John Curl's Blowtorch preamplifier part III

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It probably isn't the factual content of critical feedback that is off-putting to those on the receiving end. It is your particular way of always trying to prove/demonstrate you are the smartest guy in the room, that what you happen to believe is the only real truth, and that your behavior is the ideal model that all other true EEs should aspire to.
Simple way to counter that is to show the other real truth.
 
Yes. It is a very good DAC. However depends what are you seeking for. It is transparent and strictly on a neutral sound side. Ask KSTR (member), he knows quite a lot about this DAC.

Thanks Pavel,

It would be to see if a little cleaner sound could be had from my elac ds-s101g sever/streamer than it’s internal dac......the elac is nice but I believe it’s a better streamer than dac. Would be plugging the cd in also......this would free up the recievers digital inputs for the smart tv and dvd.

And I’ve been wanting some dsp eq options anyhow.....I would hope this would give a cleaner performance than say, adding a mini dsp?

Also has balanced to try with the Hint.....I know it’s just a ‘long cable run’ thing but would just like to see if it made any difference.

It has a cap on each side of the chip.....I’ll see if I can’t find a pick.
 
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Alrighty then.....

RME ADI-2 dac?

As PMA said, it’s very good. There is a lot of attention to detail in their products it seems - on the version with the ADC they added another digital filter to correct the passband ripple in the AK557x ADCs built-in filter.

You don’t need to use the DSP as far as I know. I wouldn’t be afraid to use a little EQ anyway.

I’d prefer to buy from RME rather than a “hi-end” company.
 
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Thanks Pavel,

It would be to see if a little cleaner sound could be had from my elac ds-s101g sever/streamer than it’s internal dac......the elac is nice but I believe it’s a better streamer than dac.

Re "cleanliness" and dynamics and S/N, I would have no doubts about RME ADI and would recommend it. But, again, subjective taste may come into the game and also the rest of the audio chain. If you like transparency, low distortion and neutrality and you have such amplifier and speakers, then RME ADI is the choice. Otherwise, better try to borrow a piece and listen.
 
It probably isn't the factual content of critical feedback that is off-putting to those on the receiving end. It is your particular way of always trying to prove/demonstrate you are the smartest guy in the room, that what you happen to believe is the only real truth, and that your behavior is the ideal model that all other true EEs should aspire to.

You believe what you want to believe. Otherwise, routed to /dev/nul as all ad hominem, of course.
 
As PMA said, it’s very good. There is a lot of attention to detail in their products it seems - on the version with the ADC they added another digital filter to correct the passband ripple in the AK557x ADCs built-in filter.

You don’t need to use the DSP as far as I know. I wouldn’t be afraid to use a little EQ anyway.

I’d prefer to buy from RME rather than a “hi-end” company.

Cool thanks, seemed like a ‘sleeper’ and they don’t sling anything but facts on their website....no fluff!
 
Re "cleanliness" and dynamics and S/N, I would have no doubts about RME ADI and would recommend it. But, again, subjective taste may come into the game and also the rest of the audio chain. If you like transparency, low distortion and neutrality and you have such amplifier and speakers, then RME ADI is the choice. Otherwise, better try to borrow a piece and listen.

Yes Sir,
Whole system is based in clean dynamics......remember, I’m the snob that can only listen to hq recordings :D

I’ll buy from a retailer that has a no questions return policy just in case.

I’ll get up with the feller you mentioned b4 pulling the trigger.
 
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A thin sheet of aluminum will do **** to screen magnetic fields. Make it 12mm thick and 200mm high on both sides of the board and we can talk about.

But with an output inductor it is a varying magnetic field and aluminum will screen it. Although aluminum is only about 52% as effective as iron.

At 20 hertz the magnetic skin depth in aluminum is just over 1 centimeter.

I suspect a heatsink with 1" fins will pretty much attenuate whatever magnetic field a simple output inductor can muster.

The issue really is how much the magnetic field can find something to couple into. At low frequencies you would require a large loop area to capture significant signal. At higher frequencies the shielding would be dominant.

Also a consideration would be the flux density surrounding the style of inductor. Length of the simple round coil inductor would be the consideration for that.
 
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I said Like my statement says for the purposes of the experimenter the design is spacious and there are clearances to change or add caps and supercaps, there is provision for oscillator rolling and there is provision of connection to external dac stage pcb.
There is easy access to adding and swapping other components including the regulator.....all these qualities combined on an economical prebuilt board is unusual and does count as well laid out for the purposes of the experimenter.
Close inspection will show that for two layer assy the board is electrically quite good with copious earth pours and ample stitching throughout.
For $50.00 or at any price this 'semi-disposable' board is really good sounding and is also a physically ideal starting point for the DAC experimenter.
Your turn now Bill.
And on my side I will show you a picture of the curryman DAC which is only a few $ more but was designed by some of the community here. It's I2S in but that is exactly what I need in my system.



Not the location of the crystal and the decoupling around the chip. Now look at your glom it special with a graveyard of through hole parts. Curryman Clock is close to the DAC. Yours appear to to be miles away (bad angle to be sure and I could be wrong there).



So for the glom it on and fsck it up crowd I am sure $50 well spent, but surely starting with something where there is some local knowledge and documentation would seem to be a much better use of your money. Mixed signal requires decoupling to be close as possible to the device and I see little evidence of this having been considered.
 

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.remember, I’m the snob that can only listen to hq recordings :D

Then you should check out Arthur HIGH-END AUDIO and Arthur Salvatore .
I think his points about THD not THD+N should be measured as the output goes to 0 (so does Earl Geddes BTW) are very interesting. Everyone worries about cleanly driving their speakers out of their surrounds.
 
But with an output inductor it is a varying magnetic field and aluminum will screen it. Although aluminum is only about 52% as effective as iron.

At 20 hertz the magnetic skin depth in aluminum is just over 1 centimeter.

I suspect a heatsink with 1" fins will pretty much attenuate whatever magnetic field a simple output inductor can muster.

The issue really is how much the magnetic field can find something to couple into. At low frequencies you would require a large loop area to capture significant signal. At higher frequencies the shielding would be dominant.

Also a consideration would be the flux density surrounding the style of inductor. Length of the simple round coil inductor would be the consideration for that.

Check with JN. 52%, where did you get that number from? At what frequency?

Was anybody mentioning shielding a permanent magnet?

What we are talking here is a 0.062" aluminum sheet used to cool the drivers. Nope, zero magnetic shielding at audio frequencies, through hole construction, always large-ish loops to capture. A sheet of tin can would be much better!

You need to build and measure a power amp to see the magnetic field coupling adding an otherwise perfectly avoidable 2nd harmonic distortion.
 
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