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Old 6th September 2006, 07:38 AM   #701
KOHTOPA is offline KOHTOPA  Europe
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> My panels are 10mm thick...

Wow, very... solid state

And last question - how are you going to finish it?
Are there any companies which could make anodizing
of the custom aluminium case/panel?
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Old 9th September 2006, 05:05 AM   #702
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I’m putting together a pga2310 preamp (Russ White’s layout and schematics). I have three questions

1. Will the bypass capacitors value on the datasheet (figure 5) degraded the sound? Russ uses 47uf instead
of 10uf

2. Anyone tried Walter Jung ad815 composite amp as an output buffer?

3. What is the purpose of the -5volt supply?
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Old 9th September 2006, 09:24 AM   #703
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Sorry forget I spoke of the -5voltage supply. I needed some sleep
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Old 16th September 2006, 01:06 PM   #704
maxw is offline maxw  United Kingdom
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Hey guys,
The 5V rail drops to 4.6 when I run my darwin off of it. Its 5V when the darwin is left unconnected.
Is this normal and OK?
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Old 21st September 2006, 08:35 AM   #705
maxw is offline maxw  United Kingdom
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Quote:
Originally posted by maxw
Hey guys,
The 5V rail drops to 4.6 when I run my darwin off of it. Its 5V when the darwin is left unconnected.
Is this normal and OK?
Bump. Anolog V+ stays at 5V but digital V+ drops to 4.6V when the darwin is connected. The Darwin only draws 38mA so I don't think there is a short or anything. It works fine though. Is this OK?
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Old 21st September 2006, 10:06 AM   #706
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That actually looks slightly low for the PGA's digital section (recommended 4.75V - 5.5V), but if it's working okay...
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Old 21st September 2006, 01:31 PM   #707
curtvm is offline curtvm  United States
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Quote:
Originally posted by maxw


Bump. Anolog V+ stays at 5V but digital V+ drops to 4.6V when the darwin is connected. The Darwin only draws 38mA so I don't think there is a short or anything. It works fine though. Is this OK?
Please ignore me if I'm wrong, but r1 (on the schamtic I have) is 10 ohms which 5v goes through to get to pic/pga. 40ma/10ohms/4.6v - that combo seems tailor made for something to do with ohms law (or whatever law is working here). .04x10=(5-4.6). My theory holds up (I think) only if you are getting 5v from the digital side of r1.

Get 5v for darwin from volume pot instead.
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Old 2nd October 2006, 11:23 PM   #708
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Quote:
Originally posted by jaudio
I’m putting together a pga2310 preamp (Russ White’s layout and schematics). I have three questions

1. Will the bypass capacitors value on the datasheet (figure 5) degraded the sound? Russ uses 47uf instead
of 10uf

2. Anyone tried Walter Jung ad815 composite amp as an output buffer?

Because of the difference in the pga2310's supply requirements(not to mention the AD815 composite), Im not using Russ White layout.

But can anyone answer the questions I posted earlier?

Thanks
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Old 2nd October 2006, 11:29 PM   #709
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Quote:
Originally posted by jaudio


Because of the difference in the pga2310's supply requirements,Im not using Russ White layout.

But can anyone answer the question I posted earlier?

Thanks

The cap value is not critical

10-100uf is fine.

Any good buffer should work just fine on output. The 815 circuit you mention would probably be just great.
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Old 11th November 2006, 08:43 PM   #710
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Default Strange problem when using v1.1 PIC

Hi there,

I recently purchased an assembled Kookaburra from a friend and have been having a lot of fun with it. I received a few extras with it including a PIC labelled v1.1 (the installed PIC was unlabelled).

I decided to connect a 50K log pot in place of the original. I know a logarithmic pot is not ideal, but it's motorized, and I'm too lazy to get up every time I want to change the volume :-)

So, I turned everything on, sat back on the couch and proceeded slowly turn up the volume. When the pot had travelled only a few degrees there was a sudden burst of full volume sound which triggered the amplifier protection circuit. Oh dear, I thought...

To cut a long story short, after some experimentation I found with the v1.1 PIC, when the 50K log pot is a few degrees from minimum, it causes very short bursts at full volume. These bursts are a fraction of a second, with about 1/2 second gap between them. Once the pot has passed this point, the volume level is low and increases gradually as expected. At least one burst will occur whenever the pot passes this point. With careful adjustment I get the continuous bursts.


This doesn't happen with the original unlabelled PIC, which I guess is v1.0.

If anyone (Russ?) has any ideas about what's causing this I'd be interested.

Best regards,

Andrew.
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