hi apex, I recently found a lot of original motorola 2N3773 trannies.Now i want to make a powerfull amp by using these.I am interested in B550. I have some questions.
1.What is the maximum psu voltage with the maxmum no. of 2N37773 for max.output with this circuit.
2.I think this circuit is only suitable for bass amp ?
3. MJE drivers are hard to find here,2sa1943/2sc5200 is easily available though these are o/p devices , i think it can be used for drivers also.
4.With above drivers how many pairs of 2N3773 is needed for bridge application
One thing more that i am not merely putting questions but i am going to make this amp within some weeks so a reply from you will be highly helpful for me.
1.What is the maximum psu voltage with the maxmum no. of 2N37773 for max.output with this circuit.
2.I think this circuit is only suitable for bass amp ?
3. MJE drivers are hard to find here,2sa1943/2sc5200 is easily available though these are o/p devices , i think it can be used for drivers also.
4.With above drivers how many pairs of 2N3773 is needed for bridge application
One thing more that i am not merely putting questions but i am going to make this amp within some weeks so a reply from you will be highly helpful for me.
3773 have max Vce0=140V.
I recommend no more than +-65Vdc for a power supply.
For bridged you must design each half with the ability to properly drive a reactive load impedance of half your speaker impedance.
If you have 8ohm speaker, then you design the amp to drive 4ohm and/or 1r5 from the supply rails.
If you have a 4ohm speaker, then your challenges are going to stretch you.
Expect the output stage total wattage to be between 5 to 6times the expected maximum output power.
+-65Vdc will give ~200W into 8r0 and ~400W into 4r0.
to drive 400W into 4r0 then expect ~2000W to 2400W of BJT output stage power dissipation capability.
You need two of these to get your 800W into 8ohm amplifier so total output pairs is ~ 4400/150=~30pairs (15pair in each half). Yes, 60 2n3773 for a bridged Quasi driving 800W into 8r0.
I recommend no more than +-65Vdc for a power supply.
For bridged you must design each half with the ability to properly drive a reactive load impedance of half your speaker impedance.
If you have 8ohm speaker, then you design the amp to drive 4ohm and/or 1r5 from the supply rails.
If you have a 4ohm speaker, then your challenges are going to stretch you.
Expect the output stage total wattage to be between 5 to 6times the expected maximum output power.
+-65Vdc will give ~200W into 8r0 and ~400W into 4r0.
to drive 400W into 4r0 then expect ~2000W to 2400W of BJT output stage power dissipation capability.
You need two of these to get your 800W into 8ohm amplifier so total output pairs is ~ 4400/150=~30pairs (15pair in each half). Yes, 60 2n3773 for a bridged Quasi driving 800W into 8r0.
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i have built this amp
http://i907.photobucket.com/albums/ac278/sunsheat/IMG_0875.jpg
http://i907.photobucket.com/albums/ac278/sunsheat/IMG_0876.jpg
http://i907.photobucket.com/albums/ac278/sunsheat/IMG_0877.jpg
with 2n5551, mje150332/33, and 6 pairs of 2sc5200
my question, can i feed it with +-90v???
any suggestions pls..
Thanks for reply, Can you suggest some other circuit using 2N377 with better configuration.I think that at least this circuit must have some type of current adjusment desiging for o/p transistor.Is it safe to add so much of trannies without current adjustment circuitry.
i have built this amp
http://i907.photobucket.com/albums/ac278/sunsheat/IMG_0875.jpg
http://i907.photobucket.com/albums/ac278/sunsheat/IMG_0876.jpg
http://i907.photobucket.com/albums/ac278/sunsheat/IMG_0877.jpg
with 2n5551, mje150332/33, and 6 pairs of 2sc5200
my question, can i feed it with +-90v???
any suggestions pls..
What about the performance like noise,stability,heating,power etc.
Thanks for reply sir,
I have already made simple amps like p3a with a1943/c5200 and a simple quasi using 2n3773 with +/-35 psu and i want to upgrade my quasi thats why i am asking these questions.
I suggest +/-65V DC rail voltage with 4 pairs 2N3773 in output stage as best version of this amp.
Regards
Attachments
I suggest you this design http://www.diyaudio.com/forums/solid-state/175192-mosfet-bjt-quasi-amplifier-protect.html
First pcb by 'Mihailo' (post #80) is with DC protect and outputs on pcb. If you have some protect and outputs are on heatsink use second pcb, it's same amp anyway.
Regards
sir can you re design your qusai with a op amp input?
Q1, 2, 4, 5 2N3440/5415 or MJE 340/350
Bias transistor, just about anything.
Outputs (and drivers) 2N3773, MJ15022/24, etc.
Opamp LM318 (50V/µs slew rate)
Protection was a DC crowbar, a thermal cut-out on the heatsink, and a circuit-breaker on the transformer primary.
Q1, 2, 4, 5 2N3440/5415 or MJE 340/350
Bias transistor, just about anything.
Outputs (and drivers) 2N3773, MJ15022/24, etc.
Opamp LM318 (50V/µs slew rate)
Protection was a DC crowbar, a thermal cut-out on the heatsink, and a circuit-breaker on the transformer primary.
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