Go on... just put it on a piece of wood until you get the time!
(I'm hoping we get to the 20 needed for production..).
the source feeding the pre must have impedance balanced outputs. That is both resistors and capacitors and maybe the parasitics since at the 0.01% levels of matching required for excellent CMRR can become significant.
The load after the pre has to have the same level of precision/matching.
To complete the impedance balancing, the pre itself must also be impedance balanced @ both input and output. BPutzeys being so thorough has probably already done the parasitics for you in his PCB layout. That just leaves the resistors and capacitors.
But matching is labour intensive. It's probably better to do that oneself, or pay dearly to get someone else to prematch the required components.
The load after the pre has to have the same level of precision/matching.
To complete the impedance balancing, the pre itself must also be impedance balanced @ both input and output. BPutzeys being so thorough has probably already done the parasitics for you in his PCB layout. That just leaves the resistors and capacitors.
But matching is labour intensive. It's probably better to do that oneself, or pay dearly to get someone else to prematch the required components.
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Does that mean the ready made boards won't be doing their job? Or are we just talking about getting it to sound it's absolute best?
Scrap that: I see from the BOM that critical components are very high tolorence e.g. 0.1%
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Hmm... what does interference interfere with if not the sound in a negative way?
I'm the audience and with this and ncores I guess I'm not paying much in relative terms to hear every nuance... which is a paradox because if I'm not paying much then I shouldn't care so much what I hear. :lol:
Bruno's schematic is, in his own words an example of applying the right thought processes to produce a much better sound (rather than spending more and more on boutique and fancy parts). So I would have thought his aim for the balanced impedance design is to improve sound quality first and foremost.
Anyway, wrong thread for this discussion. I've put myself down for 2 ready-built modules!
I'm the audience and with this and ncores I guess I'm not paying much in relative terms to hear every nuance... which is a paradox because if I'm not paying much then I shouldn't care so much what I hear. :lol:
Bruno's schematic is, in his own words an example of applying the right thought processes to produce a much better sound (rather than spending more and more on boutique and fancy parts). So I would have thought his aim for the balanced impedance design is to improve sound quality first and foremost.
Anyway, wrong thread for this discussion. I've put myself down for 2 ready-built modules!
if the interference is inaudible then then can be no audible improvement in sound by attenuating the interference further.
Balanced impedance connections are used where the interference would be audible and the extra interference attenuation is intended to make it either inaudible, or at least tolerable.
That to me does not mean the same as makes the sound quality better.
Balanced impedance connections are used where the interference would be audible and the extra interference attenuation is intended to make it either inaudible, or at least tolerable.
That to me does not mean the same as makes the sound quality better.
I calculate very roughly and with individual prices, including the PCB cost, the BOM adds to roughly €240 (and the only 20% tax I took into account was for the hypex regs). If I'm correct in thinking that mouser, farnell et al don't quote VAT then the BOM cost comes to €280..
I've no idea what the costs are for having a small run of boards with specified, non-regular parts are (including the Hypex regulators being mounted), but €55 per board on a small run of 20 seems reasonable from my point of view as a lay person (i.e. someone inexperienced in this area..).
There are 24 x ~€5.50/ea 0.1% vishays in there for example! That's €132 alone... Yeah, sure costs go down on bulk purchases but it's still all within the ballpark .
I've no idea what the costs are for having a small run of boards with specified, non-regular parts are (including the Hypex regulators being mounted), but €55 per board on a small run of 20 seems reasonable from my point of view as a lay person (i.e. someone inexperienced in this area..).
There are 24 x ~€5.50/ea 0.1% vishays in there for example! That's €132 alone... Yeah, sure costs go down on bulk purchases but it's still all within the ballpark .
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Maybe this is the time to mention that Bruno also has designed a mic/line level cable for balanced (or unbalanced) connections that is essentially inaudible even when you step on it?
I believe they just sold 50 km of it to a recording studio which is being remodeled. IIRC it is Grimm TPR cable. Two conductors & a screen. I've gone through 50m of it, still need more to change ALL my cables, including those in the lab.
Disclosure: I like the guy and think he is brilliant so don't count on me being objective...
Jan
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