DIY Front End 2022

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Citation19

Citation19

Member
Joined 2020
derekr said:
The 3.3uF WIMA's in Pa's BOM (here) are non-stock at Mouser - in fact their part number isn't even 'Assigned' so the WIMA's must clearly be from the authentic OPL Non-Disposable Facility. However, Digikey have one or two that might fit - lead spacing appears to be the same 10mm on both.
Click to expand...
Your 100% correct on this....and I just pulled the trigger on some slightly too large ones.... I guess this is how I get extra parts. I think lead spacing is 15mms though, double check me (PCM15)
 
stonegreen

stonegreen

Member
Joined 2020
Hi Dirk,
was the offset adjusted via R6 with a trimmer?

R6.jpg


Can you please measure the voltage across R7 and R8 and tell us.

thanks
 
EUVL

EUVL

Member
Joined 2003
xen-audio.com
Again, bear in mind J113 is rated at 35V maximum Vds.
The frontend will have no issues.
The current source at the output will exceed that at full swing if you use say +/-20V rails.
It is like most opamps, +/-18V would be fine.

But of course, no risk no fun, right ?
Just make sure you have speaker protection.

And if you can ge genuine NXP J113s, you are good to 40V.


Patrick
 
D

derekr

Member
Joined 2009
cubicincher said:
Hello members,
you can use the search engine 'octopart'. https://octopart.com/search?q=wima+3,3+uF&currency=USD&specs=0
But WIMAs with 15 mm lead spacing seem to be rare at the moment- also in Germany (WIMA is a german company in Aurich).
Cheers
Dirk :yes:
Click to expand...

Re the PCM lead spacing: maybe Jim can confirm…there are two sizes listed on the data sheet with 10mm and 15mm PCM so we need to know what the board accepts. I assumed 10mm spacing and the 6x13mm size but it could be the larger of the two 63VDC sizes listed which indeed has 15mm spacing so we need someone with the board to let us know.
 
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D

derekr

Member
Joined 2009
If it’s the bigger 7x18mm cap with 15mm lead spacing and you want to use WIMA then the Digikey number is this and they have 2500 in stock via the Marketplace.

Mouser don’t appear to stock it and Octopart shows some alternate suppliers although, interestingly, they don’t list the one quoted by Digikey as their Marketplace supplier, TAW Electronics - who are, according to their website, the first US distributor for WIMA and 100% woman-owned. With Digikey quoting TAW stock of 2500 wonder why they aren’t listed by Octopart?
 
B

BATE VANKO

Member
Joined 2013
Paid Member
Hi Everyone,
The police files indicate that ''MKS4 3.3/63/10 PCM15'' is an alias for ''Mouser#: 505-MKS4C043304DKSSD'':):
https://www.mouser.com/ProductDetail/WIMA/MKS4-3.3-63-10-PCM-15?qs=QvDlfNMtgEW7Nagn6BRtoQ==
https://www.mouser.com/ProductDetail/WIMA/MKS4C043304D00KSSD?qs=2G4irm/qADwK20hDuRAEAw==
https://www.wima.de/wp-content/uploads/media/e_WIMA_MKS_4.pdf
BUT....the same problem occurred concerning the availability. Non-Stocked. 4.7Uf-will it be a problem? 4.7Uf have the same package/case:
18mm x 7mm x 14mm
lead spasing - 15mm
 
D

derekr

Member
Joined 2009
BATE VANKO said:
Hi Everyone,
The police files indicate that ''MKS4 3.3/63/10 PCM15'' is an alias for ''Mouser#: 505-MKS4C043304DKSSD'':):
https://www.mouser.com/ProductDetail/WIMA/MKS4-3.3-63-10-PCM-15?qs=QvDlfNMtgEW7Nagn6BRtoQ==
https://www.mouser.com/ProductDetail/WIMA/MKS4C043304D00KSSD?qs=2G4irm/qADwK20hDuRAEAw==
https://www.wima.de/wp-content/uploads/media/e_WIMA_MKS_4.pdf
BUT....the same problem occurred concerning the availability. Non-Stocked. 4.7Uf-will it be a problem? 4.7Uf have the same package/case:
18mm x 7mm x 14mm
lead spasing - 15mm
Click to expand...

Note that the description for the cap NP quoted in his BOM and which you link to in your first Mouser link does not specify a lead spacing.

It is available, like NP’s BOM implies ‘10P15’, or in two different lead spacings and sizes in the 63VDC model. So, for those who choose to buy the Store kit, before orders are made for the parts that will not be supplied in the Store’s ‘essentials’ kit we need someone with one of the boards that are going to be sold in the Store to confirm which lead spacing applies. Once we know that we can knock ourselves out with WIMA, Panasonic, TDK or whatever is available in our favourite emporium.

All that said, if you HAVE to order before confirmation, a rough onscreen measurement of the lead spacing of the C4 or C5 cap shown in NP’s document in the first post (whose data sheet shows a 5mm lead spacing) can be compared to the lead spacing for the specified WIMAs - and seems to indicate the wider, 15mm, spacing is correct. So my 10mm Digikey part number quoted above is probably wrong and the follow-up link to the 15mm PCM part is probably more accurate. Apologies for any confusion.
 
C

cubicincher

Member
Joined 2016
Hello wwwtttwww,

value of R6 is 1.8 kOhm in parallel with trimpot (2,2kOhm) adjusted to an overallresistance of very lowish 54,5 Ohm ( measured in the circuit over R6 with the FLUKE!)
R7 = 330 Ohm ; measured voltage over R7 = 1,053 V (so U/R= I = 0,0032 A or 3,2 mA). I think I should lower R7 to increase the current of the CCS (Q3)?
R8 = 100 Ohm ; measured voltage over R8 = 0,707 V.
I don't remember the Idss. Have to look in those plenty of papers with projects laying around... I only remeber the Vgs off was at -1.59 to -1,61 V for all 8 JFets.
Voltages over R11 = 19,47V and over R12 = 19.5 V.
Cheers
Dirk
 
Zen Mod

Zen Mod

Official Court Jester
Joined 2003
zenmod.in.rs/
Paid Member
cubicincher said:
Hello wwwtttwww,

value of R6 is 1.8 kOhm in parallel with trimpot (2,2kOhm) adjusted to an overallresistance of very lowish 54,5 Ohm ( measured in the circuit over R6 with the FLUKE!)
R7 = 330 Ohm ; measured voltage over R7 = 1,053 V (so U/R= I = 0,0032 A or 3,2 mA). I think I should lower R7 to increase the current of the CCS (Q3)?
R8 = 100 Ohm ; measured voltage over R8 = 0,707 V.
I don't remember the Idss. Have to look in those plenty of papers with projects laying around... I only remeber the Vgs off was at -1.59 to -1,61 V for all 8 JFets.
Voltages over R11 = 19,47V and over R12 = 19.5 V.
Cheers
Dirk
Click to expand...

I've told ya
vary R7, leave R6 original

you're keeping OLG, thus NFB, thus CLG where Pa wanted it ....... and having it same for both channels
 
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