Eric,
Don't you already have the original Prasi boards from BanglaH? You should build that - it works fine with the changes suggested. Just look at the posts showing actual values used. I posted a schematic showing what I did. Rather than try to get the latest and best (but untested PCB), you would actually be better off risk wise by using a tested (albeit, imperfect as is) board. That's just my opinion if you are hoping that the newer boards will be "better". Maybe so - but there could be errors as they are un-tested.
The double BJT output version by Hugh is certainly exciting. But there is probably some work to be done between now and first successful build.
Don't you already have the original Prasi boards from BanglaH? You should build that - it works fine with the changes suggested. Just look at the posts showing actual values used. I posted a schematic showing what I did. Rather than try to get the latest and best (but untested PCB), you would actually be better off risk wise by using a tested (albeit, imperfect as is) board. That's just my opinion if you are hoping that the newer boards will be "better". Maybe so - but there could be errors as they are un-tested.
The double BJT output version by Hugh is certainly exciting. But there is probably some work to be done between now and first successful build.
Hi X,
Very good suggestion. I was lucky, I do have some PCBs, this why I mentionned; If nobody will update their PCB I will simply use my present one and add the few required components, it would just be nice to know if someone intend to work on this.
The double BJT is not for me, I'm building the Quasi for a friend and all he's got is two transformer of each 300VA, +/-20Vac, for the PSU, choices are:
1. A low power Quasi at about +/-28VDC supply with 1 PSU per channel (double mono)
2. If I wire the secondary windings in series I'll have 2 transformers of each 1 x 40Vac winding, if I use them both (can I do that ??) it would give a single +/-40Vac supply (or about +/-55VDC). 1 PSU for 2 channels..aiming for the Big Quasi with such a high DC voltage.
I'll stick with the present design for now.
Thanks,
Eric
Very good suggestion. I was lucky, I do have some PCBs, this why I mentionned; If nobody will update their PCB I will simply use my present one and add the few required components, it would just be nice to know if someone intend to work on this.
The double BJT is not for me, I'm building the Quasi for a friend and all he's got is two transformer of each 300VA, +/-20Vac, for the PSU, choices are:
1. A low power Quasi at about +/-28VDC supply with 1 PSU per channel (double mono)
2. If I wire the secondary windings in series I'll have 2 transformers of each 1 x 40Vac winding, if I use them both (can I do that ??) it would give a single +/-40Vac supply (or about +/-55VDC). 1 PSU for 2 channels..aiming for the Big Quasi with such a high DC voltage.
I'll stick with the present design for now.
Thanks,
Eric
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Hi Eric,
If you want big mosfets, check out Digikey.com. They have a parametric search which is a bit tetchy but does work. I have sent you an Excel list of large mosfets for this job, 150-300V, 40-70A, TO3P (or 247/264 packages) and reasonable costs. Sadly I cannot append this to this post on the forum as it does not permit xls spreadsheets.
Cheers,
Hugh
If you want big mosfets, check out Digikey.com. They have a parametric search which is a bit tetchy but does work. I have sent you an Excel list of large mosfets for this job, 150-300V, 40-70A, TO3P (or 247/264 packages) and reasonable costs. Sadly I cannot append this to this post on the forum as it does not permit xls spreadsheets.
Cheers,
Hugh
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I like it... and also "Prazi"🙂🙂.. thanks for remembering me...
also use metal washers on top to clamp down the o/p, as big as you can fit...will help in uniform load distribution...
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Thiago/Prasi,
You are both artists and this latest quasi layout is wonderful -- tight spacing and elegant.
What concerns me is how long it takes before this pcb and its brothers appears on Ebay - and how much profit is made by some anonymous entrepreneur whom no one here will ever know....
Hugh
You are both artists and this latest quasi layout is wonderful -- tight spacing and elegant.
What concerns me is how long it takes before this pcb and its brothers appears on Ebay - and how much profit is made by some anonymous entrepreneur whom no one here will ever know....
Hugh
I know... late to the party as usual. 1st channel up and running. No drama. +-36 volt rails. No hum or buzz. Dacz layout is tight but all the components fit. The second channel should come together a bit faster. 1st impression says it's worth putting the second channel together for a real listen.
Thanks to all for all the work put in to make this happen.
Evan
Thanks to all for all the work put in to make this happen.
Evan
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Very nice work !
Keep us posted on your listening impression once it running in stereo.
Good to know that the Dacz layout works great, people now have many PCB layout choices.
BR,
Eric
Keep us posted on your listening impression once it running in stereo.
Good to know that the Dacz layout works great, people now have many PCB layout choices.
BR,
Eric
Nice job! So Dacz layout works as prescribed on silkscreen with. No changes needed?
Wellcome Evan.Good job!
Thanks to Prasi Thiago Dacz and other guys
for all the pcb work.
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Dacz layout and silk screen are perfect. The only tight parts are the electrolytic caps I used. I only had higher voltage then is needed on hand. It will probably take me a couple days to get the second channel running. I'll report back.
PS. I used IRFP 240 and MJL 3281A. The 1381 parts are F rank.
PS. I used IRFP 240 and MJL 3281A. The 1381 parts are F rank.
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One of the electrolytic cap is a concern, to improve bass performance people will want to use C6 as a 220uF, 50/63V instead of the 100uF, 50/63V. Kind of wonder if it will fit on these compact PCB ?
BR,
Eric
BR,
Eric
Eric,
I have found that the larger electro does not improve bass. 100uF is just fine..... and you can use small ones with high ripple factor, 100KHz rating and 63VW for low cost. Generally, I use Nichicon, but in N America the biggy is CDE.
Cheers,
Hugh
I have found that the larger electro does not improve bass. 100uF is just fine..... and you can use small ones with high ripple factor, 100KHz rating and 63VW for low cost. Generally, I use Nichicon, but in N America the biggy is CDE.
Cheers,
Hugh