QRV01 output stage

[goldkenn]

Not sure I should use both T19/20/21/22 along with T24/25/26/27 or either one set?

[peranders]

I can help you next weekend with this.

[goldkenn]

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 :-)

[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.

[goldkenn]

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!

[goldkenn]

Any news?

[peranders]

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.

[peranders]

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

[goldkenn]

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

[peranders]

The suggested type will almost fit but not entirely.

[goldkenn]

Which from farnell could entirely fit? Since some pdf not in English, I can't make sure the measurement.

[peranders]

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

[goldkenn]

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?

[peranders]

MJE340 is a small power transistor with for me unknown HF properties. I would use the BC transistors in this position.

[goldkenn]

How to tune P1 and P3? Can't find any info since you have not yet finishe the instrcution section yet......