A mirror image, although appealing is not really necassary. I used to do it too
and it's particularly cute when both circuits are on the same board. But since you are using two separate boards for ea. channel I wouldn't bother with extra trouble of mirorring, BTW two exactly same boards for ea. channel are more likely for ea. channel to sound exactly the same.
As to 10u caps use the smallest you can. I won't be using C7 because offset can be adjusted in that location for 0V . Maybe you could use Black Gate (10u starts from $2) or those brown Panasonic polypropylenes Nelson is using (from Digi-Key). Also don't limit yourself to exactly10u because the value isn't really important here (8u is still fine )
http://www.passlabs.com/prodlit/xonolit.htm
and it's particularly cute when both circuits are on the same board. But since you are using two separate boards for ea. channel I wouldn't bother with extra trouble of mirorring, BTW two exactly same boards for ea. channel are more likely for ea. channel to sound exactly the same.As to 10u caps use the smallest you can. I won't be using C7 because offset can be adjusted in that location for 0V . Maybe you could use Black Gate (10u starts from $2) or those brown Panasonic polypropylenes Nelson is using (from Digi-Key). Also don't limit yourself to exactly10u because the value isn't really important here (8u is still fine
)http://www.passlabs.com/prodlit/xonolit.htm
Bouke,
Thanks for the reply. I'll take 2 boards of each, (the amplifier and the power supply) for complete dual mono.
I agree with Peter that mirror imaging is not worth it, unless you will be staring at your boards as artwork.
The Panasonic poly caps that Nelson uses from Digikey are fine. In fact, if you are able to look at the Digikey catalogue and design the board so that it uses standard parts from that catalogue as well as yours (Farnell?) that would be appreciated for the North American guys!
Finally, can you incorporate a pot to adjust offset so that the output capacitor is not required, as Peter mentioned in another thread? Why have a cap when you dont need one
Cheers,
RonS
Thanks for the reply. I'll take 2 boards of each, (the amplifier and the power supply) for complete dual mono.
I agree with Peter that mirror imaging is not worth it, unless you will be staring at your boards as artwork.
The Panasonic poly caps that Nelson uses from Digikey are fine. In fact, if you are able to look at the Digikey catalogue and design the board so that it uses standard parts from that catalogue as well as yours (Farnell?) that would be appreciated for the North American guys!
Finally, can you incorporate a pot to adjust offset so that the output capacitor is not required, as Peter mentioned in another thread? Why have a cap when you dont need one
Cheers,
RonS
transducer said:Bouke,
Thanks for the reply. I'll take 2 boards of each, (the amplifier and the power supply) for complete dual mono.
I agree with Peter that mirror imaging is not worth it, unless you will be staring at your boards as artwork.
You're right... It's not really an improvement for the sound, and indeed doubles the work
The Elko's weren't really the problem. I've taken the specs from Rubycon Elko's, and they are quite the same for Panasonic...
Like I posted earlier, I mostly pondered about the capacitors on the circuit. I have now used the shapes for LCR Polystyrene and at more crucial places I've used Polycarbonate. For the sake of versatility, I'll use several shapes and pinouts for most caps.
Finally, can you incorporate a pot to adjust offset so that the output capacitor is not required, as Peter mentioned in another thread? Why have a cap when you dont need one
Cheers,
RonS
I shall incorporated both
Bridge the one you don't want I have almost finished shaping the components... Except Q5 (2SK389). This is a dual JFET housing. I can't find any datasheets for this device, nor can I find replacements... Any suggestions?
Bouke
I have the 2sk389 data sheet at home, I can email it to you tonight. There is no substitute for it.
I would not use polycarbonates for any crucial caps. Polystyrene is prefered, followed by polypropylene. Of course, Teflon is best but too expensive The Panasonic metalized film caps are good, I believe that is what Nelson uses based on the photo's of the Xono. Small value polystyrenes for the MM input are fine as well, I used Phillips in my phono stage, little blue ones.
RonS
I would not use polycarbonates for any crucial caps. Polystyrene is prefered, followed by polypropylene. Of course, Teflon is best but too expensive
The Panasonic metalized film caps are good, I believe that is what Nelson uses based on the photo's of the Xono. Small value polystyrenes for the MM input are fine as well, I used Phillips in my phono stage, little blue ones.RonS
If you could get me the datasheet for the 2SK389, then that would be really great! It is in fact the last shape (footprint) I need to start routing.
As for the Caps: Most axial caps will fit, unless you start using really exotic stuff
In the RIAA filter I've placed options for Silver Mica Caps
Bouke
It is in fact the last shape (footprint) I need to start routing.As for the Caps: Most axial caps will fit, unless you start using really exotic stuff
In the RIAA filter I've placed options for Silver Mica Caps
Bouke
Did you have a chance to read that link on picking capacitors that I posted?
Ron,
This is my mail adress It's not Hotmail, so attatchment size won't be a real problem.
I haven't read the link yet, but I've bookmarked it for reading tomorrow thanx for the info.. That was what I was really looking for
Goodnight to you all,
Bouke
This is my mail adress It's not Hotmail, so attatchment size won't be a real problem.
I haven't read the link yet, but I've bookmarked it for reading tomorrow thanx for the info.. That was what I was really looking for
Goodnight to you all,
Bouke
Bouke,
I haven't been able to find the data sheet for 2SC1844, I believe it is an NEC part. Here is a link to NEC data sheets http://www.ic.nec.co.jp/discrete/english/document.html
They list 2SC1843 and 2SC1845 but no 2SC1844. Try searching the net, I gave up after half an hour. I haven't tried for the mosfets, but I'm sure they're out there.
Cheers,
Ron
p.s. did you get the 2SK389 data sheets?
I haven't been able to find the data sheet for 2SC1844, I believe it is an NEC part. Here is a link to NEC data sheets http://www.ic.nec.co.jp/discrete/english/document.html
They list 2SC1843 and 2SC1845
but no 2SC1844. Try searching the net, I gave up after half an hour. I haven't tried for the mosfets, but I'm sure they're out there.Cheers,
Ron
p.s. did you get the 2SK389 data sheets?
Ron,
I guess then that we were searching on the same site with the same results, and I gave up too after about an hour.
Anyway, It was only for me to know the pinouts, And if the 2SC1843 and the 2SC1845 are both pinned E-C-B, than chances are small that the 2SC1844 will be pinned differently
Well.. than I've got all of it I guess.... I'll take one more look at the caps tonight and then I will start the routing job!
Bouke
I guess then that we were searching on the same site with the same results, and I gave up too after about an hour.
Anyway, It was only for me to know the pinouts, And if the 2SC1843 and the 2SC1845 are both pinned E-C-B, than chances are small that the 2SC1844 will be pinned differently
Well.. than I've got all of it I guess.... I'll take one more look at the caps tonight and then I will start the routing job!
Bouke
There it is again: The Ono Thread
For while the Routing and Placing of the Amplifier PCB is going on fine (but still a lot of work to do) The following question came up:
Is it a good idea to build all (or at least as many als possible) paired transistors/fets with a thermal coupling, and therefore reducing thermal differences between them?
In that case I would Pair up: Q1 and Q2 (current mirror), Q6 and Q17 (voltage bias?), Q7 and Q18 (output fets), Q21 and Q21 (Inverter Differential Pair)
Do or Don't?
Bouke
For while the Routing and Placing of the Amplifier PCB is going on fine (but still a lot of work to do) The following question came up:
Is it a good idea to build all (or at least as many als possible) paired transistors/fets with a thermal coupling, and therefore reducing thermal differences between them?
In that case I would Pair up: Q1 and Q2 (current mirror), Q6 and Q17 (voltage bias?), Q7 and Q18 (output fets), Q21 and Q21 (Inverter Differential Pair)
Do or Don't?
Bouke
I don't think I'd bother. I haven't seen it on any other gear (but I'm sure that some audio gear might use it). The only thing I've seen it on is my test gear, like my signal generator. There the small transistors have metal bands around them to couple the parts. I think these bands are difficult to obtain. Without them you don't have the thermal coupling.
Nelson didn't use it on his Ono
Ron
Nelson didn't use it on his Ono
Ron
Re: little metal bands for thermal coupling.
One solution I've seen used is to cut a short, narrow strip of suitable size from a spare length of copper pipe (Copper sheet would be easier, but less likely to be hanging around the average shed/garage) Bend it around a former that is slightly larger than your transistor pair.
Having done that, very carefully crimp it around the transistor pair sufficiently tightly that it stays in place, along with a tiny bit of thermal paste between the transistors. I've also seen this idea in an electronics magazine some years ago, that too was for an amplifier circuit.
One other idea I've seen is to twist a length of cooking foil, wrap it around the pair and then twist it together (as one would with a garden tie). I didn't that idea!!!
One solution I've seen used is to cut a short, narrow strip of suitable size from a spare length of copper pipe (Copper sheet would be easier, but less likely to be hanging around the average shed/garage) Bend it around a former that is slightly larger than your transistor pair.
Having done that, very carefully crimp it around the transistor pair sufficiently tightly that it stays in place, along with a tiny bit of thermal paste between the transistors. I've also seen this idea in an electronics magazine some years ago, that too was for an amplifier circuit.
One other idea I've seen is to twist a length of cooking foil, wrap it around the pair and then twist it together (as one would with a garden tie). I didn't that idea!!!
I have had contact with my PCB supplier, And for what regards the Power Supply boards I now know the following. I can have two versions made:
- The "Luxury Edition"; featuring Soldermask (that green insulation layer on the soldering side) and silkscreen text on the component side. Tinned traces and pre-drilled PCB
- The "Cheap Edition"; just copper PBC (without tinning), without all the extras mentioned above (But it will be pre-drilled).
The Luxury edition will cost about €10,- per piece ex. VAT. (A single prototype costs €75,-)
The Cheap Edition will cost about €5,- per piece ex. VAT. (A single prototype costs €40,-)
The Amplifier PCB's will likely be more expensive, as they are larger an maybe double-sided
Of course, I can only choose either one of those. So my question to you guys is: Which one do you prefer?
Bouke
(PS: I forgot to mention that these prices are valid for a total quantity of 20 PCB's made. More PCB's become cheaper, but I don't want to end up with a box full of them)
- The "Luxury Edition"; featuring Soldermask (that green insulation layer on the soldering side) and silkscreen text on the component side. Tinned traces and pre-drilled PCB
- The "Cheap Edition"; just copper PBC (without tinning), without all the extras mentioned above (But it will be pre-drilled).
The Luxury edition will cost about €10,- per piece ex. VAT. (A single prototype costs €75,-)
The Cheap Edition will cost about €5,- per piece ex. VAT. (A single prototype costs €40,-)
The Amplifier PCB's will likely be more expensive, as they are larger an maybe double-sided
Of course, I can only choose either one of those. So my question to you guys is: Which one do you prefer?
Bouke
(PS: I forgot to mention that these prices are valid for a total quantity of 20 PCB's made. More PCB's become cheaper, but I don't want to end up with a box full of them
)I don't think that the solder mask is all that important in the power supply, the traces are not likely to be that close to each other. You could have a component stuffing guide so that you don't need the silkscreen. BUT, the tinning I think is important so that the copper doesn't oxidize.
Well, for 5 Euro's difference, I guess I'm okay with either route
How are you doing with the amplifier board?
Cheers,
RonS
Well, for 5 Euro's difference, I guess I'm okay with either route
How are you doing with the amplifier board?
Cheers,
RonS
Ah yes, The amplifier boards..
It turns out to become one of the most complex boards I have ever made
But it's going well, and this is how it goes: (The pictures are quite large, so I'll just post links).
The first time you realise: "What have I done??"
But really, it fits!
So I make a first attempt to route the damn thing (PS: Red is bottom layer, Green is top layer)
The 1s route attempt is complete, and all connections are made (400 pins in total!), But it is by far not optimum. A lot of work needs to be done! The boards will become 8cm x 27cm.
Bouke
It turns out to become one of the most complex boards I have ever made
But it's going well, and this is how it goes: (The pictures are quite large, so I'll just post links).
The first time you realise: "What have I done??"
But really, it fits!
So I make a first attempt to route the damn thing
(PS: Red is bottom layer, Green is top layer)The 1s route attempt is complete, and all connections are made (400 pins in total!), But it is by far not optimum. A lot of work needs to be done! The boards will become 8cm x 27cm.
Bouke
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