Schematic of 0.5 msec Analog Delay for Through-Zero Flanging

[stm]

Puretube:

Can you tell me which are those cheap IC's?

Mike:

Which is the karaoke approach? Is there an IC?

Regards,

STM

[Vsat]

Ed and stm,
The karaoke approach does indeed use the  Mitsubishi or Princeton echo chips.. one is a fixed delay, while the other delay is variable and voltage-controlled (analog clock, smooth operation.... no digital stepping). It is possible to make fixed or variable delays considerably shorter than the 100 mS minimum specified for these chips.
Regards, Mike

[puretube]

"karaoke approach", coz those chips
http://diystompboxes.com/sboxforum/viewtopic.php?t=25250
are mainly used in far east karaoke toys/amps for adding a little echo/verb.

I was referring to the stock BL3207/8 BBDs currently produced in China
-Smallbear got`em-
(as opposed to expensive scarce NOS/surplus chips)

[stm]

Puretube:

I feel you have some negative vibes about the NOS expensive and scarce BBD's.  Don't disregard that the MN3007 has over 80 dB of signal-to-noise ratio, as opposed to the 73 dB specified for the BL3207.  A chorus made with the latter surely needs some sort of noise reduction.

Regards,

STM

[Mark Hammer]

Don't disregard that the MN3007 has over 80 dB of signal-to-noise ratio, as opposed to the 73 dB specified for the BL3207.  A chorus made with the latter surely needs some sort of noise reduction.

Just for clarification, as the Matsushita line made the transition from earlier versions that used a higher supply voltage (MN30xx) to later ones that could work with much lower supply voltages (MN33xx), S/N ratios dropped.  I gather this had something to do with headroom available at the various supply voltages.  This should NOT be confused with any differences between the Matsushita and Beiling product lines.  It is entirely possible that Beiling's quality control is not the same as Matsushita's was for the same product; I honestly couldn't say but it still can't be dismissed outright as a possibility.  However it would be a mistake to immediately attribute S/N differences between the MN3007 (w/higher supply voltage rating) and the BL3207 to differences in product quality.

Bear in mind that S/N specs are derived from steady-state tones, not the highly varying music input signal such devices are going to process.  My sense is that if you broke down a typical music signal into those msec fragments where the input signal was at the max level that clean headroom permitted, and those fragments where it was far below that, the average S/N ratio of any BBD made by anyone is likely to be < 60db most of the time, in which case noise reduction of some form, whether brickwall lowpass filtering, companding or whatnot, will always be called for, whether one's layout is flawless of not.  

BBD's are like the Stephen Hawkings of the music processing world - they have much to contribute that is delightful and inspiring, but sonuvabitch they need a lot of technical support.

[puretube]

I just have mixed "availability-vibes" about the MN3007, which I`d otherwise prefer due to headroom&S/N.
If s.o. offered me 2000pcs for under 2K$, I might think things over...

For similar reasons I stick to 12AX7s in my tube-projects...


EDIT: just noticed Mark`s post (been distracted by a phonecall, right after starting this reply...), and totally agree with him!

[stm]

I never meant to imply that the BL units are lower quality than the MN (either made by Panasonic or Mitshubishi).  I am familiar with the specs variations regarding the different operating voltages.  In fact, the MN3207 has the very same 73 dB S/N ratio as the BL3207.

I'm pretty sure that the guys from BL didn't reinvent the wheel, and it is very likely they acquired the know-how and rights to produce mentioned IC's from Panasonic or Mitsubishi (or whoever owned them) after the product was discontinued.  As such, it is very likely to be a real close substitute.

I agree also with Mike's comment regarding the nature of music; it is very likely that you will ever take full advantage of the dynamic range of a device (and in consequence its S/N).  Anyway, specs are specs, and the lower the S/N the better.

[puretube]

OTOH, the S/N ratio is related to a nom. signal level which is about a quarter Volt, for less than 0.5% THD;
- well I don`t mind running a guitar signal of over half a Volt in there -
(I call it BBD-saturation),
as long as the bias is centered nicely, the "clipping" is tolerable, and the noise is a couple of dBs lower than this signal level...

[StephenGiles]

I put my English tongue in cheek and pontificate that the fuzz box brigade may not be over cautious about S/N ratio in such a flanger, and might "just" be happy to see the NE571 dealing with surplus noise! But that might up the parts count over the edge for some, unless perhaps the Bel Noise Reduction circuit is used which might make it worthwhile.

STM - surely if one half of SAD1024 has fixed delay, it will need a separate clock from the modulated clock used in the other half, and I'd wager $10 worth of pirate CDs from Quito that would introduce some fairly quaint noise to the equation.
Stephen

[stm]

Stephen:

I agree that if you build a dual-clock dual-BBD circuit on a protoboard, perfoard or single-sided PCB you will have all sorts of intermodulations, birdies and artifacts for sure.

On the other hand, if you use a double sided PCB, with one side devoted to the ground plane, keep separate analog and digital grounds just joined at a single point, use tantalum plus ceramic decoupling capacitors on the supply pins of each and every IC, filter independently both BBD's outputs, and do a careful signal layout (i.e. avoid running clocks near audio lines), my feeling is that IT SHOULD WORK PROPERLY.

I don't think its impossible. It's just harder to do (IMHO).

:roll: Mmmhhh. this sounds like a challenge to me: "bust the don't use two unsynchronized BBD's myth"  :wink:

I have experience with high frequency digital and analog electronics, as well as microstrip and RF PCB design techniques. My former job was for a solid-state AM/MW transmitter manufacturing company, where I participated in the design of a 100 kW transmitter (currently on-air in Belo Horizonte, Brazil).

Regards,

STM

[StephenGiles]

STM
I see what you mean. PCBs of any sort are what other folks make to me so I wait patiently!!!!!!! Still now that you've mentioned it, I may well give it a try - on protoboard (is that breadboard?) at any rate. Too many things to do, not enough time! It's bad enough after 2 week's holiday getting used to routine household chores after being waited on in hotels.
Stephen

[puretube]

I don't think its impossible. It's just harder to do

absolutely correct!

(I`m quite sure you can do it.... :wink: )

Mmmhhh. this sounds like a challenge to me: "bust the don't use two unsynchronized BBD's myth"  

iirc, I posted a pic of my approach a few months ago...?...

[stm]

Puretube: thanks for the confidence vote!

Stephen: I call protoboard the white plastic board with many holes connected inside and stripes devoted for power supply. I tend to think of breadboarding as any means of building a circuit prototype.  That's the way I see those terms (english is not my native language).

Regarding the use of protoboard for the dual BBD task, I think you will be able to test your circuit and see how it sounds, however, you will have a bad time with the intermodulation, especially if you raise the regeneration level. I don't think it will be possible to eliminate those artifacts at this level.

After you have something you like, you may have to go for a well designed circuit and PCB as I described above.  It will be a bet or "leap of faith" to take that step, though.

Good luck!

P.D. I understand your housekeeping blues. Fortunately here in Chile it is still reasonably priced to hire someone to do the house cleaning, laundry and cooking.  When the person is sick or on vacation then my life as I know it collapses!  Just picture me trying to take a nap after a hard week at the office with my two daughters jumping on top of me.

[StephenGiles]

Ah - you live in Chile! You have probably read that we were in Equador from 2 - 12 September, a wonderful country. My wife, who is Anglo-Argentine, is planning our next holiday in 2005 to Argentina - can't wait. I don't think we will visit Chile this time, but we plan to return to Equador sometime in the future, and we may spend a few days in Chile at that time.
Stephen

[stm]

Stephen:

If you ever come to Chile just let me know so we can arrange a DIY meeting.  I'm pretty sure our wives will have plenty of things to talk about too.  

Regards,

Sebastian Tepper, aka STM

[puretube]

iirc, I posted a pic of my approach a few months ago...?...

before: (with "birdies")


after:

[StephenGiles]

I discovered a link to this thread on which the last post was 8 years ago yesterday! Well worth another read through.

[puretube]

...dunno if it was mentioned in this TZF-thread or in another one,
but I still don`t like the total signal annihilation at the culminationpoint...
(that`s why the Flanger-Hoax got a switchable (frequency-dependant) "almost annihilation option")
[Mark: again not mentioned in the user`s manual...]

BTW.: "the market" just got a new TZ-flanger: The "Tunnelworm" by Mr. Black-pedalz...
http://www.mrblackpedals.com/products/tunnelworm

[Mark Hammer]

Again, most of the benchmark examples of TZF that we are all familiar with have usually been applied to a mix and seldom to a single instrument.

Maybe "almost annihilation" is what you want for a single instrument, and through zero is what you want for a synth or mix?

[armdnrdy]

I agree with "whole mix" and "annihilation" for a single instrument. If you've looked around Dave Foxes sight you would have found numerous mentions (almost to the point of arm twisting!) about putting a fuzz box or distortion before the Paradox. Dave even states that if you are the kind of guitarist that plays with a distorted amp and doesn't use distortion boxes, maybe this isn't the flanger for you!

I take this as sort of a disclaimer for the potential disappointed customer. If one plays through a through zero flanger without the fuzz/distortion in front, it is not near as impressive and "in your face" through zero flanging. (You have to listen for it or you'll miss it!)

I've been working on a variable gain, adjustable tone, fuzz/distortion section (glorified built in fuzz box) to incorporate into a through zero build that I completed. Along the lines of the Jet Phaser/Final phase idea but with a flanger.