Morning, all.
I'm thinking about modifying a Sony WM-DC2 Pro walkman. There are eight 1uF tantalum coupling caps in each channel, which I would like to replace with something that causes less distortion (going by what Cyril Bateman wrote in his series of articles on cap distortion in Electronics World a while back). Trouble is, I'm very, very limited in terms of space inside the walkman, and 5mm dia x 5mm high electrolytics are just a bit too big. Does anyone know of any alternatives which are smaller? The voltage rating on the cap doesn't need to be more than about 6V-9V (if that, actually. I might be able to get away with 4V).
I had a look at Panasonic's specialty polymer SMD caps, but I couldn't find any in a 1uF capacity. Any suggestions greatly appreciated.
Cheers, Jon.
I'm thinking about modifying a Sony WM-DC2 Pro walkman. There are eight 1uF tantalum coupling caps in each channel, which I would like to replace with something that causes less distortion (going by what Cyril Bateman wrote in his series of articles on cap distortion in Electronics World a while back). Trouble is, I'm very, very limited in terms of space inside the walkman, and 5mm dia x 5mm high electrolytics are just a bit too big. Does anyone know of any alternatives which are smaller? The voltage rating on the cap doesn't need to be more than about 6V-9V (if that, actually. I might be able to get away with 4V).
I had a look at Panasonic's specialty polymer SMD caps, but I couldn't find any in a 1uF capacity. Any suggestions greatly appreciated.
Cheers, Jon.
afaik, there's no ceramic cap up to 1uf
tantalum is what he wants to get rid of
if electrolytics are too big, film caps are the only choice left
and metalized polyester (MKS) has the higher capacity/space ratio
so if there's no 1uF MKS cap that fits...
use a smaller value (1uF seems high for a line level AC coupling, and low for a 32R headphone coupling)
keep your tantalums
direct couple if you can (or change the topology to be able to direct couple)
tantalum is what he wants to get rid of
if electrolytics are too big, film caps are the only choice left
and metalized polyester (MKS) has the higher capacity/space ratio
so if there's no 1uF MKS cap that fits...
use a smaller value (1uF seems high for a line level AC coupling, and low for a 32R headphone coupling)
keep your tantalums
direct couple if you can (or change the topology to be able to direct couple)
There ARE ceramic caps that big, but if anything they will have much worse shock noise figures and would be a poor choice for a walkman.
You might consider aluminum/organic polymer caps; they might not be as good as film but they are probably superior to tantalum, and are easily available in large sizes.
You might consider aluminum/organic polymer caps; they might not be as good as film but they are probably superior to tantalum, and are easily available in large sizes.
Look at the Blackgate PK and N or NX HiQ types. The smallest are 4 by 7 mm.
A bit pricy but perhaps they fit.
Rob
http://www.partsconnexion.com/catalog/CapacitorsElectrolytic.html
A bit pricy but perhaps they fit.
Rob
http://www.partsconnexion.com/catalog/CapacitorsElectrolytic.html
digikey carries panasonic smt film caps
they have a "submicron" ECP-U series with 1 uF 10,16V in 1206,1210 smt packages
http://industrial.panasonic.com/ww/i_e/26550/technical_e/technical_e/ecpupoint.pdf
I think this is PEN (mylar?), not the best film but miles ahead of any electro or hi K ceramic - these are probably a little worse than typical 50/100 V polyester caps
I would use the higher V 1210 part
they're small enough the truly obsessive could parallel/series them for lower V stress (and presumably, lower distortion) - for coupling just paralleling a few would drop the corner freq and might be worthwhile
they have a "submicron" ECP-U series with 1 uF 10,16V in 1206,1210 smt packages
http://industrial.panasonic.com/ww/i_e/26550/technical_e/technical_e/ecpupoint.pdf
I think this is PEN (mylar?), not the best film but miles ahead of any electro or hi K ceramic - these are probably a little worse than typical 50/100 V polyester caps
I would use the higher V 1210 part
they're small enough the truly obsessive could parallel/series them for lower V stress (and presumably, lower distortion) - for coupling just paralleling a few would drop the corner freq and might be worthwhile
Many thanks for all the informative replies. I'll check out the link to the Panasonic caps.
I don't know what the distortion is with the tantalum caps - I was just thinking of trying to use cap types which, according to Cyril Bateman's articles, would produce less distortion. Maybe I've got too much time on my hands... OTOH, I do like my DC2.
I'd probably struggle to direct couple the existing circuitry, because of lack of sufficient electronics knowledge, lack of space, and only a single supply rail. I had thought about pulling out all the existing circuitry bar the motor controller and starting from scratch with someone else's tape head and headphone amp, but life's (probably) too short.
Cheers, Jon.
I don't know what the distortion is with the tantalum caps - I was just thinking of trying to use cap types which, according to Cyril Bateman's articles, would produce less distortion. Maybe I've got too much time on my hands... OTOH, I do like my DC2.
I'd probably struggle to direct couple the existing circuitry, because of lack of sufficient electronics knowledge, lack of space, and only a single supply rail. I had thought about pulling out all the existing circuitry bar the motor controller and starting from scratch with someone else's tape head and headphone amp, but life's (probably) too short.
Cheers, Jon.
Mmmm, those Panasonics seem very promising. I've had a quick look on google.co.uk for suppliers, and the only people I've been able to find in the UK are Flint (who sell by the reel from what I can see). Is it a case of trying to persuade them to part with some samples? If so, how many do you think I should ask for to make it look plausible (I've never tried going the free-sample route). Of course, if anyone knows of a supplier who will take small order quantities, preferably in the UK, I'm happy to cough up some cash.
Cheers, Jon.
Cheers, Jon.
jcx said:
PEN is a close cousin of PET --
PEN is polyethylene napthalate, PET is polyethylene terephthalate
I have some polyphenylene sulfide surface mount devices in 100nF, I think that Panasonic ECG in the 2825 package go up to about 0.22uF
sidebar -- if they can ever make PEN cheaply it will be the end of glass bottles!!
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.