Hifonics BX1205D

m4ick · 24th August 2011, 06:41 PM

The power supply was blown when I got this.

The drivers are BCX55s. There are BCX55, BCX55-10 and BCX55-16. Are these just the plain BCX55s?

Perry Babin · 24th August 2011, 08:32 PM

They are all the same basic transistor but the -10 and -16 have higher gain than the one with no suffix.

Are you sure that this is the transistor you want? The 2SB1260 is marked with BE like the BCX55 but is a PNP transistor (BCX55 is an NPN). The 2SB1260 is much more common.

Look in the 'semiconductor datasheets' folder in the section 'Transistor marked BE...'.

m4ick · 24th August 2011, 10:08 PM

That's probably right, I haven't seen NPNs drive a power supply before, I was kind of wondering about that.

Perry Babin · 24th August 2011, 10:15 PM

In power supply drive circuits...
NPN transistors are generally only used with PNP transistors. Many times, PNP transistors are used without NPN transistors so if there is only one drive transistor per bank, they're almost certainly PNP transistors.

m4ick · 11th November 2011, 09:21 PM

I finally decided to dig into this amp again.

I soldered some KTA1266GRs in the place of the 2SB1260s for testing purposes.

The amp has 22ohm gate resistors in the power supply so I replaced the 50N06s with 3205s. It powers up and everything looks clean.

My question is, I'm kind of broke and those are what I have on hand, if I use some fixative on the A1266s so they don't break, do you think this amp may just be fine the way I have it? I know you would rather use original components but aren't power supplies kind of forgiving being that they don't switch too fast?

Perry Babin · 11th November 2011, 10:31 PM

The 1266s are used to drive 3205s in other amps so they will likely be OK here. I'm assuming that this is your personal amp and not an amp for a paying customer.

m4ick · 11th November 2011, 10:58 PM

Yes it is, it was returned when an output failed and blew the power supply. I took it in trade for labor and it's going into my car.

Thanks a lot!

m4ick · 13th November 2011, 02:29 PM

Well, it seems to be protecting when you turn it up past a certain point.

I'm looking for the 2SB1260, all I can find is 2SB1260T100 Q, R, and P. Q has the highest hFe, is that the one I should be looking for?

m4ick · 13th November 2011, 02:33 PM

Actually, I guess R is the highest hFe but Q seems to be the most readily available.

Perry Babin · 13th November 2011, 04:03 PM

Any of those should work.

If it's going into protect, Q7 and Q11 on the audio driver board are suspect.

24th August 2011, 06:41 PM	#1
m4ick diyAudio Member Join Date: Jan 2010 Location: Gainesville, FL	Hifonics BX1205D The power supply was blown when I got this. The drivers are BCX55s. There are BCX55, BCX55-10 and BCX55-16. Are these just the plain BCX55s? __________________ Scope - DMM - 460W Computer PSU - Tutorial

24th August 2011, 08:32 PM	#2
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	They are all the same basic transistor but the -10 and -16 have higher gain than the one with no suffix. Are you sure that this is the transistor you want? The 2SB1260 is marked with BE like the BCX55 but is a PNP transistor (BCX55 is an NPN). The 2SB1260 is much more common. Look in the 'semiconductor datasheets' folder in the section 'Transistor marked BE...'. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

24th August 2011, 10:08 PM	#3
m4ick diyAudio Member Join Date: Jan 2010 Location: Gainesville, FL	That's probably right, I haven't seen NPNs drive a power supply before, I was kind of wondering about that. __________________ Scope - DMM - 460W Computer PSU - Tutorial

24th August 2011, 10:15 PM	#4
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	In power supply drive circuits... NPN transistors are generally only used with PNP transistors. Many times, PNP transistors are used without NPN transistors so if there is only one drive transistor per bank, they're almost certainly PNP transistors. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

11th November 2011, 09:21 PM	#5
m4ick diyAudio Member Join Date: Jan 2010 Location: Gainesville, FL	I finally decided to dig into this amp again. I soldered some KTA1266GRs in the place of the 2SB1260s for testing purposes. The amp has 22ohm gate resistors in the power supply so I replaced the 50N06s with 3205s. It powers up and everything looks clean. My question is, I'm kind of broke and those are what I have on hand, if I use some fixative on the A1266s so they don't break, do you think this amp may just be fine the way I have it? I know you would rather use original components but aren't power supplies kind of forgiving being that they don't switch too fast? __________________ Scope - DMM - 460W Computer PSU - Tutorial


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11th November 2011, 10:31 PM	#6
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	The 1266s are used to drive 3205s in other amps so they will likely be OK here. I'm assuming that this is your personal amp and not an amp for a paying customer. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

11th November 2011, 10:58 PM	#7
m4ick diyAudio Member Join Date: Jan 2010 Location: Gainesville, FL	Yes it is, it was returned when an output failed and blew the power supply. I took it in trade for labor and it's going into my car. Thanks a lot! __________________ Scope - DMM - 460W Computer PSU - Tutorial

13th November 2011, 02:29 PM	#8
m4ick diyAudio Member Join Date: Jan 2010 Location: Gainesville, FL	Well, it seems to be protecting when you turn it up past a certain point. I'm looking for the 2SB1260, all I can find is 2SB1260T100 Q, R, and P. Q has the highest hFe, is that the one I should be looking for? __________________ Scope - DMM - 460W Computer PSU - Tutorial

13th November 2011, 02:33 PM	#9
m4ick diyAudio Member Join Date: Jan 2010 Location: Gainesville, FL	Actually, I guess R is the highest hFe but Q seems to be the most readily available. __________________ Scope - DMM - 460W Computer PSU - Tutorial

13th November 2011, 04:03 PM	#10
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Any of those should work. If it's going into protect, Q7 and Q11 on the audio driver board are suspect. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

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