Good power amplifiers 6W---25W4R

Good power amplifiers 6W---25W4R.
Other audio transistors and the Franco-Polish licenses do not are not good for audio stuff.
 

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Ian Finch

Member
Paid Member
2010-04-11 4:22 am
Coffs Harbour, NSW
Good power amplifiers 6W---25W4R.
Other audio transistors and the Franco-Polish licenses do not are not good for audio stuff.
Of course, you are entitled to an opinion on what is "good audio stuff" but when it was obsolete >40 years ago, you need to consider whether collecting and using such antique components is sensible for others who read this but can't economically source them. You will be aware that original Philips BD139 /140, for example, are unobtanium so you can only buy approximate substitutes or fakes anyway.

Use modern leaded components while they are still in production. These are much cheaper and every bit as good as the old steel cased ones though many Japanese types are far better performers again in some applications. Read a bit of other people's work - get out and about and see the possibilities in different components and topologies to the basic ones we grew up with. If the limitation is the library of your software, it's time to get another free package like Simetrix's Simplis version or LT Spice perhaps -at least others can then easily read and understand them.
 
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Ian Finch

Member
Paid Member
2010-04-11 4:22 am
Coffs Harbour, NSW
Nothing better and nothing could be better.
Well, with imaginative claims like that, you must think we are idiots! You choose old designs, rework the values and components to something in your drafting software and claim something like this...???

Give us a break Adorn, or give us some test or simulation figures that support your opinions. That may include independent, alternate assessments or comparisons even.

Also, tell us what you mean by "clean". It could mean low noise, low distortion or tonally neutral. Either or all can be achieved with many topologies other than those presented. If you claim these old designs are better than more recent ones, let's see them compared formally and open the discussion to people who may be interested in the results.
 
Nothing else will show you how I showed.



BD140/139 (Rcd=800R) Ic max=25mA-Io=10mA min=15mAp max!!!.

BD313/211 (Rcd=800R) Ic max=25mA-Io=4.5mA min =20mAp!!!

XTR. Rcd>50R Ic max =25---27mA max!!!
BD355/354 Rcd<25R Ic =250mA max -Io=20mA min =230mAp max!!!
 

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Ian Finch

Member
Paid Member
2010-04-11 4:22 am
Coffs Harbour, NSW
http://tranzystor.com.pl/photos/tranzystor-mocy-cemi-bd355b-to66-p-n-p-najtaniej-2847979431.jpg
Along with BD354, only made by Unitra, Tesla and only shortform specs. available. Is it as good a driver as Toshiba's 2SC4793/2SA1837?
....Linear? :rolleyes:
http://www.customworks.cz/wp-content/uploads/2012/09/2sc4793.pdf
BD139/40 are not manufactured to Philips original specs.
http://www.datasheetcatalog.org/datasheet/stmicroelectronics/5238.pdf
http://www.datasheetcatalog.org/datasheet/philips/BD139-16.pdf