Aleph 30 - fuse blowing

[Tomasz Rodak]

Thanks to everybody for opinions, suggestions a nd advices. With regard to Peter Daniel opinion: for my amp I used schematic received from one of diy member with 4 A SB fuses at the secondary. But I will follow your suggestion and remove them this evening to prevent my speaker's woofers from damaging. For my project I simply followed advices given in this forum, my example also shows that no practical experience in electronics is needed to build such amps and enyoy their performance (this is my first project)

For the top I used parts from RITTAL automatic control cabinets (German made) - answer for Dennis Hui question.

 

[richwalters]

Looking at your figures, you give the voltage across the lo ohm power resistors in each o/p stage. You don't give the DC offset voltage present at the LS terminals. BY the time you get this email you would probably have all up and running.

It should be less than 10mV. Most solid state amps in good nick register 1-5mV. If it is greater than 10mV, then the LS cone will start to offset and that could indicate trouble ahead.

Using a fuse in the speaker o/p is a contentious issue. For solid state I use one because fast ones can protect......you may regret not fitting one, if the signal earth comes adrift and the amplifier B/W blasts into the RF spectrum. You won't hear that bit.

):rich

 

[Tomasz Rodak]

Last night I measured DC offset in my Aleph and here are the readings:

right channel: 14 mV
left channel: 19 mV

for me it seems good enough but I'm not sure. Please put me right if I'm wrong.
Regards

 

[richwalters]

I was a bit conservative on those figures I gave you, I seemed to remember from pat experience that 20mA is more the figure.
As both channels seem symmetrical; (which is a good test)
I would leave it at that.
r):

 

[LennyK]

Great job, congratulations!!!

Leszek

PS Pokaza³eœ klasê, po raz kolejny (reg. g³oœnoœci).

 

[Tomasz Rodak]

I have used my amp since 2002 and I'm pleased with it but now I think about resistors replacing I mean 3W metal film for some better ones (now I have some probobly Chinese made MF 5% matched) I saw some on www.intertechnik.de metal film 6W for 3.80 EUR per piece. I don't know whether I should expect considerable sound improvement and whether it is worth to invest to. Thank you for your opinions and advices.

 

[isabido]

Tomasz, my level english is very bad for explained (only read)

Can you replay the you used schematic and pcb?

My transformer is AC 2x24V 500VA,

Have I problem with those 4V of but?

Ideal is AC 2x20 no?

Thanks!