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Old 10th June 2012, 02:17 PM   #11
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yeah ...470pf miller caps on the drivers ? i wonder why .....
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SERVICE ΕΝΙΣΧΥΤΩΝ ΚΑΙ ΙΑΠΩΝΙΚΩΝ ΜΗΧΑΝΗΜΑΤΩΝ ΗΧΟΥ www.eastelectronics.gr
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Old 2nd May 2013, 02:06 AM   #12
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Lightbulb YIROSHI

Quote:
Originally Posted by andrewlebon View Post
hope this PCB helps. i will post full PCB later

Warm Regards
Andrew Lebon

More information:

DIAGRAMA

PCB
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Old 2nd May 2013, 04:05 AM   #13
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Quote:
Originally Posted by sakis View Post
yeah ...470pf miller caps on the drivers ? i wonder why .....
Miller cap is mandatory with amps having LTP input stages, however,somewhat larger value than normal is at expense of slew rate and limited power at HF.
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Old 2nd May 2013, 08:48 AM   #14
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PLEASE
@Andrew lebon and sergio DS

Stop reproducing this circuit by YIROSHI it is simply a ticking bomb especially if made with this type and style of pcb

For starts this pcb has never been tested ( to my understanding ) and if put to test it will blow with in a few minutes of full power

If you like me to explain the reasons i am willing to but i don't see the reason to do so since this is told almost a million times already in numerous posts threads ..

Kind regards
Sakis
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Old 2nd May 2013, 10:12 AM   #15
Vostro is offline Vostro  South Africa
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Yeah I guess thermal compensation sux

Might as well link a nice pimped amplifier is you like this type of amplifier.

thanks to Mr Mile from Apexaudio
Studio Reference Amplifier

Its not a simple amp but it is fantastic

Regards
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Old 2nd May 2013, 10:13 AM   #16
AndrewT is offline AndrewT  Scotland
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Quote:
Originally Posted by Ricdelros View Post
Miller cap is mandatory with amps having LTP input stages
NO !!!
The LIN topology amp with the LTP as input stage can and does operate properly without any added capacitance across the CB junction of the second stage.
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Old 2nd May 2013, 10:28 AM   #17
JMFahey is offline JMFahey  Argentina
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That "Yiroshi" amplifier will never never never never provide 200W into 8 ohms.
Besides being horribly underbiased : 2 diodes + 10 ohms to forward bias 4 (four) BE junctions?
And unstable (no Zobel network) to the point of self destroying with any real world speaker load at the end of any real world speaker cable.
Maybe that's why those 470pF caps had to be added, but that's not the right place or value.
Did I mention no short protection?

Just because the link was provided, I checked other "Yiroshi" schematics at Scribd.
Ouch !!!
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Old 2nd May 2013, 10:48 AM   #18
FoMoCo is offline FoMoCo  United States
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Wow! A poorly designed class B amplifier! The only thing I could see this being used for is a subwoofer with a built-in amplifier. Even then you'd be better off with a chip amp. If you have to build it yourself, one of Rod Elliot's amps would be better and just about as simple.
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Old 2nd May 2013, 11:09 AM   #19
AJT is offline AJT  Philippines
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classB (or is it calssB2 says JMFahey) is fine for PA duities, at high volume levels, you can not distinguish it from a classAB.....
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Old 2nd May 2013, 12:25 PM   #20
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Quote:
Originally Posted by JMFahey View Post
That "Yiroshi" amplifier will never never never never provide 200W into 8 ohms.
Besides being horribly underbiased : 2 diodes + 10 ohms to forward bias 4 (four) BE junctions?
And unstable (no Zobel network) to the point of self destroying with any real world speaker load at the end of any real world speaker cable.
Maybe that's why those 470pF caps had to be added, but that's not the right place or value.
Did I mention no short protection?

Just because the link was provided, I checked other "Yiroshi" schematics at Scribd.
Ouch !!!
I agree with you.
This amplifier used Otala - Hitachi symmetry topology. If you like this topo, try ''The Techno'' and ''Sigma'' from Dr. Bora. It's simple and higher quality.
50VDC rail would send you 100W/8 Ohms. Higher supply voltage will get higher power output, but, not use Toshiba's devices. Sanken/ON Semi better!
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