Yes i received my board in the Netherlands on 21st December and the archive by email.
The better studio-quality USB/Firewire audio interfaces boxes are all pretty good and you can have specs like you describe. A "good enough" box to allow you to make plot of speaker freq. responce and plot spectra from amps you are testing from harmonic distortion is the $150 "audio box" from Presonus. Of course much better gear is available but this will do what most need to do. For another $100 you can have something like this
Focusrite Saffire PRO 14 | Sweetwater.com
What you will find is that performance is limited by the quality of the preamps. The A/D conversion is far better than a simple op amp based preamp. So you try building with discrete transistors. That is only the start cost of parts goes up real fast. As you try for THD < .001% and flatness 20Hz-20KHz < .1dB. You will not get there on the first try, so figure in the cost of multiple prototypes and even more than that, the cost of test equipment to measure your prototype.
ChrisA,
I agree, some external (and internal) sound cards can have similar specs as my design. I don't claim that is an "ultimate specs" design.
Except that with these external sound cards you haven't :
A Fully isolated design (no common ground with computer).
BNC connectors (more convenient and robust for electronics hobbyist).
Fully DC coupling path.
All design infos.
...
And also, and that is very important for me (but maybe not for you), the real
pleasure to design and build my own measurement tools.
Regards.
Frex
I agree, some external (and internal) sound cards can have similar specs as my design. I don't claim that is an "ultimate specs" design.
Except that with these external sound cards you haven't :
A Fully isolated design (no common ground with computer).
BNC connectors (more convenient and robust for electronics hobbyist).
Fully DC coupling path.
All design infos.
...
And also, and that is very important for me (but maybe not for you), the real
pleasure to design and build my own measurement tools.
Regards.
Frex
Hello,
Two buyers of the AA5381 PCB located in USA (AR2 and grenert) informed me they still have not received their letter.
All has been sent on the 15 December 2010 in international priority letter.
I hope that the late is due to holiday and that all buyers will receive their letter soon.
In order to follow all shipments, i added a "received" status column on the buyers table in the dedicated wiki page.
Please, fill this status for you yourself or just send me PM or e-mail, i will fill it.
Wiki is HERE.
Frex
Two buyers of the AA5381 PCB located in USA (AR2 and grenert) informed me they still have not received their letter.
All has been sent on the 15 December 2010 in international priority letter.
I hope that the late is due to holiday and that all buyers will receive their letter soon.
In order to follow all shipments, i added a "received" status column on the buyers table in the dedicated wiki page.
Please, fill this status for you yourself or just send me PM or e-mail, i will fill it.
Wiki is HERE.
Frex
All extremely impressive. Could I ask why it is preferable to build an oscillator rather than generate the sine wave in software using, say, a 24 bit DAC? Is the performance just not achievable?
Would it be possible to get a bit more info on a few parts (perhaps part numbers which I can cross-reference datasheets with to make sure the parts are equivalent?):
S5
S4,S6
U17
RR1
L1-L6
Also, a few parts I'm having trouble finding substitutes, are these the only parts that will work in these cases?:
TR1
TR2
U13
Also, 10M .1% resistors with the specs listed seem hard to find as well.
Thanks!
S5
S4,S6
U17
RR1
L1-L6
Also, a few parts I'm having trouble finding substitutes, are these the only parts that will work in these cases?:
TR1
TR2
U13
Also, 10M .1% resistors with the specs listed seem hard to find as well.
Thanks!
Hello Luvdunhill,
I completed mine a couple of days ago.. I sourced everything from mouser and farnell except APEM miniature switches which are available only at RS.
here we go:
RR1 mouser ref. 858-BCN164A473J7
U17 mouser ref. 549-C3391-24.576
L1-L6 mouser ref. 70-ILHB1812ER601V
TR1-TR2 mouser ref. 771-BSS123-T/R
U13 farnell ref. 1225776 (newark in US)
S5 RS ref. 664-294
S4,S6 RS ref. 132-3067
please note: R49 and R50 values are swapped, those resistors are used for setting lt1763 output which should be 5V (see schematic and datasheet)
pay attention to lower mounted leds, terminals may touch BNC metal shells on the other side of the pcb.. It took me headaches to discover this problem on mine..
happy building..
regards
Vale
Hello luvdunhill and thank to Vale for his answer.
I complete below with mine.
S4,S5,S6 are APEM toggle switches.
S5 is a 3 stable positions inverter right angle PCB mount, APEM
ref:TL39WW050(Radiospares 664-294)
S4 and S6 are a 2 positions astable right angle PCB mount, APEM
ref:TL32WW050(Radiospares 132-3067)
About the oscillator U17, it have a dual PCB pattern to allow use of standard IQXO70(SMD) or DIP8( through hole) oscillators.
You can use any 24.576MHz oscillator using one of these pattern (working
with 3.3V supply).
RR1 is a standard quad resistors array in 1206 package.
Any value between 10k to 100k is ok.
L1..L6 are chock inductors. These parts are used to attenuate high frequency noise.
If you don't find the exact reference in the BOM, you can use others type.
It is not very critical.
(Note that if you omit all and replace them by short circuits, the ADC will
work too...)
TR1 or TR2 are a SPDIF transformers.
The SC947-02(TR1) is high performance version but it is hard to find and
expensive.
You can use a DA101MC(TR2), it's a Murata low cost transformer that you can
easily find to your reseller.
Both work perfectly.(Farnell 132-2401 // Mouser 580-DA101C).
(If you are not able to get any of these, you build yourself the transformer
with small ferrite toroid and
some turns of copper wire.)
For the 10M resistor,the precision in the BOM is a mistake.
You can use 1% or 5% value without any problem.
Just use metal film type, no carbon(high noise).
Note too that a DIYers has inform me of an error:
The resistor R49 and R50 are inverted.
For proper work you should use;
R49=750 Ohms (but no 249)
R50=249 Ohms (but no 750)
Regards.
Frex
I complete below with mine.
S4,S5,S6 are APEM toggle switches.
S5 is a 3 stable positions inverter right angle PCB mount, APEM
ref:TL39WW050(Radiospares 664-294)
S4 and S6 are a 2 positions astable right angle PCB mount, APEM
ref:TL32WW050(Radiospares 132-3067)
About the oscillator U17, it have a dual PCB pattern to allow use of standard IQXO70(SMD) or DIP8( through hole) oscillators.
You can use any 24.576MHz oscillator using one of these pattern (working
with 3.3V supply).
RR1 is a standard quad resistors array in 1206 package.
Any value between 10k to 100k is ok.
L1..L6 are chock inductors. These parts are used to attenuate high frequency noise.
If you don't find the exact reference in the BOM, you can use others type.
It is not very critical.
(Note that if you omit all and replace them by short circuits, the ADC will
work too...)
TR1 or TR2 are a SPDIF transformers.
The SC947-02(TR1) is high performance version but it is hard to find and
expensive.
You can use a DA101MC(TR2), it's a Murata low cost transformer that you can
easily find to your reseller.
Both work perfectly.(Farnell 132-2401 // Mouser 580-DA101C).
(If you are not able to get any of these, you build yourself the transformer
with small ferrite toroid and
some turns of copper wire.)
For the 10M resistor,the precision in the BOM is a mistake.
You can use 1% or 5% value without any problem.
Just use metal film type, no carbon(high noise).
Note too that a DIYers has inform me of an error:
The resistor R49 and R50 are inverted.
For proper work you should use;
R49=750 Ohms (but no 249)
R50=249 Ohms (but no 750)
Regards.
Frex
sorry. this part no. is for T1 and T2 on BOM. my mistake.
as correctly stated by Frex, TR1 and TR2 are spdif transformers.
I used murata da101c which is through hole part.. simply bend the terminals to adapt it for smt mounting. da101mc which is the smd part is not available at mouser.
regards
Valeriano
Thanks!
The only remaining question is the 10M .1% resistor. I cannot find anything in this tolerance, is this important?
The only remaining question is the 10M .1% resistor. I cannot find anything in this tolerance, is this important?
I am happy to report that, today, my board showed up im my mail box! Frex has sent this board on Dec.15th, by the date on custom's label. Stamp shows 2011, but exact day I cannot read. So the package left France most likely some 21 days after it was sent. Now that I am remembering, the same thing happened to me with parcel from France a few years back. I do not mind as long as if arrives. This one came in a very good shape and it looks good.
Thank you Frex!
Like I mentioned before, now in my collection from you, I am missing DAC
😛😛😛
Thank you Frex!
Like I mentioned before, now in my collection from you, I am missing DAC
😛😛😛