Aleph-X builder's thread

[yoke]

Re: supply voltage aleph-x

Hi

This is my second project about aleph.
I want to change the supply voltage +/-22V to +/-18V.
What parts should I change on circuit?

Thanks

I would like to use +/-18V olso...so any toughts what to change ???

 

[Nixie]

Since the IRFP240 flanges are coinnected to the drains, can I mount all on one side and half to copper bus bars without insulation, and put the insulation between the copper bus bars and heatsink?

 

[Nixie]

Wow, two weeks and no reply...

 

[jleaman]

Since the IRFP240 flanges are coinnected to the drains, can I mount all on one side and half to copper bus bars without insulation, and put the insulation between the copper bus bars and heatsink?

NO don't do that.. You should buy some ceramic isolation pads. Do you want a pic of what they look like ?

Jase

 

[Nixie]

OK, and what's the reason then?

 

[jleaman]

Because you will short each of them together....

 

[Nixie]

I'm talking of using multiple paralleled output devices (12 per monoblock), and having the paralleled ones on the same bus (3x). They're already connected at the drains anyway.

 

[jleaman]

Can't said we didn't warn you.. But hey if you have loads of money go nut's.

J'

 

[Nixie]

That still doesn't answer my question, what exactly is wrong what I suggested? If I have 12 devices per channel, the drains of the four 3x pairs are all connected together in the schematic. So why do you think they flanges should not make contact with each other through a piece of copper bus bar (that's itself insulated from the heatsink)?

 

[Babowana]

. . . having the paralleled ones on the same bus (3x). They're already connected at the drains anyway.

You would hardly see what is wrong. 😀

I wonder how you are going to plan the electrical insulation
and thermal conduction between the bars and the heat sink.
If you have any solution to this question. . . why not. . . ?

 

[Nixie]

I've very large mica sheets of the same thickness as used in the usual insulators.

My question was more regarding say capacitance between the now-connected to drains bus bar and the heatsink, or the inductance of the long bus bar, etc.

 

[Babowana]

The larger plate area increases the capacitance.
Might lose high frequencies. . . all. . . ?

 

[tenderland]

PCB

I am interested in building the Aleph x , low power version and would like to know where I can get circuit boards.



j

 

[Nixie]

I've some spares, but see if you can find another source first, as I'm not quite certain I won't need them.

 

[chrismercurio]

Getting started...transformers and boards

I have two 1000VA 35v secondary Plitron transformers at home that I bought about five years ago. I took them out recently and decided that I would like to build a power amplifier with them. I searched the forums and have done quite a bit of reading over the last four weeks on the SKA, Aleph-X, and various ChipAmps. I haven't found anyone using the transformers that I have with the Aleph X but would like some guidance as to how appropriate they are for the job as well as a possible source for boards to ease construction. if they are not going to work, perhaps a suggestion as to what project to build as it seems a waste to not use my big beautiful heavy chunks of copper for something.

Thanks!

 

[Netlist]

I can't comment on other amps but I believe 35V is a bit high for AlephX.

/Hugo

 

[gl]

I too think that the voltage is too high for the Aleph-X. However, the transformers would make a great basis for a pair of Aleph 2's.

Graeme

 

[tenderland]

resistors

Hello , Pardon me for this rudementary question. I am in the process of digesting Grey Rollins original 15v Aleph x schematic and was wondering about some of the resistor values... 392 ohm,221 ohm, 68.1k ohm. How do you obtain these uncomon values?



J

 

[Zen Mod]

Re: resistors

Hello , Pardon me for this rudementary question. I am in the process of digesting Grey Rollins original 15v Aleph x schematic and was wondering about some of the resistor values... 392 ohm,221 ohm, 68.1k ohm. How do you obtain these uncomon values?



J

uncommon?
nope- common values in 1% metal film - E48 (is it ?) nomenclature

 

[tenderland]

oh boy

sory i think I didnt check around enough, I just looked at MCM , seems like Mouser has a plethora of said values.



Thanks

J