I'm interested if finding a nice DAC kit to try and squeeze in as well. Looks like I'll have to go and check out Jeff's DAC then or maybe a Buffalo DAC?
rbrook Looks like you have succeeded making a proper job of it. Nice 1U rack cases those, they don't show scratches too readily , and the aluminium front panel isn't flimsy either. After you fit the JLH, I doubt that you will have much room left for anything else, unless you relocate the transformer to a small case of it's own.
Yea the two layer board on the right is for the VU meter (top layer is just buttons for setting it up) I'm unsure if it will affect the sound so i set up the RCA sockets to be able to by-pass it if need be.
I've got Ferrite capsules between transformer and PSU board and between PSU board and SCHA. From my very limited understanding of them they help remove any high frequencies that may be present in the cables they are clamped around, I am also trying out the ferrite beads on the output resistors as i spotted on mikes build.
Cheers Will, yep its my first build although I've done some PC modding before and used to be into electronics back in collage. its just like ridding a bike isn't it
Layout might need some adjustment to squeeze in a DAC
I'd have to say the Jaycar 1U rack case is nice to work with as long as you use the half height mounting hex nuts for the PSU and JLH, to allow the caps to sneak in under the ceiling. Plenty of ventilation too. Now to work on the CAD file to get a laser cut front panel made. ;D
Nice build I wish I liked listening to headphones, 'cause I really like this project.
Are there a couple of resistors missing on the JLH? (R7 33 ohms)
It's not a good idea to use the mounting bolt of the toroid for the earth. If you ever make another earth connection to the chassis then you will get a closed loop around the toroid and we all know what happens next?
If you decide to move the earth to the chassis, then ensure the bolt doesn't touch the metal lid.
BTW: I find Weetbix taste better using a soup spoon rather than a desert spoon. The difference is not as much as the difference between Weetbix and VitaBrits. One of my friends doesn't agree with me but she likes VitaBrits so she must have a cloth tongue. Strange but true.
Greg No, rbrook didn't forget the 2 x 33 ohm resistors Don't forget too, that this is a preliminary photo as the PSU PCB isn't completed yet either. Well spotted about the earth via the toroid bolt. Alex
Gregerskine the 33ohm resistors are mounted under the JLH i dont know why but this is how it came from Mike. Could you enlighten me on the affect of a closed loop around the toroid? I'm still learning about audio grounding so more info the better.
The photos are of a working example. The PSU and JLH are joined under the PCB's.
Does the V in and V out locations on the JLH really matter as there are no components in between just bare tracks on the board, I'm still trying to get my head around how the JLH works.
Does the V in and V out locations on the JLH really matter as there are no components in between just bare tracks on the board, I'm still trying to get my head around how the JLH works.Richard.
Richard Yes, for best results it does matter, as the tracks have inductance and resistance. You have it the correct way around.
A simple explanation is that the 2 x 2,200uF capacitors are part of a capacitance multiplier circuit, where their capacitance effectively is multiplied to about .5 Farad. The circuit draws a small standing current. The pairs of BC550C and BC560C amplify noise and ripple that is present. This ends up modulating the standing current in opposition to the original noise and ripple, and cancels most of it out.
Could you enlighten me on the affect of a closed loop around the toroid?
This becomes in effect a shorted turn around the transformer, overloading it, and in all probability burning it out, unless the main fuse (500mA in this case) blows VERY quickly.
P.S. You may get to curse about hard wiring the modules as you have, instead of using the terminal blocks, if you need to either service it, or make further modifications.
Thanks for the explanation its all starting to come together now.
Also would there be any benefit to thickening up the main power tracks (with a few strands of copper) on the PSU through the JLH and on the SCHA? Just a thought from Mikes post about using mechanical contact and solder just to hold in place on the signal inputs.
There has been a huge difference but i did also put in the Toshiba transistors and the LM4562HA at the same time. ;D
rbrook It's highly unlikely that you would get any audible benefit from adding more copper to the tracks. I have constructed a larger JLH PCB previously with greater attention to the +,- and 0Volt rails, and it doesn't sound any different to recent ones using the same components. Alex
Amp finally finished, lots of pictures folks during build process up to final product....
Final resting place...
Special thanks to Robert- the chip is the icing on the cake mate, cheers for that; Phil, the JLH board worked a treat, great work mate, and finally Alex K, it would never of had any sound coming out of the bloody thing if it wasn't for you, thank you very much mate for your help in getting the amp firing on all cylinders.
Now after all that work i'm going to drink a bottle of wine or 2 and soak up some guitar biased loveliness. Thank you everyone who contributed to this build, it sounds great, looks nearly as good and i am over the moon with the final outcome
Unfortunately, the photos don't even come close to showing the superb attention to detail of Nick's cabinet and metalwork. You just can't buy quality like this ! You can see only the top of the lid, but believe me the other side that you can't see is fabulous too. Even the mesh screen is so well integrated into the top, that it is simply flawless. Incredible work Nick ! Alex P.S. The full frontal photo doesn't do it justice either. I had reservations about Nick's choice of Rocker switch with inbuilt red LED, but it just suits this front panel so very well, and the red LED in it make it all look so stylish too.