwards of 650 milliamps steady state. It deserves to be fed by a quality & quiet power supply. Anybody here have a tested favorite? To this point I have been using my dev lab power supply.

This project requires a +/-15 volt supply that can sink 1 amp (allows for project addons). Bring out your power supplies!

Anybody here have a 'tried and true' low parts count series pass dual regulator using a MOSFET as the pass element??

That would be interesting ...

Although it does not quite fit your spec, I have used the design at Power Supply for Preamps several times without any problems at all. It does go back to 2007 .

George
 
Although it does not quite fit your spec, I have used the design at Power Supply for Preamps several times without any problems at all. It does go back to 2007 .

George

Hello George,

Yea, that's a very standard (yawn ...) design straight from the TI app notes . I have a similar (if not the same) circuit as a stock item myself. In fact I have a couple of variations committed to fabbed PCBs on hand should anyone be interested.
 
Excitement

Hello George,

Yea, that's a very standard (yawn ...) design straight from the TI app notes . I have a similar (if not the same) circuit as a stock item myself. In fact I have a couple of variations committed to fabbed PCBs on hand should anyone be interested.

Yes, it would be nice to have something a little more exciting..and which works well of course. I guess we need some more input on this one.
 
Great!

Let's start a group buy list. I'll leave it up for 30 days or so. Expect delivery to be mid to late November

georgebrooke - 1kit
Halauhula - 1 kit
hfxrzw - 2 kits
PJN - 1 kit
kiroje - 1 kit
still4given - 1kit
GlennW - 1kit
erik777 - 1 kit
arthur - 1 kit
zrxshack - 1 kit
rock12 - 1 kit
canute - 1 kit

If you have asked to be added to the list but don't see your name be sure to let me know!
 
Great!

Let's start a group buy list. I'll leave it up for 30 days or so. Expect delivery to be mid to late November

georgebrooke - 1kit
Halauhula - 1 kit
hfxrzw - 2 kits
PJN - 1 kit
kiroje - 1 kit
still4given - 1kit
GlennW - 1kit
erik777 - 1 kit
arthur - 1 kit
zrxshack - 1 kit
rock12 - 1 kit
canute - 1 kit
Somakmaitra - 1 kit

If you have asked to be added to the list but don't see your name be sure to let me know!
 
Great!

Let's start a group buy list. I'll leave it up until November 1st. Expect delivery to be mid to late November

georgebrooke - 1kit
Halauhula - 1 kit
hfxrzw - 2 kits
PJN - 1 kit
kiroje - 1 kit
still4given - 1kit
GlennW - 1kit
erik777 - 1 kit
arthur - 1 kit
zrxshack - 1 kit
rock12 - 1 kit
canute - 1 kit
Somakmaitra - 1 kit
MosfetDemon - 1 kit

If you have asked to be added to the list but don't see your name be sure to let me know!
 
@Carl_Huff

Carl

If you are still looking for a PS, I through this together earlier this year. It's a LDO design, can use Mosfets or BJT, with changes to resistors and zeners, in fact I designed it to be quite variable. It can be configured for about 3-4vDC to maybe 100vDC and upto maybe 4A. It uses a 317 for reference and MC34071 for control. The size is bigger than I wanted, I didn't want to redesign for every project and I wanted more options, bigger caps, bigger heat sinks, etc.

Mad
 

Attachments

  • varps.jpg
    varps.jpg
    127.2 KB · Views: 2,054
Carl

If you are still looking for a PS, I through this together earlier this year. It's a LDO design, can use Mosfets or BJT, with changes to resistors and zeners, in fact I designed it to be quite variable. It can be configured for about 3-4vDC to maybe 100vDC and upto maybe 4A. It uses a 317 for reference and MC34071 for control. The size is bigger than I wanted, I didn't want to redesign for every project and I wanted more options, bigger caps, bigger heat sinks, etc.

Mad

Looks good! Could you please post a schematic? We need clean and quiet +/- 15v at 1A for this project. Right now we are looking at a traditional power supply followed by SuperRegulators.
 
Carl

Here is the basic circuit (positive side only, negative much the same using LM337), like I said before, a lot of options. I will draw up something for +/- 15 vDC 1 A. What ripple are you looking for, is the load current steady state, how much line variability needed(pass device dissipation, heat sink size)? Think you want the shutdown circuit? How much capacitance on preamp board? How much output adjustment, if any? Nothing more humbling than a PS.

Mad
 

Attachments

  • PSUWBR.pdf
    18.9 KB · Views: 837
Carl

Here is the basic circuit (positive side only, negative much the same using LM337), like I said before, a lot of options. I will draw up something for +/- 15 vDC 1 A. What ripple are you looking for, is the load current steady state, how much line variability needed(pass device dissipation, heat sink size)? Think you want the shutdown circuit? How much capacitance on preamp board? How much output adjustment, if any? Nothing more humbling than a PS.

Mad

Welcome to the project!

The baseline current of the prototype on my bench stable at 650mA. Crafting a power supply capable of 1 amp allows the user to add goodies, say for example a headphone amp to the project.

I like your design, especially for the fact that it's not overly complicated. A goal of this project is to have it all fit in a 1U chassis. That of course limits the height of both the heatsinks and caps. I have built similar power supplies in the past and have been quite happy with 3 x 470uF caps (your C1, C2 & C3 positions). However feel free to leverage your experience. The goal is of course pristine DC and fit in a 1U height box. I look forward to seeing what you come up with.
 
Curious why one would use a lm317 as a voltage reference, for a series pass regulator? I would suggest to use a TL431 or similar, if you need something that is variable.
You could use only one ref and make a dual tracking regulator.
Take a look at some old Sansui designs, for non IC based, such as the ones used in the AU-X1 or similar.
But for this tone control all you really need is a Lm317/337 combo esp if you are going to use cap multipliers as extra filters. Take a look at the Elektor 2012 pre-amp PS, it does the job.