I arrived home last night from work (construction of a BIG building far, far away)
http://www.conway.com/ssinsider/bbdeal/bd040621.htm
to find 2 packages waiting for me: Brian's parts kit and PE's 48 VCT buy-out transformers. Ooooh! this is gonna be great fun.
Brian, you went over the top. Sorting , then packing. Attention to detail. Considerate and most helpful.
Russ, I continue to watch your ongoing developments. You go, boy!
Mauro, we'll be glad to let you know.
http://www.conway.com/ssinsider/bbdeal/bd040621.htm
to find 2 packages waiting for me: Brian's parts kit and PE's 48 VCT buy-out transformers. Ooooh! this is gonna be great fun.
Brian, you went over the top. Sorting , then packing. Attention to detail. Considerate and most helpful.
Russ, I continue to watch your ongoing developments. You go, boy!
Mauro, we'll be glad to let you know.
everything did safely arrived in the Netherlands
Guys,
You have done a wonderfull job!!!
Everything, pcb, kit and heatsinks, did arrive safely, in good condition in Holland.
Brian, no customs problems did occur!.
Will be a lot of work tonight and hope to listen as well. I will start of with kit and design as is and will try the suggested mods further down the road.
thanks again from some very happy earsandeyes
Guys,
You have done a wonderfull job!!!
Everything, pcb, kit and heatsinks, did arrive safely, in good condition in Holland.
Brian, no customs problems did occur!.
Will be a lot of work tonight and hope to listen as well. I will start of with kit and design as is and will try the suggested mods further down the road.
thanks again from some very happy earsandeyes
rambling thoughts
Russ, Brian, et al
I'm sittting here looking at my soon-to-be stuffed board, heatsink and transformer. I'm brainstorming good ways to orient things into a case.
It helps that I went to the "integrated sign and display" company yesterday. From their waste aluminum dumpster I got pieces of sheet stock between .009" and .125". I also retrieved a length of 6" square tube of almost .125". The tube has nice, square corners. I got enough for several cases, handed the man $10 and came home.
I'm thinking of cutting a section of the tube to match the length of the heatsink. From that I'll harvest 2 "L" sections, size them and attach one to each side of the heatsink. These will become the surfaces for mounting rca's, speaker binding posts and power inlet module. My heatsink fins will be outside on the back of the casework. My hope with this arrangement is to be able to remove the board from the case while still attached to the heatsink. Having the backside connectors attached to the heatsink simplifies this.
I think the front and sides of the case will be wood. The top and bottom will be aluminum sheet. I'll provide some air holes in the top and bottom for circulation around the transformer and heatsink.
I urge all who are going through this excercise to post some of their experiences.
We have the opportunity to tweak this (and the next) generation of boards and amps into a "form factor" that makes best use of the resources at hand. As an example, I'm real happy with the heatsinks provided. I'm considering cutting one down to more closely match the height of the transformer I use. Not a big change, mind you; just an effort to balance the proportions between height, width and length. TBC
Russ, Brian, et al
I'm sittting here looking at my soon-to-be stuffed board, heatsink and transformer. I'm brainstorming good ways to orient things into a case.
It helps that I went to the "integrated sign and display" company yesterday. From their waste aluminum dumpster I got pieces of sheet stock between .009" and .125". I also retrieved a length of 6" square tube of almost .125". The tube has nice, square corners. I got enough for several cases, handed the man $10 and came home.
I'm thinking of cutting a section of the tube to match the length of the heatsink. From that I'll harvest 2 "L" sections, size them and attach one to each side of the heatsink. These will become the surfaces for mounting rca's, speaker binding posts and power inlet module. My heatsink fins will be outside on the back of the casework. My hope with this arrangement is to be able to remove the board from the case while still attached to the heatsink. Having the backside connectors attached to the heatsink simplifies this.
I think the front and sides of the case will be wood. The top and bottom will be aluminum sheet. I'll provide some air holes in the top and bottom for circulation around the transformer and heatsink.
I urge all who are going through this excercise to post some of their experiences.
We have the opportunity to tweak this (and the next) generation of boards and amps into a "form factor" that makes best use of the resources at hand. As an example, I'm real happy with the heatsinks provided. I'm considering cutting one down to more closely match the height of the transformer I use. Not a big change, mind you; just an effort to balance the proportions between height, width and length. TBC
Hey bg,
Good scrounging! That's $10 well spent. 
I think your ideas for mounting things sound great so far. In fact it models Mauros suggestion pretty well that you keep the trafo on the rectifier side of the board. I am very happy with the form factor of the board. I only have one complaint. You need to spend about 20 seconds on the belt sander or equivalent and take about 1/32" off the chip side of the board so that the chips will sit flush against the sink. I am not sure if its a problem with the gerbers, or with the PCB manufacturer, but it is a simple fix.
Even without fixing it you can still get a flush fit, you just have to bend the legs of the LM3886 a lttle, and it helps to get everything test mounted prior to final install to check the fit.
Have fun with your build! Keep us posted.
Cheers!
Russ
Good scrounging!
That's $10 well spent. I think your ideas for mounting things sound great so far. In fact it models Mauros suggestion pretty well that you keep the trafo on the rectifier side of the board. I am very happy with the form factor of the board. I only have one complaint. You need to spend about 20 seconds on the belt sander or equivalent and take about 1/32" off the chip side of the board so that the chips will sit flush against the sink. I am not sure if its a problem with the gerbers, or with the PCB manufacturer, but it is a simple fix.
Even without fixing it you can still get a flush fit, you just have to bend the legs of the LM3886 a lttle, and it helps to get everything test mounted prior to final install to check the fit.
Have fun with your build! Keep us posted.
Cheers!
Russ
I milled a grove in the heatsink to accomidate the board edge (wasn;t that your idea, Russ?). I have all the stuff mounted on a .125" sheet of aluminum right now. My wife and sone are visiting the in-laws, and have the camera, so I can't post any pics. I'll try tonight when they get home.
I think we are all going to come up with a similar layout. Mine has the heatsink proruding from the back of the case (well, theoretical case at this point) with it's base plate inside the amp. I actually drilled and tapped two 6-32 holes in the top and bottom of the heatsink, and screwed up from the bottom into it, making it a very sturdy back wall and rear mount for the pcb.
The top of my case will be another sheet of aluminum (actually some designer office shelving that was being thrown away at my old job). It's mounted slightly off-center on the base. The power will mount on one side of the HS, RCAs on the other.
The transformer is bolted to the base plate in front of the board.
I am using an Alpha 10K pot as a passive volume control right now, and it works great (from JayCar). I will probably add Russ' Freebird Pre, however, as well as a rotary switch source selector.
I am thinking the the front and sides will be walnut, with the top fixed to the front-side unit. There will be a dado that the base slides into, so the front, sides, and top can be slide forward and off as a unit. The two screws into the heatsink through the top plate will secure the whole shabang. I am going to epoxy some aluminum flashing to the insides of the walnut for shielding. Did this before and it works great.
One more thing: grounding. The transformer I am using (PE buyout job) is a CT, fo only one 0V connection. I ran the spare AC gnd from the pcb to my chassis ground, which is one of the transformer bolts. Mains ground also connects here. The amp is 100% silent, even with my ear to the speaker, and no case.
I think we are all going to come up with a similar layout. Mine has the heatsink proruding from the back of the case (well, theoretical case at this point) with it's base plate inside the amp. I actually drilled and tapped two 6-32 holes in the top and bottom of the heatsink, and screwed up from the bottom into it, making it a very sturdy back wall and rear mount for the pcb.
The top of my case will be another sheet of aluminum (actually some designer office shelving that was being thrown away at my old job). It's mounted slightly off-center on the base. The power will mount on one side of the HS, RCAs on the other.
The transformer is bolted to the base plate in front of the board.
I am using an Alpha 10K pot as a passive volume control right now, and it works great (from JayCar). I will probably add Russ' Freebird Pre, however, as well as a rotary switch source selector.
I am thinking the the front and sides will be walnut, with the top fixed to the front-side unit. There will be a dado that the base slides into, so the front, sides, and top can be slide forward and off as a unit. The two screws into the heatsink through the top plate will secure the whole shabang. I am going to epoxy some aluminum flashing to the insides of the walnut for shielding. Did this before and it works great.
One more thing: grounding. The transformer I am using (PE buyout job) is a CT, fo only one 0V connection. I ran the spare AC gnd from the pcb to my chassis ground, which is one of the transformer bolts. Mains ground also connects here. The amp is 100% silent, even with my ear to the speaker, and no case.
Hi, Brian.
Yep I did cut a 3/32" slot in my heatsink to slip the PCB into. I forgot to mention that.
I only mentioned the belt sander technique as on the second amp I am building for my brother in law I decided to do that instead as it is a little easier.
Still I am glad you brought it up, it is actually a great mounting option as that 1/32" into the groove makes the board quite stable and not prone to flex at all.
Your mounting plan sounds excellent.
I don't seee any reason however to connect the second PG spade to anything. I believe it is there to allow the use of dual secondary type trafo where you simply join two leads to get a center tapped secondary.
I personally always connect the mains ground to the chasis(in metal cases) but I would not connect that ground to your circuit at all. It serves no purpose and gives you no benefit, and it could add a ground loop if you attach a poorly designed piece of gear to your amp.
Just my 2C.
Cheers!
Russ
Yep I did cut a 3/32" slot in my heatsink to slip the PCB into. I forgot to mention that.
I only mentioned the belt sander technique as on the second amp I am building for my brother in law I decided to do that instead as it is a little easier.
Still I am glad you brought it up, it is actually a great mounting option as that 1/32" into the groove makes the board quite stable and not prone to flex at all.
Your mounting plan sounds excellent.
I don't seee any reason however to connect the second PG spade to anything. I believe it is there to allow the use of dual secondary type trafo where you simply join two leads to get a center tapped secondary.
I personally always connect the mains ground to the chasis(in metal cases) but I would not connect that ground to your circuit at all. It serves no purpose and gives you no benefit, and it could add a ground loop if you attach a poorly designed piece of gear to your amp.
Just my 2C.
Cheers!
Russ
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