After getting conflicting hfe readings from a multimeter hfe tester and a cheapo transistor tester I built up the Hesener's test circuit shown on pg.7 post #67 of the Paradise Builders Thread.
Using Hesener's circuit the difference between the BC32740BU's and BC33740BU's decreased considerably. I ended up with a good number of parts overlapping around hfe of 420 or so. I'm not sure which method of measuring is best but I tend to trust Hesener's method as more parameters are controlled. So it does seem that 200 of each would be enough to get some usable matches.
Is there by any chance you tested 512-BC33740TA and 512-BC32740TA from Mouser with Hesener circuit as well?
I measure all mine with a Peak DCA Pro meter, and then curve trace my final selection once they're batched up. Time consuming but worth it. The last lot I did ended up giving only 0.5v offset with the servo out of circuit. That's very good. A typical 10% accuracy match will yield about 2.5v offset before the servo.
Ime you can clearly hear the difference between 1% and 10% matched parts..
Ime you can clearly hear the difference between 1% and 10% matched parts..
I measure all mine with a Peak DCA Pro meter, and then curve trace my final selection once they're batched up. Time consuming but worth it. The last lot I did ended up giving only 0.5v offset with the servo out of circuit. That's very good. A typical 10% accuracy match will yield about 2.5v offset before the servo.
Ime you can clearly hear the difference between 1% and 10% matched parts..
First of all, thanks for your vast contributions on this project.
I'm considering buying another batch of 327 and 337 and since the Diotec I've got are having HFE all over the place.
Since I'm located near the region where Mazzer is, I thought maybe I checked with him since the supply chain should be from the same source.
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Is there by any chance you tested 512-BC33740TA and 512-BC32740TA from Mouser with Hesener circuit as well?
I ordered another 200 each of the 512-BC33740TA and 512-BC327TA before using Hesener's circuit on the 512-BC337BU and 512-BC327BU's that I have. They should be here in a couple of days or so. I can report what I find when they arrive.
512-BC32740TA & 512-BC33740TA readings
Here is what I got:
512-BC32740TA
hfe____________qty.
360 - 400----------30
401 - 415----------70
416 - 425----------65
426 - 500----------25
512-BC33740TA
hfe___________qty.
400 - 430---------50
431 - 460---------60
461 - 490---------40
491 - 600---------50
Measurements were taken at 71.5 degrees all in one sitting using Hesener's circuit - no fan or gloves, just handled them quickly. I will do more careful matching during the build. Most matches are between 410 - 435.
Parts were ordered from Mouser and sent from Mansfield, TX.
Here is what I got:
512-BC32740TA
hfe____________qty.
360 - 400----------30
401 - 415----------70
416 - 425----------65
426 - 500----------25
512-BC33740TA
hfe___________qty.
400 - 430---------50
431 - 460---------60
461 - 490---------40
491 - 600---------50
Measurements were taken at 71.5 degrees all in one sitting using Hesener's circuit - no fan or gloves, just handled them quickly. I will do more careful matching during the build. Most matches are between 410 - 435.
Parts were ordered from Mouser and sent from Mansfield, TX.
Here is what I got:
512-BC32740TA
hfe____________qty.
360 - 400----------30
401 - 415----------70
416 - 425----------65
426 - 500----------25
512-BC33740TA
hfe___________qty.
400 - 430---------50
431 - 460---------60
461 - 490---------40
491 - 600---------50
Measurements were taken at 71.5 degrees all in one sitting using Hesener's circuit - no fan or gloves, just handled them quickly. I will do more careful matching during the build. Most matches are between 410 - 435.
Parts were ordered from Mouser and sent from Mansfield, TX.
Thanks for the report. Greatly appreciated.
Hi Sylvain,
To date I have not received the Calvin boards. Please can you check shipping for me?
Many thanks
James
To date I have not received the Calvin boards. Please can you check shipping for me?
Many thanks
James
Yup, still none here either.Hi Sylvain,
To date I have not received the Calvin boards. Please can you check shipping for me?
Many thanks
James
Indeed difficult to ship them when I haven't received them yet 😉 International shipment is very slow at the moment, and that will include my shipment to you. Most post small parcel were shipped on commercial airline, since most commercial airlines are shutdown, delivery time will certainly increase, think 'by boat' kind of delay. Over here everything (except the post service, grocery, drug store, etc) are shut down for at least three weeks. So expect delay. At least we can still take a walk outside. I'll do my best.
Thanks for your understanding and check this thread for updates.
SB
Thanks for your understanding and check this thread for updates.
SB
It's a tricky business this, and I am suitably embarrassed that I haven't followed the thread properly. Apologies Sylvain and thanks for the effort!
Indeed difficult to ship them when I haven't received them yet.
SB
That's not a valid excuse! You should have flow to pickup the pcbs yourself! I mean, I paid $5 US dollars for shipping. That should cover your flight to the pcb shop, the purchase of a face mask and sanitizer for the trip and treatment afterwards if the facemask and sanitizer don't work!
😀
Oh Palmito you're certainly someone difficult to please, but I'll try my best next time 😉
5 kits of Calvin buffer pcb left...
SB
5 kits of Calvin buffer pcb left...
SB
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Found envellops. Will start packing the kit with pcb only. Will ship them maybe today or tomorrow. Will send you an email once it is done. Stay tuned.
Thanks
SB
Thanks
SB