Damn this video just opened my eyes. I have a pair of NT3s, and i always hated that bump, and eq-ed it out. First thing in the morning i am getting my soldering station and getting that part of the circuit out. Thank you so much!
I hope that all of us that are following Doug Ford's wonderful explanations, understand that this is a one-in-a-million chance to learn from Doug's career. Try going to Rhodes or other manufacturer and attempt to get them to teach you these trade secrets. You couldn't pay enough to learn any of this. With what I have learned, I could go into the microphone manufacturing business (if I wasn't retired). I once had the president of a company, say, "Anyone can see what we did, but the hard part, is learning WHY we did it." Thanks for taking the time to create, edit, and upload this material to RU-vid.
Exellent series Doug and Dave. Thankyou, most entertaining and educational. Rhode might be a bit pissed though seeing all their trade secrets explained ): Doug is a real character
I have an original Rode NT1 (battleship grey version, not the 'A' model), best mic I've ever owned! Great to see the designer behind it and the genius in design. I'd love to see more pro-audio related videos on EEVBlog!
I'm pretty sure the old Rode NT1 is a Jim Williams design and not a Doug Ford's, it also wasn't made by Rode in australia, it was made by 797 audio in china, I believe back when rode started, they didn't make their own mics.
@@MangotundeThe thing about the electronics hobby is you learn about it through watching and reading stuff of this nature repeatedly. I have been an experimenter for 30 years and have had no formal education in electronics apart for some mentoring and I had no problems with it. So that's my suggestion, get really interested in it and watch and read things repetitively and you'll learn a lot. Do you like to experiment with circuits much?
@Dazzwidd I haven't really experimented with any circuits, though I am interested in electronics and how they function. I've just never had the ability to get certain parts and design things myself in my free time.
@@Mangotunde Well you only learn from practical experience and that comes from playing around. Start in an area you're most interested... audio, radio whatever. I build circuits using blank pcb and employing what's known as "Rats nest" construction. You can even roll out a coffee tin and use that glued to a piece of wood if you want to keep it really cheap
Would love to see more videos with Doug. He's a class act, and analog design is a great subject. How about designating a day of the week as "Doug Ford Day"? :)
This is a fantastic series that I had not yet seen. Doug is a good teacher, and his designs are very interesting. Also interesting to hear about production issues/cost savings, etc. Thanks.
I've watched EEV Blog for years but this is by far the most informative video I've seen! Thank you! Lots of great stuff in this one! Thanks Doug and Dave!
I really love this series. I'm familiar with Rode microphones, and it's really cool to hear Doug talk about the designs. Thanks again Doug and Dave. Really awesome.
I watched this video before and after taking my first VLSI design class. After learning to design Opamps from Fets everything in this video makes sense. This might be one of the best displays of a good/real design process on RU-vid, everything is organic and logical
I think I've watched almost all the videos, but I skipped this series about microphones. But as usual, now I'm very interested in microphone techniques, and this is a gold mine! Thanks, Dave, yet again. The RU-vid channel that keeps giving.
Ok, so now I added some R0DE mics to my amazon cart :-) Thank you for doing this, and please more content like this. I really appreciate the deeper dives into practical analog
This video is incredibly educational and well explained in such a way that I enjoyed watching. Thank you for creating this. I designed my own preamp / mic processor and ribbon microphone from scratch and it's nice to see youtube has some videos out there like this to help people learn right from the source.
Years and several hour-long web searches later, and I think I have found Doug's jFET. Only match I could find is the Solitron FND15. Not a very common part; and I couldn't find that particular topology built from discrete components anywhere. CIA, you say? A conspiracy theorist might suspect that defense contractors have tried to redact all knowledge of this chip. By the way, we haven't heard anything from Doug in quite a while...
He mentioned Siliconix, and their Si1000 are a good match. There's an app note in their 1986 databook on using it for electrets etc. The databook is available on bitsavers.
This has been a fantastic series, Dave. Hope to see more from Doug in the future. Maybe you could get some other designers from other companies to discuss the products they've worked on too?
I love this video. Not only does it have a highly informing value, but is also very entertaining.... especially when the two of you have a great genuine laugh about them silly mic customers demanding more excitement in the upper range. I would say that many artists have way too much excitement in their own upper region (brain) anyways. Thank you for this great video D^2.
I dont know why in the hell im just now seeing this but it is awesome. Some of it is flying over my head at lght speed but im determined to be able to do this before im dead. I would love to see more of this type of content. Just designing different things.
Yupp, disconnected T bridge network, this is one hell of a mic now (even tho it was that allready, but less sibilant now). I'll have to do a tutorial on that.
I've zapped my lips a when using my first DIY valve amplifier + PA not sharing the same ground. Apart from the groin and heart, I think that's the worst spot to get zapped. It was the fastest lesson ever learnt.
I enjoyed learning about the construction of the NT1000 as I've experimented with it before, very easy to make recordings at low volume with this mic, and hardly any gain needed. Now I know why!
I went to Sydney uni electrical engineering, we did some basic opamp stuff, I wish we were taught more practical designs and testing. We did more maths with pen and paper and maybe some simulations. Thanks Dave!
Yeah, i feel like today you can explain things differently. like explaining how transistors work together to make "topologies" rather than too much math that you forget what you are trying to even do.
Do white board markers ever work properly? This video brought back memories of lectures in the 90's when lines were drawn, then drawn over again because they were faint, then drawn over a third time before the lecturer said "@#%& it" and threw the marker in the bin. Every lecturer saw two or three white board markers hit the bin :-)
learned alot from this series. Thanks. I like to tinker with wide band audio in CB communications. Now I have some better ideas for mic preamps and mic choices.
What a beautiful mind. I using rode microphones in my studio btw. Thanks for very interesting topic and some topology suggestions, very exciting. Especially at the hi end of frequency response :)
damn you and thank you very much for dominant pole compensation, i have a failed guitar amp that i could not troubleshoot; analogue audio amps were glossed over in college
My god! I would love it if an engineer would write "more excitement in this region" on the data sheet. I dont care what kind of device it is, but thats something that needs to be in a datasheet :)
Wow Nick, I needed this video, I have a ubit Xv6:2, the mic is the part I'm not happy with, the audio pre amp and compression, is the other part that, and here it is all together. Marvellous thankyou Nick , Paul M0BSW
That's an old but nice one with a real deal mike design pro! Very interesting and enlightening. Makes me wish I could work with Doug and learn tons of cool stuff he knows. 35V RMS? Then you just put a step-down transformer on the output, but then I'd just o for an all-tube construction putting the transformer in the plate circuit. I bet a low-noise +48V to filament and plate converter is perfectly viable especially if you go for a hybrid design where the tube (subminiature, preferably) is there for specific distortion rather than being an amplifying workhorse.
What a super series - absolutely fascinating! A big thank-you from me, Dave. I'm curious about one thing. Doug used a JFET in the early part of the video, which I might understand to be because of their high input impedance and low noise (compared to say, a BJT). Would a MOSFET also be ok in that position or is a JFET preferred? Thanks for any light you can shine on this point.
MOSFETs are pretty much all enhancement mode devices, which means the gate sits at a voltage somewhere between the source and the drain and it's a pig to set a reproducible dc bias point. JFETs, on the other hand are depletion mode devices, and their gates sit at a voltage below the source, making it easier to set a dc bias point, especially if you have a source resistor to stabilise it.
Rob B I just know that designing digital systems exclusively is on their own often a very challenging work. And from my today's point of view, I simply like it more.
14:33 Amateur question, why don't they add the different transfer wobbles with EQ? *presses play again* Oh, I see. So it's really just the "buy more stuff and show it off" drive.
I'm a mining engineer, I'd love to see a very low frequency mic schematic or a tweak to one of those mentioned that allows for very low frequency pickup.
Your best video yet. But i cant stress enough: your trade is a SCIENCE. Recording music is an ART. If your favorite songs were recorded with flat freq response mics and everything dead flat - quite simple they wouldn't be your favorite songs any longer. It's OK... we laugh at product engineers and electronic technicians also at some choices made. That guy in your video (ex-Rode) is an absolute genius. I use both the NT1K & NT3 every week! Great mics are some of the others made by Rode. Lately seems they are to focused on consumer level goods however - worryingly.
I'm with Dave. As an engineering "purist", I'd suggest a flat response at the preamplifier and let them boost treble at the mixing board. That is ... unless that preemphasized response were part of an accepted industry standard. (Or at least make it switchable for customers who DON'T want it.)
Thank for a very good lecture on condenser mic pre-amp's , especially on the valve pre-amplifier; is there limit on the Ht supply voltage on the condenser element when useing valve pre - amp
I still don't understand how to use BJTs because of their nonlinear behaviour. It's confusing. I am going to play with some JFETS or MOSFETS, because of their more linear response. (Mind you, my background is from mathematics, so I want things that are more ideal/linear.)
A BJT has an intrinsic exponential relationship between base-emitter voltage and collector current. An FET has an intrinsic square law relationship between gate-source voltage and drain current. Neither of them is linear, and transistor circuit design consists of ways of using them in such a way that the effect of variance in transistor characteristics becomes negligible. Good luck with the MOSFETs and let us know if you manage to bias one to your calculated design without using a trimming potentiometer.
EEVblog, and I'm SURE you wouldn't mind a few thoughtful people "borrowing" that low noise power supply configuration (around the 30 min. mark) for a modern preamp... would you? LOL
When you run a dynamic mic with the phantom power on it can be hard to sing. Happened to me on a mixer that could only have phantom on or off for all inputs rather than individual inputs.
@EEVblog: Even by watching the video again (don't know how many times) I can discover some new details again and again! I also liked the frequency with the little more "woohoo" very much. :-D That kind of videos are very interesting and very well in teaching electronics basics and circuit design - wouldn't that be good to have some more of those type of videos? Maybe (if you are allowed to) some more out of your field of operations back from your days at other companies?
The one thing I don't like about Dave is that he tries to finish everyone's sentences to show that he's aware of the topics too. This may be due to an insecurity about where his knowledge level is. Other than that, great stuff.
I was thinking the same thing when I was in EE school some years ago. It comes with practice. Read some electronics books that aren't your textbooks. The Art of Electronics (Horowitz and Hill) is a must. It's expensive, but worth it. Anything by Bob Pease, Jim Williams, and Doug Self. Cheap but harder to find: The old databooks (both tube and transistor) from RCA and GE. The old US Navy electronics course materials. The ham radio stuff from ARRL. Try libraries, used bookstores, and EBay for the old stuff. Find schematics of things that interest you, and study them. Model them in SPICE and play with each segment of the circuit until you understand what each voltage and current is doing. Try making them better. Try making them worse in interesting ways. Cut and paste bits from different circuits and learn to make them work together. Then try to build them with real parts. Use them, test them, modify them, break and fix them. Rinse and repeat. You'll get there!
