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#270 – An Interview With Dafydd Roche

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2015-10-08 11-38-56.166

Welcome, Dafydd Roche of TI and ExpatAudio!

    • Dafydd works in the audio group at TI as a definition engineer. One example product is the PCM1865, also discussed on /r/nicechips
    • Almost all chips need to be marketed for the mass market now, not single customers.
    • Rule of thumb: Number of bits * 6 = dB of range
      • 24 bit = ~144 db of range
    • The eardrum tightens when subjected to loud noises.
    • Zipper noise
    • Dafydd has a side business with another UK expatriate called Expat Audio.
    • He has an ECM93 Pick and Place machine. Another rule of thumb is if you’re not going to use the machine weekly, it’s probably not worth it.
    • Hardware controlled chips are easier because it just takes resistors to set functions on the chip (no FW)
    • Development boards allow engineers to try out new features by “blue wiring it in”
    • Peak Music Power Output – PMPO
    • Watts are often listed as a percentage of THD.
    • Speakers are 1%. Additionally, toom accoustics will ruin the best speakers
    • One of the parts Dafydd has helped design is 600W single chip amplifier.
    • NPR did comparisons on bit rates to show that most people can’t hear the difference. 
    • 1V RMS signal w/ 130 dB range…ends up being tens of nV at the low end of the scale. 
    • Henry Ott was on the show, Dafydd loves his book.
    • We asked about the low material chip packages, in case audio could have the same problem as the Xenon flash bug for RPi. Dave did a video about this:
    • Future projects will be remote control of analog, recall setups using storage.

Many thanks to Dafydd for being on the show, you can reach him as @ExpatAudio on twitter and on their FB page

 

Comments

  1. I haven’t listened to all others, but what a show! Both amusing and informing. Now on to the one with the guru Henry Ott or what his name is 😀

  2. Chris, I googled If Roger Waters farted during the recording of Dark Side of the Moon…

  4. Best episode i’ve listened to in a long time! Fantasticly entertaining and educational. This is the amp hour I love! Thanks for sharing your knowledge, experience and joy Dafydd. And thank you Chris and Dave for such a great interview.

  5. This was a great interview. You could probably get another hour of material out of Dafydd.

  7. The general rule-of-thumb of 4 engineers = 1M, seems kinda high… assuming a $100k of salary, the overhead for 1 engineer is $250k?!

    I’m reminded me for some reason of this post on visualizing how much $1B is
    https://np.reddit.com/r/news/comments/3o05gh/the_man_who_created_the_5hour_energy_drink_says/cvt5xe3?Context=3

    Was this the Hank Zumbahlen application note on ADCs?
    http://www.analog.com/library/analogDialogue/archives/46-06/staying_well_grounded.pdf

  8. I really enjoyed this episode. Dafydd was great to listen to, a really good guest on the show. Nice one 🙂

  11. As a new listener to the amp hour, I’m absolutely loving this show. Thank you Dave and Chris, keep it up!

  12. Very nice guest, very nice interview.

    Dave had a blogpost a while ago about support forums of companies, if someone remembers, there he posted some statements ( which are pretty true ) that a lot of persons contribute without earning money ( I am in the e2e Forum , that is the Texas Instruments one ).

    Now, Dave you could have had the chance of talking about that with the guest, did you?

    • Elecia did a podcast (embedded.fm) with someone spending tons of time doing free support for one of the EE giants. dont remember who it was or which episode 🙁

        • thanks a lot, will listen to it , actually i never listened to embedded.fm I tried the fran blanche episode but dont know, guess chris and dave just seem more entertaining to me, i give it another go though 🙂

  14. Wonderful interview! A really, really funny episode- had me laughing out loud at work. A friend of mine who is super into high end esoteric audio gear (cryogenic treated cables, special sound deadening cones under his preamp, etc.) had me over at his place to listen to some new audio gear and he would sit there with the music just unbelievably loud and say “You hear that? You hear the difference? It’s amazing.”

    I couldn’t hear the slightest damn bit of difference. As I told him, “If you think it’s better and you’re happy with your purchase then who am I to disagree?”

    My next door neighbor used to build speakers at Avalon. Now that is some crazy money…

  15. Great episode.

    I design Audio systems and would like to add a point to the discussion about ‘remembering’ sound. After 20 years of working in audio, I can tell you a frequency of a sound by hearing it, just like you can tell me a color by looking at it. Similarly, when you think of ‘Red’, you remember what that color looks like. So by using that learned skill with frequencies, I can actually remember and compare sounds I heard previously.

    I would also add for the record that I do not believe in, endorse, sell or otherwise use ‘snake oil’ audio products in my designs.