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Old 23rd July 2010, 03:39 PM   #2561
exojam is offline exojam  United States
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Andrew,

I do not see anywhere in the manual where it shows an unbalanced connector can be connected to the amp (either written or a picture of this).

Unfortunately I am not going to be able to modify the amp input. That is why I was wondering if I would lose any benefit of the B1 by either coming out of the B1 with an RCA and using a RCA to XLR connector to the amp OR going RCA from the B1 into my Onkyo CD inputs (which I am doing now). I hope all of that makes sense. Thanks.

James
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Old 23rd July 2010, 03:47 PM   #2562
AndrewT is offline AndrewT  Scotland
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you have chosen to ignore the second and third paragraphs of that previous post.
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Old 23rd July 2010, 04:02 PM   #2563
exojam is offline exojam  United States
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Andrew,

I did not choose to ignore them, just "missed" what you stated when I read them

Thanks again for your information and time.

James
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Old 23rd July 2010, 04:55 PM   #2564
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James, there's no benefit in placing a B1 if you don't remove the Onkyo for the signal path. Not that it's a bad pre, but having 2 preamps at the same time is silly.

The DCB1 outputs a singled-ended signal (aka: not balanced). Use an adapter from RCA to XLR, or make yourself a proper cable.

Regards,
Regi
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Old 23rd July 2010, 04:57 PM   #2565
exojam is offline exojam  United States
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Regi,

That is what I was looking for. Thanks to all for their time and help.

James
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Old 27th July 2010, 02:02 PM   #2566
kffern is offline kffern  Australia
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Default Turn on thump

Hi,
I have completed my B1 and it seems to work fine apart from a loud turn on thump. It is being tested with a chipamp and an old pair of speakers. I have a single pole switch on the DC power in for the +ve. Pulling out the power plug also causes a thump but probably not so loud.

I checked the DC on the output and it reads 0.15V and decreases to 0 in around 2 mins. The diode (1N914) has the bar towards the middle of the board.

Should I have a 2 pole switch for ground and +v?. I am using a laptop power supply with 19.5V.

Thanks,
Kffern
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Old 27th July 2010, 04:42 PM   #2567
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Have you sequenced turn on/off? Or tried turning it on w/volume at zero?

Sequencing would be turning the pre on 15-30 seconds before the amplifier and turning them off in reverse order...

Chris
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Old 27th July 2010, 05:47 PM   #2568
AndrewT is offline AndrewT  Scotland
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the B1 has a DC blocking capacitor on it's output.
This cap must charge to it's final operating voltage after start up. This will send a pulse to the next stage.

Similarly the capacitor must discharge after switching off. This will send another pulse to the next stage.

There are disadvantages to single ended ClassA, this is one of them.
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Old 27th July 2010, 05:53 PM   #2569
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what I suggested should work to ameliorate this...
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Old 27th July 2010, 09:52 PM   #2570
Marra is offline Marra  United Kingdom
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I'm with Chrismercurio on this one. I always turn on source;pre; leave a couple of minutes then power amp. Of in reverse order but no need to wait any time switching of the pre. I did'nt realise people did it any other way. Never suffered any pops at all.
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