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Flickinger consoles - where was the "magic"?
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Geoff738
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#1
1st February 2012
Old 1st February 2012
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Flickinger consoles - where was the "magic"?

Ok, I understand they were all a bit different. Maybe more than a bit.

but do you think it was mostly the pres, eq, summing. the fact they kept the studio toasty warm?

Some think they were the best sounding board ever. Why? What in particular? Again, pres, eq, summing, lows, mids, highs?

Very doubtful I'll ever hear one so, what about the skibbe pres and comps (and whatever else)? How do they stack up to the real thing?

Seminal recordings? Sly, Boston (er, not sure I hear a lot of sonic similarity there), others?

Thanks!

Cheers,
Geoff
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1st February 2012
Old 1st February 2012
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Quote:
Originally Posted by Geoff738 View Post
Seminal recordings? Sly, Boston (er, not sure I hear a lot of sonic similarity there), others?
I think Funkadelic? And/or Parliament.
bee
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1st February 2012
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I'd contact Bill Skibbe at Key Club Recorders for Flickinger related questions.
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1st February 2012
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In my experience, there are two dominant things responsible for the sound character of Flickinger consoles:

– The 535 op amp
– The 150 ohm input impedance in the mic pres

I've had the good fortune of talking with Dan himself a few times, and I once asked him to respond to the charge that the 535 was a "ripoff" of the Spectrasonics opamp. He admitted without hesitation that the topologies were very similar, but pointed out that although the Spectrasonics opamps boasted excellent performance specs, "they didn't sound very good, and I figured out why."

He went on to explain that during transient peaks, when the opamp was pushed toward clipping, the Spectrasonics circuit "collapsed" resulting in an unstable and unpredictable condition during the duration of the transient. This type of thing could easily be overlooked during basic audio performance testing using sine wave test tones.

Dan's contribution was to tweak the circuit until the opamp was better able to handle transients. I assume it had to do with tweaking the bias and operating conditions of the various transistors, but I don't know.

I suspect this is also the reason for the low input impedance. Lower input impedances typically reduce the dynamic range of a microphone's output, therefore reducing the likelihood of overloading the opamp even further. Basically, he took an amplifier design that was great under most conditions and terrible under some, and made sure the terrible conditions wouldn't happen.

The 535 sounds amazing when powered by the +/-24V power supply rails that it was designed to run on. Running it on anything less defeats the point of Flickinger's improvements (IMO), because lowering the supply voltage correspondingly lowers headroom, and transient response relies on good headroom. Worse, the 535 can't drive low impedance loads when powered by lower voltages. It basically turns into a square-wave generator, with a wide spread of all harmonics. Maybe it doesn't matter if you're always plugging straight into a recorder with a 20k input, but it's still a step in the wrong direction when you consider the tedious tweaking they did to get the thing to perform as well as it does.

The best thing about Dan Flickinger is that he was (is) a seriously creative problem solver. Many of his designs were based on other people's ideas, but he contributed significant improvements to them and made them his own. He said something like, "I was always interested in concepts. I didn't care about the absolute values of circuit components, etc. I was more interested in coming up with ideas and getting my other engineers to implement them."

Case in point: Flickinger was (arguably) the first person to use degenerative and regenerative feedback in order to achieve an adjustable Q and sweepable frequency equalizer, but he gives credit to George Massenburg for figuring it out too and publishing it first, and for giving it the name "parametric."

"I just called it sweepable."
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Geoff738
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3rd February 2012
Old 3rd February 2012
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Good stuff!

I'm pretty sure I read - possibly in a thread here - that a few consoles made their way to Nashville and more than one of them caught fire as they ran really hot.

Did Gamble and Huff have one as well?

Cheers,
Geoff
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9th February 2012
Old 9th February 2012
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For a rock album theres: 18th Dye's _Tribute to a Bus_.

There were about 25 Flickingers consoles made. From my count.

I've worked on a half dozen of them, and I can say for certain very little was ripped off directly from other makers (like the Spectra Sonics of the period, as well as the Auditronics and quad eight). They're different circuits, period.

Dan's additional urge was to make his opamp affordable. (this is the 535 that electronaut was talking about). Go read his patent on op amp design. He states low cost as one of his motivations.

This is good, as he was able to fit more op-amps onto the little 5" square cards of the first parametric EQ's. Being low cost had the side effect of having a simple signal chain, something you have to pay a lot more for now!

The EQ's often have 4 discrete op amps and 3 discrete open loop buffer amps on the little board. They work, and they're very effective with 15dB cut and boost labeled, which as measured is more like -18 and +17 if I remember correctly (for their max settings). The board is very dense--the densest of anything from that time audio or otherwise from what I have seen.

Distortion is about 0.05% for normal audio levels.
The typical configuration stays class-A in _all_ of it's circuits up to +12dBu.
The max output level (from an EQ) is +25dBu ... 39 Vp-p !!!
You obviously don't get 39 Vp-p off 15V rails.
All lines in and out are transformer coupled, all 600 ohm impedance.

There were things that happened at the Flickinger factory that are so amazing, it's difficult to imagine there being much copying being done of other companies. Go back and look at trade literature for 1972. (Google books is a start). The Flickinger consoles in the ads are WAY more advanced than the offerings by anyone else. It's only when a couple years later when everyone adopts IC chips, that you see the functionality catch up. But the Flickingers, especially the earlier ones, are all-discrete for everything.

One significant reason these consoles sound so ?natural? is the mix topology. I can't comment on the later consoles that used FET switching for this role, but the early consoles, and the more mass-marketed consoles use nothing but silver plated switches and metal film resistors for the mix buses, along with a forward referencing grounding scheme.

This means that the entire mix is wire, resistors, and one summing amp, followed by a transformer. So the entire mix bus uses a total of 8 transistors running in class-A up for all but the crests of hot waveforms.

Flickinger did a lot of experimentation with FET switching of audio on the later consoles. From the bits and pieces of this I've seen, these implementations were a bit too cutting edge. The Sly console, the Sound Pit console and the monitor controller from the Paragon console all used this approach, and it's not clear that it was a good one. There may be other opinions, but it's hard to beat a signal path devoid of anything but copper wire, precious metal relay contacts, transformers and class-A amplifiers (no fet switches, no VCA's e.g.).
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10th February 2012
Old 10th February 2012
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Quote:
Originally Posted by lektracoustics View Post

All lines in and out are transformer coupled, all 600 ohm impedance.
I always wondered if the 150 ohm inputs on the preamps and schematics I've seen were some type of oversight. The input transformers were terminated by a 604 ohm resistor, which would create a 600 ohm input if they were 1:1, but the transformers were configured as 1:2, so they actually loaded the microphone with 150 ohms. I wonder if the design originally called for a 1:1 and when they changed it, they forgot to recalculate the termination resistor vaue.
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14th February 2012
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That resister is usually chosen to control the high-frequency response. To dampen the transformer's resonant point. Some people will say 'square wave response', which is the same thing. I'm not used to seeing a value as small as 600 ohm for this role.

For the Flickinger it turns out that this value is better for the input noise of the op amp as well as making the transformer work for it, if you will. The first is probably deliberate, while the second may be witchcraft.

The relatively large amounts of low-end distortion in the original transformers is partly due to the fact that this resistor is there. It's also due to the transformers being small.
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15th February 2012
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Quote:
Originally Posted by lektracoustics View Post
That resister is usually chosen to control the high-frequency response. To dampen the transformer's resonant point. Some people will say 'square wave response', which is the same thing. I'm not used to seeing a value as small as 600 ohm for this role.

The relatively large amounts of low-end distortion in the original transformers is partly due to the fact that this resistor is there.
I'm putting my money on this theory:

They were overly optimistic about the noise floor of the 535 and chose a 1:1 input transformer terminated by 600 ohms. The 600 ohm resistor was there to create a reflected load impedance of 600 ohms for the microphone. Then they realized the noise floor was higher than they thought and rewired the input transformers for 1:2, and forgot to swap the resistor for a 2400 ohm value to keep the microphone's load at 600 ohms.

That's the only thing that makes sense to me. I find it hard to believe that they would need a 600 ohm resistor to dampen resonances. If they really needed a value that low, it seems like they would have done the more common thing and put a cap in series with it (Zobel) and tuned the network to the resonant frequency, therefore avoiding the low frequency distortion caused by it.

lektracoustics, did you happen to notice if the consoles you've worked on were also set up with 1:2 input transformers terminated by 600 ohms?
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17th February 2012
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Concerning Flickinger input turns ratio:

I have a modern-vintage knockoff of a Flickinger preamp. The guy I got it from said it was copied directly out of a real Flickinger console.

This preamp has a Lundahl 4:20 (wired as 1:5) input transformer ...

Oh, and it also has a 600 ohm resistor across the output. So, maybe this is where they're getting that little bit of extra mojo ... that extra special sound.

But yeah, it's a rookie mistake from an engineering point of view.
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17th February 2012
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The transformers in my console are wired to a nominal 1:1 ratio, with a 600 ohm load. All 16 of 'em, except for the one channel I sent to Triad Magnetics when I was reverse engineering them.

The other thing that may be helpful to know, is that of all the ones I went through there were several with different DCR's for the windings, indicating that different wire gauges were used. From my tests the differences from one to the next suggested occasionally mixing up wire gauges (as opposed to lots or wire composition) based on the step size in DCR change.

This was a QC issue in the original manufacture, a lax spec, a low-grade part, or simply the best practice for 1970/71.
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18th February 2012
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Flickinger consoles - where was the "magic"?

Not to say the Flickinger isn't special, I'm very intrigued by it. But I'm pretty sure we've got some of the "magic" right here:

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11th May 2012
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I bought one of the Skibbe 736's and it sounds rightous! The closest thing i can compare it to is my Electrodyne 501. It is very similar in color, but has a bigger bottom end. The Electrodyne is more focused in the low mids, but doesn't have the heft on the bass drum. I am definitely going to buy another one of the 736's although I wish it had a di input on it. I cut a couple of records on a Flickinger desk back in the 80's down in Nashville at Ray Stevens place . The console was 32 channels and had a push button programmer like an 8128. I remember the console sounded huge. I wished later that i had bought it when they got rid of it! Anyone know what happened to that console? I would be very interested to do a shootout between the original preamps and the new ones. Does anyone have any of the originals?
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7th June 2012
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thought i'd chime in and set the record straight..

the 535-7 performs quite well on +-15v. a bit less headroom, a tiny bit more distortion, (as expected!), but not a square wave generator by any means.
the pads are still on the pcb for voltage converters to bring the the power up to +- 24v. this is a simple modification, and if anyone is interested i can provide part numbers. (the addition of the converters will void the api vpr certification!).


i would like to point out that the 535 is NOT unity gain stable! flickinger has the need for speed! this is a big factor in the sound of the desks.. the amp runs at about 12db of gain.. and then is padded back down.. completely "wrong" from a design standpoint.. but the consoles do sound amazing!.. (and if you open up the channel you can get tape hiss simulation for protools!)..

the sound of the flickinger console is anything but "natural". thats why i like them.. they sound hyped, especially on the low end. big and thick like a 1073 but with an extended bottom. less focused in the low mids.. and a rounder, very smooth top.. less sizzle than a 1073.. i had a bcm 10 in my studio for a while and it was similar enough to the flickinger that i sold it and bought a melbourne and couple of 49's.. couldn't justify the $ tied up in it for such a similar sound. the melbourne sounds sooo different.. bright and tight.. i like it for different things..

there were several different eq's...but the first sweep "4button" was designed by j.weit, and the second.. "6 button" by bill isenberg.. both sound fantastic.. very musical.. 3 band, hipass, shelving on the hi and low bands.. the 4 button is non reciprocal.. and has about 12 db cut/boost.. the 6 button is reciprocal.. has a bit more cut/boost and individual in/out for each range..

Quote:
Flickinger did a lot of experimentation with FET switching of audio on the later consoles. From the bits and pieces of this I've seen, these implementations were a bit too cutting edge. The Sly console, the Sound Pit console and the monitor controller from the Paragon console all used this approach, and it's not clear that it was a good one. There may be other opinions, but it's hard to beat a signal path devoid of anything but copper wire, precious metal relay contacts, transformers and class-A amplifiers (no fet switches, no VCA's e.g.).
it is not clear it was a bad one... no switch crackles! my console is still going strong.. built in 1970.. i haven't had any of the problems of the earlier flicks (or any other consoles from the era) with the pushbutton style matrix.. imagine 720 dirty, broken switches.. also i think it is foolish to question the sound of the fet consoles...ike and tina (nutbush!), sly, pfunk, ray stevens, johnny cash, glaser brothers (waylon!), sound pit (bohannon!)... and mine is still making hits today.... ha! maybe distortion from the FETs is the secret to the sound?!

i have done many tests with opamp/transformer combinations, and i can say the the transformers play a huge role in the flickinger tone. we've also tried a variety of different op amps in place of the 535-7.. and the magic is in the combo of the amp and the trannies.. (and tantalum caps)..go figure..

two more things..
one... is that i've found that quite often the flickinger schematics differ from the actual circuit.. i think that they were never corrected..maybe it was out of laziness, or just the fact that they were hurrying to get done.. and besides ..the schematics weren't intended to be distributed to the clients!

two.. i don't believe that any of the flick consoles caught on fire! i know that marty feldman of paragon studios had one of the first m56 machines go up..(before mincom put the pancake fans in).. and he had a flickinger.. maybe the stories are getting crossed..

remember that more often than not.. a byproduct of the designers original intention is the the thing that people like about gear! (sorry guys!).. there are so many factors that go into designing gear (price point, availability of components, deadlines!).. the final "sound"...the thing producers and engineers will latch onto... is completely impossible to predict from a design standpoint..what a designer may consider "wrong" is actually the factor that makes the gear sound good! look at neve! he wouldn't design a 1272 again! that is why its important to get the gear into the studio and use it everyday.. try it out.. put it up against other gear..very revealing!

crayotone... i will consider a di on future runs of the 736.. i just liked the aesthetic without a di.. contact me off forum and we can talk about doing a side by side comparison of originals and the 500 series 736.. ray stevens console was sold by blevins years ago, and has been parted out! you are welcome to come to the keyclub and record!

Geoff738 if you'd like to try out some gear.. please lemme know.. we have demo units out there!
cheers
bill skibbe
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