Hi tinitus,
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I see some small issues with board layout
only 2 mounting holes
transistor legs solder points seems a bit far from heatsink
it cannot be mounted horisontal without mounting angle
parts of supply rail line seems smallish
many paralel copper lines
ofcourse I dont know, but it seems to me you may find it better to have supply and groundplane closer to the middle of board
if boards a professionally done, it would be natural to use double sided boards
but ofcourse that would make a DIY copy difficult
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I am also worried about the problem of the mounting holes (I mentioned that in some previous post). I think it would be a lot better if there are mounting holes on the 'other' side of the pcb too.
As for the distance of the power trannies from the board, you have miss this : the body of the trannies can be half-way under the pcb, not exactly the way it is shown in the pcb drawing, so they can be a lot closer to the board.
The thickness of the power rails (and the output) can be a potential problem. For me, I would make some voids on the soldering mask along those tracks so I can solder in a 1mm single strand (or even thicker) bare wire to reinforce them. Kind of bad looking for perfectionist but I think it solve the problem.
But the board is not yet in its final design stage, isn't it?
Question not concerning the amp :
Anyone kind enough to tell me how to use the 'quote' function? Tks.
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I see some small issues with board layout
only 2 mounting holes
transistor legs solder points seems a bit far from heatsink
it cannot be mounted horisontal without mounting angle
parts of supply rail line seems smallish
many paralel copper lines
ofcourse I dont know, but it seems to me you may find it better to have supply and groundplane closer to the middle of board
if boards a professionally done, it would be natural to use double sided boards
but ofcourse that would make a DIY copy difficult
--------------------------------------------------------------
I am also worried about the problem of the mounting holes (I mentioned that in some previous post). I think it would be a lot better if there are mounting holes on the 'other' side of the pcb too.
As for the distance of the power trannies from the board, you have miss this : the body of the trannies can be half-way under the pcb, not exactly the way it is shown in the pcb drawing, so they can be a lot closer to the board.
The thickness of the power rails (and the output) can be a potential problem. For me, I would make some voids on the soldering mask along those tracks so I can solder in a 1mm single strand (or even thicker) bare wire to reinforce them. Kind of bad looking for perfectionist but I think it solve the problem.
But the board is not yet in its final design stage, isn't it?
Question not concerning the amp :
Anyone kind enough to tell me how to use the 'quote' function? Tks.
I'll say!
I've had my eye on this thread since the first sketch was posted a few days ago and it's really blown up since then--all the while Alex is throwing down revisions left, right, and centre! Never ever have I seen anyone work that fast!!
I'll go back to lurking now
Hello
I was interested on these Goldmund , actually these is the mono block verison .
Unfortunately after a while I gave up because I didn't got enough information .
I do not want to hijack the tread just I want to share a nice clone!
Because more information on these I'm more open now , I got new hope even do not the exact same type I wanted to build but still better to try one of these amp
http://www.diyaudio.com/forums/soli...-audio-forum-guys-china-hong-kong-taiwan.html
There are some very nice pictures from these clone.
http://www.hkdg.hk/viewthread.php?tid=877&extra=page=12&page=1
The PC Board I was interested used 4 pair Hitachi laterals 4 on the top and 4 on the bottom.
I think is very important to find orig Japanese Hitachi laterals ! I tested in another project some Renesans and to me there is a huge difference between the two.
I think is good to talk about the parts we will use .
How Aksa wrote half the success the schematic and the another half the parts and those parts well matched (selected) to bring out the best from a amp.
Just some thoughts I tough I would like to share !
Of course I'm interested now on these project , it look like we will have enough information to put these amp together .
Greetings
I was interested on these Goldmund , actually these is the mono block verison .
Unfortunately after a while I gave up because I didn't got enough information .
I do not want to hijack the tread just I want to share a nice clone!
Because more information on these I'm more open now , I got new hope even do not the exact same type I wanted to build but still better to try one of these amp
http://www.diyaudio.com/forums/soli...-audio-forum-guys-china-hong-kong-taiwan.html
There are some very nice pictures from these clone.
http://www.hkdg.hk/viewthread.php?tid=877&extra=page=12&page=1
The PC Board I was interested used 4 pair Hitachi laterals 4 on the top and 4 on the bottom.
I think is very important to find orig Japanese Hitachi laterals ! I tested in another project some Renesans and to me there is a huge difference between the two.
I think is good to talk about the parts we will use .
How Aksa wrote half the success the schematic and the another half the parts and those parts well matched (selected) to bring out the best from a amp.
Just some thoughts I tough I would like to share !
Of course I'm interested now on these project , it look like we will have enough information to put these amp together .
Greetings
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What??? I saw only one 47pF in the input and 4 others are 4.7pF. Those 4.7pF caps caught my attention the first time I saw the schematic. Smaller cap will sound better but decrease stability. It was the only reason I could understand if this is a high (enough) slew rate amp.
Stochino amplifier has SR above 200V/us, but it uses VMOS. With LMOS I expect a super duper compensation scheme. I have been tempted to build the Stochino with Pavel Dudek's DP-330 output stage. This one I guess will not come close to the Stochino slew rate but I already dropped previous project for this one. Tho with unfortunate use of different choice of transistors (especially JFET, where I have prepared matched K389BLs) I have a feeling this will not better than the NSA amplifier (Stochino input stage).
Personal attacks deleted. Yellow cards given.Hi, NagysAudio
I have 2 questions for you, since you said that you have the original schematic:
1. why not any source resistors on the output mosfets for current sharing ? this assume that we have mosfets well matched regarding Vgs, otherwise current sharing and power dissipation will not be optimal
2. what type of diodes are used in the power supply ? normal bridge, soft recovery ? 1 bridge (4 diodes) for both secondaries or 2 bridges (8 diodes, 4/secondary) topology ? (I suppose that you have also power supply section on the schematic - maybe it would be useful to have it posted too)
thank you for sharing
regards, Tibi
I have 2 questions for you, since you said that you have the original schematic:
1. why not any source resistors on the output mosfets for current sharing ? this assume that we have mosfets well matched regarding Vgs, otherwise current sharing and power dissipation will not be optimal
2. what type of diodes are used in the power supply ? normal bridge, soft recovery ? 1 bridge (4 diodes) for both secondaries or 2 bridges (8 diodes, 4/secondary) topology ? (I suppose that you have also power supply section on the schematic - maybe it would be useful to have it posted too)
thank you for sharing
regards, Tibi
Hi Alex,
Can you send your gerber files for the 4 layers (just an old project or sample will do) so that I can check if I read the files generate by your software OK?
tony_chan_cf@email.com
Other guys,
If everything is ready : price acceptable, able to read Alex's gerbers, guys think that the design is all right to function, (maybe still a long way to go?), I will start a group buy for this.
But of course, if Alex agrees to share his work in the first place.
Can you send your gerber files for the 4 layers (just an old project or sample will do) so that I can check if I read the files generate by your software OK?
tony_chan_cf@email.com
Other guys,
If everything is ready : price acceptable, able to read Alex's gerbers, guys think that the design is all right to function, (maybe still a long way to go?), I will start a group buy for this.
But of course, if Alex agrees to share his work in the first place.
this thread is very interesting. Component selection is going to be critical, is there any issues with supply of any of the components?
also power supply construction seems to be another critical area given the references to power supply construction in the goldmund literature.
Either way, i am really interested in participating in this DIY endevour!
-Par
also power supply construction seems to be another critical area given the references to power supply construction in the goldmund literature.
Either way, i am really interested in participating in this DIY endevour!
-Par
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allow me just one small note
I would consider this an experts project only
for those who still want the very very best, but also prefer something easy to build and reliable, I would suggest to keep an eye on MIRAND
also bare in mind that should you build this, and it for any reason doesnt work as supposed, the needed experts you would need to help you may not be here
so far there are no building manual, or setup instructions
whether there will be one some day, or not, no one knows
you really need to know what you are doing, to build this, or at least to make it the promissed "worlds best"
please, its not to start a debate
just note it, and ignore
I would consider this an experts project only
for those who still want the very very best, but also prefer something easy to build and reliable, I would suggest to keep an eye on MIRAND
also bare in mind that should you build this, and it for any reason doesnt work as supposed, the needed experts you would need to help you may not be here
so far there are no building manual, or setup instructions
whether there will be one some day, or not, no one knows
you really need to know what you are doing, to build this, or at least to make it the promissed "worlds best"
please, its not to start a debate
just note it, and ignore
Is it possible to take a vote or reach a compromise as to the number of OUTPUT pairs, and to weather or not to include a ground plane on the component side at least in the area of the input and VAS. I see that on the original and believe it is critical to the overall quality. The use of 4 pairs is in MHO necessary for NON TO-3 outputs for SOA sake.
Unless this is done maybe some one can make boards that will be an alternative to what ever group buy comes up.
There was SOME discussion before, but it lapsed into the void. I hope OS can lend his expertise to this TOO.
Thanks to all for an interesting and stimulating Thread...We all seek the best even if by different paths to the summit.
Unless this is done maybe some one can make boards that will be an alternative to what ever group buy comes up.
There was SOME discussion before, but it lapsed into the void. I hope OS can lend his expertise to this TOO.
Thanks to all for an interesting and stimulating Thread...We all seek the best even if by different paths to the summit.
some design considerations (my own)
1. Improving a very good sounding amp is hard to impossible
It will mostly be "technical" improvements
2. If you change anything, it will most likely change the function, stability, and sound
3. A copy will hold changes of some kind
It will never be a 100% exact copy
4. One may consider improvements that support the changes that are evident
5. In the end it will be a different amp
Not better, nor worse, just different
6. Its a matter of getting the best out of what is possible
And preferably as simple as realisticly possible
7. Make sure you can get spare parts in case of failure
one point where I think it fits well
a power limiter may be a commercially elegantly technical and safe way to deal with possible power issues
Personally I would instead prefer a "conservatively sound" relationship between number of transistors, supply voltage, and heatsinks
1. Improving a very good sounding amp is hard to impossible
It will mostly be "technical" improvements
2. If you change anything, it will most likely change the function, stability, and sound
3. A copy will hold changes of some kind
It will never be a 100% exact copy
4. One may consider improvements that support the changes that are evident
5. In the end it will be a different amp
Not better, nor worse, just different
6. Its a matter of getting the best out of what is possible
And preferably as simple as realisticly possible
7. Make sure you can get spare parts in case of failure
one point where I think it fits well
a power limiter may be a commercially elegantly technical and safe way to deal with possible power issues
Personally I would instead prefer a "conservatively sound" relationship between number of transistors, supply voltage, and heatsinks
According to the schmatices on page one this is the only time I have seen a design where the outputs have significantly higher voltage rails than the frontend or VAS.
Could anyone shed some light on this for me. Just about every RELIABLE amplifier I have taken the lid off with 80 volt rails had 6-8 output pairs and those were metal can devices.
Tad
Could anyone shed some light on this for me. Just about every RELIABLE amplifier I have taken the lid off with 80 volt rails had 6-8 output pairs and those were metal can devices.
Tad
Circuit with two diodes 1N4004 and cap 470uf make double voltage, on 220uF/250V will be about 120V DC, and about 90V DC on emiters of BD249/250.
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As tinitus has said this amp project is an "expert" project. I would agree with that; it looks at first sight way above my own current technical abilities.
However, I do not think that this should remain the case. The "world's best amplifier"!? should not be exclusivley available to those with a certain level of expertise. It is eminently possible to put together a sufficiently complete and detailed set of build and set up instructions that can be followed by those who are able to follow them.
I suspect this thread will be huge and grow for a number of years with alot of disagreement about parts, power supply spec etc, althought the pcb looks well advanced already due to the work of Alex.
It will be some time no doubt before a final agreed project can be made available to anyone who is not an expert for this amp.
Please do not forget about us "non-experts".
I'll follow this thread with great interest.
However, I do not think that this should remain the case. The "world's best amplifier"!? should not be exclusivley available to those with a certain level of expertise. It is eminently possible to put together a sufficiently complete and detailed set of build and set up instructions that can be followed by those who are able to follow them.
I suspect this thread will be huge and grow for a number of years with alot of disagreement about parts, power supply spec etc, althought the pcb looks well advanced already due to the work of Alex.
It will be some time no doubt before a final agreed project can be made available to anyone who is not an expert for this amp.
Please do not forget about us "non-experts".
I'll follow this thread with great interest.
Guys, the entire power supply is already on the board itself. The only thing missing is a normal bridge and a transformer. You can use 2 transformers if you like, it doesn't matter. For this amplifier, Goldmund used 2 transformers per channel. For Mimesis 3 and 6, they only used 1 transformer per channel. This is completely up to the builder and has nothing to do with the functionality of the amplifier. Again, the schematic is only missing 2 components, the normal/standard bridge and a power transformer.
3 pairs of MOSFETS is better than 4, I would not change it.
3 pairs of MOSFETS is better than 4, I would not change it.