[fillemon]

hello people,

i'm building my ck2III, and got a kit from jeff. still i'm waiting for some parts.
but i have found 3 CK2III boards from the groupbuy, finally i found them. Well now i'm thinking on going balanced;
(i thought of going with a beta22, but that is a bit more expensive)

i have searched a lot already, but didn't find anyhting which i could do something with.
so here i go;

1)does my source has to be absolute balanced? i have a coax dac (monica) ? if so i need another dac : something like an opus ?

2)did someone build an ck2III balanced ?
what about the matching, i know amb delivers match parts for a stereo board, but i might think that now it needs to be matched over the two boards ?

thanx people, i'l just wait for the answers before asking more.

greetings fillemon

 

[holland]

1) No, but it kind of defeats the purpose otherwise. Re: DAC, or you can build your own. Of the better DACs that I know of, they have balanced out from the DAC chip with a balanced to single ended conversion done later.

2) Yes. Check the gallery at http://www.amb.org/audio/ck2/

I have read of other balanced ck2IIIs in progress or completed as well.

 

[ericj]

you can build a balanced line driver out of a quad opamp (or a couple duals (or four singles)) if you need to feed it from a single-ended source.

you can even buy a board from digi01 for that if you want.

 

[fillemon]

aha, thanx a lot.

so i have to rebuild my dac first. or just buy a new one.
well just for the knowledge. i have a monica dac, i want to build the SS i/V stage, i will first look if that is possible and how to convert the tda1545 dac into a balanced one.
then i'll be back.

but if someone is using a balanced ck2III please let us know how it does, and if there are any complications involved.

thanx
greetings fillemon

 

[Epicurean]

Quote:

Originally Posted by fillemon /img/forum/go_quote.gif but if someone is using a balanced ck2III please let us know how it does, and if there are any complications involved.

I had a balanced CK2III for a few months but I decided I actually prefer my PPAv2 with my HD650s so I'm taking it apart and building two single ended ones instead(easy since I fortunately never got a case for it). In any case my source (a Zapfiltered Zhaolu 2.0) has enough voltage swing to drive my balanced HD650s directly to ear-splitting volume so I'm trying various buffers to get away with less parts in the signal path. So far I've tried using a single bjt biased at 100mA with excellent results and I'm going to try with some diamond buffers as soon as I get my parts. So in short the balanced CK2III didn't quite live up to balanced hype IMO but the CK2III is a great amp nonetheless.

edit: Oh, and setting the two boards for balanced drive was very straightforward. One board for the left channel and the other for the right channel. Both boards shared a 40VA toroidal transformer and I used a Joshua Tree attenuator from Twistedpearaudio for volumecontrol. The parts used for the CK2IIIs were pretty much the recommended parts on Ambs site except I used Toshiba 2sc4793 and 2sa1837 for output transistors.

 

[fillemon]

well Epicurean, thanx a lot for that explanation.
i was thinking about ordering some parts for the second board, but i'm just gonna wait a little bit. also my dac isn't balanced. so that would take a bit of working out. still i'm quite interested in it. still i'm a bit afraid, having akg headphones with the ck2III could be a bit to bright, i have put 2sa968 and 2sc2238 on it. i'll have a look at yours to.

thanx a lot
but i have seen that there are a few people out there who have just ordered or finished their balanced ck2III.
let's see what they have to say.

greetings

 

[MASantos]

I was in the process of starting a balanced CK2 for another member and also a balanced OPUS DAC.

As it has been said, it's pretty straightforward, use amb', wiring and ground schemes in the Beta22 section if you need some guidance on how to wire everything together. You'll need a four gang pot. the cheapper way to go is a quad RK27, search ebay for member familygate. he's from germany and has them all the time. YOu can go with a stepped attenuator but it will set you back at around 250$ almost as much as the boards+parts.

As for the OPUS DAC, if you build it with just one of the input modules(either USB or SPDIF) it will go for around 200$ or the boards and trafo, and you can get a cheap case for it and connectors probably around 30-50$.

If you decide to go awead with it, make sure you post pictures.

 

[fillemon]

thanx a lot masantos,

if i go ahead with it, i will certainly post pictures.
just got my cases in from hifi 2000, when i got all the material, i'll just take some pictures;

greetings

 

[Edwood]

Quote:

Originally Posted by MASantos /img/forum/go_quote.gif I was in the process of starting a balanced CK2 for another member and also a balanced OPUS DAC. As it has been said, it's pretty straightforward, use amb', wiring and ground schemes in the Beta22 section if you need some guidance on how to wire everything together. You'll need a four gang pot. the cheapper way to go is a quad RK27, search ebay for member familygate. he's from germany and has them all the time. YOu can go with a stepped attenuator but it will set you back at around 250$ almost as much as the boards+parts. As for the OPUS DAC, if you build it with just one of the input modules(either USB or SPDIF) it will go for around 200$ or the boards and trafo, and you can get a cheap case for it and connectors probably around 30-50$. If you decide to go awead with it, make sure you post pictures.

You can go more expensive with a Pot.

http://cgi.ebay.com/ALPS-Potentiomet...QQcmdZViewItem

I've held one of those big brass behemoths before.

-Ed