Using 22/24 MHz SC-cut crystals and BFR182 resistor value should be a bit higher, I expect 33k or 39k.
BFR182
I know the BFR182 is a BJT, but, after a search of TWTMC threads, I don't see that it has been mentioned before. Is the BFR182 recommended in place of the MMBT5179 when using SC-cut xtals?
I know the BFR182 is a BJT, but, after a search of TWTMC threads, I don't see that it has been mentioned before. Is the BFR182 recommended in place of the MMBT5179 when using SC-cut xtals?
Yes, please download the TWTMC-D Assembly guide at
http://www.diyaudio.com/forums/digi...hase-noise-jitter-crystal-oscillator-141.html
post #1403
For SC-cut crystals you should use the BFR182 or the NE85633. If you want to use the MMBT5179 you should select it for hfe > 200.
Does anyone try the oven on SC-cut crystal? Is the sound affected by temperature? I have the oven board, but I am thinking about skipping the oven since I need another VCC for that purpose.
You must have the oven for SC crystals; they would not be on-frequency
with the wrong temperature, have activity dips, nothing would be right.
with the wrong temperature, have activity dips, nothing would be right.
Yes, I am aware of frequency deviation of SC-cut XO under room temperature. I found this chart from a manufacturer. It looks like the deviation is within 20ppm. Do you think this will still cause problems?
I dont think that causes problem, the oscillator will work on room temperature IMHO, but if I remember well the 80 C deegrees is the optimal the SC crystal for lowest PH (highest Q at this temperature, maybe?)
I would at least run it hot, even if unregulated. There is more to
crystals than stability of the nominal resonance. There are spurious
responses that vary with temp. and excitation level. It is entertaining
to watch a crystal on the network analyzer and playing with the
conditions.
I also find some hybris in the intention to make it better than the
commercial manufacturers and then skimping on the basics.
regards, Gerhard
crystals than stability of the nominal resonance. There are spurious
responses that vary with temp. and excitation level. It is entertaining
to watch a crystal on the network analyzer and playing with the
conditions.
I also find some hybris in the intention to make it better than the
commercial manufacturers and then skimping on the basics.
regards, Gerhard
Thanks for the info. I will try to build the oven though. I am so curious about the effect on temperature. It is interesting to build a ovenized SC-cut oscillator by hand.
GB update
Crystals arrived and shipped to all the members who have ordered crystals and bare boards.
Next days I start building for the members who have requested finished boards.
Attached the individual measurements of each crystal.
Crystals arrived and shipped to all the members who have ordered crystals and bare boards.
Next days I start building for the members who have requested finished boards.
Attached the individual measurements of each crystal.
Parts in stock
If someone was interested, the following parts are available:
Crystals:
2 x AT 11.2896 MHz fundamental
3 x AT 12.288 MHz fundamental
3 x AT 22.5792 MHz fundamental
2 x AT 24.576 MHz fundamental
2 x AT 33.8688 MHz 3rd overtone
1 x AT 98.304 MHz 5th overtone
1 x SC 22.5792 MHz 3rd overtone
1 x SC 45.1584 MHz 3rd overtone
1 x SC 49.152 MHz 3rd overtone
4 x SC 90.3168 MHz 3rd overtone
6 x SC 98.304 MHz 3rd overtone
Finished boards:
1 x TWTMC-D finished with AT-Cut 98.304 MHz
1 x TWTMC-P finished without crystal (AT-Cut 22.5792 MHz available)
1 x TWTMC-D finished without crystal (AT-Cut 11.2896 MHz available)
1 x TWTMC-D&D finished with rect.filt./regs./switch.logic (15V-3V3)
If someone was interested, the following parts are available:
Crystals:
2 x AT 11.2896 MHz fundamental
3 x AT 12.288 MHz fundamental
3 x AT 22.5792 MHz fundamental
2 x AT 24.576 MHz fundamental
2 x AT 33.8688 MHz 3rd overtone
1 x AT 98.304 MHz 5th overtone
1 x SC 22.5792 MHz 3rd overtone
1 x SC 45.1584 MHz 3rd overtone
1 x SC 49.152 MHz 3rd overtone
4 x SC 90.3168 MHz 3rd overtone
6 x SC 98.304 MHz 3rd overtone
Finished boards:
1 x TWTMC-D finished with AT-Cut 98.304 MHz
1 x TWTMC-P finished without crystal (AT-Cut 22.5792 MHz available)
1 x TWTMC-D finished without crystal (AT-Cut 11.2896 MHz available)
1 x TWTMC-D&D finished with rect.filt./regs./switch.logic (15V-3V3)
Crystals
Andrea,
I will take 1 each of the AT-cut crystals at 22.5792 MHz and 24.576 MHz.
Thanks,
George
Andrea,
I will take 1 each of the AT-cut crystals at 22.5792 MHz and 24.576 MHz.
Thanks,
George
Hi George,
your last order has been already shipped, so please send me a new order form for the above crystals.
Thanks
Andrea
Parts in stock - update
If someone was interested, the following parts are available:
Crystals:
3 x AT 12.288 MHz fundamental
1 x AT 24.576 MHz fundamental
2 x AT 33.8688 MHz 3rd overtone
1 x AT 98.304 MHz 5th overtone
1 x SC 22.5792 MHz 3rd overtone
1 x SC 45.1584 MHz 3rd overtone
1 x SC 49.152 MHz 3rd overtone
4 x SC 90.3168 MHz 3rd overtone
6 x SC 98.304 MHz 3rd overtone
Finished boards:
1 x TWTMC-D finished with AT-Cut 98.304 MHz
1 x TWTMC-P finished without crystal
1 x TWTMC-D finished without crystal
1 x TWTMC-D&D finished with rect.filt./regs./switch.logic (15V-3V3)
If someone was interested, the following parts are available:
Crystals:
3 x AT 12.288 MHz fundamental
1 x AT 24.576 MHz fundamental
2 x AT 33.8688 MHz 3rd overtone
1 x AT 98.304 MHz 5th overtone
1 x SC 22.5792 MHz 3rd overtone
1 x SC 45.1584 MHz 3rd overtone
1 x SC 49.152 MHz 3rd overtone
4 x SC 90.3168 MHz 3rd overtone
6 x SC 98.304 MHz 3rd overtone
Finished boards:
1 x TWTMC-D finished with AT-Cut 98.304 MHz
1 x TWTMC-P finished without crystal
1 x TWTMC-D finished without crystal
1 x TWTMC-D&D finished with rect.filt./regs./switch.logic (15V-3V3)
1N5711
The 1N5711 is out of stock at Mouser in the US. Would a MMSD701T1G be an appropriate substitute? The datasheet is here http://www.mouser.com/ds/2/308/MMSD301T1-D-83023.pdf
Thanks,
George
The 1N5711 is out of stock at Mouser in the US. Would a MMSD701T1G be an appropriate substitute? The datasheet is here http://www.mouser.com/ds/2/308/MMSD301T1-D-83023.pdf
Thanks,
George
My package has arrived, very nice, thank you, Andrea!🙂
I have a little question, the boards needs 3,3v and 6v. So do I apply one supply LDO for 2 boards of 6v (or 3,3v) or for the better performance I have to apply separate LDO-s for all supply input? (I have just one 6v supply now)
I have a little question, the boards needs 3,3v and 6v. So do I apply one supply LDO for 2 boards of 6v (or 3,3v) or for the better performance I have to apply separate LDO-s for all supply input? (I have just one 6v supply now)