Flickinger 535 op amp schematic

[hodad]

Anyone have any idea what the originals were? The earlier ones were TI epoxy type with what looks like a 2N4036/7 output pair?

2N3566, 2N4294 (I think--I tend to transpose numbers on this one), a couple more 2N3566,  then a 2N2102 & a 2N4036. 

 

[syn]

2N4249 it is.

Anyone knows the original values for feedback network and gain network for these? I  used 51k+22p for feedback and 50k pot+4700u+470r for gain and it works well, but I was wondering about the original values .

 

[hodad]

You may get some insight from this pic:  https://www.flickr.com/photos/101051783@N04/9705208226/

These cards are purpose designed for modding a Spectra Sonics mixer, but there's info to be gleaned from the picture. 

On the upper amp of the dual card, the feedback  resistor is the 10K7 (or the passive EQ that can be switched in) that is standard on SS mixers.  Both lower & upper are set to give about 20-ish db of gain (I've measured--it's easier for me to do that than do the math.)

 

[syn]

Thanks for the  info.

 

[Bill Wilson]

Dan Flickinger direct copied some Spectra Sonics circuits. Spectra was started & owned by William Dilley. He sued Flickinger & Dan disappeared from the scene around 1975. He was a very corrupt person who thought he could get away with outright theft.
No one knows where he disapeared to.

When I was service Mgr. for the Nashville MCI Dealer; I went out to a customers studio on hos back yard. He had a Flick. console
& no schematics; that thing was a horror!

 

[ruffrecords]

Dan Flickinger direct copied some Spectra Sonics circuits. Spectra was started & owned by William Dilley. He sued Flickinger & Dan disappeared from the scene around 1975. He was a very corrupt person who thought he could get away with outright theft.
No one knows where he disapeared to.

Interesting information Bill. So how does this all fit in with Flickinger's own patent granted in March 1973?

https://groupdiy.com/index.php?topic=69980.msg892565#msg892565

Cheers

Ian

 

[hodad]

That info from Bill is not exactly the story.  Dan Flickinger left audio but didn't disappear.  Last I checked he's still alive.  Years ago PRR did a great analysis of Flickinger's first (to my knowledge) amp card (that may have happened at the old place.  I probably have the info on a computer somewhere, & PRR may still have it posted somewhere.)  That circuit is not a copy of an SS amp, and the 535 is not at all a 101 or 110. 
Flickinger did start out using SS parts to build mixers, before he started making his own circuits.  (Early on, I don't think Spectra Sonics made consoles--just EQs and amp cards.  The SS 1020 console, at least originally, was manufactured by Auditronics in Memphis using SS amp cards and EQs.  Eventually Auditronics' quality control issues pushed Dilley to start making consoles in house.)

I've heard tell of "counterfeit" 101s and passive EQs that were credited to (or blamed on) Dan Flickinger.  I've also heard that after Flickinger left audio some former employees carried on with some of his work--at least some of it with his blessing.  It's an intriguing snippet of audio history, & I wish I knew more about it.

There was (and still is) bad blood there.  That much I'm certain of. 

 

[PRR]

https://www.thecrimson.com/article/1959/3/20/dining-hall-department-faces-price-squeeze/

 

[justinheronmusic]

Saw that 535-7 OpAmps are for sale on Reverb & Ebay. Anyone up for drawing up a schematic to drop these into?