Dan's Aleph Build Thread

[monarodan]

I got a few of the fans. Boy are they quiet. On the "high speed" setting, which is only 800RPM, you can not hear them unless you're ear is practically in the blades. I put a couple in my computer and it's made it a lot quieter! They really do push a lot of air, so I'm willing to trust the manufacturers specs at this point and expect that a single fan will be more than adequate for one monoblock.

So, I'm going to go down the fan assisted cooling route. Heatsinks and fan come out to AU$200 to do both monoblocks! I costed the passive route at AU$333 for Conrad heatsinks.

The plan is to get the heatsinks, assemble them as a tunnel, attach a fan to one end and burn some heat to test the cooling capacity. Does onyone have any comments on the easiest way to do this? I guess the simplest way a few power resistors and some thermal paste...

[monarodan]

Hi All,

Progress is being made. I have MOSFETs, heatsinks, fans, PCBs, power supply capacitors (in the post) and a mate that does metal work (now that's handy).

Does anyone know anything about Nuvotem toroids (http://www.nuvotem.com/)? RS Components sell the 1000VA 2x40V toroidal for AU$161 and qualifies for free shipping. That is the best price on toroidals that I've found.

I'll be using a CLC filter in the power supply. PSU designer shows that I should hit very close to 45V with the Nuvotem toroid, the caps on order and Erse 2.2mH air core inductors (0.328 DCR). There is no Erse distributor in Australia - where is best to buy from? From those that advertise price on their web site, Zalytron has the best price.

Alternatively, I found these listed on eBay:

http://cgi.ebay.com/ws/eBayISAPI.dll...tem=9727797592

I would have gone for 14ga. Would 16ga suffice for an Aleph 2 power supply? If so, I will find out more about these inductors.

Cheers,

Dan

[Babowana]

Originally posted by monarodan


I would have gone for 14ga. Would 16ga suffice for an Aleph 2 power supply? If so, I will find out more about these inductors.

As I understand,
If we make 2mH air coil with 1.2mm dia magnetic wire
the Rdc is approximated about 0.55Ohms

Since Aleph 2 draws 3A bias per channel
3x3x0.55 = about 5W heat per coil
I don't foresee any problem with 16ga . . .

[spzzzzkt]

Nuvotem aren't too bad - sonic frontiers/parts connexion used their smaller potted toroids in the assemblage DAC's back last century

You should also give Harbuch a call. I bought transformers from them for a pair of aleph 30 monoblocks and they seem very nicely made. They use high quality Antrim cores and will wind just about anything you need if they don't have them in stock. They have much better pricing than RS Components - but to be honest I think anywhere is cheaper than RS

http://www.harbuch.com.au/


cheers
Paul

[monarodan]

Hi Paul,

Harbuch's quote for the standard Antrim range was only slightly higher than the Nuvotem from RS Components. Once shipping is factored in, RS is considerably cheaper. I know it's hard to believe - initially I didn't bother checking with RS for toroidals as I expected them to be far too expensive.

I also tried Tortech, but their quote was much higher than others.

As for RS's prices, they seem quite variable. Some items are very competitively priced while others are way over the top. The other factor to cosider is that RS is giving away a crappy remote control car if you spend over $400... I hate to admit it, but this appeals to me .

I think I'll go with RS this time round to get my free remote controlled car and try Harbuch for my next project.

Dan

[spzzzzkt]

I stand corrected... I must admit I do use RS a fair bit because they have a reasonable range at their trade counter. However Farnell has far better stock and low volume discount points vs RS. Mind you for panasonic PSU caps etc etc it's cheaper to order from digikey (even with the obligatory fedex shipping) than either of the local "houses".

The transformer I needed wasn't a standard value anywhere except Harbuch. Tortech wanted an arm and leg to custom wind. Not sure why Mark Finnis recommends them to be honest as they seem to be _very_ pricey??


enjoy the car

I'll just keep twiddling my thumbs until my parcel turns up from digikey sometime today

[Zen Mod]

dunno for shipping,but did you saw what Apex.jr have on his site.......always cheap and good caps,sinks and I'm sure that I saw appropriate chokes

[GeorgeBoles]

Hi folks,

Just a little praise for Harbuch. The man in charge knows his work very well. You want an unusual transformer, he will make it. Describe your intended purposes and he will advise wisely. (I do not know about audio output transformers, but certainly for all power transformer needs.) They will also supply low flux designs if you are worried about transformer hum in higher current requirement designs.

And their starting prices are by way cheapest ... including Jaycar.

The postage remains a killer though. I wonder why Wes Components can mail a whole set of Orion woofers (4 Peerless XLS woofers - significant weight and volume) from Melbourne to Townsville for less than $15 (via Toll, or some similar company) and other transport companies start their fees at $25 or so.

Regards,
George.

[monarodan]

Thanks for your feedback George. Your sentiments seem to be in line with all opinions I've heard about Harbuch. I couldn't dig up any dirt on them!

I'm starting to realise just how isolated Perth is given all the mail order stuff I'm doing lately... Damn shipping charges. RS Componets wins out this time with no shipping charges on this order, plus, I can grab a bunch of other small component (that aren't stocked by the like of Jaycar) at the same time.


Zen Mod - thanks for the like to Apex Jr. I've not seen that sight before!


Dan

[juma]

Originally posted by monarodan
I got a few of the fans. Boy are they quiet. On the "high speed" setting, which is only 800RPM, you can not hear them unless you're ear is practically in the blades.

This post influenced me to buy couple of NOCTUA fans (NF-S12-800) and I can confirm what monarodan said. They are unbelievably silent and guaranteed MTBF is 150.000 hours. I put one on the back plate of my Mini Aleph and now the teperature on MOSFET cases is only 55 deg. Cels. (47 deg. on heatsinks) with 60 W dissipation per channel. With NOCTUAs I see no reason to avoid fans anymore. Amp's details are on my web site.