The 0,1% MELF can still be used in the actual PCB but you have solder them manually and with a bit of attention.
Look in my post 67 where I list the details for the correct BOM and few pictures including the SMD resistors soldered.
I am using this preampli for a while now and I am really really happy about...
Look in my post 67 where I list the details for the correct BOM and few pictures including the SMD resistors soldered.
I am using this preampli for a while now and I am really really happy about...
I have just posted this on the build/discussion thread, where Jan Didden and Hans Polak have both built modules.
@ Jan Didden + Hans Polak.
Hi guys, the group buy for these boards has taken on new momentum with a change of CEO Bertel has handed over the reins to tfboy.
There appears to be some discrepancy over the resistors to be used.
Apparently the PCB pad spacing is set for 1% SMD but is has been said that 0.1% MELF
resistors are essential.
Which did you guys use and is there a workaround.
Many thanks for your input.
http://www.diyaudio.com/forums/anal...eamp-well-balanced-volume-control-really.html
@ Jan Didden + Hans Polak.
Hi guys, the group buy for these boards has taken on new momentum with a change of CEO Bertel has handed over the reins to tfboy.
There appears to be some discrepancy over the resistors to be used.
Apparently the PCB pad spacing is set for 1% SMD but is has been said that 0.1% MELF
resistors are essential.
Which did you guys use and is there a workaround.
Many thanks for your input.
http://www.diyaudio.com/forums/anal...eamp-well-balanced-volume-control-really.html
I believe there should be no problem using 0805 parts as specified on the original article.
The BOM proposed at the beginning of the thread includes not compatible parts as emyeuoi has painfully found out.
Why not use low ppm resistor parts from the susumu 0805 range in 0.05 tolerance? disipation?
Capacitors as suggested by emyeuoi.
The question of LM4562 vs TL072 for dc servo also remains to be solved...
Glad to see some movement around here!
The BOM proposed at the beginning of the thread includes not compatible parts as emyeuoi has painfully found out.
Why not use low ppm resistor parts from the susumu 0805 range in 0.05 tolerance? disipation?
Capacitors as suggested by emyeuoi.
The question of LM4562 vs TL072 for dc servo also remains to be solved...
Glad to see some movement around here!
Well actually I haven't followed all that 'has been said' but I do know that Bruno wrote several pages describing his project. Surely the answers are in that article?
... and you may have missed this: http://www.edn.com/design/consumer/...oject---A-balanced-volume-controller#comments
Jan
Last edited:
1% smd and 0.1% smd resistors have the same pads.
It's whether melf, or thin film, are equivalent.
Why were melf originally specified?
What parameter do melf have that makes them irreplaceable?
1% and 0.1% might have the same sizing, I think the issue is that the available 0.1% at the proposed vendor do not.
Obviously 0.1% is the spec and that need sot be maintianed.
Obviously 0.1% is the spec and that need sot be maintianed.
no the spec is 'precision thin film'. This could mean any number of things. But 0805 in 0.1 0.05 or 0.01% should be readily available anywhere. No need for MELF unless you think Bruno got it wrong.
We will all come and join you in Alicante.
When we have finished our preamps..
I also had the same problem on the Linear site..
When we have finished our preamps..
I also had the same problem on the Linear site..
OK Chaps,
I need some clarification here.
I had initially sent the generic BOM from the article (I painstakingly put the graphic it into Excel). They quoted against this.
I then sent them an email last night saying basically "sorry, I now have a more specific BOM with specific part numbers. Can you please quote against these parts".
They haven't got back to me yet, but I really need a final, approved BOM, whether it contains specific parts or not (any standard 1% will do, 0.1% for precision, no need for melfs or anything else fancy).
I cannot go back to the lab every other day changing the BOM against which they are researching and getting specific pricing. I want to help out with this, but I'm not prepared to ruin any possible future relationship with these people if I appear to change my mind all the time!
So can we please have a complete, approved, detailed where necessary BOM so I can give them a final BOM against which everyone is happy.
Thanks 🙂
I need some clarification here.
I had initially sent the generic BOM from the article (I painstakingly put the graphic it into Excel). They quoted against this.
I then sent them an email last night saying basically "sorry, I now have a more specific BOM with specific part numbers. Can you please quote against these parts".
They haven't got back to me yet, but I really need a final, approved BOM, whether it contains specific parts or not (any standard 1% will do, 0.1% for precision, no need for melfs or anything else fancy).
I cannot go back to the lab every other day changing the BOM against which they are researching and getting specific pricing. I want to help out with this, but I'm not prepared to ruin any possible future relationship with these people if I appear to change my mind all the time!
So can we please have a complete, approved, detailed where necessary BOM so I can give them a final BOM against which everyone is happy.
Thanks 🙂
Do we really need to use 1/5 watt resistors for this preamplifier? If not, there's always the nice Susumu 0805 resistors which are available in 1/8 watt with 0.1% tolerance and 25ppm or 10ppm and price is really affordable...
Here's a few examples
RG2012P-473-B-T5 Susumu | Mouser
RG2012N-473-B-T5 Susumu | Mouser
Thanks
Do
Here's a few examples
RG2012P-473-B-T5 Susumu | Mouser
RG2012N-473-B-T5 Susumu | Mouser
Thanks
Do
Otherwise there's a whole bunch of them in the 0.1% <=25PPM in 1/5W or 1/4W but a bit more expensive...
0.1 % 0805 Thin Film Resistors - SMD | Mouser
Worry not. As soon as we can get hold of the Farnell BOM we can X-check and mutis mutandis have you a final BOM for the supplier.
So it is Paul Hendriks interpretation but not a Bruno made BOM that the link above point to?
It says melf.
//
Linear Audio BOM attached for those who had access problems....
It says melf.
//
Linear Audio BOM attached for those who had access problems....
Attachments
Last edited:
Bruno quoted resistor matching as a critical requirement for the design so I would say 0.1 % is the minimum required.
Though human nature dictates that others will think differently.
I suspect we may need one batch of bare pcbs and one with pre soldered resistors.
How to achieve 'majority decision' resistor brand/tolerence ?
Bruno also states that the spec. sheet for resistors only inform you how far they deviate from Ohms law and that no resistor follows Ohms law perfectly.
I think maybe ask the board vendor which brands of resistors his preferred supplier/s can offer at 0.1%.
- Status
- Not open for further replies.