API 312 Thread!

[tmuikku]

Hi, they are the normal KK type. I think 0.1" (2.54mm).

About pitch, you say in general, you mean for this board, or for any board? I'm not sure if the image I posted is 1:1 scale. I will check. If so, then just print and measure. Or I could check my files and post pitch here (I assume for the electrolytic caps, right?).

EDIT:
cap pitch is mostly 5mm. All the wimas, the lytic in the gain adj circuit, the output lytic (might be 5.5mm, I'm measuring with a ruler atm), and the feedback cap.
The exception to the rule are the power filtering caps which are 3.5 or 4mm. It will for sure fit 100-150uF 35V PAnasonic NHG, FC, or FM caps. You could use smaller caps as well (47uF is probably fine) and 100 is a nice average.

Hope that answers your question!

Thanks! Yes I ment with any project. I don't own a printer so didn't event think about using a ruler Cap pitch seems to be good reference for eye inspection.

 

[ilfungo]

sorry where I can find 312 PCB?
Thanks

 

[bobschwenkler]

sorry where I can find 312 PCB?
Thanks

Which one?

 

[ilfungo]

This!
thanks

 

[bobschwenkler]

The link in my signature.

 

[mac]

Hey guys,
I have four of mitsos boards on the way and am assembling parts. I am struggling to find bipolar panasonic FC's locally. Does anyone have Farnell codes for the 330uf and 470uf bipolar caps?


cheers,
Mac

 

[mitsos]

Hi Mac,
Panasonic's nice bipolar ones are the SU line (added this info to BOM), they are a sort of purplish color, and available at Digikey and TAW (TAW should have all the caps for this board, btw, give Laura a call).  TAW doesn't normally stock the 330uF (you could easily use the normally stocked 220uF with the BOM values I posted, the difference will be very near nothing) but Laura was kind enough to order some 330uF for me and they may still have some in stock since I didn't buy all 200 they ordered. If they still have them, that's your best bet, they ship all over the place.

Farnell does carry them, but I could only find up to 100uF.  You could also use Nichicon Muse SE (the lime green ones) in these spots, but I don't know many places that carry them (www.hndme.com has them but I've never ordered from them). I've never tried the Nichicons but I checked the datasheets when I made the PCBs to make sure they'd fit because people seem to think they are really good.  In all reality any bipolar will work, but you should use the best you can find. The Panasonics and Nichicons are top quality, and should mostly be clean, especially with the 0.1uF MKP in parallel. 

All in all, you have many options, (including polarized caps) and these caps should arguably have an effect on sound, so you could try different things and see what you like best. I always planned on sticking sockets on the cap places and playing around with different caps, but who's got the time?

Keep in mind that the cap in the gain circuit will depend on the pot you use, because it will dictate the feedback R and C, and shunt R. These values will work fine if you are using a 22K-25K pot. For a great discussion on this and calculations by Bo and Harpo see this thread:

http://www.groupdiy.com/index.php?topic=26948.0

hope that helps!

 

[mac]

Thanks Mitsos - awesome info. I will see how I go. I have been trying to order from farnell and RS a bit lately (as they offer free shipping in Oz).

Otherwise I will probably send Laura an email.

cheers, mac.

 

[mrcase]

hey all!
I´m in the process of sourcing parts for mitsos 312 boards and got some newbie questions...
I`m going with eds transformers (EA2622 and EA2503).
So do I need the 1000pf  RF filter caps and if yes should they be also silver mica or styrene or C0G (what would you recommend)?
will I need the zobel cap and R and where to source?
would I be cool with 90K as an input load resistor?

thank you!
regards, martin

 

[tmuikku]

hey all!
I´m in the process of sourcing parts for mitsos 312 boards and got some newbie questions...
I`m going with eds transformers (EA2622 and EA2503).
So do I need the 1000pf  RF filter caps and if yes should they be also silver mica or styrene or C0G (what would you recommend)?
will I need the zobel cap and R and where to source?
would I be cool with 90K as an input load resistor?

thank you!
regards, martin

Hi Martin!

I just ordered most of the parts from Mouser. Shipping is free to most countries when ordering more than 100$ worth (75€). I've got eds transformers too. For zobel and filter caps check out how Jeff (http://classicapi.com/catalog/product_info.php?cPath=22_47_55_91_93&products_id=158) does it in his VP312 and what parts are used

 

[mac]

Is my computer on drugs or do you two guys have the same avatar???

Mc 

 

[tmuikku]

Hehe, yes it is the same. Good ol F Mercury If I remember there was some avatars to choose from and I had mustache when I joined the forum so this avatar suited me most

 

[mrcase]

hehe! yeah, same same!
hey tmuikku, thanks for the tips. gonna look that through.

 

[Cosmonaut]

Hi all!

one rapid question:

Where to buy the omeg 22k pot in europe?

I don't find it in digikey or farnell...

 

[mitsos]

direct at:  www.omeg.co.uk

They have minimum 10 quantity I think.  If you are going to mount them on board, get the ECO series, PC16ECO I believe, and you can get the mounting brackets separately as well.  Don't forget it's 22K REV LOG.  They make 4mm, 6mm and 6.35 (1/4") shafts, I believe. I got 4mm which is a bit larger than 1/8". I got a few 4mm Sifam knobs I plan on using for 4-8ch builds that are more compact, but I also have some 1/8" knobs which just require slight drilling to make them 4mm knobs. That's what I plan on doing for the classicapi knobs.  Get the longest shaft available as they are plastic and easily cuttable.

 

[Cosmonaut]

Thanks a lot Mitsos!

 

[statzern]

Hey guys - just started reading this thread... haha and my 312s are pretty much done. I have sound. The only problem is that I'm not getting any gain. When I turn the switch, it never gets louder or quieter. Possibly a short on the teeny switch pins?

Will check/reflow solder soon.

Anyone else ever have this issue?

 

[mitsos]

What PCBs are you using? Is the sound clean? Check the gain pot's path to ground through the series R.  Also double check the feedback R.

 

[statzern]

Hey Mitsos, thanks for the response.

I'm using Schwenkler's PCBs. I will report back as soon as I get a chance to check. Stuck at work for the moment

 

[mitsos]

How critical is the 18pF value on Fabio's 312 board DI? I have one channel that, with a guitar inserted and MAX gain (not a very useable setting but anyway) SQUEALS like a banshee. I've swapped DI boards between 2 identical channels and the symptom follows the DI board. Swapped everything on the DI board but the 18pF cap because I have none atm. (Well, also did not swap the plug, but I did clean it in case that was the issue).  At lower than absolute max gain, the DI works fine.

The DI stops doing this if I remove/jumper the 18pF/2M2 RC thing, so that is why I think it is the cap. If anything, I guess I'll try a 27-33 pF cuz I saw some of those lying around.  But if you guys have some insight, please let me know!

thanks!

EDIT: Found a 22pF cap, popped it in, no change, the DI is still howling at me at max gain. ???