500 series mic pres vs. 19" mic pres

Well, I have seen the different threads around on the subject but normally never say anything. The API 500 format was originally only for the consoles. The consoles were designed with bipolar +/-16V PSU's. A 312 card in the console running on +/-16V rails will sound exactly the same as a 312 card in any standalone 500 series rack that is also running on +/-16V rails. The circuitry before and after the 312 card in the console and how the card is racked for standalone use will effect it more. Good clean DC is the same as long as the voltages are the same. Increasing the supply voltage to +/-18V for example will increase headroom. In conclusion, as far as API style gear goes, 1RU, 500 series or running on a bench supply will operate and sound the same. I should add that the PSU in all situations needs to have enough current available. A 312 draws very little current though and nowhere near the 130mA VPR 500 series spec.

Since the 500 format is +16V and -16V, you actually have 32V of DC at hand to work with. Simple math will tell you that is more than single ended 24V. Clever designers like Colin from AML have no issues getting their Neve style designs to work great in a 500 series rack. I have no idea why Mr. Tanner doesn't want to mess with it but I am sure he has his reasons.

I am not super familiar with the Helios stuff but IIRC they do use opamps but the discrete components are all on the main PCB, not a smaller block type sub-assembly.

Even Neve is doing modules in the 500 format these days!

Indeed. As long as the supply delivers good, clean DC with enough current to do the job at hand, there should be no issues.

Sounds like inadequate current available with the old PSU. Maybe you should just ditch that rack and get one of my new 11 spacers!

jK, Money is an issue of course, and I hate to bring you down, but I can tell you if that rack ur using now is starving current wise, the stuff ur using in the rack NOW is more than likely being sonically compromised. You could possibly be surprised by the sound improvement of old gear with a psu or 500 series rack upgrade?

And I won't buy 500 gear because I seriously see no point until someone comes up with something besides a power frame.

The Radial Workhorse was my first temptation to ever get involved. The idea that it I could throw a couple 512s in with some filters and variable phase--and do a blend of two MICS and a zero latency cue of the blend...now, we have a functional purpose. Is that a 3U rack with an 8x2 mixer and the ability (I believe) to internally patch the slots together...that sounds like a great guitar amp recording toolbox.

Obviously, there's a huge point if you're doing DIY. My buddy has this pedal building "board" for trying out this and that--common switching and power supply and IO...so he doesn't have to wire all that up until he wants a finished pedal out the door. But, to buy preassembled? Ends up being SLIGHTLY less expensive long term for what most anyone would consider a limiting platform. There's a thread here about compressors...and there's just no way to get the transformers and tubes into a 500 series unit--which doesn't mean you can't design a nice compressor, but there are some specific sounds it just will never do.

I have heard there are major crosstalk issues in the Radial summing rack. I have never used one myself so YMMV.

I thought I was done with 500 series till I heard the VP28... then I was back in and picked up a few other items while I was at it... ez1073, LaChapell 583s... love them all.

Woohoo! arny is back!

Yep, and now the Chandler TG2...

jsteiger, looks like I will be buying a 11 slot 500 box from you soon...

Hey Arny - check your messages...I just messaged you...

The recording community throws around a lot of technical terms which sadly turn into buzzwords for marketing and people repeat these things over and over again without a true understanding of what is actually happening. There is a significant history in console design that is really taken for granted as a result of this.

An Operational Amplifier, or Opamp, very simply, is an amplifier that depending upon how you set it up in a circuit, can do a variety of functions. "Opamp" does not refer to a chip, you can make an opamp from Vacuum tubes if you wanted. While a long list of advantages can be listed for the use of opamps in design, from my point of view the primary advantage is that you can build a console using ONE amplifier. This is highly advantageous to a manufacturer. API is the classic example most people know of an Opamp Console, it primarily uses a discrete opamp (2520) to do most of the functions in the console, from the mic and line inputs to EQ buffers, to virtual ground summing buss, to output drivers. In some spots there was a 2510 but we can keep it simple and say that you can take the amp out of the mic pre and stick it on the buss and it will work, its the same amp doing a completely different function. By the mid 70's onward, opamp consoles were generally the standard and while many companies manufactured consoles using discrete opamps, certainly the trend towards the 80's was towards chip opamps in design. A console with an opamp can be made to sound very good, or not very good, good design is good design.

PRIOR to the widely accepted use of opamps in design there was this other thing, and this other thing hasnt been catch phrased by dealers yet and it is the transistor gear that most of you guys are truly fiending after. We refer to it as purpose designed amplifier stages and that is evidence that we'll never be marketing folks and simply designers... It is almost a guarantee that if your record was recorded in England in 1970 or 1971 you were doing it on a console that had completely purpose designed amps. What this means is that in each stage, the amplifier is specifically designed to function in that stage alone and more often than not, these amps are not interchangeable throughout the console the way the typical opamp console can function. In our product, the mic pre was tuned specifically for the mic pre and will not work anywhere else in the circuit, the same goes for the line amp. The line amp and mic pre dont sound much like each other. The EQ buffer is completely different. At every stage you are designing the amp sitting there to do a specific function. This has advantages in that you can tune the hell out of a circuit to get it to sound EXACTLY how you want it to but of course you are building all kinds of different amps out of different stuff so its not as streamlined as manufacturing with opamps can be. Again, if you were making a recording in Northern Europe in 1970, it was on a console built like this. "Discrete" doesnt paint the full picture as you can have discrete "opamps" or discrete "purpose designed amps" or whatever youd like to call them. Both have advantages and disadvantages and both yield very different consoles. This distinction really hasnt been made very well IMO and this of course is evidenced by the amount of "neve vs api" discussions there have been over the years in which the true design differences between these consoles are not often brought to light.

The real drawback to designing for 500 is the amount of connectors you can have which is born of the rack. Almost anything else can be compensated for with good design. If you dont have a good sounding audio circuit in 500, it is not directly the fault of 500 itself, thats for sure. 19" is not necessarily the solution to "poor performing" 500, better design is. Obviously there are constraints, but for average music and dialogue recording you can make 500 work for you. Sure, Id rather be recording classical music on a 100v system but you can make something nice that will impress for "general use" yielding high quality results with +/ 15v.