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Old 17th April 2011, 06:01 PM   #41
masood is online now masood  India
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Talking bjornogain 180w amplifier

dear sir,
can some one send me 180 w amplifier pcb as above mentioned.at
khan.shahid251@gmail.com
thanking you
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Old 17th April 2011, 10:15 PM   #43
holger1 is offline holger1  Germany
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I sent a copy of the pcb layout to your personal email address. Please note, that the MOSFETs in the output stage must be mounted directly on the pcb, with an L profile of aluminium between the MOSFETs and a decent heatsink. The schematic has been already published in this thread. Good luck!
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Old 26th April 2011, 02:32 PM   #44
masood is online now masood  India
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dear oodi sir i saw your mini crescendo attached thumbnail.for seing this i compare my kit .so plz.show your complete diagram such as protector circuit as it peep in in yor thubnail. my e mail khan.shahid251@gmail.com
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Old 26th April 2011, 03:29 PM   #45
holger1 is offline holger1  Germany
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Hello,

I don't have a schematic for this protection circuit. But it is simple to develop one. You need a power on reset, which can be done with an NE555 timer. Secondly, you need to rectify the output from the power stage, low pass filtered to remove any audio frequency. Take a DC transistor amp, connect it to a relay which switches the connection between your speakers and your power amp. This can be soldered on a breadboard. And forget the DC protection from Elektor. This circuit does not work properly. You can also take a HA12002. The datasheet is available on the internet.

HA12002 pdf, HA12002 description, HA12002 datasheets, HA12002 view ::: ALLDATASHEET :::

Holger
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Old 4th October 2011, 04:54 PM   #46
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Default Ultimate modification of Crescendo

Or how to get 1500V/µs and 10Mhz of bandwidth, with increased stability, simply in changing some resistances values and... Removing two transistors.
A way to demonstrate the advantages of the Current Feedback topology against Voltage controlled feedback.
Thanks for the fantastic Lazy Cat for his help .
http://www.diyaudio.com/forums/elekt...ml#post2734172
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Old 13th November 2011, 03:19 PM   #47
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Quote:
Originally Posted by Esperado View Post
Or how to get 1500V/µs and 10Mhz of bandwidth, with increased stability, simply in changing some resistances values and... Removing two transistors.
Moved here:
www.esperado.fr - Le crescendo revisité
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Old 2nd December 2011, 08:44 AM   #48
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Hi,

I also built these beasts about 25 years ago. I modfied them, according to the supplements by ELEKTOR, and I added 7 volts on both supply rails for the driver section, as given by the GIGANT amp. The only problem I encountered with is hum, as already mentioned above. Fortunately I have no problems at all with oscillations. The amps (I built a stereo version with separate power supplies for each channel) simply work as it should. Total output power just before clipping ist well over 300 watts @ 4 Ω per channel, due to the increased driver supply voltages.

And yes, the CRESCENDO is not undestructible: As my elder son connected a bunch of speakers to it, with no respects on the total impedance, he blew both power MOSFETs of one side of one channel. This fortunately was the only thing I had to fix until now.

Interested in pics of my amp?

Best regards
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Old 9th December 2011, 05:33 AM   #49
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Quote:
Originally Posted by Kay Pirinha View Post
Hi,

I also built these beasts about 25 years ago. I modfied them, according to the supplements by ELEKTOR, and I added 7 volts on both supply rails for the driver section, as given by the GIGANT amp. The only problem I encountered with is hum, as already mentioned above. Fortunately I have no problems at all with oscillations. The amps (I built a stereo version with separate power supplies for each channel) simply work as it should. Total output power just before clipping ist well over 300 watts @ 4 Ω per channel, due to the increased driver supply voltages.

And yes, the CRESCENDO is not undestructible: As my elder son connected a bunch of speakers to it, with no respects on the total impedance, he blew both power MOSFETs of one side of one channel. This fortunately was the only thing I had to fix until now.

Interested in pics of my amp?

Best regards
can you upload schematics,pictures of it ?
thank
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Old 20th January 2012, 03:09 PM   #50
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Hi dungdochi,

finally here are some pics of my CRESCENDO stereo power amp. Have fun and thanks for waiting!

Best regards
Attached Images
File Type: jpg Front_2.JPG (872.1 KB, 796 views)
File Type: jpg Rear.JPG (854.3 KB, 756 views)
File Type: jpg Bottom_2.JPG (902.4 KB, 925 views)
File Type: jpg Top_1.JPG (879.0 KB, 707 views)
File Type: jpg Top_2.JPG (843.8 KB, 696 views)
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