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The BA-3 as preamp build guide
The BA-3 as preamp build guide
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Old 22nd May 2018, 03:18 AM   #1021
Dudeisms is offline Dudeisms  United States
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Quote:
Originally Posted by Hikari1 View Post
Pass uses what appears to be clarity cap esa in xp pre. Should be good enough.
So I ordered ESA Claritycaps 10uf and there was a stocking issue, then a wait for a shipment from the U.K.... And I received CSA versions instead. Vendor shows no new stock of ESA's and they seem to be particularly scarce online in general.

Thoughts on CSA vs ESA claritycaps?
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Old 22nd May 2018, 03:24 AM   #1022
Hikari1 is offline Hikari1  United States
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CSA is the new, supposedly improved version ESA.

Personally, I wouldn’t worry about it too much. Tweaking P3 a few turns will have a greater effect than the coupling cap.
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Old 22nd May 2018, 03:38 AM   #1023
Dudeisms is offline Dudeisms  United States
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Cool, thanks for the quick reply!
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Old 24th May 2018, 02:17 PM   #1024
RonD2 is offline RonD2  United States
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The BA-3 as preamp build guide
Finished building a balanced BA-3 a few weeks ago. It's a simple balanced in-blanced out. It feeds a pair of balanced f4 monoblocks which have served me very well for several years with a variety of pre-amps.

Some pictures are attached not so much to show off, just as proof!

I am very happy with the sound. Amazed actually.

I set P3 at the midpoints. But just for the challenge I tried to set up a computer/sound card to adjust them. Understand, I am way too much of a paint-by-numbers builder with no measuring expertise beyond DMMs.

I didn't get very far.

I tried to use half of one balanced channel, e.g. the + to ground, to the sound card but that doesn't seem right and has little output. But at least there would be a single P3 to adjust this way.

I then tried feeding the sound card with a single, full balanced channel. This gives a nice signal.

But I am wondering if this is the correct approach as I will have to adjust two P3s at the same time. And I already have repetitive stress from all the bias, offset adjusting.

I really can't thank everyone in this community enough. You are all just amazing.
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File Type: jpg BA-3B System.jpg (425.0 KB, 200 views)
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Old 24th May 2018, 05:36 PM   #1025
Zen Mod is online now Zen Mod  Serbia
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The BA-3 as preamp build guide
it would be simple , with sound card having bal output and bal input

without that , you need something to jump few times between SE and Bal realms

so:
- card SE out - xformer for SE-Bal conversion - preamp in
-preamp out - xformer for Bal-SE conversion - card SE in

considering prices of decent xformers .... it's clever to think of cheapest external card with bal in/outs
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Old 27th May 2018, 03:38 PM   #1026
starbender is offline starbender
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I was checking my ba3 for bias offset. It was working fine. But i got strange readings..I got 0.4v dc after the output cap. Before cap offset dancing between 0-80mV. After cap there is 0.4v dc. Other channel also have similar readings. Around 0.1vdc. What is wrong?

Thanks
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Old 27th May 2018, 03:45 PM   #1027
ichiban is offline ichiban  United States
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The BA-3 as preamp build guide
Quote:
Originally Posted by starbender View Post
I was checking my ba3 for bias offset. It was working fine. But i got strange readings..I got 0.4v dc after the output cap. Before cap offset dancing between 0-80mV. After cap there is 0.4v dc. Other channel also have similar readings. Around 0.1vdc. What is wrong?

Thanks

Is the cap output connected to the input of another component, i.e. an amplifier?

The cap needs a load, after the cap connect a 100k resistor to ground for measurement.
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Old 27th May 2018, 03:50 PM   #1028
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Ah. I forgot that.
Thanks.
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