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 Post subject: Re: MCA - Son of ZCA
PostPosted: 18 Sep 2016, 08:18 
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Joined: 06 Jun 2008, 18:23
Posts: 4949
Location: Australia
I think it is the second on this site anyhow.

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 Post subject: Re: MCA - Son of ZCA
PostPosted: 18 Sep 2016, 08:52 
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Joined: 09 Apr 2013, 02:59
Posts: 48
Location: Germany
Wow, thats making me proud :)
Firstly I have made a try on a piece of wood but got too much hum from the input.
After installing everything in a proper enclosure there is absolutely no hum (and i have very sensitive speakers).
The temperature is higher than with the ZCA: the enclosure gets approx. 50° Celsius.
The sound is much more direct, some sort of punchy. The best match to the Fostex i can imagine.
I have not heard a lot of that directly sounding systems even on HighEnd exhibitions.

I enjoy a lot!
Best regards
Stefan

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 Post subject: Re: MCA - Son of ZCA
PostPosted: 18 Sep 2016, 09:07 
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Do yo have any way of determining the max power output prior to any distortion. Usually you would use CRO and look for the 1K sine wave to start to alter shape while driving an 8ohm resistor.

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Projects: "Lagoon" - tube preamp with cathode follower | "retro-Oatley 6J6" - 6J6 push-pull headphone amp with OPTs | "retro-Hiraga" - Jean Hiraga Le Monster
Website: retro-thermionic


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 Post subject: Re: MCA - Son of ZCA
PostPosted: 18 Sep 2016, 09:09 
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Joined: 06 Jun 2008, 18:23
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Location: Australia
Yours is definitely the most pro looking. Do you have an image of the enclosure, lid on, front and back.

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Projects: "Lagoon" - tube preamp with cathode follower | "retro-Oatley 6J6" - 6J6 push-pull headphone amp with OPTs | "retro-Hiraga" - Jean Hiraga Le Monster
Website: retro-thermionic


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 Post subject: Re: MCA - Son of ZCA
PostPosted: 18 Sep 2016, 09:36 
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Joined: 09 Apr 2013, 02:59
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Location: Germany
It is like i mostly do with speakers, at the moment it is "on line" i don't want to disattach anymore because i enjoy listening so much :)
So to measure the output power is a duty to do somewhen....
As well as the photo's with the lid on.
So please have mercy and give me a time to do that, will certainly take a week or so.

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 Post subject: Re: MCA - Son of ZCA
PostPosted: 18 Sep 2016, 10:05 
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Joined: 09 Apr 2013, 02:59
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Location: Germany
OK, a picture from the front is not too difficult
MCA is bottom left... ;)


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 Post subject: Re: MCA - Son of ZCA
PostPosted: 18 Sep 2016, 15:38 
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Joined: 18 Jan 2015, 15:50
Posts: 14
Hello max130

Very very good job ,it looks nice and pro.

I show you my beta version , 8-) . I agree it sound better than ZCA in general but anyway the ZCA also I like much.

My MCA its less powerful than yours , mine have 16v of power supply , and the bulbs are feed with 10v approx. 700ma.

Regards


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 Post subject: Re: MCA - Son of ZCA
PostPosted: 18 Sep 2016, 15:41 
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more pics


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 Post subject: Re: MCA - Son of ZCA
PostPosted: 18 Sep 2016, 15:57 
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Joined: 09 Apr 2013, 02:59
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Location: Germany
Hi Makjoe
Thank you very much for your compliment (also to Mark).
Apart from the fan (which i don't like so much) your unit looks very good also to me.
I like the lamps with their protective brackets.
Any photos of the inside by chance?

...and yes, the ZCA is very good as well.... But after having heard the MCA I have stored it away...

Best regards
Stefan

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 Post subject: Re: MCA - Son of ZCA
PostPosted: 18 Sep 2016, 17:46 
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Joined: 06 Jun 2008, 18:23
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Location: Australia
Makjo, that's different and your MCA must be, as with Stefan's, is one of three that I am aware of. This design came about by others building ZCAs and liking them and asking if I had any other ideas. From that came the MCA mainly because I wanted to make an amp with a bipolar transistor and not a FET. But for years no one ever built one and mine was only a "proof of concept". But now there are at least thee in the wild which I'm aware of.


The best part is you all seem to enjoy the sound and that is what it is all about. I'm yet to build one for myself but the day is coming. Also I'm thinking of an integrated version. So you might say a "MCIA" (you could pronounce it a "Mc-ear-a" - lol). What I'm thinking is a BoZ preamp section, then pot then a MCA power section. It maybe the one I build to prove that the idea works.

Thanks guys for going to the effort of putting a scetchy idea and a poor prototype to the test. Best part is all you get to enjoy the result. Thanks again.

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Projects: "Lagoon" - tube preamp with cathode follower | "retro-Oatley 6J6" - 6J6 push-pull headphone amp with OPTs | "retro-Hiraga" - Jean Hiraga Le Monster
Website: retro-thermionic


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