How far can a pair of SAP15 being pushed into a 4 ohm???

Leolabs · 16th January 2007, 12:24 AM

Assume that the supply voltage is +/-45V,able to reach 200W???

sixtek · 16th January 2007, 08:13 AM

Safe operating are and the maximal ratings (sissipation) don't enough. Then you'll need 2 pairs of them (4 pcs per channel). For PA I would use even 3 pairs .
And for 200W-rms at 4ohm you'll need 50-55V idle rails. Maybe the 45V you wrote is the loaded value of the rails?

sajti · 16th January 2007, 08:47 AM

I know one amplifier, which use 1pair of MJL21193/94, with +/-50V rails, and gives about 200W 4ohms, every night in a disco club. I'm still impressed, that it still working. I would not recommend to build 200W amplifier with one pair of any BJT-s I know.

sajti

sixtek · 16th January 2007, 09:42 AM

Sorry, there are some error in my upper comment:
"Safe operating are" = "Safe operating area"
"sissipation"="dissipation"

AndrewT · 16th January 2007, 04:26 PM

Hi,
how does sap15 vary from sap16? I have 16 data.

Give me some data to work with and I'll do some numbers.
Vdc @ quiescent,
smoothing caps,
regulation,
maximum heatsink temperature or Tc,
Tj max,
Vce0 max,
Ic @ 30Vce
Ic @ 45Vce
Ic @100Vce

Do you want speakers limited to moderate types with phase angle <=45degrees or severe type with phase angle <=60degrees?

jacco vermeulen · 16th January 2007, 04:42 PM

You probably mean the 150 watt SAP15N/SAP15P !
Problem with the SAP15N/P is their case size, accounting for a high R case-to-sink. For 200watts/4 Ohm you will need something like a 0.10-0.15 C/W heatsink to handle the max dissipation of a single pair at 45Vdc rails in 4 ohms.
The total max dissipation of the determines the power handling capability, not just the device and number.
Possible, but not economical. (it is also possible to get 200W/4 from 45Vdc rails)
Beter to invest both in output devices and heatsinks.
The economical division generally is an equal share.

16th January 2007, 12:24 AM	#1
Leolabs diyAudio Member Join Date: Dec 2004 Location: Bukit Mertajam	How far can a pair of SAP15 being pushed into a 4 ohm??? Assume that the supply voltage is +/-45V,able to reach 200W???

16th January 2007, 04:42 PM	#6
jacco vermeulen diyAudio Member Join Date: Oct 2004 Location: At the sea front, Rotterdam or Curaçao	You probably mean the 150 watt SAP15N/SAP15P ! Problem with the SAP15N/P is their case size, accounting for a high R case-to-sink. For 200watts/4 Ohm you will need something like a 0.10-0.15 C/W heatsink to handle the max dissipation of a single pair at 45Vdc rails in 4 ohms. The total max dissipation of the determines the power handling capability, not just the device and number. Possible, but not economical. (it is also possible to get 200W/4 from 45Vdc rails) Beter to invest both in output devices and heatsinks. The economical division generally is an equal share. __________________ Not so much,.......if it says "ZM" in the corner.

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16th January 2007, 08:13 AM	#2
sixtek diyAudio Member Join Date: Jan 2007	Safe operating are and the maximal ratings (sissipation) don't enough. Then you'll need 2 pairs of them (4 pcs per channel). For PA I would use even 3 pairs . And for 200W-rms at 4ohm you'll need 50-55V idle rails. Maybe the 45V you wrote is the loaded value of the rails?

16th January 2007, 08:47 AM	#3
sajti diyAudio Member Join Date: Apr 2003 Location: Vác, Hungary	I know one amplifier, which use 1pair of MJL21193/94, with +/-50V rails, and gives about 200W 4ohms, every night in a disco club. I'm still impressed, that it still working. I would not recommend to build 200W amplifier with one pair of any BJT-s I know. sajti

16th January 2007, 09:42 AM	#4
sixtek diyAudio Member Join Date: Jan 2007	Sorry, there are some error in my upper comment: "Safe operating are" = "Safe operating area" "sissipation"="dissipation"

16th January 2007, 04:26 PM	#5
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi, how does sap15 vary from sap16? I have 16 data. Give me some data to work with and I'll do some numbers. Vdc @ quiescent, smoothing caps, regulation, maximum heatsink temperature or Tc, Tj max, Vce0 max, Ic @ 30Vce Ic @ 45Vce Ic @100Vce Do you want speakers limited to moderate types with phase angle <=45degrees or severe type with phase angle <=60degrees?