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GB for DC coupled B1 buffer with shunt PSUs

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#2,921
DimZ said:
I'd like a black one of theese spares :yummy: ....

not as a kit , if that cant be done then let it be a full kit ....
Click to expand...

DIMZ, I will put you on wait list for one. But all the extra boards I think are spoken for with the Black, White and red kits. I will offer some more of these kits to black DCB1 purchasers who have already bought, but Salas says I need to make a different thread on that, since it's a full blown kit offering and not a GB. So I will once I get my stuff together.
 
#2,924
Thanks, Salas.

After I get the pre done I might look into building the gain stage with it's own supply and try to incorporate it into the box.

I have a similar setup with my current ancient PS preamp; I only use the switchable gain for movies. Not needed for music sources with the amps/speakers I'm using.

Thanks again for all your work on this.
 
#2,928
How to connect my B1 buffer

Hello there,

1) I attached my usage of DCB1 (Hipnotize version), however I don't know which option be chose ?

2) Another picture I am not sure these 3 resistors value and rating also the supply AC voltage for the board ?

Thanks for your kindly instructions.

CK
 

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#2,929
1. Option 2
2. Its either 47//47 for small DC current available (less heat) or one 10R 5W (more current, heat, more good sound). Use 2X15VAC transformer.

*This is a GB thread, please post technical questions to the build threads.
 
#2,935
Request for comments,
I can order a special resistor kit from PRP,
PRP9372
4-220R 25PPM .1% 1/4 Watt
2-220K 25PPM .1% 1/4 Watt
2-1M 25PPM 1% 1/4 Watt
The cost would be in the 12-15 dollar range for a set like this. Not sure if anyone would be interested in these. Going with .1% drives up the cost, the 25PPM is half the normal tempco of typical online resistors. I am not sure they would sound any different than average PRP's, but wanted to offer an alternative to a Caddock/TX2575 combo that costs much more.
 
#2,936
regardless of tolerance i'm not sure any grade of prp compares to foils. dont get me wrong i like prp a lot and use them whenever I can, but critical signal path always gets foils for my taste, if you buy direct its a LOT cheaper than buying at PCX. on the overall scheme of things its not a huge expense.

however you may be right, for those unwilling to blow 10 bucks on a resistor this may be the way to go. pretty in red too =) do they offer relative matching as well as global?
 
Last edited:
#2,938
what you are talking about is global, or absolute matching, which basically means that each resistor that makes the grade is measured within 0.1% of that value, so a 100ohms resistor would fall from 99.9R-100.1R. Relative matching is usually done in pairs or quads and its a matter of what type of match takes priority, as larger groups get more and more difficult.

for instance you could have a 1% global value match, but a relative match of 0.1% would mean that a pair or quad measured within 0.1% of the other, but only within 1% of the nominated absolute value ie. 100R. so a 100R resistor would need to be from 99->101R, but its 'partner' would have to be within 0.1% of it.

so for example a pair could be 99.1R and 99.2R not so close to 100R, but very close to each other. for most of our situations the relative match is more important for CMMR, noise, distortion etc, but if gain is 9.8x instead of 10x its not so vital

does that make sense?
 
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