Author Topic: QRV01 output stage  (Read 9506 times)

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Offline goldkenn

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QRV01 output stage
« 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?

Offline peranders

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Re: QRV01 output stage
« Reply #1 on: July 31, 2010, 09:46:48 PM »
I can help you next weekend with this.
/Per-Anders Sjöström, owner of this forum

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Offline goldkenn

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Re: QRV01 output stage
« Reply #2 on: August 01, 2010, 08:26:35 AM »
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 :-)

Offline peranders

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Re: QRV01 output stage
« Reply #3 on: August 01, 2010, 09:05:23 AM »
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.
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Offline goldkenn

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Re: QRV01 output stage
« Reply #4 on: August 01, 2010, 01:01:22 PM »
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!
« Last Edit: August 02, 2010, 07:58:57 AM by goldkenn »

Offline goldkenn

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Re: QRV01 output stage
« Reply #5 on: August 09, 2010, 11:21:32 AM »
Any news?

Offline peranders

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Re: QRV01 output stage
« Reply #6 on: August 09, 2010, 12:49:12 PM »
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.
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Offline peranders

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Re: QRV01 output stage
« Reply #7 on: August 09, 2010, 12:51:29 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
/Per-Anders Sjöström, owner of this forum

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Offline goldkenn

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Re: QRV01 output stage
« Reply #8 on: August 10, 2010, 12:44:46 PM »
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

Offline peranders

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Re: QRV01 output stage
« Reply #9 on: August 11, 2010, 08:47:15 AM »
The suggested type will almost fit but not entirely.
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Offline goldkenn

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Re: QRV01 output stage
« Reply #10 on: August 12, 2010, 08:01:10 AM »
Which from farnell could entirely fit? Since some pdf not in English, I can't make sure the measurement.

Offline peranders

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Offline goldkenn

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Re: QRV01 output stage
« Reply #12 on: August 21, 2010, 08:09:12 PM »
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?

Offline peranders

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Re: QRV01 output stage
« Reply #13 on: August 22, 2010, 08:44:32 AM »
MJE340 is a small power transistor with for me unknown HF properties. I would use the BC transistors in this position.
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Offline goldkenn

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Re: QRV01 output stage
« Reply #14 on: August 28, 2010, 08:04:34 AM »
How to tune P1 and P3? Can't find any info since you have not yet finishe the instrcution section yet......