Industrial AlephX High Power version

[Edwin Dorre]

Originally posted by Netlist
Edwin,
Whether I short the inputs or not, the hum stays the same. Because it's 100Hz it comes from the PSU, so IMO it has nothing to do with grounds or inputs.
I'm getting more and more convinced that the CRCRC option could bring the solution. As I only have four caps of 68.000µF it will be CRC. Maybe a CLC would be better (and more expensive) then.

/Hugo

I am running CRCRC with 22000uf for each C and 0.11 ohm 20W for each R . I have a ripple measured on a scope of about 0.5V on full load (24.8V-0-24.8V).

Edwin

[Edwin Dorre]

Originally posted by Cobra2
But I have a pair A-X boards finished, and just wonder if it's worth buying a caps, ribs/chassi + super-large trafo, that hardly can be used for anything else? ( In case I do not like the result / endless hum-problems...).
Well, I could probably use the trafo for a 10+ channel GainClone if it does not work out.....
(Damn 24% import tax + handeling fees make the missing parts so expensive, that they has to be put on use, one way or another).

Arne K

Just for the record... I hear NO HUM whatsoever... If you do not short any wire, just let them hang around, you can hear a very very very small 50hz on a 95db speaker... When you connect to something or short the thing it is dead silent, no hiss, no hum, nothing!

Edwin

[Netlist]

Hi you cap engineers
I decided to change the caps in my AlephX because their max voltage is 25V and that's not high enough.
The actual caps are: EEGBA1E683FE :
http://www.farnell.com/datasheets/23859.pdf

Problem is I can't decide which on to buy:
http://www.farnell.com/datasheets/363.pdf
17473
or
http://www.farnell.com/datasheets/360.pdf
17473

The first one is much cheaper and if the second one wouldn't improve anything, it would be wasted money.
Any thoughts?

/Hugo

[SisterOfMercy]

In my opinion it's better to use a capacitor with a lower capacitance with a higher ESR, ripple current, lower internal impedance. (they all depend on each other).

If you look at the datasheets of the 363 and the 360, you'll see that at 40 Volts (which you'll probably need), the 363 has @ 150000 uF an Ir (100Hz) of 20 Amperes. The 360 only goes to about 68000 uF with the same case size. Here the Ir at 100 Hz is 30 Amperes.
Even for a lower capacity with the 360's the ripple current is higher, the ESR is lower, and the internal impedance is also lower.

And yes, they would probably be much more expensive. I don't know if it's worth it, but if you really want a low impedance of your power supply, that's one way to do it..

Also, about your speaker setup. You might want to try to suspend some damping material (pritex) from the ceiling on a few wires. If you care more about looks, you can also try a curtain or something like that. I have troubles with reflections (if you clap your hands, you'll hear it echo), and with the pritex plates in place it's gone.

[Edwin Dorre]

[QUOTE]Originally posted by Netlist
[B]Hi you cap engineers
I decided to change the caps in my AlephX because their max voltage is 25V and that's not high enough.
The actual caps are: EEGBA1E683FE :
[QUOTE]


I use 6 times 22000uf 63V BC Components type 154 elco's per channel. In a CRCRC with each R=0.11 ohm 20W (4 per channel) . This gives a ripple of total overall top-to-top 0.5V on 25V-0-25V with about 400W load.

This is enough for a dead silent no hiss no humm power supply on my 92db/W/m Nautilus 802's.

Perhaps you can compare specs of the caps:

http://www.bccomponents.com/Uploads/...ets/154pec.pdf

Edwin

[grataku]

Netlist and/or Edwin

did you guys look at the output of the amp using a scope? If so how does the waveform look in proximity to clipping at say 10 kHz looks vs. at 1 kHz?

[Edwin Dorre]

Originally posted by grataku
Netlist and/or Edwin

did you guys look at the output of the amp using a scope? If so how does the waveform look in proximity to clipping at say 10 kHz looks vs. at 1 kHz?

As I remember; I looked with my old 20Mhz scope (Hameg) from 1hz to 200Khz from sine waves to square waves from low to full power and all looked about the same to me. They even clipped the same regardless of the frequency The only difference was in amount of power and the loss of dB because of the higher frequency. All into 4 ohm and 8 ohm power resistors.

When using a square waves the rising and lowering times of the squares looked the same at 1khz 10Khz and 100Khz... I use 10pF instead of the 5pF. With 5pF I got overshoot on the square wave.

Edwin

[Netlist]

Originally posted by Edwin Dorre


I use 6 times 22000uf 63V BC Components type 154 elco's per channel. In a CRCRC with each R=0.11 ohm 20W (4 per channel) .

Thanks Edwin, I just ordered 12 X 47.000µF 40V 154 types from BC.
Together with 8 X 0.1ohm 25W resistors.
I took the 47.000 because they have the best Farad/money value.
I'll keep you informed.

Originally posted by grataku
Netlist and/or Edwin

did you guys look at the output of the amp using a scope? If so how does the waveform look in proximity to clipping at say 10 kHz looks vs. at 1 kHz?

Grataku, what waves would you like? Squarewave to see the pattern, or sinewave to see the clipping? Or both?

/Hugo - will take some pictures.

[Netlist]

Took some "unpolished" pictures.
Some of them look quite frightening and maybe some improvements could be done to the amp.
All squarewaveshots taken just before clipping.
Upper wave= input
lower wave = output
first pic: 1Khz load 4ohm.

[Netlist]

10Khz 4ohm