Aleph 30 questions - Page 2

needtubes · 1st November 2005, 10:39 PM

I found some 3W metal film resistors at Mouser (they are Xicon). However, they do not have .47-ohm - only 1-ohm. I know I could run two each in parallel for every place where a .47-ohm resistor is needed, but would it really be worth it? It'll cost more in total.

Also, I am getting skeptical about my heatsink choice. I have been reading through the Aleph-mini thread and noticed that some guys have found that the Aleph-mini runs quite warm on heatsinks of similar size to the ones I was going to use. For reference, these are the heatsinks I am planning on using. At 12", they say .375 C/W. Is this possible from a heatsink of this size/shape? I looked at some other similarly sized heatsinks from another manufacturer and ended up with .5 C/W or worse. I have been thinking about pushing the length to 15" per sink.

I am also thinking I'll order a spare set of Aleph-mini PCBs to make a mini with later. I'll also have the extra four output boards, so perhaps an Aleph 2 is in order? Hypothetically speaking, if I were to attempt Aleph 2 monoblocks with the same heatsinks above (but with six devices per sink, in this case) would I still be OK? I would most likely need 15" length, correct?

Thanks all

AudioFreak · 1st November 2005, 11:17 PM

The fins on those are really too close to get optimal cooling without a fan.

needtubes · 2nd November 2005, 01:34 AM

What will that mean exactly? Will it run way too hot?

Algar_emi · 2nd November 2005, 01:44 AM

To remove the inrush current use a CL-60 RTD resistor as used in the Aleph30 service manual schematic. You can get them at digikey.com.
Bye...

fcel · 2nd November 2005, 01:55 AM

needtubes,
Did you say you need heatsinks? Check out this thread. R-Theta 65340 Heat Sink for sale
There are two left. $100 + Shipping.

needtubes · 2nd November 2005, 07:22 PM

What about these heatsinks? They are similar in size to the ones I linked to earlier, but have fewer fins. I emailed the seller and he estimated that the thermal resistance is about 1 C/W per 3", so I guess that would be close to .3 C/W for the total length. Or maybe these would be better? But with these, I'd have to run one channel of the Aleph 30 per heatsink, so they would see the full 100-ish watts. What do you guys think?

1st November 2005, 11:17 PM	#12
AudioFreak Warp Engineer On Holiday Join Date: Oct 2001 Location: Queensland, Australia	The fins on those are really too close to get optimal cooling without a fan. __________________ - Dan

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1st November 2005, 10:39 PM	#11
needtubes diyAudio Member Join Date: May 2003 Location: USA	I found some 3W metal film resistors at Mouser (they are Xicon). However, they do not have .47-ohm - only 1-ohm. I know I could run two each in parallel for every place where a .47-ohm resistor is needed, but would it really be worth it? It'll cost more in total. Also, I am getting skeptical about my heatsink choice. I have been reading through the Aleph-mini thread and noticed that some guys have found that the Aleph-mini runs quite warm on heatsinks of similar size to the ones I was going to use. For reference, these are the heatsinks I am planning on using. At 12", they say .375 C/W. Is this possible from a heatsink of this size/shape? I looked at some other similarly sized heatsinks from another manufacturer and ended up with .5 C/W or worse. I have been thinking about pushing the length to 15" per sink. I am also thinking I'll order a spare set of Aleph-mini PCBs to make a mini with later. I'll also have the extra four output boards, so perhaps an Aleph 2 is in order? Hypothetically speaking, if I were to attempt Aleph 2 monoblocks with the same heatsinks above (but with six devices per sink, in this case) would I still be OK? I would most likely need 15" length, correct? Thanks all

2nd November 2005, 01:34 AM	#13
needtubes diyAudio Member Join Date: May 2003 Location: USA	What will that mean exactly? Will it run way too hot?

2nd November 2005, 01:44 AM	#14
Algar_emi diyAudio Member Join Date: Oct 2002 Location: Canada, Qc	To remove the inrush current use a CL-60 RTD resistor as used in the Aleph30 service manual schematic. You can get them at digikey.com. Bye...

2nd November 2005, 01:55 AM	#15
fcel diyAudio Member Join Date: Sep 2001 Location: LA County	needtubes, Did you say you need heatsinks? Check out this thread. R-Theta 65340 Heat Sink for sale There are two left. $100 + Shipping.

2nd November 2005, 07:22 PM	#16
needtubes diyAudio Member Join Date: May 2003 Location: USA	What about these heatsinks? They are similar in size to the ones I linked to earlier, but have fewer fins. I emailed the seller and he estimated that the thermal resistance is about 1 C/W per 3", so I guess that would be close to .3 C/W for the total length. Or maybe these would be better? But with these, I'd have to run one channel of the Aleph 30 per heatsink, so they would see the full 100-ish watts. What do you guys think?

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