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SuSy dynahi v2

Kevin Gilmore's higher-powered version of the dynalo

Re: SuSy dynahi v2

Postby DEFL » July 8th, 2015, 1:23 am

mloutfie wrote:We should be aiming 750mV of bias voltage actually not 75mV. I read in some post that says 75mV which is wrong and led me to a wrong path when I started building mine.

Yes, 750mV of course. Typo.
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Re: SuSy dynahi v2

Postby mloutfie » July 8th, 2015, 4:27 pm

not sure if I've posted this before but this looks good as a quad stepped attenuator for the Dynahi http://www.ebay.com/itm/Balance-XLR-23- ... 4197c5f6bf
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Re: SuSy dynahi v2

Postby amb » July 8th, 2015, 5:39 pm

That's the same one we used in the "group build β22". It's good for the price. I wished for more steps and a better feel.
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Re: SuSy dynahi v2

Postby mloutfie » July 9th, 2015, 3:37 pm

hows the sound quality? I've used the valab stereo stepped attenuator for by bottlehead crack and it's pretty good but looks like the design is different to the balanced one. I think I need to change the khozmo stepped attenuator because it's 50k. I head slight floor noise on the right channel. THis mostly caused by the attenuator mismatch right?
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Re: SuSy dynahi v2

Postby amb » July 9th, 2015, 5:28 pm

It "sounded" fine.

I don't know what's causing noise only one one channel without knowing more information.
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Re: SuSy dynahi v2

Postby mloutfie » July 10th, 2015, 2:10 am

I'll try to borrow a cro to trace where the noise starts but when I start building this the cro shows that the noise shows up on the attenuator output point
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Re: SuSy dynahi v2

Postby mloutfie » July 11th, 2015, 4:28 am

Still having problem with ground noise. Quick question. Is the signal ground supposed to be connected to both power ground and chassis ground? That's what I have now.
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Re: SuSy dynahi v2

Postby amb » July 11th, 2015, 6:02 am

There are different grounding schemes. How well it works depends on actual implementation, and what other equipment is used in the audio chain. I prefer the grounding schemes shown at the β22 website, in the "Wiring & ground" section.
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Re: SuSy dynahi v2

Postby mloutfie » July 11th, 2015, 6:39 am

Thanks for that. That write up for b22 is great. I think I found the issue as per the note in that page. My headphone jack is not isolated from the chassis ground. I will replace it with an isolated headphone jack. The xlr shouldn't matter right? Since there is no ground connection there. Or will I get better noise performance if I use a plastic isolated xlr plug there too?
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Re: SuSy dynahi v2

Postby amb » July 11th, 2015, 6:45 am

You don't need to use a plastic XLR connector. As balanced headphone jacks, the XLR connector's outer shell isn't used for anything.
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