5 transistors output stage

[KCC]

Hi,
I've heard(not actually seen) that company uses five output transistors in output stage in stead of the normal two complementary pairs.I am wondering how these arrangement is made.I believe the idea is to provide more current draw. Anyone has opinions on this?

Peter

[Jan Dupont]

Hi Peter,

If I understand you correct, you mean amps using 5 NPN and 5 PNP transistors in the output stage....

This is quite common for heavy amps, and it is done for the amp to be able to deliver more current (as you believed correctly ).

Most output transistors (espesially those used in audio) have limited Ic (current flow throug the collector) of 10-15 Amps and Ptot (the total power handling of the transistor) of 150 to 250 Watts. This means, that for the amp to be able to handle more power than one pair of transistors can handle, you have to add additional output transistors i parallel (2, 3, 4 or more...)

You could take a look at my website under projects, where you find a temporarely schematic of my LYNX power amp using 2x 4 output transistors.

Hope this was of any help.

[KCC]

Hi Jan,
Thanks for the quick reply. I understood the idea to use more transistor pairs to provide more current draw. And I actually built different output stages using different quantity of transistor pairs for comparison purpose. But the impression I read from this company's brochure that offer 5 transistors per side for upgrade to the Hafler DH200 amp (which using 2 complementary pairs of output transistors) that puzzles me. Obviously,4 out of the 5 are refering to two complementary pairs. So where does the lone transistor relate to?

Peter

[Jan Dupont]

Hi again,

Do you have the schemaitc of the output circuit?
I don´t recall to have seen this upgrade...

[jan.didden]

Originally posted by KCC
Hi Jan,
Thanks for the quick reply. I understood the idea to use more transistor pairs to provide more current draw. And I actually built different output stages using different quantity of transistor pairs for comparison purpose. But the impression I read from this company's brochure that offer 5 transistors per side for upgrade to the Hafler DH200 amp (which using 2 complementary pairs of output transistors) that puzzles me. Obviously,4 out of the 5 are refering to two complementary pairs. So where does the lone transistor relate to?

Peter

5 transistors per side refers to 5 for pos, 5 for neg side, per channel. Then in each channel you have 5 pairs.

Jan Didden

[Jan Dupont]

Janneman:

= Just an ordinary output stage using 10 transistors pr. channel

[KCC]

Jan,

Ok. I think what they mean is five transistor pair per side per output stage.
For I can not figure out how a lone transistor relate to the circuit.I do not have the schematics so I can not confirm anything. Thanks for your ideas.

Peter