To all,
I originally started this thread to gauge interest in another group buy of the Leach/Jens 10 transistor amp, of which several hundred were ordered, however, it seems that Jens has a new layout similar to the original with the output section in the middle and a few other refinements.
One member suggested a 12 output section pcb with a snap off if you wish to use less output devices.
If Jens is able to provide us with this latest creation then the group buy will proceed with the newest version. Just wish to clear this up. In any case these are superbly designed pcb's with proven, in actual use, features. I will order the boards with the heavy fiberglass and 2 oz. copper tractk. They will be green with white solder mask as in the past.
I believe that PA is going to open up a wiki for this project --PA?? Then we can see how it progresses. The best prices start to develop when we reach 100+ boards. Once the final design is in I will get a quote and post here.
Tad
I originally started this thread to gauge interest in another group buy of the Leach/Jens 10 transistor amp, of which several hundred were ordered, however, it seems that Jens has a new layout similar to the original with the output section in the middle and a few other refinements.
One member suggested a 12 output section pcb with a snap off if you wish to use less output devices.
If Jens is able to provide us with this latest creation then the group buy will proceed with the newest version. Just wish to clear this up. In any case these are superbly designed pcb's with proven, in actual use, features. I will order the boards with the heavy fiberglass and 2 oz. copper tractk. They will be green with white solder mask as in the past.
I believe that PA is going to open up a wiki for this project --PA?? Then we can see how it progresses. The best prices start to develop when we reach 100+ boards. Once the final design is in I will get a quote and post here.
Tad
hi
Pictures of the pcb and other pertinent information can be found under the Jens Rasmussen leach clone thread.
Do you have the link to this thread ?
Thanks
Serge
Pictures of the pcb and other pertinent information can be found under the Jens Rasmussen leach clone thread.
Do you have the link to this thread ?
Thanks
Serge
Configuration?
Should the main board be with 2 x 3 output transistors, with an extra 2 x 3 placed on a break off section?
Or ??
\\\Jens
Should the main board be with 2 x 3 output transistors, with an extra 2 x 3 placed on a break off section?
Or ??
\\\Jens
Jens,
I will personally leave the pcb design up to you. I like the 12 output idea and the breadoff section. With 2 extra outputs the overall dimensions only change about 22 centimeters. In breakoff I guess you mean something you will have to take some care to cut or can the traces snap with the fiberglass? I plan to leave mine with all 12.
It seems quite a bit of interest has found it's way to this group buy at such an early stage.
PA. Thanks for the Wiki.
Tad
I will personally leave the pcb design up to you. I like the 12 output idea and the breadoff section. With 2 extra outputs the overall dimensions only change about 22 centimeters. In breakoff I guess you mean something you will have to take some care to cut or can the traces snap with the fiberglass? I plan to leave mine with all 12.
It seems quite a bit of interest has found it's way to this group buy at such an early stage.
PA. Thanks for the Wiki.
Tad
Schematics
Hi,
I updated the schematics... now with 12 output transistors!
What size cap should C21 +C27 be? diameter + pin spacing??
\\\Jens
Hi,
I updated the schematics... now with 12 output transistors!
What size cap should C21 +C27 be? diameter + pin spacing??
\\\Jens
c21 and c27 10,000uF 100 volts??? (only because I have just replaced out of leach 6 and have spares)
As an asside small matter would we be able to get all chassis / heat sink wholes issolated this time please. I found it quite a hassle to deal with last time! So only ground earthing would be done through speaker terminal to star earth and isolated out post???
Just some thoughts. I will leave it up to you experts.
Ian
As an asside small matter would we be able to get all chassis / heat sink wholes issolated this time please. I found it quite a hassle to deal with last time! So only ground earthing would be done through speaker terminal to star earth and isolated out post???
Just some thoughts. I will leave it up to you experts.
Ian
Holes are isolated.
10.000µF 100V are big... how about going for 2 x 2 x XXµF 100V?? Maybe the board can be made somewhat shorted this way....
\\\Jens
Jens,
What size area do you have to work with. The short stubby Panasonics are a good cap and have some decent choices in output. I would like to keep the area reasonably compact so as not to get in the way of chassis placement. The caps you chose for the amps on your old website were a good size.
Tad
What size area do you have to work with. The short stubby Panasonics are a good cap and have some decent choices in output. I would like to keep the area reasonably compact so as not to get in the way of chassis placement. The caps you chose for the amps on your old website were a good size.
Tad
Why not a second PCB ( mezzanine ) with the same amp pcb dimensions to put the 10000µf capacitors ?
Serge
Serge
Hello
Here is a link to PDF with board details....
www.noermoelle-rasmussen.dk/DIYaudio/Leach_ver_1.00.12_brd.pdf
\\\Jens
Here is a link to PDF with board details....
www.noermoelle-rasmussen.dk/DIYaudio/Leach_ver_1.00.12_brd.pdf
\\\Jens
Jens,
Let,s build these things. I like it. We get the gerbers to Advanced Circuits and I will buy you a set for you and Jens Jr. to work on together.
Tad
Let,s build these things. I like it. We get the gerbers to Advanced Circuits and I will buy you a set for you and Jens Jr. to work on together.
Tad
Quote:
Holes are isolated.
10.000µF 100V are big... how about going for 2 x 2 x XXµF 100V?? Maybe the board can be made somewhat shorted this way....
\\\Jens
Thanks Jens. I ended up replacing the 10,000uF with 4700uF for space / chassis reasons. So 4700uF seems to be a nice compromise. Is there any reason that they have to be on the board at all?
Ian
Still like the idea for 2 x 3 output boards.
Holes are isolated.
10.000µF 100V are big... how about going for 2 x 2 x XXµF 100V?? Maybe the board can be made somewhat shorted this way....
\\\Jens
Thanks Jens. I ended up replacing the 10,000uF with 4700uF for space / chassis reasons. So 4700uF seems to be a nice compromise. Is there any reason that they have to be on the board at all?
Ian
Still like the idea for 2 x 3 output boards.
Like this?
www.noermoelle-rasmussen.dk/DIYaudio/Leach_ver_1.02.12_brd.pdf
The board is 29.5 cm long... what heatsink should we get?
\\\Jens
www.noermoelle-rasmussen.dk/DIYaudio/Leach_ver_1.02.12_brd.pdf
The board is 29.5 cm long... what heatsink should we get?
\\\Jens
I haven't checked the lead spacing, but it appears that 4 sets of thermaltrak devices may fit on this board (leave out the middle pair of each section), and then hardwire the diode leads.
Jens, did you ever build a prototype using those devices? I've been thinking about trying it, but haven't taken the plunge yet. I may be in for an extra set of boards just to give it a try.
Jens, did you ever build a prototype using those devices? I've been thinking about trying it, but haven't taken the plunge yet. I may be in for an extra set of boards just to give it a try.
the NJL have the BJT all to one end and the diode to the other end. They cannot easily be fitted in place on a PCB designed for MJL devices.
With 6 output pairs this amp should easily bias into class A, for at least the first 60+ watts, given the heatsink is large enough.
Barrodboss here on DIY Audio has some nice large heatsinks, for a really good price, that with a little extra chassis work should provide good cooling for this layout. You can do a search here and on EBAY for his sinks. He had them extruded using input provided by the members and they have nice tall, approx. 2.250 inch fins.
Jens, The final PDF layout looks very nice. Will you have any gerber files ready for prototyping anytime soon. I can not wait to put one of these together. I have some of your regulator boards Bob was selling which should do nicely on the frontend section.
Tad
Barrodboss here on DIY Audio has some nice large heatsinks, for a really good price, that with a little extra chassis work should provide good cooling for this layout. You can do a search here and on EBAY for his sinks. He had them extruded using input provided by the members and they have nice tall, approx. 2.250 inch fins.
Jens, The final PDF layout looks very nice. Will you have any gerber files ready for prototyping anytime soon. I can not wait to put one of these together. I have some of your regulator boards Bob was selling which should do nicely on the frontend section.
Tad
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