Aleph J-X Amp Project

[derwhalfisch]

More reading of that thread might turn up more info though, using the Aleph J's R8 value (1k) plus a parallel pot might end up with a resistance too low. Maybe R8 ought to be a 2.2k with a 5k P1? That'd give you a wide range above and below the 1k of Aleph J.

[SCAIFF001]

The house I live in now has allot of static electricity in it due to the winter dry air and electric furnace. Should I wait until end March or April to pair together the MOSFETs ? The air will be damp again in the spring and the static disappears, dose anyone have an idea about this or just waiting is the best ?

Thank You
scatterbrain001

[Zen Mod]

if that's so much worry to you - make DIY working area - kitchen Al foil as working sheet - grounded , thin wire clipped to your wedding ring and grounded ;

unpack parts on foil and work

if you aren't married - then you should wait 'till damp

( nota bene - there's nothing more important than peace of mind ..... so do that even if I can't see how you can kill your mosfets even in those conditions )

[3GGG]

As I am making 108db sensitive horn wont be needinh to build X version.
Has anyone used these toroids from tortech
300VA Toroid Transformer

I only need 25 watts so these look sufficient to me.

[SCAIFF001]

Hi, I have not looked at this Thred for a while because I had to allocate my finances to other projects, but now I am back and am ready to purchase the finnal components to build two mono Aleph J-X amps.

Right now I aam looking for information on what value of fuses should be used for:
1. each AC line into transformer
2. each of the four transformer(600VAC with18+18 secondary) output cables
3. each of the +&- outputs from the two bridge rectifiers used
per mono channel, thats one bridge rectifier for each rail (positive & negative)

Thank You For Your Help

Ian Scaiff
(scatterbrain001)

[BobEllis]

You only need to fuse the hot mains lead. The fuse should be the first thing connected to the hot lead when it enters the case - before the power switch and inrush limiting. With a 600 VA transformer using a 50% overload on 120V mains you want around a 7.5A fuse, depending on your inrush current limiting scheme. You may want to use a slow blow fuse.

No need to directly fuse the secondaries, just connect them to the bridges. If you have a bridge problem a properly sized mains fuse will blow. The same argument could be made for not fusing the rails. A problem arises when you have to size the mains fuse unreasonably large to survive the startup inrush of the the transformer and main filter caps. The safest way is to fuse the rails.

If you choose to fuse the rails individually, then choose something like 2.5 x the bias current you have running. If you bias at 2A, choose a 5A fuse and so on. This will allow you to protect against catastrophe and safely pass the maximum current that the amp can draw.

[Zen Mod]

why 4pcs of 600VA xformers ?

[derwhalfisch]

I think he meant the four leads coming from each of (2?) transformers

[SCAIFF001]

Originally Posted by BobEllis

You only need to fuse the hot mains lead. The fuse should be the first thing connected to the hot lead when it enters the case - before the power switch and inrush limiting. With a 600 VA transformer using a 50% overload on 120V mains you want around a 7.5A fuse, depending on your inrush current limiting scheme. You may want to use a slow blow fuse.

No need to directly fuse the secondaries, just connect them to the bridges. If you have a bridge problem a properly sized mains fuse will blow. The same argument could be made for not fusing the rails. A problem arises when you have to size the mains fuse unreasonably large to survive the startup inrush of the the transformer and main filter caps. The safest way is to fuse the rails.

If you choose to fuse the rails individually, then choose something like 2.5 x the bias current you have running. If you bias at 2A, choose a 5A fuse and so on. This will allow you to protect against catastrophe and safely pass the maximum current that the amp can draw.

Thank You

Ian

[SCAIFF001]

Originally Posted by BobEllis

You only need to fuse the hot mains lead. The fuse should be the first thing connected to the hot lead when it enters the case - before the power switch and inrush limiting. With a 600 VA transformer using a 50% overload on 120V mains you want around a 7.5A fuse, depending on your inrush current limiting scheme. You may want to use a slow blow fuse.

No need to directly fuse the secondaries, just connect them to the bridges. If you have a bridge problem a properly sized mains fuse will blow. The same argument could be made for not fusing the rails. A problem arises when you have to size the mains fuse unreasonably large to survive the startup inrush of the the transformer and main filter caps. The safest way is to fuse the rails.

If you choose to fuse the rails individually, then choose something like 2.5 x the bias current you have running. If you bias at 2A, choose a 5A fuse and so on. This will allow you to protect against catastrophe and safely pass the maximum current that the amp can draw.

I lost my Internet Explorer Favorites for the period I was looking over a internet site recomended by you for purchasing electronic components and other stuff, I should remember his address but I am drawing a blank, could you please refresh my memory because I need my power supply heat sinks and other stuff from him ?

Thank You

Ian