Any interest for a 'Redux' FE?
In these days I'm playing a bit with a reduced FE board:
This PCB differs from the standard FE one in the following:
Any comment is welcome...
In these days I'm playing a bit with a reduced FE board:
This PCB differs from the standard FE one in the following:
- smaller (same dimensions of TP board, it should be a near perfect replacement in actual builds, including drilling and heatsink mounting)
- same input cap limitation of TP board (22.5mm lead spacing)
- single bridge, a bit less performing but allow the use of a single transformer for two monoblocks.
- Not as optimally spaced and optimized as Fremen Edition board.
Any comment is welcome...
Attachments
Dario,
Very interesting. It looks like the big power supply caps are the same size. Is this correct? Personally, I find the single bridge interesting as it makes it easier to bi-amp and tri-amp speakers. The cost of transformers for multiple monoblocks is a bit higher, but they also take up a lot of space.
I have powered both channels of my FE using one transformer with circuits in parallel and without problems. The shorted input hum measured the same and it sounded the same, so even though monoblock is the recommended approach, I am comfortable with either the dual bridge or single bridge approach.
As for the smaller input cap, so far I have been using caps that are either too big (K75) or a very tight fit (K71). I don't mind the cap extending "off-board".
Very nice work. How much different from optimized do you see this board?
Jac
Very interesting. It looks like the big power supply caps are the same size. Is this correct? Personally, I find the single bridge interesting as it makes it easier to bi-amp and tri-amp speakers. The cost of transformers for multiple monoblocks is a bit higher, but they also take up a lot of space.
I have powered both channels of my FE using one transformer with circuits in parallel and without problems. The shorted input hum measured the same and it sounded the same, so even though monoblock is the recommended approach, I am comfortable with either the dual bridge or single bridge approach.
As for the smaller input cap, so far I have been using caps that are either too big (K75) or a very tight fit (K71). I don't mind the cap extending "off-board".
Very nice work. How much different from optimized do you see this board?
Jac
Hi Jac,
No, they're 30mm like in TP boards.
BTW the FE BOM uses 30mm caps so not a real difference.
Good to know
Yes, not a big limitation.
Thanks
Particularly on the upper left corner area the layout is too much congested, the DC protection circuitry is probably too much near to the input cap.
If this is a problem in a real build... who knows... we should build it and, possibly, measure.
No, they're 30mm like in TP boards.
BTW the FE BOM uses 30mm caps so not a real difference.
Good to know
Yes, not a big limitation.
Thanks
Particularly on the upper left corner area the layout is too much congested, the DC protection circuitry is probably too much near to the input cap.
If this is a problem in a real build... who knows... we should build it and, possibly, measure.
Parts
Around 76€ per board (premium industrial BOM) which can be lowered to 52€ (On a budget BOM)
PCBs
It will depend on the number of partecipants....
50 PCBs (25 stereo kits) -> 18€ each
100 PCBs (50 stereo kits) -> 14€ each
200 PCBs (100 stereo kits) -> 13€ each
300 PCBs (150 stereo kits) -> 12€ each
400 PCBs (200 stereo kits) -> 11€ each
500 PCBs (250 stereo kits) -> 10€ each
These prices are an estimate for a single PCB, they include 1€ donation to DIY Audio and PayPal fees, they're subject to change.
update
I am almost ready to finally power up these boards, but I am waiting for some rikens from parts connexion so I had a little spare time this week. I decided to do a little enclosure work. Most of what I have put together so far is from parts and pieces that I have laying around, except the copper. I had to run to the hardware store for it.
Here are a few blurry cellphone pics..let me know what you think
I am almost ready to finally power up these boards, but I am waiting for some rikens from parts connexion so I had a little spare time this week. I decided to do a little enclosure work. Most of what I have put together so far is from parts and pieces that I have laying around, except the copper. I had to run to the hardware store for it.
Here are a few blurry cellphone pics..let me know what you think
Attachments
IMHO yes, my 120VA R-Cores sound fuller and more powerful than my 225VA Toroid toroids.
But it seem I'm the only one that made a comparison...
Wow! Impressive work!
If' you're asking about layout I think it's pretty good very similar to the one I'm using.
I would, BTW, consider a plain Furutech gold plated inlet in place of the filtered one I can see in pictures.
An externally hosted image should be here but it was not working when we last tested it.
Thanks Dario, the layout just seems logical. As for the iec inlet, it is not the filtered type. It houses a power switch and a fuse all in one package. That is why it appears larger like the filtered inlets. I like having a switch at the inlet on the back of the device where little hands can't get to just for extra safety!
It is too bad the filtered iec inlets are not suitable for audio.
. As for the iec inlet, it is not the filtered type. It houses a power switch and a fuse all in one package. That is why it appears larger like the filtered inlets. I like having a switch at the inlet on the back of the device where little hands can't get to just for extra safety!It is too bad the filtered iec inlets are not suitable for audio.
I'd love to try some but still haven't found a source where the shipping didn't equal or exceed the cost of the transformers. Still searching.
Just bought today's Mega-Milloins Lotto ticket, so maybe.......
Looking at partsconnexion that furutech inlet really isn't too expensive, somthing to consider, but I do like the convenience of the switch and fuse holder in the one I have....choices, choices.
As for the filter. My understanding was that any mains noise they "filter out" is simply diverted to ground. Which for most electronics would be acceptable, but in audio this "filtered noise" could become audible. Maybe my thought on this is flawed?
As for the filter. My understanding was that any mains noise they "filter out" is simply diverted to ground. Which for most electronics would be acceptable, but in audio this "filtered noise" could become audible. Maybe my thought on this is flawed?
As for the filter. My understanding was that any mains noise they "filter out" is simply diverted to ground. Which for most electronics would be acceptable, but in audio this "filtered noise" could become audible. Maybe my thought on this is flawed?
First of all we should establish if you find that power cables, inlets and filters on AC power have audible effects... let's assume we both trust it.
As in all design choices you have advantages and drawbacks... if your AC power is really dirty, noisy, etc. an AC filter would be an advantage (also soundwise) even if the caps in the filter have an effect on sound.
If the AC power is reasonably clean an unfiltered connection would avoid the caps contribution.
Most commercial power amps have no filtered inlets, but it's not rare to find really simple filters made with X or Y caps.
I use an hot to neutral X type (Kemet/Acrotronics R41, Mouser 80-R413I21005000K) polypropilene cap as a basic filter.
Choices... choices...
BTW the Fremen Edition is less sensitive than a plain My_Ref to parts in the AC power path.
Last edited:
%20%201B.jpg){kind=link}
GB for final boards
http://www.diyaudio.com/forums/grou...n-edition-interest-group-buy.html#post3356205
Final boards are not supposed to be an upgrade to RC boards.
http://www.diyaudio.com/forums/grou...n-edition-interest-group-buy.html#post3356205
Final boards are not supposed to be an upgrade to RC boards.
Favorite Alternative DIY Amp?
Now that Dario has offered a GB on more boards, I find myself thinking about future products and whether I should just go ahead and by more Fremen Editon PCBs. I have to admit that I am still really happy with the sound from the FE and can't think how I would improve it. That said, I don't have broad experience with other DIY amps.
I'm just curious, of this group that has already experienced the FE or other more refined MyRefs, are there other DIY amp designs that you have experienced and would recommend in comparison to the FE?
Jac
Now that Dario has offered a GB on more boards, I find myself thinking about future products and whether I should just go ahead and by more Fremen Editon PCBs. I have to admit that I am still really happy with the sound from the FE and can't think how I would improve it. That said, I don't have broad experience with other DIY amps.
I'm just curious, of this group that has already experienced the FE or other more refined MyRefs, are there other DIY amp designs that you have experienced and would recommend in comparison to the FE?
Jac
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.