Thanks Bertel.
For those thinking that the cost of the built modules are high, is it possible for you to assure them that the BOM costs are necessary because of the precision of some of the resistors?
By my calculations the BOM is not far off the cost you're proposing for the built modules and so these costs will be similar for anyone building their own using the unpopulated boards..
For those thinking that the cost of the built modules are high, is it possible for you to assure them that the BOM costs are necessary because of the precision of some of the resistors?
By my calculations the BOM is not far off the cost you're proposing for the built modules and so these costs will be similar for anyone building their own using the unpopulated boards..
I agree and I also would like to "push" some of you on the list for the pcbs to consider that.
Yes, normally we all make (and solder) our amps ourselves, but in this case (smd etc.) it makes a lot of sense to go for the ready built modules. Consider not only the costs of the (selected) parts but also the effort to purchase them (via different vendors perhaps).
Yes, normally we all make (and solder) our amps ourselves, but in this case (smd etc.) it makes a lot of sense to go for the ready built modules. Consider not only the costs of the (selected) parts but also the effort to purchase them (via different vendors perhaps).
Guys the overall cost corn for the pre built modules is the cost right?
Let's just forget about the high grade parts and solder for those who would like to build the pre amp using boutique kind of stuff, hence making it even more expensive.
If you are trying to bring more people on built boards try offering an option which would reduce the cost of the module itself, say a built pre without regulators. This would allow people to get the built board now cheaper while spend some additional money on the psu later on. Or even get their own in place if they already have one in mind.
For example I am going for PCBs, just because I have some other projects in the pipeline.
Sent from my ONE A2003 using Tapatalk
Let's just forget about the high grade parts and solder for those who would like to build the pre amp using boutique kind of stuff, hence making it even more expensive.
If you are trying to bring more people on built boards try offering an option which would reduce the cost of the module itself, say a built pre without regulators. This would allow people to get the built board now cheaper while spend some additional money on the psu later on. Or even get their own in place if they already have one in mind.
For example I am going for PCBs, just because I have some other projects in the pipeline.
Sent from my ONE A2003 using Tapatalk
The supply section is a small part of the cost and nothing fancy at all.
The larger costs are for the precision SMD resistors but without these precision SMD resistors the whole project becomes a pointless exercise because the whole build is precisely about matched, balanced impedences in the circuit - if they are not matched to the right level there is no point.
People buying the unpopulated PCBs hopefully realise this and acknowledge that they will have to source these high-precision SMD components themselves - I don't think they can be bought in small enough quantities, so yet another group buy would likely be necessary and little money will be saved by doing so.
I'm not so sure though that everyone buying the PCBs does actually realise that it is for SMD parts!
Of course I understand this is a DIY forum so there will be many wanting to build their own SMD board and will enjoy the process of sourcing etc and will already have the tools and skills. If anyone is simply after a great pre however, self-build might not be the right answer on this occasion.
The larger costs are for the precision SMD resistors but without these precision SMD resistors the whole project becomes a pointless exercise because the whole build is precisely about matched, balanced impedences in the circuit - if they are not matched to the right level there is no point.
People buying the unpopulated PCBs hopefully realise this and acknowledge that they will have to source these high-precision SMD components themselves - I don't think they can be bought in small enough quantities, so yet another group buy would likely be necessary and little money will be saved by doing so.
I'm not so sure though that everyone buying the PCBs does actually realise that it is for SMD parts!
Of course I understand this is a DIY forum so there will be many wanting to build their own SMD board and will enjoy the process of sourcing etc and will already have the tools and skills. If anyone is simply after a great pre however, self-build might not be the right answer on this occasion.
+-0.1% is a range of 0.2%
That is the minimum standard for a balanced impedance connection.
If you can do better, go for it.
A range of 0.05% (+-0.025%) will give a small improvement in interference rejection.
It's part of the reason for the laser trimmed resistances inside the balanced receiver and why it costs more than an ordinary opamp.
That is the minimum standard for a balanced impedance connection.
If you can do better, go for it.
A range of 0.05% (+-0.025%) will give a small improvement in interference rejection.
It's part of the reason for the laser trimmed resistances inside the balanced receiver and why it costs more than an ordinary opamp.
Hi Robert,
I am sorry to jump in your GB but look like there is no more interest and that’s is really pity… the Bruno preampli is an amazing design and deserve in my opinion much more attention.
I downloaded the gerber files that Linear Audio kindly make available and I realized the board as it is. Because I need more than 2 inputs I designed an additional board for the back panel that allow up to 6 balanced input.
Unfortunately I “blindly” place the order on Mouser for the parts based on the BOM published in the thread. There is more than one mistake:
- The expensive SMD resistors R2, R3, R13, R14, R30, R31, R40, R41, R8, R17, R35, R44, R19, R22, R46 and R49 are wrong.
The size of the 0207 serie resistors proposed in the BOM cannot fit in the pcb. The only available size with the same characteristic is the serie 0204 that is a little bigger than the other resistors but (being really careful) can fit the footprint
- The C10, C16, C26, C27, C28, C29 can’t fit in the pcb. Changed on ELNA SilmicII RFS-25V220ME3#5
- The C12, C13, C14, C15 can’t fit in the pcb. Changed on Nichicon UKT1E102MPD
For the C4, C7, C8, C9, C21, C23, C24, C25 I choose Nichicon UES1V100MEM
Anyway the preampli is playing since few days now and I am really impressed. Frankly I didn’t expect a so incredible result. This preamplifier really deserve to be realized. The bass are tight and controlled, the voices are incredible and the high tone are really nice and smooth. The 3D image is impressive and there is a correct space and position for all the instruments.
Thanks Robert to introduce to us this simple but amazing design and thanks to Bruno Putzeys to share with all of us his design.
Best Regards,
Enrico
PS: If someone is interested I still have 4 sets of PCBs
I am sorry to jump in your GB but look like there is no more interest and that’s is really pity… the Bruno preampli is an amazing design and deserve in my opinion much more attention.
I downloaded the gerber files that Linear Audio kindly make available and I realized the board as it is. Because I need more than 2 inputs I designed an additional board for the back panel that allow up to 6 balanced input.
Unfortunately I “blindly” place the order on Mouser for the parts based on the BOM published in the thread. There is more than one mistake:
- The expensive SMD resistors R2, R3, R13, R14, R30, R31, R40, R41, R8, R17, R35, R44, R19, R22, R46 and R49 are wrong.
The size of the 0207 serie resistors proposed in the BOM cannot fit in the pcb. The only available size with the same characteristic is the serie 0204 that is a little bigger than the other resistors but (being really careful) can fit the footprint
- The C10, C16, C26, C27, C28, C29 can’t fit in the pcb. Changed on ELNA SilmicII RFS-25V220ME3#5
- The C12, C13, C14, C15 can’t fit in the pcb. Changed on Nichicon UKT1E102MPD
For the C4, C7, C8, C9, C21, C23, C24, C25 I choose Nichicon UES1V100MEM
Anyway the preampli is playing since few days now and I am really impressed. Frankly I didn’t expect a so incredible result. This preamplifier really deserve to be realized. The bass are tight and controlled, the voices are incredible and the high tone are really nice and smooth. The 3D image is impressive and there is a correct space and position for all the instruments.
Thanks Robert to introduce to us this simple but amazing design and thanks to Bruno Putzeys to share with all of us his design.
Best Regards,
Enrico
PS: If someone is interested I still have 4 sets of PCBs
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I have no numbers to give you but the pot work very well and as expected... completely mute at full attenuation and increase gently. Normal and quite loud listening pot position (at least for me) at 11 o'clock. I can't go up more than to 2 o'clock leaving in a building
is it? It harks back to the "no limiting" of gain.
And if there is excessive gain, then one finds one cannot use the top end of the vol pot rotation.
And the poster confirmed that with 2o'clock being above comfortable.
Whereas, if gain is limited to a usable maximum value, then one should find that lower level signals from a source can use the max vol pot rotation and only just reach clipping of the receiver. Unfortunately high level signals from a higher source component will still need the vol pot to be backed off to avoid clipping. That too could be overcome by having a sensitivty adjustment, not unknown.
And if there is excessive gain, then one finds one cannot use the top end of the vol pot rotation.
And the poster confirmed that with 2o'clock being above comfortable.
Whereas, if gain is limited to a usable maximum value, then one should find that lower level signals from a source can use the max vol pot rotation and only just reach clipping of the receiver. Unfortunately high level signals from a higher source component will still need the vol pot to be backed off to avoid clipping. That too could be overcome by having a sensitivty adjustment, not unknown.
And this is a problem because? Or does it offend some sensibility that you have
So? Same with my current B1 on all sources bar 1.
With +18dBm max output the preamp is not likely to be the thing clipping. I really don't understand your hang up here. Or are you just OCD about your gain structure?
I organized a GB in a different forum, and we had 42 PCB's made. I myself am just about to build my third sample, this time with a relay-switched volume attenuator.
Can with pleasure fully confirm the very high objective and subjective performance of the design.
The original volume control with the pot in the NFB path does indeed produce a problem at the maximum CW rotation point. The gain at this pot position is extremely high and can cause a terrible shock to the loudspeakers (I got burned with my first sample).
The recommendation in the GB project was to mechanically limit the farthest position of the pot near the end of CW rotation.
Regards,
Braca
Can with pleasure fully confirm the very high objective and subjective performance of the design.
The original volume control with the pot in the NFB path does indeed produce a problem at the maximum CW rotation point. The gain at this pot position is extremely high and can cause a terrible shock to the loudspeakers (I got burned with my first sample).
The recommendation in the GB project was to mechanically limit the farthest position of the pot near the end of CW rotation.
Regards,
Braca
And here's a photo of one populated board. MELF's where needed etc.
An externally hosted image should be here but it was not working when we last tested it.
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