Author Topic: Mars Kit 2 Mk 2 update  (Read 664 times)

Offline Mars

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Mars Kit 2 Mk 2 update
« on: November 21, 2016, 11:32:58 PM »
We are packing a kit for a client, and photographed the content for general interest:

Coupling Capacitors - metallized polyester film



Tube sockets



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Offline Mars

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Re: Mars Kit 2 Mk 2 update
« Reply #1 on: November 21, 2016, 11:50:41 PM »
Panel mount RCA connectors:

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Offline Qualityten

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Re: Mars Kit 2 Mk 2 update
« Reply #2 on: November 24, 2016, 12:58:01 AM »
Thanks.  I look forward to seeing more pics.

Offline Mars

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Re: Mars Kit 2 Mk 2 update
« Reply #3 on: December 28, 2016, 08:07:19 AM »
Speaker binding posts



Tag strips



Power transformer

Primary 230V AC
Secondary 330V 400mA
                    6.3V 4A
                    6.3V 4A



Output transformer

35 Watt
Primary impedance 6000 ohms : 8 ohms
Primary Inductance 100 Henries
Three primary and secondary sections



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Offline fredeb

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Re: Mars Kit 2 Mk 2 update
« Reply #4 on: December 28, 2016, 11:12:04 AM »
Beautiful Karel ! Do you mind telling us all a little about your transformers please ?
“And those who were seen dancing were thought to be insane by those who could not hear the music.”
― Friedrich Nietzsche

Offline Mars

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Re: Mars Kit 2 Mk 2 update
« Reply #5 on: December 28, 2016, 12:20:05 PM »
Certainly, fredeb

Starting with the Output transformers:



This a 35 watt design that has a
- Primary impedance of  6300 ohms : 8 ohms
- Primary inductance is about 140 Henries, giving you a low frequency roll off at full power of less than 20Hz.
- High frequency roll off (at full power) is just under 100kHz (93kHz)
          (We layer the windings with 0.25 mm transformer paper. This shifts the sections's self resonating frequency to about 115kHz, and we adjust the total transformer    roll of by tweaking the inter section paper gap. Usually this is 0.6mm carton which brings the roll off down to 100kHz.)
- Standard EI96 laminations are used and the stack is 50mm high. This gives a core cross section of about 16 cm square. Flux density at full power/bandwidth is about 0.9 Tesla.
- we use a three section design like shown below:
3-section-transformer by Karel Mars, on Flickr

As you can see it is an ultra linear design with taps at 33%.

Mars OPT 6k:8ohm by Karel Mars, on Flickr
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Offline fredeb

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Re: Mars Kit 2 Mk 2 update
« Reply #6 on: December 28, 2016, 12:27:09 PM »
Wow ! Impressive specs - works of art in themselves . Are all the Output Transformers used in your designs wound by yourself ?
« Last Edit: December 28, 2016, 12:29:11 PM by fredeb »
“And those who were seen dancing were thought to be insane by those who could not hear the music.”
― Friedrich Nietzsche

Offline Mars

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Re: Mars Kit 2 Mk 2 update
« Reply #7 on: December 28, 2016, 12:44:21 PM »
IMG_7510 by Karel Mars, on Flickr

The power transformer:

Primary Voltage: 230V AC
Secondary 1: electrostatic screen
Secondary 2: 330V AC 500mA
Secondary 3: 6.3V AC 4 Ampere
Secondary 3: 6.3V AC 4 Ampere

- 216VA design using 114mm Standard grade laminations on a 60mm stack giving a core cross section of 22.8 cm^2
- 1 Tesla flux in core when delivering full current.
- losses in copper and iron are equal at just under 10% for both at full load
- the transformer is potted in wax
- OEM design and manufactured in our workshop.

IMG_7505 by Karel Mars, on Flickr

IMG_7507 by Karel Mars, on Flickr

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Offline Mars

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Re: Mars Kit 2 Mk 2 update
« Reply #8 on: December 28, 2016, 12:47:13 PM »
Wow ! Impressive specs - works of art in themselves . Are all the Output Transformers used in your designs wound by yourself ?

Yes, indeed.

We do all the power transformers, chokes and output transformers ourselves. (mostly me, but Louis is starting to help with chokes :mates:)
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Offline fredeb

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Re: Mars Kit 2 Mk 2 update
« Reply #9 on: December 28, 2016, 01:51:08 PM »
Thank you for the comprehensive reply , and well done for keeping the art of Output Transformer winding alive .
“And those who were seen dancing were thought to be insane by those who could not hear the music.”
― Friedrich Nietzsche