Richard Lee's Ultra low Noise MC Head Amp

1) Digi-Key's web site shows their locations as TRF, MN, as well as a couple business offices -- one in Fargo and one in the Twin Cities. It's likely that they bulk ship to Winnipeg and then the orders get split for Canadian delivery. This is done by many companies.
2) I've asked D-K people on the phone and they've told me that 100% of their orders are shipped from TRF (unless direct-shipped from the manufacturer in cases of some large/specialty items)
 
1) Digi-Key's web site shows their locations as TRF, MN, as well as a couple business offices -- one in Fargo and one in the Twin Cities. It's likely that they bulk ship to Winnipeg and then the orders get split for Canadian delivery. This is done by many companies.
2) I've asked D-K people on the phone and they've told me that 100% of their orders are shipped from TRF (unless direct-shipped from the manufacturer in cases of some large/specialty items)

Maybe, but the shipping manifest shows shipping straight from Winnipeg, a couple of hours after the order was placed. Unless they have a way to teleport merchandise to Winnipeg I don't understand how this happens. Whatever...
 
Even more off topic, I got yesterday a Metcal MX-5220 soldering station and a bunch of cartridges, to replace my dying Weller station.

What can I say, I don't understand how I survived for so long without one. Absolutely amazing tool.


YES! YES! YES!

When I got it, I was really angry that I did not buy that 10 years earlier.

I have 2 pencils on the 2 outputs: ultra fine and fine.
with both at the same time you can remove those 0603s easily without
killing the pads and without the need to switch on the hot air.

The Ultra fine has a 0.14 mm tip. Soldering under the microscope
is fun now. But the tiny tip is still strong enough to solder old TTH ICs.


Yesterday I got these nekkid GaN FETs. Chip scale, no epoxy,
0.8 mm square with 4 solder bumps.

The solder mask goes onto parts of the the pads to help center the chip
by surface tension.
PCBway flagged that as questionable but I could convince them. That will be
interesting to see if the boards a good enough for that adventure.
 
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Maybe, but the shipping manifest shows shipping straight from Winnipeg, a couple of hours after the order was placed. Unless they have a way to teleport merchandise to Winnipeg I don't understand how this happens. Whatever...

Example from today:

Order placed at 1:35PM, at 4:56PM order was picked by FedEx in Winnipeg. The package could make it over the border and through customs, 250Km from Thief River Falls to Winnipeg in 3 hours only by teleportation. Or perhaps they hired a private flight for my order :D.
 

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From Wikipedia:

"Digi-Key is located in a single, centralized location in Thief River Falls, Minnesota. Its facility measures 800,000 square feet (74,000 m2) and houses over 3,400 employees. In 2017 the company began work on a 1 million square foot expansion to their Thief River Falls facility at an expected cost of $200 million to $300 million. The expansion was helped by government incentives and tax exemptions and is expected to add another 1,000 jobs at Digi-Key."

Google maps says Winnipeg is a 2.5 hour drive from TRF, MN
 
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I just entered a test order.
No warning, no box that I could check.
I’m afraid that in the Dutch translation on the Digikey site this box got lost, or it is hidden somewhere deep down inside where nobody ever comes.

Hans

Hans.... it´s in the end of ordering, where you have the possibility to change the shipping. The standard (where mouser takes care of the import duty charges) is always chosen by default. To Denmark they ship by UPS. You can choose different shipping methods, but other than the standards you yourself are in charge of the import duties.
Must say, that they recently have cleaned up their act. They used to have all kind of fees and charges sometimes close to fraud (not DigiKey but the shipping companies, specially FedEx and UPS). Now is a different story. In my last shipment, I was notified by a tracking update e-mail, that I had chosen to pay import duties and that i could pay online 66 DKr (10u$). No brokers fee, no extra charges for handling... just the 10 bucks. Very pleasant to do business with them both. The reason for me to choose DigiKey is, that Mouser ships by default using FedEx, and that company (in Scandinavia at least) is the least flexible of them all. Here DHL Express and UPS are flawless at their service :)
 
#375's gain is limited by R4 & 5, which feed the current mirror and appear in parallel with the output resistor R7.
Nope. #375 gain is limited by the power supply voltage. It is independent on R4/R5.
Duraglit has a similar 'limitation' with supply voltage.

But at the high gains which seem to be of most interest to herve00fr, Duraglit has some 40dB more gain potential than #375
___________________________

For yus Brexit emigrants, I can vouch for Cooktown, Oz, as a good place to be a beach bum. Not sure about Digikey/Mouser services though. The crocodiles often stop the camel trains from getting through. :)
 
Nope, it is completely different in this respect. The gain depends on the load and the bias resistors.

And the bias resistors depend on the supply voltage.

But at the high gains which seem to be of most interest to herve00fr, Duraglit has some 40dB more gain potential than #375
 

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To add insult to injury, too much gain in the head amp is bad for the overload margin. IMO, anything between 15dB and 30dB is good enough, no need to go for more. 40dB or more of gain would also challenge the MM input the head amp is supposed to connect.

It's diy, you can lower the gain of the MM RIAA preamp.
For very low noise purpose, high gain in the first stage is mandatory.