Transistors Comparison

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#21
Ian Finch said:
Hi Sakis. Ah-ah-achoooo! 😱 heh,heh - I like it a lot and I prefer colour to B+W TV too - don't we all?

Seriously though, a lot of guys don't understand what distortion really sounds like in various mixes and what psychological effects low order harmonics can have in small amounts. They probably just see an ugly word and assume it always means bad, like disease.

However, the harmonic distortion I'm referring to isn't just a random spray of all harmonics but a carefully trimmed order that for most tastes, would decline from 2nd to 5th harmonic of fundamental tones right up through the midrange, where we focus on information about the environmental sounds we hear, such as their position and movement. That would be an unlikely as a result of a poor design or part swapping.

Actually, I enjoy making and hearing even more details in the sound than were recorded 🙂
Click to expand...

Yes, you are right.
With me, I never think harmonics distortions are bad. But I just don't like it when hearing from a storage, I try to make the output sound as close to the recorded files or disks as I can.
I love the harmonics distortions when I play with my guitar and my nasty tube amp (GU-50 PP) 😀
 
#22
That is partially wrong Suppose your transistors are fake and you have a 1943 that inside is no more than a TIP 3055 well then yes you will have audible problems beyond stability

Farther more if you have any amplifier that works with Toshiba 1943-5200 and works well and you replace them with fairchild 1943-5200 then you will notice that bias will hit the sky and performance will be altered

Even though the Toshiba's i use is the real thing it proved that Fairchild makes them with another cook resulting other bias characteristics and in general much "harder" sound In practice also tests proved that the Fairchild semi was far more rugged could handle more power without problems next to a Toshiba .....

I wish i could tell why ....
 
#23
east electronics said:
That is partially wrong Suppose your transistors are fake and you have a 1943 that inside is no more than a TIP 3055 well then yes you will have audible problems beyond stability

Farther more if you have any amplifier that works with Toshiba 1943-5200 and works well and you replace them with fairchild 1943-5200 then you will notice that bias will hit the sky and performance will be altered

Even though the Toshiba's i use is the real thing it proved that Fairchild makes them with another cook resulting other bias characteristics and in general much "harder" sound In practice also tests proved that the Fairchild semi was far more rugged could handle more power without problems next to a Toshiba .....

I wish i could tell why ....
Click to expand...

Who and what problems are you talked to? 😕
I didn't have mentioned about 2SC5200/2SA1943
 
#25
east electronics said:
I am talking that different makes and different quality of transistors will eventually have some impact in the sound characteristics of a given amplifier beyond stability and thermal issues .

Kind regards
Sakis
Click to expand...

Oh, now I understand. 😛
Ah, any suggestion to improve P3A amp? I have removed input caps, miller caps are silver-mica, all drivers, Vbe multiplier and VAS have one common heatsink.
 
#27
east electronics said:
Read my thread you might find some useful things from me and other members there
Kind regards
Sakis
Click to expand...

I have seen it and realize that I have already did few like in the thread 😀 .
Thank you so much!
I want to power up my amp by using +-40VAC (550VA) from transformer (lower voltage not available), since 150W are enough to push the current-hungry speakers. Also my current-using +-22VAC transformer is too small (100VA) to play loudly without over-heat. I will double the output stage with 2xNJW3281/1302 like in Rod's P68 sub amp. My heatsink are overkill for 150W 😀
 
#28
Nikolai Petrenko said:
Agree!
All I want is the performance. I don't care about what will they sound. With me, low distortion, stablity and flat response are the most important thing 😀 . I also love the simple very much!
Click to expand...

The fast NFB of any circuit that you add all these transistors to
will compensate for the non- linear x-over region (and the full on current gain region) much faster
than the differences in transistor silicon (even die structure).

The only (superior) differences in semi's (in a given circuit) have been in
the x-over region (Sanken BJT's - ring emitter). Or , if you are comparing
20'th century <10mhz Ft to the faster modern 25mhz 21'st century units.
(NFB can correct the x-over region with less bias/heat).

Oh , yes ... stability . You must design layout and decoupling more
thoroughly. Look at most of the forums EF2/EF3 present amps.
We discuss all this to great detail.

OS
 
#29
ostripper said:
The fast NFB of any circuit that you add all these transistors to
will compensate for the non- linear x-over region (and the full on current gain region) much faster
than the differences in transistor silicon (even die structure).

The only (superior) differences in semi's (in a given circuit) have been in
the x-over region (Sanken BJT's - ring emitter). Or , if you are comparing
20'th century <10mhz Ft to the faster modern 25mhz 21'st century units.
(NFB can correct the x-over region with less bias/heat).

Oh , yes ... stability . You must design layout and decoupling more
thoroughly. Look at most of the forums EF2/EF3 present amps.
We discuss all this to great detail.

OS
Click to expand...
Thanks for reply.
About my layout I don't see any stability problems. No oscillate, no ringing.....
only lack space for fuse so I use external fuse holder 😀
 
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