Very cool W12 psu board Randy! Pair them with active rectification, oh Yeah!! Will they be available to buy?
Are you sure a 5U 400mm Modushop chassis is good for dissipating 300W?
I used that case for an Alpha Nirvana amp that sunk 100W into each heatsink. The sinks were 52°C@22° ambient temperature.
300W = Super FearLess
🤟
Are you sure a 5U 400mm Modushop chassis is good for dissipating 300W?
I used that case for an Alpha Nirvana amp that sunk 100W into each heatsink. The sinks were 52°C@22° ambient temperature.
300W = Super FearLess
🤟
I’ll be building my Aleph 60 in a 4U 500 for precisely the reasons you brought up! I like 50-55 degrees, no more! I probably won’t get to 150 watts/ch dissipation…I‘ll have to rename it Aleph 50 🤣
Best,
Anand.
Best,
Anand.
The two bolts may still be connected through the bottom plate, but as long as the top plate doesn't conduct between the two bolts, it's good.
I am building Aleph 60 monoblocks when I get around to it. 2 x 5U 300s per each monoblock. The caps in my power supply are only rated for 35V so I may not get to 35V rails unless I build another power supply.
These look pretty slick. I've never messed around with these boards...
Has anyone tried skipping the board and just using a switch like this?
https://www.mouser.com/ProductDetail/Schurter/1241.6823.1114000?qs=gW2F9ojQNeEzE81PmSnvEQ==
It looks like it's good for 12A AC, which is plenty for most of the First Watt style amps.
It's an expensive switch, but I imagine by the time you get all the bits for the board and a lower cost switch the total is much higher than this switch. Thoughts?
Very cool W12 psu board Randy! Pair them with active rectification, oh Yeah!! Will they be available to buy?
Are you sure a 5U 400mm Modushop chassis is good for dissipating 300W?
I used that case for an Alpha Nirvana amp that sunk 100W into each heatsink. The sinks were 52°C@22° ambient temperature.
300W = Super FearLess
W12's will be for sale. Let me test this one myself on a XA252 and a SissySIT(42), then I'll get some more made based on demand. Probably a group buy thread. Stay tuned. If you're itching for one ASAP, PM me. I think I might have an extra from this run.
Regarding 300W - I'm simply quoting what Papa Nelson published in his thread. 158W per sink. Note, his calcs show 30degC, not 25degC.
Store Heat Sinks - Thermal Numbers
https://www.diyaudio.com/community/threads/store-heat-sinks-thermal-numbers.392902/
Thinking about the shorted turn problem, one solution is to cut a gap in the plate to split it into two. The small transformer could then be moved to the right plate where there is some room.
I plan to do the same and I will not go above 29-30V. Papa's heatsink estimates are for "fearless builders" (someone says) not for Sissies (like myself)
For my build I will probably use the risers from the Store with long turrets and leave the bolt of the toroid free.
Ask me as I know about this issue. No actually, don't ask..
As you know I did build an Aleph 4+4 in a 5U 400 Deluxe chassis as @Toadroller was asking for. With around 150 watts dissipation the 5U 400 is at it's thermal limit and additional measures like forced ventilation is needed to achieve a sane temperature level on the outside of the chassis.
So Nelson's recommendations are indeed for fearless builders that don't need an amp that is save to be touched by partners, children or cats. But it looks like Nelson's thermal suggestions are save enough for the output transistors. I use my Aleph 4+4 build a lot without any technical problems until now.
The heat output of the amp could be lowered by using a SMPS instead of a linear supply.
When I first got started I used the AMB/Bulgin solution because it worked and work well. Now that I’ve been doing this for awhile I’ve found there are a number of very interesting alternatives.
Regards,
Dan
In using MJs soft start board, it works a treat. Can use cheap Chinese buttons
My Aleph 'raffle' amp still in place with some sort of chassis parts around it! No lid or back yet. Pah....who needs em!
My Aleph 'raffle' amp still in place with some sort of chassis parts around it! No lid or back yet. Pah....who needs em!
I've used one like this: https://www.mouser.com/ProductDetail/Schurter/1241.6821.1120000?qs=NJQRv7dW2TVB7LvB/%2Bv6/w== directly with lots of capacitance and CL-60 thermistors.
It's not illuminated, but it's a lot cheaper. 12A seems OK for steady state, but turn-on current spikes are a different matter. I haven't had it very long, so I'm not sure how it will hold up in the long term. Accordiing to the data sheet it is rated for 0.02 million actuations @ 250 VAC /16 A.
Actually, that's an excellent idea. I must have missed it the first read through here.
Regards,
Dan
As as start to my shorted turn issue I'm going remove the two 'positioning washers' from the transformers.
These metal washers currently reside directly below the aluminum plate seen in my pic. I've ordered the shoulder washers Mike suggested
and when I'm receive them I'm going to drill the two holes larger to accept them. After this is done there should be no continuity between the two
transformer mounting bolts and my shorted turn issue should be resolved.
Many thanks for the suggestions,
Dan
These metal washers currently reside directly below the aluminum plate seen in my pic. I've ordered the shoulder washers Mike suggested
and when I'm receive them I'm going to drill the two holes larger to accept them. After this is done there should be no continuity between the two
transformer mounting bolts and my shorted turn issue should be resolved.
Many thanks for the suggestions,
Dan