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ε21 group buy: 2-channel version of ε22 backplane

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Re: Interest check: 2-channel version of ε22 backplane

Postby amb » July 26th, 2014, 4:19 pm

For a headphone amp, possibly serving as light duty speaker amp, yes.
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Re: Interest check: 2-channel version of ε22 backplane

Postby amb » July 27th, 2014, 5:20 am

I updated the first post of this thread with new information, including:

- pricing
- schematic diagram
- PCB layout
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Re: ε21 interest check: 2-channel version of ε22 backplane

Postby dsolodov » July 27th, 2014, 7:21 am

On schematic it looks like the 'J13:Out' (J13:4) is wired to 'J8:ChB' (J8:3) and 'J14:Out' (J14:4) is wired to 'J8:ChA' (J8:1). What's the purpose of 'Out' on J13:4 and J14:4?

What is purpose of 'J11:OG' (J11:1) on 'DC Power In' header?

Are the extra 8 mounting holes along the long edges of Beta22 board due to the weight?

What's the gap between the mounted boards for air circulation around heat sinks in the middle? Would it be possible to add either cutouts or hole to let air raise through the backplane?
Completed AMB projects: M³, σ11, σ25, ε24, γ1, γ2, LCDuino
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Re: ε21 interest check: 2-channel version of ε22 backplane

Postby amb » July 27th, 2014, 2:10 pm

dsolodov wrote:On schematic it looks like the 'J13:Out' (J13:4) is wired to 'J8:ChB' (J8:3) and 'J14:Out' (J14:4) is wired to 'J8:ChA' (J8:1). What's the purpose of 'Out' on J13:4 and J14:4?

These connect to the OUTPUT terminals on the β22 boards, just like they do on the ε22.

What is purpose of 'J11:OG' (J11:1) on 'DC Power In' header?

In 2-channel passive-ground configuration, this is the ground return line from the TRS headphone jacks (and the speaker output taps). It should be wired to the PSU ground on a separate wire than the zero-volt reference "G" wire. If you're using two ε21s for balanced, then the OG wires are unused.

Are the extra 8 mounting holes along the long edges of Beta22 board due to the weight?

They are there for a really stable platform, it's your choice whether to use them. The ε22 was the same way.

What's the gap between the mounted boards for air circulation around heat sinks in the middle? Would it be possible to add either cutouts or hole to let air raise through the backplane?

There is no gap, and my experience with the ε22 is that none is necessary. Just provide ventilation in the case and you'll be fine.
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Re: ε21 interest check: 2-channel version of ε22 backplane

Postby dsolodov » July 27th, 2014, 7:19 pm

Thank you for the answers.

amb wrote:Still waiting for some people to reply...

Some folks from Europe may be on 2-4 weeks long vacation. In Sweden some smaller companies just close for a month in Jul due to staff vacations.
Completed AMB projects: M³, σ11, σ25, ε24, γ1, γ2, LCDuino
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Re: ε21 interest check: 2-channel version of ε22 backplane

Postby amb » July 27th, 2014, 9:18 pm

dsolodov wrote:
amb wrote:Still waiting for some people to reply...

Some folks from Europe may be on 2-4 weeks long vacation. In Sweden some smaller companies just close for a month in Jul due to staff vacations.

We're down to only 4 people who have not responded. Of those four, only one is in Europe. The others are in Brazil (1) and the US (2).
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Re: ε21 interest check: 2-channel version of ε22 backplane

Postby helzerr » July 28th, 2014, 7:47 am

Hi Ti,

I'll take one.
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Re: ε21 interest check: 2-channel version of ε22 backplane

Postby Marcus » July 28th, 2014, 9:40 am

Am I in time for two boards?

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Re: ε21 interest check: 2-channel version of ε22 backplane

Postby amb » July 28th, 2014, 10:15 am

Marcus wrote:Am I in time for two boards?

Thank You

Yes, of course.
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Re: ε21 interest check: 2-channel version of ε22 backplane

Postby nickodj » July 28th, 2014, 11:37 pm

Hi Ti,
is it possible to order all the items in the BOM with the boards (order from you) ? Quite difficult for me to search all the parts in my town.

thanks
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