Regarding rack version: I have noted the interest in this and out of curiosity I started drawing a rack version of the layout to see how it would fit. With all the connectors on the back panel and all the switches on the front panel. Still fits in the same Hammond box. Mechanically it's more complex, involves two PCB's, but I think it should be ok.
I have not got around to building and testing it yet, and I'd like to do that before publishing it.
But perhaps I am going about it the wrong way. Perhaps I should publish it early and if someone else has the time and is willing to take the risk they could help out with the prototyping and testing. What do you think?
I have not got around to building and testing it yet, and I'd like to do that before publishing it.
But perhaps I am going about it the wrong way. Perhaps I should publish it early and if someone else has the time and is willing to take the risk they could help out with the prototyping and testing. What do you think?
@ojg
Dear ojg
I'm a little confused about your project. help me Thanks..
THAT1510 MAX power supply is -+ 22V, +48V power How to ensure its power supply? This is a single power supply of 44V?
Is it different from positive and negative voltage supply?
2 * BC546 What role does it play?
Yes The power problem is really troublesome. I want to use 36V lithium battery and OPA202 to form a voltage follower to generate -+15V power. Is this feasible?
Thanks.
Dear ojg
I'm a little confused about your project. help me Thanks..
THAT1510 MAX power supply is -+ 22V, +48V power How to ensure its power supply? This is a single power supply of 44V?
Is it different from positive and negative voltage supply?
2 * BC546 What role does it play?
Yes The power problem is really troublesome. I want to use 36V lithium battery and OPA202 to form a voltage follower to generate -+15V power. Is this feasible?
Thanks.
@ojg
Dear ojg
Is D15 D16 D17 18V Zener regulator? I have roughly simulated your power supply circuit with a similar Zener regulator. You can get about+33~35V power supply, which can meet the demand of single power supply. Is it possible to add a voltage follower to generate a ± 15V~± 17V power supply?
Dear ojg
Is D15 D16 D17 18V Zener regulator? I have roughly simulated your power supply circuit with a similar Zener regulator. You can get about+33~35V power supply, which can meet the demand of single power supply. Is it possible to add a voltage follower to generate a ± 15V~± 17V power supply?
Attachments
Correct! D15 and D16 forms a zener regulator with Q2 as the pass transistor to make a 35V supply for the THAT1510.
D17+C18 creates a stable mid-supply reference, so there is no need for a +-15V supply in this case.
All that is needed is a single 48V supply. You can also use a single 36V supply, then the phantom-power for the microphone will be lower than normal, but most microphones will handle that just fine.
D17+C18 creates a stable mid-supply reference, so there is no need for a +-15V supply in this case.
All that is needed is a single 48V supply. You can also use a single 36V supply, then the phantom-power for the microphone will be lower than normal, but most microphones will handle that just fine.
Hi. I just joined here because of this project, awesome work. I am a total noob on github but little experience with Kicad and a ton of guitar pedals built. I would like to download the pcb files for thsi and would like to check if I could be able to make this project at some point. Would appreciate some help with the download if this can be done, thanks. The rack version sounds interesting and I was also thinking if you could have two in the box with the same power. Is there any change someone has a link to a compatible power unit at Thomann for instance ?? Thanks, Have fun folks.
I have not tried it, but I don't see any issues with this approach. This is what I would do, yes.
Now if you build several channels into a rack-mount enclosure, for a professional look you might want an internal AC power supply. You could go with a traditional so-called linear supply with transformer-rectifier-caps-regulator. But I would worry about 50/60Hz hum getting into the circuit from the transformer this way.
So I would instead choose one of the compact AC/DC switching supplies like Mean-Well RS-15-48 or similar. Hard to beat for the price, and easy and safe to use. This could power 4 channels in a 1RU enclosure or 8 channels in a 2RU enclosure without problem. It switches at a frequency far above the audio band, and the cap-multiplier filters on the ThatMicPre boards will filter out the remaining ripple very well.
Welcome to diyaudio!
If you just want to download the files and don't want to deal with git, you can click the green "Code" button and choose "Download as zip"
New rackmount version available!
Finally got around to build the new rack version. Happy to say that the mechanical fit was good, so I went ahead and built the rest.
As you can see there is now a separate sub PCB for the front panel which the gain switch and gain resistors are mounted to. There are female angled single-row pin headers underneath the main PCB, and regular pin headers on the front-panel PCB that connects them.
The circuitry is otherwise almost exactly the same as the desktop version, and there are no measurable differences. This one I built with the THAT1512, and it measures exactly as predicted in the datasheet.
Documentation on github is updated.
Happy building!
OJG
Hi everyone!
I just got done building v1.1 a couple of weeks ago and finally got around to making the first recordings - it's working perfectly! Now I finally have a preamp for my Shure SM7B since only one of my audio interfaces has a strong enough preamp to record it properly.
To be honest, I'm actually surprised that I apparently didn't make any errors, what with my soldering skills... Thank you so much, OJG!! This was an awesome project to build, the PCBs are spot on, also together with the Hammond case.
Do you have any plans for creating any other open hardware audio equipment? Or do you guys have any recommendations for other projects that are as well-documented as this one? I'm kind of hooked...
Here are some pictures (the knob is still WIP, I need to print another one that's less clunky..):
Again - thanks for this valuable new piece of equipment!
Joachim
I just got done building v1.1 a couple of weeks ago and finally got around to making the first recordings - it's working perfectly! Now I finally have a preamp for my Shure SM7B since only one of my audio interfaces has a strong enough preamp to record it properly.
To be honest, I'm actually surprised that I apparently didn't make any errors, what with my soldering skills... Thank you so much, OJG!! This was an awesome project to build, the PCBs are spot on, also together with the Hammond case.
Do you have any plans for creating any other open hardware audio equipment? Or do you guys have any recommendations for other projects that are as well-documented as this one? I'm kind of hooked...
Here are some pictures (the knob is still WIP, I need to print another one that's less clunky..):
Again - thanks for this valuable new piece of equipment!
Joachim
Thank you for posting your build, it looks excellent! Black-on-silver looks good!
For further designs, the first that comes to my mind is a power supply. A 48V PSU is not something anyone has laying around, so a boost converter to take 9-12V input, or even USB-C and create 48V output would be useful.
For more audio circuits it could be interesting to implement one of THAT's design-notes on a compressor to go with this mic preamp.
What do you think?
For further designs, the first that comes to my mind is a power supply. A 48V PSU is not something anyone has laying around, so a boost converter to take 9-12V input, or even USB-C and create 48V output would be useful.
For more audio circuits it could be interesting to implement one of THAT's design-notes on a compressor to go with this mic preamp.
What do you think?