This is not just another Aleph

[Peter Daniel]

OUCH!!!

This must be a soundtrack to your moniker movie.

This is how high the original B&W stands and I was reading review stating that the tweeter sounds best at around 42" height.

My preamp is BOZ, but in a main system there is no preamp, volume is installed in a DAC.

 

[jleaman]

what is 42" hi...?

 

[Peter Daniel]

Actually it's 47". Tweeter from the floor.

 

[jleaman]

the sub boxes look like there about 5 feet tall. that is why i asked..

 

[planet10]

I'm using original B&W tweeter, Accuton ceramic midrange and Cabbase 8" woofer in transmission line design.

You should write up an article for my web site

dave

 

[Peter Daniel]

I might do it after I finish the review of Aleph X. Here's the cross-section of the bass enclosure.

 

[roddyama]

Peter,

A Cross-section! You never cease to amaze.

Rodd Yamashita

 

[Nelson Pass]

Such class!

 

[grataku]

And handsome, too!

 

[carpenter]

with a lovely child for companionship...........

 

[MikeW]

Peter, how much heat do you think you are disappating with the +/- 15 volt rails? Great work.

 

[fcel]

Yes ... Peter, let's get this heatsink discussion rolling again. This time for Aleph-X. Give us some rule of thumb or some heat dissipation comparison with the Aleph 2, 4 or 5 amps.

 

[Peter Daniel]

OK, time for some numbers. Initially I was hoping for 20V rails and 6A total current. It came down to 15V rails, 6A current and the heatsinks are just about 50 deg. C.

Those are the same heat sinks as A75 monoblock and the temp is exactly the same.

The rails are +/- 15V, I'm using 4 pairs of devices per side (for a total of 16 per channel), my source resistors are 0.56 ohm and voltage drop is 0.420V on ea. The heatsinks are 11" x 11" and 2' deep with 23 fins (I'm using 2 per channel).

Did I miss something?

 

[carpenter]

What's the appropriate method to measure heat from a heatsink?

 

[Peter Daniel]

Now I'm doing it by hand. But before I got the feeling, I was using big thermometer (used for photography) with a rubber band around it, and I was just puting it between the fins.

 

[jleaman]

Hey peter since you have all the latest and gratest tools you should invest 149.99 for a thermomiter that plugs into your fluke meter. my dad has one and it is awsome works for every thing..: O )


P.s your picture looks awsome i like them speakers..

 

[vpharris]

Measuring Temperature

I use one of these- Radio Shack 63-1009. I drill an extra hole next to the semiconductor so that the tapered probe jams in the hole. I was careful not to drill all the way through the heatsink. I think it was a 7/32 hole.

Works great for current price on the web of 13.99. You can switch it to measure the ambient too.

 

[fcel]

quote "Did I miss something?"

Peter,
You have 16 output transistors per channel. What is the approximate output wattage per channel is that? Sorry, I have not been following the Aleph-X thread (except lately - the beta Rev 1.0 boards) and thus I'm not familiar with the in and out of this amp.

 

[Peter Daniel]

I think it's something like 80-90 W into 4 ohms, but i'm not really sure. I'm not into power these days.

 

[carpenter]

Hey Vince,

Nice tip!