Not sure I should use both T19/20/21/22 along with T24/25/26/27 or either one set?
I can help you next weekend with this.
If possible, please advise a working configuration, since from QSXM2 phono, due to too many opttions, I wasted too much time and money upon SMD configuration (finally not working using SMD transisitors, I know more calculations and testing upon something like resistor value could make it work but I did spent too much on it, so finally simply swapping back to all BC550C/560C configuration), and as QRV01 have almost the same many options as QSXM2, I am tried for possible configurations, thanks peranders :-)
The reason for having footprints for SOT23 was that it's easier to find good parts and harder in TO92. They have the same performance if they have the same data.
Bt the way, other then the output stage:
1) Can I use SSM-2210/SSM-2220 for MT1/2/3/4? If okay then what resistor value should I use for current supply?
2) The "class A temperature regulation circuit " you mnetioned to forget is which part? Am I need to omit some parts or do some jumper wiring for modifications?
3) Any easy find replacement (possible to buy from RS or Farnell) of BF471/BF472? Nothing could find here in Hong Kong, and I am not sure which replcement no need for any re-calculation of components value.
Thanks!
Any news?
1 You don't have to change anything.
2 Omit R47, OC1, IC10 and all parts around. The same goes for the other channel in corresponding locations.
3 Use BC5xx transisitors if you can't find any similar types with low capacitances.
Quote from: goldkenn on July 31, 2010, 08:03:32 PM
Not sure I should use both T19/20/21/22 along with T24/25/26/27 or either one set?
T19-T22 or T24-T25 or T26-T27
Thanks P-A :-)
By the way, did this transformer match the PCB pin layout?
http://hk.farnell.com/block/fl14-15/transformer-14va-2-x-15v/dp/1131496
The suggested type will almost fit but not entirely.
Which from farnell could entirely fit? Since some pdf not in English, I can't make sure the measurement.
I'm not sure you can find any flat transformer that will fit.
https://www.elfa.se/elfa3~se_en/elfa/init.do?shop=ELFA_SE-EN#toc=18744;item=56-172-12;
http://www.hahn-trafo.com/english/flat-type-transformators-ui39.php
Did MJE345/350 replace BF471/472 perfect in QRV01? I found serveral pairs MJE340/350 from my drawer, and I serach did found many examples they do replace each others and work great, however, the pdf of MJE340/350 have not shown the capacitance, since you have mentioned low capacitance is needed, will MJE340/350 work?
MJE340 is a small power transistor with for me unknown HF properties. I would use the BC transistors in this position.
How to tune P1 and P3? Can't find any info since you have not yet finishe the instrcution section yet......
I'll get back to you tomorrow evening.
THANKS
Those pots are for trimming the bias of the output stage.
Quote from: peranders on August 29, 2010, 08:44:07 PM
Those pots are for trimming the bias of the output stage.
Of course! This is a servo amp and I can guess the trimmer is for bias, but how? Please advise.
Trim for decent temperature, "not too hot" and hot may be 50-60 deg C.