MN3011 Are Available

Started by smallbearelec, June 03, 2005, 12:16:45 PM

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Mark Hammer

Quote from: smallbearelecHi Mark--

My policy on obsolete BBDs has always been to refuse requests for bulk sales from my stock and discourage hoarders (other than me). In the interest of making the profits that help fund the less-lucrative DIY business, I have from time-to-time brokered a bulk sale of scarce items. But what's on the stock list will always be "retail only."

SD

Well, fella, that's pretty much why we love you. :)

Mark Hammer

Quote from: James PMark, Puretube et all, i've been thinking about making a replica of the Fender Reverb unit to go inline with my Tweed Deluxe (ala Neil Young) but haven't got the time or money at the moment to make one from scratch. And besides, i'm not really learning something from building a clone...

Is it a feasible project to build a similar sounding unit using the MN3011 as the core of the device to be placed before the amp input?

If so, would anyone be interested in helping as i'm in a bit over my depth here, but very keen!!

Regards

James P :D

Go spring.  Seriously.  Go spring.  As much design potential as one of these chips has, tere is no innate capacity for it to go "splat" when a huge transient hits it.  The only things that BBDs do as a function of signal level is provide better and worse S/N ratios and more and less distortion (the evil kind).  Springs, on the other hand, change their behaviour in interesting ways depending on input level, which is why the much desiredFender unit is so much-desired: the Dwell control sets the amount of drive to the springs and  creates the potential for many different personalities and textures.

When there is a choice of technology A and technology B,

and

A is rarer than B

and

A can "fake" B in a barely acceptable manner

but

A does something that nothing else in the world can do....

I would always recommend using B for the task *it* does best, and A for the task *it* does best.  I mean, ask yourself, where would Tom Brady be best used, as QB or working at Arby's?  Where does Tyra Banks belong, on a runway, or as the rental agent in that apartment across town?

Go spring.

Ry

QuoteThis is one of those rare instances where the question "What were you planning to build with it?" is an interesting one.

I was planning on using the STD-1 documentation as a starting point for a fancy flanger/chorus unit.  It seems like the possibilities of this chip are amazing and that it will be able to make a really fantastic sounding flanger...with some work.  The schematic is intense to say the least.

Ry

DiyFreaque

QuoteWhy aren't people jumping for joy on this one? This was a "holy grail" chip.

Because I'm too busy genuflecting in thanks at the Small Bear Altar!

Sheesh, miss a couple of days of this forum and see what pops up!

Three Huzzahs for Steve!!!!!!!!!!!!!!!!!!!!!!!!!!

Cheers,
Scott

Mark Hammer

Scott,

Should something Steve discussed with me off-line a week and a half ago come to pass (and I will stay mum about WHAT it is since it is very tentative), a fourth huzzah will definitely be in order from a bunch of people.

Ry,

That IS a good place to start, and it's where I'm starting from too.  As is true with many of the Matsushita chips, it is easy to confuse what the MN3011 datasheets say (based on textbook use of the MN3101 clock chip) with what is true of buffered clock lines.  It is quite possible that more exotic sweeps are possible if you play your cards/chips right.

Note that, regardless of which Matsushita (or Reticon, or Philips) chip one uses, the faster the clock rate, the less necessary drastic measures for noise reduction become, since the clock and aliasing start to move well out of the audio range.  That doesn't mean one can be sloppy or slack about dealing with noise, but perhaps companding might not be as necessary as it might be for some other circuits.

Also note that one of the things this chip permits is a *true* stereo, or rather 95% true stereo.  A true stereo would, of course mean that whatever comes out of each side is entirely different.  A 95% stereo would imply that what comes out of the two channels is sufficiently different that mixing into mono in air (e.g., while listening to two amps/cabs) produces little or no cancellation. So, if tap 5 and tap 6 are each assigned to a different output, and you have just a bit of regen, the "stereo machine gun reverb" possibilities (where each repeat comes out of the opposite side in rapid fire) are very nice.

Perhaps the one feature/effect that I find most provocative (perhaps because I've never heard it) is what they call "Cloud Flanging" in the manual/brochure.  This involves using different taps for the flanging effect than are used for the regen path.  Absolutely nuts.

Okay, now imagine a modded STD-1.  Okay, now pick your jaw up off the floor and clean up your pants.  They're, uh, a little soiled.

And here's the kicker.....Zach could NEVER fit it inside a 1590B! :D  :D

DiyFreaque

QuoteShould something Steve discussed with me off-line a week and a half ago come to pass (and I will stay mum about WHAT it is since it is very tentative), a fourth huzzah will definitely be in order from a bunch of people.

Hopefully it's the same stuff a certain un-named, non-email-returning company I tried out offers......

QuoteAnd here's the kicker.....Zach could NEVER fit it inside a 1590B!  

I wound up putting the Dim C in a rack.  What I want to do to...er...with the 3011 will probably eventually fit into a 57 Chevy.

Cheery,
Scott

SeanCostello

One bit of advice: If you want a nice long reverb time, you will not get it from a single MN3011 with feedback taken from multiple taps. Delay lines like to have their feedback from a single tap - otherwise, the frequency response will be such that certain frequencies will have a gain greater than other frequencies. The result is a very colored reverb, that will probably result in runaway oscillation before you get a long reverb time.

I'm not saying that taking feedback from multiple taps won't make an interesting sound, especially in an analog system (where the maximum feedback amplitude is limited, which results in a nice self oscillating sound). Listen to "Maggot Brain" by Funkadelic to hear the results of a multitap tape delay with feedback around the whole system.

You could get around this by using 2 or more MN 3011 chips in a system. Each chip could have its own feedback path, or you could combine the feedback paths using unitary matrices (see Gerzon, Puckette, Jot for details).

Sean Costello

James P

Quote from: Mark HammerGo spring.  Seriously.  Go spring.

Thanks Mark, looks like i'll be making some turret board then!!! Thanks for your opinions guys. I do love the sound of the Fender Reverb unit but getting the right trannies and a 6K6 here in the UK is a pain, and i thought if I could get close to it using BBD technology it would be suitable. Looks like i'll have to dust off the big iron then!!!

Regards

James P
If i'm not back in 5 minutes, just wait longer...

DiyFreaque

QuoteOne bit of advice: If you want a nice long reverb time, you will not get it from a single MN3011 with feedback taken from multiple taps. Delay lines like to have their feedback from a single tap - otherwise, the frequency response will be such that certain frequencies will have a gain greater than other frequencies. The result is a very colored reverb, that will probably result in runaway oscillation before you get a long reverb time.

Tom Scholz fed the longest tap through an additional MN3007 for regen on his Rockman reverb.  It's been years since I heard a true Rockman, so I couldn't say how long the reverb sustained with it.

He also employed a gate on the front end to block any short transients from getting through and causing things to get all pingy.  The idea was that the time it took the gate to open was a bit longer in time than what qualified as a transient, but much shorter than what qualified as an intentional signal.

Patents are out there - I'm sure Ton probably knows the numbers right off the top of his head  :D

Cheerio,
Scott

Mark Hammer

Once again, the beauty of the multitapped chip is that you can slave another BBD to the same clock at just about ANY point.

For example, pack a simple MN3007 *ahead* of the MN3011, and you now have 4352 stages, with preceding taps at 1420, 1686, 2218, 2750, and 3814 stages (and I suppose 1024 as well if you wanted to use it).  If you stuck an MN3008 ahead and slaved it to the same clock, the taps would be at 2444, 2710, 3242, 3772, 4838 stages and a final output at 5376 stages.  Not too shabby.

The method for demonstrated in the datasheet for "balancing" the taps and taming any coloration is a sextet of different value mixing resistors.  The "57 Chevy-sized" thing I outlined would use pots for colorizing and decolorizing instead.  I might point out that anyone wishing to go absolutely positively nuts with this is entirely at liberty to consider use of tap-specific filtering, since each tap CAN be treated as an independent signal source in the feedback path.

Do you start to get the feeling that the reason there were few commercial products with this chip was because every time someone sent off a designer with some chips, a breadboard, and a free hand, the person always ended up in the psychiatric ward? :lol:

puretube


analogguru

Aria used the MN3011 in their Rock-Treck I (ME-30).

This unit was also sold under another brand name as Step-I

Nobels used the MN 3011 in their SST-1X (SoundStudio).
They used a 3007 ahead of the 3011 and had a stereo arrangement.
(I bought mine for $ 20,--  :D )

Schematic is not on the Nobels-website as far as I know.

analogguru

Mark Hammer

Actually, now that you mention it, didn't Gallien-Kruger use one for "reverb" or am I confusing it with a Scholz/Rockman product?

Twenty bucks, eh?  Lucky dude.

Joe Kramer

Hi!

The Arion SRV-1 pedal uses two MN3011's.  But, IMHO, given the oppurtunities available with this chip, Arion bungled it.  The pedal sounds tin-cannish mostly.  I don't have a schemo for it (does anyone?), but my guess is that they went with feeding back many or all of the taps, instead of only one, which is the recommended way to get a psuedo-natural reverb sound.  Too bad, but maybe it could be modded, or,  as a last resort,  CANNIBALIZED!

Joe
Solder first, ask questions later.

www.droolbrothers.com

DiyFreaque

I've just toyed with a couple of definitions for my cake-and-eat-it-too multi-tap delay synth module.  57 Chevy ain't going to quite cut it.  I'm looking more into a Packard chassis.

Mark, I'm ready for the straight jacket now.......

Cheers,
Scott

MR COFFEE

Hi Mark,
Yes, You are exactly right. G-K used the Mn3011 along with a Mn3007 in a slightly different configuration from the Rockman reverb using the same pair of chips, and yes, it sounds pretty damn good and doesn't go "boing" if you nudge it by accident. Gallien-Kruger used in the the 250ML and some of the head-only versions (Iron Maiden wouldn't play through any other head according to their roadie) that didn't have the 6 1/2" speakers.

I built an analog delay reverb using 4 of the the buggers back in the 80's and it was pretty damn good for those days... but noise IS an issue. Any ol digital reverb you can buy now sounds better. But for chorus and flanging, ohh yeah!!!!!!!!! :D Great chip!!!!

Especially if you clock it fast. :D
Bart