Well I'm trying to understand ... Let's consider for example 2SA1016 or 2SC2362 one of the best parts as differential input stage for 100/200W audio amplifier.
These parts seams to be almost impossible to find probably osolete or discontinued.
So may be the state of the art has change current audio amp design no longer needs differential input pair.
May be current design are based on integrated chips.
or May be there is now some thing better than 2SA1016 and very easy to purchase.
If some one has ideas let me know. Tell me which parts should I use as differential input pair to be in the state of the art.
These parts seams to be almost impossible to find probably osolete or discontinued.
So may be the state of the art has change current audio amp design no longer needs differential input pair.
May be current design are based on integrated chips.
or May be there is now some thing better than 2SA1016 and very easy to purchase.
If some one has ideas let me know. Tell me which parts should I use as differential input pair to be in the state of the art.
not sure yet who makes them. i 've been told by Yamaha, Denon and Marantz tech support to order the parts as 2SC3200 rather than KTC3200 to get the original ones, but i haven't got them yet to see who made them. i'll keep my eyes open to see what else is currently being used, there may be another suitable device to use to avoid getting the korean transistors.
Well it seams PNP is 2SA1268, I could not even find its datasheet, not a chance to find them at farnell mouser or digi key.
I would not be confident basing a design on such an exotic part.
I'm still looking for the widely availale reference that all audio designers are currently using to replace 2SA1016.
I would not be confident basing a design on such an exotic part.
I'm still looking for the widely availale reference that all audio designers are currently using to replace 2SA1016.
If I had access to purchasing at e-bay/craig's-list, I would keep an eye for old amps using matched FET or BJT. Here I can buy 5$ used amp with 5-leg LTP devices (the matched pair costs around 5$ new). Many old integrated amps do not sound good enough to be expensive, mostly because of poor preamp. But the transformer and the matched pair is useful.
You want good spec (high hfE/fT, low noise, low Cob) but can handle the design voltage (Vce). BC549C is good but only 30V.
AVE...
BC639 - 80V
BC546 - 80V
2N5551 - 180V
2N3019 - 120V
Some of those don't have high gain, and so what? You can make next stage to increase it, or even use Darlington transistors in the output stage. Also you can use simple transistor-based voltage regulator for powering the input stage...
We have saying here:
If you don't have what you like, you like what you have...
So let's use one of those:
BC639 - 80V
BC546 - 80V
2N5551 - 180V
2N3019 - 120V
Some of those don't have high gain, and so what? You can make next stage to increase it, or even use Darlington transistors in the output stage. Also you can use simple transistor-based voltage regulator for powering the input stage...
We have saying here:
If you don't have what you like, you like what you have...
Consider that an entire 600W @ 4 ohm bridged amp with pre, DA, and everything but power is now available on a $12 chip and you can see where this is going. On the one hand, audiophiles will hate it. On the other hand, audiophiles are going to purely be a hobby in less than 10 years. The psycho-acoustics of MP3 and BOSE have won. The longer they abound, the more tuned the younger audience is to that sound. ALthough it makes you want to puke - it's the truth.
With the TI chips getting higher and higher output, you will see self powered KF850's with the DIGI control programmed on the chip, and wifi sending signal. They'll probably go from SMPS to straight Rectified High Voltage like my LCOS TV. Housekeeping runs down by 115V and the rest at 370V with a hot ground all over the place.
Unfortunately my crazy CES TV has a chinese capacitor problem... and is out of commission until I rebuild the power supply and hope it works again. They EOL's it after 2 years because warranty parts were $7K - I got a CES bro deal on the display model they had to show off their ego size - everyone else paid $25K...
With the TI chips getting higher and higher output, you will see self powered KF850's with the DIGI control programmed on the chip, and wifi sending signal. They'll probably go from SMPS to straight Rectified High Voltage like my LCOS TV. Housekeeping runs down by 115V and the rest at 370V with a hot ground all over the place.
Unfortunately my crazy CES TV has a chinese capacitor problem... and is out of commission until I rebuild the power supply and hope it works again. They EOL's it after 2 years because warranty parts were $7K - I got a CES bro deal on the display model they had to show off their ego size - everyone else paid $25K...
bc546b 60Vce0
bc560c 45Vce0
Both can be used on +-50Vdc supply rails if the circuit is designed to suit the Vce0 capability.
There are higher Vce0 devices, but they are generally compromised in at least one parameter, or else the cost is much higher. Use these if you can find a retailer that stocks them.
bc560c 45Vce0
Both can be used on +-50Vdc supply rails if the circuit is designed to suit the Vce0 capability.
There are higher Vce0 devices, but they are generally compromised in at least one parameter, or else the cost is much higher. Use these if you can find a retailer that stocks them.
Such types are obsolet in general after few years, because this outline isn't made for the surface mounted technology (smt).Yes, sadly Sanyo discontinued the excellent 2sa1016/2sc2362 pair
But mostly there are SMD successors from same or at least similar process - check out e. g. the NXP successors arround the high voltage video BF series about
http://www.diyaudio.com/forums/soli...ver-stages-high-power-amplifier-overview.html
(post # 1)
Ask always for SMD successors.
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the 2SC3200 are 120V Vceo and low noise, good design usually requires "overkill" on Vceo.... i.e. 20% higher Vceo than the total rail voltage (+/- 50V=100V, +20%=120V). this improves the reliability in production amps. using a device with a marginal Vceo is asking for trouble. while a device may only be exposed to about 1/2 the total rail voltage during operation, there are times when it may be exposed to 100% rail voltage during power up settling.
Why makes yourself in hard condition? There is nothing wrong when old being obsolete. I am using BC557B for input stage with BF423 cascode and nothing wrong. Now I am test my finished one with some lemay's and wow, its classA quality, very clean and detail even with 10Hz mixed massively, still clearly good. Two stage, VAS+VoltageFollower+CurrentSense. VAS using BC557B as input and 2SC1815GR+video tr as voltage amplifier.
AVE...
Ontoaba, can you post a schematic?
In other topic about input stage transistors someone suggested using medium power transistors, pointing out however their lower gain. My suggestion is this: why not use two or more matched pairs to build matched Darlington (or Sziklai) differential input stage? Also why not use more than one stage to increase gain? And why not decrease the voltage going to the input stage so you can use transistors that are easily available?
Ontoaba, can you post a schematic?
In other topic about input stage transistors someone suggested using medium power transistors, pointing out however their lower gain. My suggestion is this: why not use two or more matched pairs to build matched Darlington (or Sziklai) differential input stage? Also why not use more than one stage to increase gain? And why not decrease the voltage going to the input stage so you can use transistors that are easily available?
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