He means "symmetrical". As noted above, I have never been apprehensive about going from single-ended into a balanced connection. Just the other way around. So if this is a fair phobia (is it?), using the balanced inputs of a sound card is fine for measuring but if you want to use the sound card for stimulus generation and don't want to attach a balanced-single-ended converter on the output maybe it is just better to use the card's single-ended connections for both (with the Juli@ the balanced and single-ended connections aren't available at the same time - you have to chose which ones are to be used).
Saturday very much a work day for freight at Heathrow. Luton isn't London and Heathrow is just plain busy.
Thanks for the recommendation. I ordered one from TME at 7pm Warsaw time on Wednesday evening and it arrived early this morning. It's about 30x bigger than the one I have been using (Uni-T UT120A I received for free) and will take me awhile to figure out how to use it properly.
I think I might switch my Juli@ around to single-ended operation and start using it for sinus stimuli rather than my Rigol DG1022.
FYI with my brand new Brymen BM869s I measure 1000.3 ohms for R105 and 1.04 ohms for parallel R107-R117.
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I love mine; the only annoyance so far is that current measurements seem to display one digit fewer than the voltage measurements.
I was lucky enough to buy a "DMMcheck" board before the mfr upgraded to DMMcheckPlus at a higher price. Maybe you might want the newer, more feature filled one anyway: link.
Building this with a combination of SMT and through-hole parts.
SG: For the CCS did you consider using the ZTX951 -- while the noise figure isn't mentioned in the datasheet, it measured lowest among BJT's tested in the new edition of "Art of Electronics" at around the current demanded.
I found that in in testing 10 BF862, 9 were a pretty close match.
SG: For the CCS did you consider using the ZTX951 -- while the noise figure isn't mentioned in the datasheet, it measured lowest among BJT's tested in the new edition of "Art of Electronics" at around the current demanded.
I found that in in testing 10 BF862, 9 were a pretty close match.
another thought came to mind -- i remember an Analog Dialog in which they mentioned that they had trouble with modulation on a low noise circuit -- it turns out that they had "clear" signal diodes and that the fluorescent light was slightly modulating their output. So I guess mine (through-hole) will get shrink-wrapped.
I built the full 8 BF862 amplifier on protoboard and it works very nicely indeed. I am going to make some boards but incorporate Walt Jung's nifty GLED 2.5V reference (which is a bit quieter than the 4x1N4148 reference) and a cascode DMOS CCS. I might allow for substitution of ZTX951 for the 2SA1312 in Sam's circuit as 8 mA is very close to their sweetspot.
