CK2III: dropped in

[fillemon]

hello people, i just bought a CK2III;
well actually i had bought 3 pcb some time ago in the groupbuy, but somehow they all got lost in moving from one house to another. they have to be somewhere, but i cannot wait for that any longer

i ordered a kit with jeff rossel, which has all the parts, very nice. but still i have to order some parts for other projects to. So here is my question.

i wanna upgrade it immediatly. so what can i do ?

1)the panasonics: i have still lying around a fm istead of fc for 1000 and 220. i don't expect to happen much but i'm gonna trow it in.

2)i will put as much as possible epcos polypropylene caps in the circuit, and removign the bipolar cap, i will have to alter the resistor from 300k to 3m.

3)but then : does it make an difference if i put mur820 instead of 1n4004 ? i will put film caps over it, no matter what diode i choose

4)and last but not least output stage. at this moment i think i'm gonna stuck with a 2sc2238 and 2sa968. but on an akg 500 it maybe a bit to bass shy ?

thanx a lot.
i will take pictures soon, but at the moment i'm waiting for some decent tools to get started, my temperature 70watt hakko iron is already here, but not the 37/63 solder. so i'm waiting , until then i populate the board with parts haha. the resistors are already there.

greetings

 

[TzeYang]

1)Sure thing, but i believe there won't be much difference.
3) Why film caps? Those don't work as good as ceramics at high frequencies. You should stick with ceramics.
4) doesnt hurt to try other alternatives such as BD139/BD140/MJE253/MJE243. Oh and in my experience, the BD138/BD137s are really full of bass

 

[d-cee]

where'd you get the CK2III kit? don't see it on glassjaraudio.com

 

[bearmann]

Hi d-cee,
have a look at Jeff's geocities webpage .... right here.

best regards,
bearmann

 

[fillemon]

hello thanx for the replies,


acout the caps, i didn't know that. i thought that film caps performed better, at the site of amb there are a lot of builders and 90% build them with film caps, well i have to read about that. but why would we need high frequency ? it is not that we are in the m-hertz region like with smps.

wel it is not that i want plenty of bass. What i certainly don't wanna loose is very good mids and high, but thanx a lot, i will try to find some lecture on those types;

indeed that is a good page: but jeff got it all, if you email him, he'll get back to you with a nice .xls file where everything is in it. So he carries the complete amb line. (at least that's what i think, i emaild him on a sigma11, that wasn't on his site, nor in the geocities, but he has it)

greetings and thanx

 

[tomb]

I took it that you were referring to the bipolars spec'd for shunting the DC servo opamp. In that case, film caps are generally better because they will do the same thing as bipolar electrolytics, but sound better - since these can be considered in the signal path.

Ceramics are out of the question in the signal path and will sound awful.

 

[fillemon]

thanx tomb, i have chosen for epcos film caps, the complete CK2III, it is so cheap that i don't even wanna "think" about it. off course if you wanna use roederstein MKV, then it would cost quite a lot of money. i took epcos polypropylene.

i thought that even the bipolars were not in the signal path ? but still everone replaced them.

beside that, i have a bunch of uf4007 fast rectifiers lying around, i can drop them in ? in stead of the 1n400X ? i thought about mur820, but that's a serious overkill for the amp (8a) and the wallet. uf4007 is fast, but not soft recovery i thouhgt, still the cap makes it up (at least that's what i think). Am i right on this ?

thanx a lot

 

[TzeYang]

Quote:

Originally Posted by fillemon /img/forum/go_quote.gif hello thanx for the replies, acout the caps, i didn't know that. i thought that film caps performed better, at the site of amb there are a lot of builders and 90% build them with film caps, well i have to read about that. but why would we need high frequency ? it is not that we are in the m-hertz region like with smps. wel it is not that i want plenty of bass. What i certainly don't wanna loose is very good mids and high, but thanx a lot, i will try to find some lecture on those types; indeed that is a good page: but jeff got it all, if you email him, he'll get back to you with a nice .xls file where everything is in it. So he carries the complete amb line. (at least that's what i think, i emaild him on a sigma11, that wasn't on his site, nor in the geocities, but he has it) greetings and thanx

"3)but then : does it make an difference if i put mur820 instead of 1n4004 ? i will put film caps over it, no matter what diode i choose"

I read this over and over again and still don't think that you should use film caps for your diodes. Ceramics are better for this application when it involves suppressing the high frequency switching noise.

Oh and tomb is also right. But he's talking about film caps in other positions, which i do agree.

However, do remember that caps are all about stability, frequency, size and linearity. You should pick them properly accordingly to the application needed.

 

[tomb]

Quote:

Originally Posted by TzeYang /img/forum/go_quote.gif "3)but then : does it make an difference if i put mur820 instead of 1n4004 ? i will put film caps over it, no matter what diode i choose" I read this over and over again and still don't think that you should use film caps for your diodes. Ceramics are better for this application when it involves suppressing the high frequency switching noise. Oh and tomb is also right. But he's talking about film caps in other positions, which i do agree. However, do remember that caps are all about stability, frequency, size and linearity. You should pick them properly accordingly to the application needed.

Yes - it appears we are talking two different things.

I agree completely with TzeYang that ceramics are best to "snub" the high frequencies around the rectifiers.

I thought the film caps were being questioned in regard to replacing the bipolars around the DC servo opamp.

 

[fillemon]

thanx guys for pointing that out to me. you are right, i just red somehting about it, but sometimes i need to get it stated twice;

strange that i have seen film caps all over the place even in the snubber circuit. or do there exist ceramic caps which look like a boxed cap ? i never seen one.

i don't know how familiar you are with the CK²III design, but i wanne put film caps everywhere exept on the diode rectification. is that okee ? or

what do you think about the diodes?

thanx guys

 

[applevalleyjoe]

Quote:

Originally Posted by bearmann /img/forum/go_quote.gif Hi d-cee, have a look at Jeff's geocities webpage .... right here. best regards, bearmann

Thanks Bearmann, this was helpful!

 

[d-cee]

Quote:

Originally Posted by bearmann /img/forum/go_quote.gif Hi d-cee, have a look at Jeff's geocities webpage .... right here. best regards, bearmann

Quote:

Originally Posted by applevalleyjoe /img/forum/go_quote.gif Thanks Bearmann, this was helpful!

yeah thanks! that's awesome

I've always wanted to build a CK2III and M3

edit: and a millet max!

 

[bearmann]

Quote:

Originally Posted by applevalleyjoe /img/forum/go_quote.gif Thanks Bearmann, this was helpful!

Quote:

Originally Posted by d-cee /img/forum/go_quote.gif yeah thanks! that's awesome

You're welcome.

Took myself quite some time till I found his second page...
Next time I'll probably order a SOHA-kit from Jeff. Nice amp and very decent kit from him, I think...

best regards,
bearmann

 

[ezzo]

Sorry to 'jack' this thread.
I have a Ck2III waiting to be built but I still have some parts to consider about, the output transistors.
I have read using the MJs gives more bass, but it is more of a 2nd/3rd hand comment and probably not reliable

Can anyone comment on the difference between the BD139/BD140 vs MJE253/MJE243?
Thanks!

 

[tomb]

BD139/140's have a reputation for being thin and bright.