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Old 7th May 2011, 02:33 AM   #1311
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Just completed the Placid power supply for B-II. Managed to figure out the current draw adjustment is simply to check there is no voltage drop for unloaded vs loaded (with B-II connected). Did a A-B comparison with an industrial type linear supply, was surprised to conclude that there isnt any distinct difference between the two! Hmm, guess money best spent elsewhere.

Need to watch out that the polarity of the two pairs of AC connection from transformer is connected as black-red-yellow-orange and not black-red-orange-yellow otherwise the transformer will hum and heat up. Not sure if this is particular to 230v AC connection, but its not stated in the Placid manual.
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Old 7th May 2011, 02:39 AM   #1312
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Quote:
Originally Posted by LeonvB View Post
Strictly spoken you don't need I/V stages. But the DAC will perform better if you do include them. A BOM is included in the integration guide, which can be found in the document repository (Twisted Pear Audio Document Repository). The choice for IVY or Legato is IMO a matter of taste.

I have connected B-II (with 3.3uF filter cap) out to TVC then to amp with decent sound but lowish gains (dependent on the input sensitivity of amps). Also, works fine with LDR with proper loading.

Any advise if I could employ a tube SRPP from raindrop_hui on ebay?
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Old 8th May 2011, 03:24 PM   #1313
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Quote:
Originally Posted by pirastro View Post
Just completed the Placid power supply for B-II. Managed to figure out the current draw adjustment is simply to check there is no voltage drop for unloaded vs loaded (with B-II connected). Did a A-B comparison with an industrial type linear supply, was surprised to conclude that there isnt any distinct difference between the two! Hmm, guess money best spent elsewhere.

Need to watch out that the polarity of the two pairs of AC connection from transformer is connected as black-red-yellow-orange and not black-red-orange-yellow otherwise the transformer will hum and heat up. Not sure if this is particular to 230v AC connection, but its not stated in the Placid manual.
No disrespect, but I think that you need to study the manual closely as well as perhaps looking up data sheets on components. To work optimally the Placid needs to have it's shunt current adjusted to ~60mA with the Buffalo running, just looking for a voltage drop will not do that, details are in the manual on the TP site.

You also really need to run the Buffalo into a I/V stage like the IVY or Legato, I am sure that other types will work but Russ and Brian have optimised their designes for the Buffalo.

Good luck and do be careful with your 230v connections !!
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Old 8th May 2011, 04:46 PM   #1314
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Not sure if we are looking at the same manual, I have the Placid rev 2.0 output I measured the current per rail across R2/R5, initially I had 250ma, but the leds on the AVCC was very dim, in fact one side wasnt lit. I finally settled for 2.2R resistor in place of VR1/2 for approx 350ma.

Thanks MartinC700
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Old 8th May 2011, 06:24 PM   #1315
waltube is offline waltube  Italy
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To Russ:

I sent two email (on you site) asking the availabilty ic a 4:1 mux Spidf. Without answer.

Please can you tell me if there are some dates?

Thanks


Walter
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Old 8th May 2011, 07:26 PM   #1316
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Quote:
Originally Posted by pirastro View Post
Not sure if we are looking at the same manual, I have the Placid rev 2.0 output I measured the current per rail across R2/R5, initially I had 250ma, but the leds on the AVCC was very dim, in fact one side wasnt lit. I finally settled for 2.2R resistor in place of VR1/2 for approx 350ma.

Thanks MartinC700

Hi,

You should really measure the voltage across R3, and set this to approximately 0.06v, this will then be giving you 60mA of shunt current. I don't know if you have Tridents installed, if you do then you will need significantly more than 350mA. If you have no Tridents, then 350mA of total current should be fine, but you would still be better off measuring and adjusting the shunt current.

Regards
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Old 9th May 2011, 03:44 PM   #1317
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Dear Russ,

Can I ask you what values you use for register 13 both in Stereo and in mono mode ?

Thanks,

Davide
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Old 11th May 2011, 02:14 AM   #1318
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Dear Russ,

Let me reformulate my question in a more general fashion:

1) is it possible to have the diagram of connection of the output of the DAC chip to the output of the board ?

2) If I use an external controller, like the arduino, what are the function of the dip switch ? Can they be ignored ?

I started to play with the Arduino and the Buffalo. It's so much fun !!!


Thanks,

Davide
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Old 11th May 2011, 06:31 AM   #1319
glt is offline glt  United States
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The output connection is specified in the data sheet. The inputs to buffalo are a bit "tricky" to figure out, but Russ disclosed it somewhere in one of the threads. You can take a look at my Arduino code to see how they are set up...

If you use an external controller, you can ignore the dip switches...
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Last edited by glt; 11th May 2011 at 06:36 AM.
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Old 11th May 2011, 08:04 AM   #1320
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Hi glt,

I wrote also a comment on your website. Great work you did. You really opened me another world. I had to figure out how to regulate the phases of the outputs of all eight channels, and it was not so easy. Finally I read the original settings of the Buffalo in mono mode, and I could figure out how to have all the DAC working together.

I made a version of the code that supports both, stereo and dual mono.

Question: why do you need a transistor for the brightness of the display ? Can you show how you connected that ?

Thanks,

Davide
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