Well, I finished stuffing my boards yesterday. This was so much more fun than my usual scabby stripboard efforts!
Only problem now is the chassis and connections, and this seems to be a far bigger headache than the boards. An MDF creation is on the way, and hopefully I'll hear my baby cry for the first time Friday sometime.
Comments so far....
Kit arrived about 3 days after posting
Great labelling- thanks Brian- you can't go wrong here
Boards look superb, real pro stuff
Easy assembly, plenty of room to swing the iron, took about 4 hours to stuff both boards. Not tested yet, but ( I think )
The only slight concern was the difference between my ref c schematic and the kit for a component or two. I 'm happy to trust you've changed things for the better here, but it might be an idea to post an up to date schematic, just for the sake of completeness. Of course, I may just have missed it.
More soon
Only problem now is the chassis and connections, and this seems to be a far bigger headache than the boards. An MDF creation is on the way, and hopefully I'll hear my baby cry for the first time Friday sometime.
Comments so far....
Kit arrived about 3 days after posting
Great labelling- thanks Brian- you can't go wrong here
Boards look superb, real pro stuff
Easy assembly, plenty of room to swing the iron, took about 4 hours to stuff both boards. Not tested yet, but
( I think )The only slight concern was the difference between my ref c schematic and the kit for a component or two. I 'm happy to trust you've changed things for the better here, but it might be an idea to post an up to date schematic, just for the sake of completeness. Of course, I may just have missed it.
More soon
Hi float,
Very glad to hear your experience has been so positive this far. I bet you can't wait to fire it up!
Although the schematic does not say so you could actually use a broad range of values for R42 from 0R to 270R I have tried 0R, 4.7R, 47R, 200R, and 270R all with success.
Mauro suggested 47R as being very stable, and thus we decided to use that value. But you could substitute anything in the range of 0R to 270R if you choose.
Mauro controls the schematic.
Cheers!
Russ
Very glad to hear your experience has been so positive this far. I bet you can't wait to fire it up!
Although the schematic does not say so you could actually use a broad range of values for R42 from 0R to 270R I have tried 0R, 4.7R, 47R, 200R, and 270R all with success.
Mauro suggested 47R as being very stable, and thus we decided to use that value. But you could substitute anything in the range of 0R to 270R if you choose.
Mauro controls the schematic.
Cheers!
Russ
Hi fellas.
What's the best way to hook up a dual secondary toroid to a Rev C mono setup? (2 rectifiers) :/
I plan to get a pair of 160VA's in future but could be a few weeks off.
Thanks to Mauro for sharing the design and all his support. Thanks to Russ & Brian for the massive effort put into the board design and kits. Excellent job all round
Cheers!
What's the best way to hook up a dual secondary toroid to a Rev C mono setup? (2 rectifiers) :/
I plan to get a pair of 160VA's in future but could be a few weeks off.
Thanks to Mauro for sharing the design and all his support. Thanks to Russ & Brian for the massive effort put into the board design and kits. Excellent job all round
Cheers!
Hey lazy,
With dual secs it is actually pretty easy. Most trafos have a wiring diagram either on the trafo itself or in the documentation. You need to wire the secondaries in series and take the center tap (GND) from the point where you join the two, and the two "ends" of the trafo go to AC1 and AC2.
Essentially you turn a dual secondary trafo into a center tapped trafo.
Cheers!
Russ
With dual secs it is actually pretty easy. Most trafos have a wiring diagram either on the trafo itself or in the documentation. You need to wire the secondaries in series and take the center tap (GND) from the point where you join the two, and the two "ends" of the trafo go to AC1 and AC2.
Essentially you turn a dual secondary trafo into a center tapped trafo.
Cheers!
Russ
lazyfly said:Hi Russ.
Thanks mate. Got that part sorted out. I'm wondering do I just run 2 wires from each secondary to the rectifiers (assuming yellow and blue are tied)?
Cheers
Code:· RED----------- +V AC1 YEL----------- 0V ----> PGND · BLU----------- +V ----< GRY----------- 0V AC2
Right you have it, you will need to run two wires from each RED,PGND, and GREY.
Red
------->Board A AC1
------->Board B AC1
PGND
------>BOARD A PGND
------>BOARD B PGND
Grey
---------->Board A AC2
---------->Board B AC2
New bits tommorow Russ White said:
Yep. Knocked this up but seems redundant now that you did it in ascii. Oh well, to justify the effort
An externally hosted image should be here but it was not working when we last tested it.
Got my parts kit today; good delivery, very good packing; the labeling of parts must have taken some time! The pcbs look professional; especially good is the values of resistors and caps, and numbering system marked on the boards for assembly. I intend to put all the resistors in 1st and go from there. With my older eyes I will need to make use of a magnifying glass! as well as a decent soldering iron.
cheers
doggy
cheers
doggy
Attachments
So, I had some free time tonight. I posted the remaining pics of the kit on the site (RevC BOM Page ).
Also started the build guide. Well, I built a single channel and took lots and lots of pictures. Should be pretty comprehensive.
I have heatsinks in now (3" and 4") and will be adding them to the site soon. I will take the opportunity, however, to photograph the drilling and tapping of holes and mounting of the LM3886.
I did all the pics tonight by myself. Might need help for the machining pics.
Also started the build guide. Well, I built a single channel and took lots and lots of pictures. Should be pretty comprehensive.
I have heatsinks in now (3" and 4") and will be adding them to the site soon. I will take the opportunity, however, to photograph the drilling and tapping of holes and mounting of the LM3886.
I did all the pics tonight by myself. Might need help for the machining pics
.
Doggy-
Just note on my construction.. The boards were “complete and easy” but mounting was fustrating. If you remember the post I made about the mains supply cap (C8) hindering the fastening of the LM3886.
If you have the "opportunity" to mount the board then solder in C8 it will make life MUCH easier.
It was an issue for me because the LM3886 mounting hole was drilled and tapped. I had to screw the LM3886 down in the very small space directly above the PCB.
If (when) I build my next, I will use a bolt & nut combo so I can tighten from the heat sink side.
On a side note,
I'm thinking of a pwred speaker (6.5" & ribbon) using this amp and the plate below to sink / mount it all on...
Just note on my construction.. The boards were “complete and easy” but mounting was fustrating. If you remember the post I made about the mains supply cap (C8) hindering the fastening of the LM3886.
If you have the "opportunity" to mount the board then solder in C8 it will make life MUCH easier.
It was an issue for me because the LM3886 mounting hole was drilled and tapped. I had to screw the LM3886 down in the very small space directly above the PCB.
If (when) I build my next, I will use a bolt & nut combo so I can tighten from the heat sink side.
On a side note,
I'm thinking of a pwred speaker (6.5" & ribbon) using this amp and the plate below to sink / mount it all on...
Attachments
Hi Troy, thats was a good tip.
One other good thing to try is simply yo use allen head type machine screws to secure the LM3886 and then you can either use a ball driver which will work at an angle, or you can use a right angle allen wrench which should fit in the space easily.
If the machine screws you have are only srewdriver types (flathead or philips) you can use a right angle screw driver which can be obtained at most hardware stores pretty cheaply.
Cheers!
Russ
One other good thing to try is simply yo use allen head type machine screws to secure the LM3886 and then you can either use a ball driver which will work at an angle, or you can use a right angle allen wrench which should fit in the space easily.
If the machine screws you have are only srewdriver types (flathead or philips) you can use a right angle screw driver which can be obtained at most hardware stores pretty cheaply.
Cheers!
Russ
Thanks Troy for the advice. I have not mounted the heatsinks yet because of that. On all the chip amps I have done, I have used a nut and capscrew. I did read your post on that earlier so I was prepared.
Another thing I do now is to leave ample room in the case for everything. It makes it so much nicer to work on and make mods. if you want to. Although I have seen amps that were basically big almost empty boxes. Better to have enough space!
cheers
doggy
Another thing I do now is to leave ample room in the case for everything. It makes it so much nicer to work on and make mods. if you want to. Although I have seen amps that were basically big almost empty boxes. Better to have enough space!
cheers
doggy
