• These commercial threads are for private transactions. diyAudio.com provides these forums for the convenience of our members, but makes no warranty nor assumes any responsibility. We do not vet any members, use of this facility is at your own risk. Customers can post any issues in those threads as long as it is done in a civil manner. All diyAudio rules about conduct apply and will be enforced.

Jens Rasmussen Leach clone group buy

Jump to Latest
#1,102
How about some progress pictures folks.
Click to expand...

FWIW,

I'm laying out the chassis for my amps -decided to go with a pair of mono amps, using some old "junk" amp chassis I picked here and there.

As soon as the panels and heat sinks are drilled/tapped (and once I get some more power supply caps), I should be ready to assemble. 😎

C'mon, guys- Let's see your images!

-Chas
 

Attachments

  • amp1.jpg
    amp1.jpg
    76.3 KB · Views: 611
#1,105
pchw said:


http://www.chipamp.com/orders.shtml

Scroll to the bottom, they are the Amplifier Power Supply PCB below the Aleph PCB. They are on sale with 20% off now. They make very neat and professional look power supply!!
Click to expand...

Thanks Fred. :up:
That is not a bad price for such a nice board.
The link for the board is probably incorrect on the website as it leads to an XLS file (BOM) instead of a picture. :dead:

==================================
I found them... http://www.briangt.com/gallery/aleph-pcb 😀
 
#1,107
Zooming in on the picture of the board it looks like it supports 4 MUR type diodes, so center tap transformers should work.

From memory, it also supports CCRC filtering - although with a Leach amp I'd just jumper out the R and use 3 parallel caps per rail.
 
#1,109
the Leach has pretty good PSRR and also Jen's version has the facility to power the voltage amp from a separate PSU, regulated or not.

The removal of R allows the whole capacitor bank to deliver transient current.

It may be that the loss of ripple attenuation is more than balanced by the improved peak current delivery.

If the resistor were to be replaced by 100turns of 0.6mm diameter enameled wire, the R value would be low and the ripple and interference suppression would be much improved. This may sound better than either of the other options.

But there's only one way to find out, try them.
 
#1,110
AndrewT said:
the Leach has pretty good PSRR and also Jen's version has the facility to power the voltage amp from a separate PSU, regulated or not.

The removal of R allows the whole capacitor bank to deliver transient current.

It may be that the loss of ripple attenuation is more than balanced by the improved peak current delivery.

If the resistor were to be replaced by 100turns of 0.6mm diameter enameled wire, the R value would be low and the ripple and interference suppression would be much improved. This may sound better than either of the other options.
Click to expand...

I doubt the class A input circuitry needs to worry about peak current delivery since it is constant current. Thus, I would assume inclusion of the resistor would be MUCH more advantageous for filtering variations due to the current pulses in the output stage than any possible reduction in peak current delivery, if that is in fact a potential problem.

If the CRC is for the output stage, I do agree that an inductor may be a better choice; especially if it is placed away from the amp circuitry, as such an inductor may radiate into the circuitry. The front end would also be the most intolerant of such radiation.
 
#1,112
pooge said:


I doubt the class A input circuitry needs to worry about peak current delivery since it is constant current. Thus, I would assume inclusion of the resistor would be MUCH more advantageous for filtering variations due to the current pulses in the output stage than any possible reduction in peak current delivery, if that is in fact a potential problem.

If the CRC is for the output stage, I do agree that an inductor may be a better choice; especially if it is placed away from the amp circuitry, as such an inductor may radiate into the circuitry. The front end would also be the most intolerant of such radiation.
Click to expand...


It appears I was talking about the wrong boards. I thought it was the Leach amp boards being discussed. So I do not disagree with what Andrew said regarding the separate PS boards.
 
You must log in or register to reply here.
Top Bottom