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LSK pre - BAF 2013
LSK pre - BAF 2013
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Old 11th April 2018, 08:14 PM   #551
woofertester is offline woofertester  United States
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Quote:
Originally Posted by Hikari1 View Post
I do not. But I have a CD with some tone sweeps...I could use that.

Bu all my sources are cap coupled as well. It really is kind of strange.
Noted. Even so, capacitors leak. It might be worthwhile to use and external cap to rule out the source being a problem.
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Old 17th April 2018, 12:16 AM   #552
Chul is offline Chul  South Korea
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Default 12 Battery?

Hi Juma,

What is the current consumption of the last circuit with bipolar 12V?
I am always tempted to use batteries.

Chul
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Old 17th April 2018, 04:34 AM   #553
Hikari1 is offline Hikari1  United States
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Hi Juma,

What is the current consumption of the last circuit with bipolar 12V?
I am always tempted to use batteries.

Chul
Juma will probably tell you for sure but there is 10-12ma through the bjt outputs...so maybe 30ma per channel?
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Old 17th April 2018, 05:35 AM   #554
Chul is offline Chul  South Korea
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Originally Posted by Hikari1 View Post
Juma will probably tell you for sure but there is 10-12ma through the bjt outputs...so maybe 30ma per channel?
Thank you Hikari1,

I have 1400mA Lipo battery packs, and maybe this can be worth trying. I will use the output cap, for (-) (+) voltage may not be the same after a while causing DC offset?

Cheers,
Chul
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Old 17th April 2018, 09:58 AM   #555
juma is offline juma  Germany
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Hi Chul,
you didn't write the post # of schematic that you are interested in, so I'll guess it's a sch. from post #539.
The consumption will depend on Idss of your JFETs and it can be anything from 15 to 25 mA, per rail, per channel (with current through Q6,Q7 set at 10mA)
Offset will drift mostly with temperature, not with small variations of PS voltage.
Read posts from #485 onwards.
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Old 23rd April 2018, 07:01 AM   #556
Chul is offline Chul  South Korea
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Hi Juma,

Thank you for your kind reply. With 1400mA battery packs that I have the current consumption is something that I can live with I think.

I ordered the parts for your circuit.
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Old 23rd April 2018, 03:06 PM   #557
Hikari1 is offline Hikari1  United States
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Originally Posted by woofertester View Post
Noted. Even so, capacitors leak. It might be worthwhile to use and external cap to rule out the source being a problem.
Found the problem. It was the power amp, not the pre.
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Old 24th April 2018, 04:47 AM   #558
watchtmouse is offline watchtmouse  Germany
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Default what was the issue with the power amp

Quote:
Originally Posted by Hikari1 View Post
Found the problem. It was the power amp, not the pre.
Hello Hikari1,

I like the detailed reports about your journey to your optimal solution. (I have a BA-3 as preamp being build(for way too long now), this one will be the next candidate)

In post #534 LSK pre - BAF 2013 you wrote:
Quote:
Power amp is very light load (Pass F5T/100K),
Did you change the Power amp or did you fix the issue with the F5T?
When fixing the F5T what did you fix?

Happy listening

Bert
PS, Ah, I see your are stil investigating: F5 dc offset issue

Last edited by watchtmouse; 24th April 2018 at 05:03 AM. Reason: adding a comment
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Old 24th April 2018, 04:00 PM   #559
Hikari1 is offline Hikari1  United States
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Originally Posted by watchtmouse View Post
Hello Hikari1,

I like the detailed reports about your journey to your optimal solution. (I have a BA-3 as preamp being build(for way too long now), this one will be the next candidate)

In post #534 LSK pre - BAF 2013 you wrote:


Did you change the Power amp or did you fix the issue with the F5T?
When fixing the F5T what did you fix?

Happy listening

Bert
PS, Ah, I see your are stil investigating: F5 dc offset issue
Yes. It appears I have some jfet leakage on the F5. It makes the DC offset on the power amp fluctuate depending on the preamp used. So, not the fault of Juma's preamp. Which is excellent and I highly recommend it.
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