I’ve had the board for this project for almost 2 weeks but needed to order parts from Mouser. I wanted to stick to the BOM they sent and get some measurements of the stock design. Mouser had a notice on their site that there were experiencing delays. I don’t know what’s going on there, but I ordered the parts on the 3rd and paid extra for 2-day shipping, thinking it might speed things up. It didn’t help much. I finally got the box today. I matched up some transistors before dinner got to soldering after doing the dishes, so I should have the board populated before bedtime.
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What’s the blue gadget do?
Its a semiconductor analizer great for identifying and matching components.
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I’m envious, they were sold out before I could get one I have 2 different kits on order from aliexpress one being the kit that Mr. Beeny loosly went off to make the FCA-001.
You have a nice set up looking forward to watching your build come together.
It should be in stock in a couple of weeks.
See his new video, think it came out yesterday. Another 100 or so boards. Only for mainland US though.
I ordered the day before he announced that more boards are on the way. Oh well. The kits from AliExpress were less than $10 each.
I should be able to put this on the test rig once I find a suitable transformer in my parts stash. I went with the NE5532 opamps and the ones I got from Amazon last week were not legit. Testing showed they don’t have protection diodes on the inputs like the genuine device. I ordered those because I was curious to see what I would actually get. Some reviews claimed what they received passed the input diode junction test, but mine did not. I threw 10 in my Mouser order and they were cheaper than Amazon’s fakes - if you don’t count the shipping cost.
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Tom, are you planning to do any upgrades or use better components? I am pllaning to get one board when they are back in stock. Hoping I can leverage your experince with this board and what and where to order from!
I’ll have to see what others say about upgrades. The only things I can see right away are different opamps and input & output coupling caps. But there’s not a ton of space left for bigger caps on the board itself.
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I couldn’t find a suitable transformer for this in my stash of junk, but you can power it from dual DC supplies. I tacked on some temporary cables thinking this would be the worst case scenario. It’s just hanging out in the open, soaking up any noise from LED lights, power supplies and other misc equipment.
Passes a decent square wave, knowing this old Tekronix probe is not nulled completely.
Pretty good at 20kHz
Not bad at 50kHz
Sine waves look fine too. A little down at 10Hz -
20K looks good -
Even 100K looks good!
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Let’s see what the QuantAsylum shows -
Pretty darn flat, but that was to be expected. -0.07dB @ 20kHz.
I really wasn’t expecting THD to be this low with no shielding of any kind. This is the volume pot wide open and the gain trimmers set to + 3dB.
Michael just posted this last night. TI had a redesign of the NE5532 opamps and now omit the diodes on the inputs. So maybe the ones I got from Amazon were the genuine article.
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I think what you guys are doing with all this is really great! Keep sharing pictures and measirements.
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Tom, what size transformer do you need? I can check my stash.
Thanks for the offer! I needed a few others for upcoming projects, so I just put in a small order with Digikey.
Supposed to 15-0-15. Doesn’t have to big, tiny one will do too doesn’t draw much. 500MA is 5 times higher than what’s needed.
He talks specifically about the transformer in the video I posted above: 7:19 time stamp.
@Tom_S might have additional specs.
I ordered some Triad F-153XPs for $10.13 each. 15-0-15v at 250ma and they are tiny. The mounting holes are only 1.75” apart.
I think this old Acurus ACT-1 Pro-logic preamp might be a suitable chassis for this project. It’s old, a pain to operate and doesn’t sound all that great. I don’t need many controls and there’s more than enough space for other boards in this thing. I would like to add an Arduino for IR volume control and input switching. I might even have enough space for the Hagerman phono preamp that’s waiting to find a home.
Measurements of the old Acurus show some degraded performance.
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That’s a cool looking chassis. Would be cool to save some of the input switching and remote volume control.
Would that transformer work?