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API 525

Discussion in '500 series' started by audiokid, Oct 22, 2011.

  1. audiokid

    audiokid Staff

    TDThe BAPI 525B is a "feedback" type compressor, originally released in the 70's such as the 1176 and 660, etc. An input (threshold) control and output (make-up gain) control are provided. An additional "Ceiling" fine tune function modifies threshold and make-up gain for precise changes in compression without changes in output. A compressionlimit switch sets ratio at either 2:1 or 20:1. Attack time is as fast as 15us. Four auto release modes are offered via two switches, 0.1s, 0.5s, 1.5s, & 2.0s. A De-Ess function inserts an inverse vocal energy curve filter in the detector for effective sibilancep-pop reduction. The API 525 is an identical re-issue of one of the most popular API products ever.

    The API 525 is perhaps the most successful solid state feedback compressor in history. It delivers dynamics control behavior unlike VCA "feed forward" compressors so common today. A remarkable multi-function "ceiling" control can increase gain reduction (lower threshold) while simultaneously raising output level to match, so the user can alter dynamics "on the fly" without level changes. This re-issue design has been taken from the original blue prints and spec control drawings from the API archives.

    Release times vary with frequency, with high frequencyfull bandwidth content released faster than just low frequency for natural envelope tracking. Attack time is fixed, chosen to catch the fastest peaks, without "pumping". Equally useful as a tracking, mixdown or program compressorlimiter, the benefits of the API 525 are most obvious to those who use compression on a regular basis. "Vintage" dynamics control, an easy to use multi-function control set, and a wide range of 500 Series mounting options assure that the 525 will surpass your most critical applications. With the addition of a hard-wire bypass switch, a balanced input, and a pinout that is the same as all the other 500 series modules, the 525 is still, after 25 years?"the sound". Two or more 525s can be linked for multi-channel compression.

    The BAPI 525 Feedback CompressorLimiterB makes use of the 2510 and 2520 op-amps and therefore exhibits the reliability, long life, and uniformity which are characteristic of API products.

    BAPI 525's featuresB

    *Reissue of API's original 525 from the early 70's
    *Peak detecting "feedback" compressorlimiter
    *Variable Threshold and Output levels
    *Unique "Ceiling" control combines key functions
    *VU meter for monitoring gain reduction
    *4 Switchable release modes
    *De-Ess function
    *Traditional API fully discrete circuit design
    *Hardwire bypass


    Attached Files:

  2. RemyRAD

    RemyRAD Guest

    Ya know I tried getting used to those and I couldn't? I could never figure out what to use them on or what they were the most flattering upon? So while I occasionally had them at my disposal, I generally dispensed without working with them. So I really never found them very useful? I could never quite figure out the attraction to those? So I've never really bothered trying to obtain one.

    Mike, you mean we had a pair of those also sitting on the shelves somewhere at WKYS? I never saw those? But I did reconstitute and refurbish, rebuild part of that API console that was there before me. I never could figure out why you guys took it out of service? And was it used for the AM or the FM side? What was it used for? Was it simply a production console? Or was it an on-air console? It certainly wasn't any console at all, when I dove into it. There was nothing in the frame. That 1604 frame. And where they're also any 550's that also went with that console? Because I never saw any of those either? I just could not figure out why anybody would take such a lovely console out of service and strip it down? Especially when I realized we were using much older junk RCA stuff? I mean like how bizarre is that?

    I heard that Darius took my console home when it was taken out of service. And really the only worthwhile active circuitry in that desk was a pair of 312 microphone preamps and the 325 output amplifiers that were replaced with those Dean Jensen 990 outputs. And I never even knew what became of those 325 cards? Maybe Darius got those also? I'll just never forget the day they took out the in-house intercom system to replace it with the RTS and they threw out all of those 312 & 325 API modules. Enough to build up a full custom 24 input API desk without the equalizer's. And which I sold most of those to Brent Averil when he still owned BAE. I just couldn't drop $30,000 on 560/550's which is why I sold all but four of those modules off. I'm still kicking myself in the ass over that one LOL. What I wouldn't give for those modules today?

    I just want to click my red slippers together and say I want to go home, I want to go home.
    Mx. Remy Ann David
  3. mberry593

    mberry593 Active Member

    I specified two API consoles while I was doing engineering for radio. One was just a small 5 fader console used in radio recording. It had 4 550s.

    The other was a fairly nice console used in control room 3 for local AM all-news. It had 5 microphone faders summed to a microphone submaster with the 2 525s on the submaster for mic compression. It then had 6 cart faders, 2 tape faders, and I believe 3 nemo faders with 550s on them. I do have a photo of it and I will try to dig it up. No, I don't know where any of that stuff ended up.

    There was also another API console. It was removed from service from the 2nd. floor in New York and sent down to us. I was downtown working for the network when that happened. I believe Sweitzer &/or Joe Hall may have rebuilt it. I think it may have seen some short service in control room 1.

    TV also had exactly one 550. It was installed in the old, old control room B (between studios A & B) and was used on David Brinkley in the 1960s.

    ..............also the 1972 rebuild of ctl. 3 included 8 API 440 faders. There were no active API parts in that-----it used Melcor preamps to replace the mic 3A preamp and the ctl. 3 microphone bus booster amp. Those Melcor amps were in a Vero frame near the bottom of Rack 104. There was also a small EMT compressor included in that project. Geoff Bryan was the engineer....IMO he did a great job.
  4. RemyRAD

    RemyRAD Guest

    He must have been in stiff competition with, what was his name over at WPGC FM? I mean they wanted to sound like WABC NYC with their EMT plate and they did. And he was also using a couple of LA-2's as I recall?

    So we had one of those $10,000 EMT PDM limiters? OMG! Yeah I think everybody walked off with those 550's & 525's. You remember that custom API I built for FM don't you? I've seen a picture of you in front of that original console before it was stripped clean. Before I ever built up that new one for FM in the basement control room. And I never knew what it looked like until I saw that picture of you in front of it. And I think it was that one? It was like a 1604 frame. And Darius did take that home when we moved to the new part of the building. I would have liked to have had it since I built it but I really had no need or use for it. I only had like four or was it six cards in the thing? Wow, what I have liked to have installed a couple of 550's and a couple of those 525's. That would have been ultra cool if that stuff had been on the shelves but it wasn't. It was already gone. And I reused those Fader length black blank panels with the cart start pushbuttons in them.

    I'm good at recycling. Always have been. Always will be. It's fun jumping into dumpsters. Because it's truly trash while being another one's fortune. And $8000 for a bunch of 312 & 325 cards is good garbage. Yeah baby! I just get sick thinking about all of those 77 DX's that got tossed just before I went to work for the TV side. Ugh! I think I'll vomit now?

    Sniff, snort, Mx. Remy Ann David
    Now I need some fresh food.
  5. RemyRAD

    RemyRAD Guest

    Something Milford?
  6. mberry593

    mberry593 Active Member

    No, although they did have one in NY. I should have been more specific. What we had was a small 256. As I recall the action was pretty good but I doubt that anyone would want one today because of audio quality. IIRC it used 741s.

  7. Paul999

    Paul999 Active Member

    I use my 525 on lead vocal. I find it incredibly useful. The deesser is really smooth. This compressor took me a while to get used to but the ceiling knob is very handy linking the input and output so that you are instantly a/b'ing more or less compression as you adjust and your relative volume stays pretty well the same. I do condition my lead vocal through some plug in compressors before and sometimes after to really get take them to the next level.

    These are awesome for tracking bass through. I don't use them on drums a ton but would use them on a drum bus no problem for certain drum sounds. This is one of my all time favorite compressors. They have that API sound (whatever that is). I sold off my LA-610’s as soon as I bought this.
  8. audiokid

    audiokid Staff

    I want a rack of this stuff. 8 hand wound 550A would be choice right now.
  9. RemyRAD

    RemyRAD Guest

    I never had any experience with that EMT limiter. Though I think it's still probably something of their PDM design? Or am I all so wrong there? It's certainly smaller than I expected which makes me think it is not a PDM unit? There was a fair amount of circuitry that had to go into those pulse duration modulation limiters. And that doesn't quite look large enough to accommodate such circuitry?

    I guess perhaps I didn't play with those 525's enough to have gotten comfortable with what I was getting, using them? They all sounded so operationally obvious to me that I never cared for them? Of course I was also in my younger years before I could have possibly appreciated what they did? I had plenty of 1176's which truly were my go to unit/units. I always got what I needed out of those. And where I also found some of the Orban compressors to be a little too bizarre for my tastes but I like the 418 A, stereo limiter of theirs. Which was essentially the original FM OPTi Mod without all of the cursory transmitter stuff included. And of course the DBX and LA-3 & 4's. And because of my earlier experience with those 525's I've never pursued them again. Maybe I'm missing something?

    Yeah, work. That's what I'm missing.
    Mx. Remy Ann David
  10. Paul999

    Paul999 Active Member

    This is true but it is a sweet very coloured sound. Granted I tried to use it for a couple sessions and didn't use it. I had to sit down, focus on it, learn it and then I started to hear how to use its sweetness. It is one of the most coloured pieces of hardware I know of.
  11. Eraserfish

    Eraserfish Active Member

    I'm liking what Paul said about coloration! I just set up a lunchbox with a 512c and a 550b and a Lindell 7x500, which has become my input chain into my DAW. I was never a studio guy so I didn't really know what the API "sound" was all about untill I heard my own vocals and guitars coming through it and was just simply amazed. I try to get as much color as I can in my vocals, guitars, and bass because my music is mostly electronic, and this is giving me some mojo to my eclectic style. I like the lindell and don't want to say anything bad about it untill I've used it more (the parallel compression knob is a great idea). I think the 525 would complete the API thing and had been looking at it hard before I decided to try the Lindell. What do you think?
  12. Paul999

    Paul999 Active Member

    I don't think I'd have a ton to complain about with your chain. I haven't used the lindell but I understand its clean. The 512 and 550 will be giving you a lot of color. For electronic music I run keys through guitar amps to get extra coolness out of them. This will do more for you then a 525.

    A 525 would be a great additional comp though.

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