Transistor equivalent

[spec]

Not a problem but I worry that free space will not large enough to mount RCA jack, headphone jack, binding post if there are too much fin. So amount of fins must be suit

Excellent! The back panel will be an engineering wonder and a thing of beauty. Don't concern yourself with the input output connections. They are not important at this stage. You just be a master caster and pretend that there is no input output. I will take care of the input output.

 

[Nikolai Petrenko]

18" wide, 4.5" high, with 2" deep fins as you said? ok let collect soda can and all alum scraps

 

[spec]

18" wide, 4.5" high, with 2" deep fins as you said? ok let collect soda can and all alum scraps

That will do for now to work on. I will be more accurate shortly. Can you cast the back panel at least 12mm thick; thicker would be OK. How thin can you make the fins? Would 5mm be possible.

When you are doing the smelting and casting can you get some pictures I would be very intrested in seeing them

 

[Nikolai Petrenko]

hat will do for now to work on. I will be more accurate shortly. Can you cast the back panel at least 12mm thick; thicker would be OK. How thin can you make the fins? Would 5mm be possible.

When you are doing the smelting and casting can you get some pictures I would be very intrested in seeing them

5mm is pretty thick, I think it only 2-3mm. I plan to do this way: casting use lost foam method. I will make a foam creation then put it in sand then pour liquid aluminium into foam. Wait until alum cool, put it out and smoothing by use a fine sand paper.

 

[spec]

5mm is pretty thick, I think it only 2-3mm. I plan to do this way: casting use lost foam method. I will make a foam creation then put it in sand then pour liquid aluminium into foam. Wait until alum cool, put it out and smoothing by use a fine sand paper.

Very clever Nikolai- lost foam casting. That is something new.

I have now worked out a new heatsink more suited to casting. If you can cast as thick as 3mm and thin as 2mm that will suit the new heatsink design well. I don't know anything about casting but my heatsink design is intended for direct rather than lost casting so that will save you one stage. Will liquid aluminium burn wood before it solidifies. I ask because I see the mould as being made of wood. The wood is then soaked in water before the liquid ally is poured in. See what you think when you see the new design.

 

[spec]

OBSOLETE PLEASE SEE POST 630


Top view of cast back panel for 70W left, right, and bass sub class AB audio amplifiers. The black shapes are slots going from top to bottom of the rear panel. They repeat horiizontally along the full length of the back panel. Material ally (aluminium or any other high thermal conductivity hard material). All dimensions in mm, unless otherwise stated. Note: amp will be compatable (with slight mods) with industry standard 19 inch racking system (3U high).

ERRATA
(1) Change horizontal dimension from 470 to 450
(2) verticle dimension line on left should be verticle
(3) Nikoli should read Nikolai

 

[audioguru]

What is "ally"? A mixture of metals is called an alloy, not an ally. An alley is a narrow road at the rear or side of buildings.
A heatsink is usually made from fairly pure aluminum, not an aluminum alloy.

 

[spec]

ally= aluminium

 

[KeepItSimpleStupid]

Ally = https://www.urbandictionary.com/define.php?term=Ally

Non-capitalized ally = https://www.merriam-webster.com/dictionary/ally

 

[spec]

OBSOLETE PLEASE SEE POST 640

 

[Nikolai Petrenko]

I think ally is sth like allies in ww2, lol

 

[spec]

I think ally is sth like allies in ww2, lol

did you look that up in a dictionary?

Ally= Allison (girls name)
Ally=Alley Palley (theatre/dance hall)
ally= aluminium
tran= transvestite
tran= transistor
cap= hat
cap= to block off
cap= capacitor
res= residence
res= resist
res= resistor
I= personal pronoun
I= current
amp= amplifier
amp= amplitude
amp= Ampre
scope= extent
scope = electronics TV thing

......................

 

[Nikolai Petrenko]

I don't understand what is slot and purpose of it?

 

[Nikolai Petrenko]

For heatsink's fins?

 

[spec]

I don't understand what is slot and purpose of it?

For heatsink's fins?

The idea of a heatsink is to lose its heat to the air by convection, as in Physics theory. To do this efficiently it needs to present as big as possible surface area to the air with enough free air around the surface to alow the easy flow of convection air currents which go upward. For this reason verticle fins are the best.

The new heatsink design is the same as the first one with the bent ally (aluminium) sheet fins, except the back of the fins, instead of being open, are now closed to make casting simpler and to stregthen the fins which would otherwise tend to crack. The flat back to the fins also looks tidyer. If you could cast the fins 3mm thick and leave about 4mm space betwen them that would be ideal.

The effective back panel should be 2.5 to 3mm thick, but not critical. The effectictive front panel, that the power transistors bolt to, sould be at least 3mm thick.

If there is anything that will be difficult to cast let me know, because the heatsink is not critical and could probably be changed in a number of ways to simplify casting. Magally would also be fine as a casting material.

I have in my mind how the casting mould should be made.

 

[Nikolai Petrenko]

I decide to use aluminum with a small amount of magnesium added, not "real" magnalium. OK, I now understand slots are distance betweem 2 fins, before you answer, I think slots are holes.
I think power transistors bolt to back panel, but you said front panel, why mount transistors to front panel?

???

 

[spec]

My confusing terms; power transistors mount to the front panel of the back panel- I should have used a better term. The arrangement is exactly like in the above image.

The slots are effectively holes. They go through the heatsink from top to bottom to allow air to flow through and cool the 'fins'.

Magally- fine.

Advise not to use lost foam casting- burnt foam contaminates ally?

 

[Nikolai Petrenko]

No, burnt foam will not contaminate alum, you can watch some videos, you can see alum surface clear, but not smooth because sand are small frags. Use sandpaper to smooth the surface. Lost foam casting require less time to prepare mould than any other method.

 

[spec]

No, burnt foam will not contaminate alum, you can watch some videos, you can see alum surface clear, but not smooth because sand are small frags. Use sandpaper to smooth the surface. Lost foam casting require less time to prepare mould than any other method.

OK I know nothing about casting, but because of the thin sections and small apertures I suspect that direct casting wold be better. Maybe more work to make muold , but easy work and less finishing required, and produce better results. I think anyway.

 

[spec]

OSOLETE PLEASE SEE POST 653