Aleph X option question

[CH2]

Hi All

I am in process of building a 4 fet per side AX using Hifizen board, as I am not electrical trained, I would appreciate if anyone can help me out on this questions:

1. I intend to use D1A (9.1v zener), Q6A (IRF610) and Q12A (j505). What are the values for R17, R24 and R26 that I should test with?
2. For J1a, and J1b what is the pros and cons of this two alternatives?


Thanks

CH2

 

[hifiZen]

I would use J1b. There is not really any trade-off, mostly advantages for using J1b instead of J1a (unless your rail voltage is higher than about +/-25V). J1a just happens to be the original connection used by Grey Rollins.

For R17, you need to know your power supply voltage, and your choice of J1a or J1b. For J1a, start with 1x your rail voltage (eg. 15V for +/-15V supply). For J1b, start with 2x your rail voltage (eg. 30V). Subtract about 12V from that for D1a and Q12a, then multiply by 1000. That should be roughly the maximum value for R17. Example: +/-15V rails, J1b, D1a, Q12a -> (30-12)*1000=18000 ... R17=18k or less. Choice of R17 will have a very small effect on the circuit, so if in doubt, you can use a lower value, or just 0 ohms / short.

R24 and R26 can be 475 and 332, respectively. There is some room here for slightly different values.

Enjoy!

 

[zygibajt]

To HiFiZen

Hi,
As I remember You organized group PCB's buy for Aleph X (correct me If I'm wrong).Do You still have any pair to sell.
Also,if You don't meybe You would share the project with me?
If it's done in Protel, I have a production house that can make them from Protel files.Would be great to get any answer from You on that subject.
Bartek

 

[CH2]

I would use J1b. There is not really any trade-off, mostly advantages for using J1b instead of J1a (unless your rail voltage is higher than about +/-25V). J1a just happens to be the original connection used by Grey Rollins.

For R17, you need to know your power supply voltage, and your choice of J1a or J1b. For J1a, start with 1x your rail voltage (eg. 15V for +/-15V supply). For J1b, start with 2x your rail voltage (eg. 30V). Subtract about 12V from that for D1a and Q12a, then multiply by 1000. That should be roughly the maximum value for R17. Example: +/-15V rails, J1b, D1a, Q12a -> (30-12)*1000=18000 ... R17=18k or less. Choice of R17 will have a very small effect on the circuit, so if in doubt, you can use a lower value, or just 0 ohms / short.

R24 and R26 can be 475 and 332, respectively. There is some room here for slightly different values.

Enjoy!

Hi Hifizen


Thanks alot for the above info. I had been reading the various thread for weeks but could not find required data.

Thanks again

Cheers
Hock Hua