© 2012 Pan60

LaChapell 503 3-Band EQ

The LaChapell Audio 503 3-band EQ Pan60: Scott! Another cool product! The 503 3-band EQ, sweet! So, Scott, tell me about this beast. Is this essentially the same EQ as is in the 503E? Scott: Yep, this is essentially the same EQ found on the 583E with a few revisions most are already aware of. Specifically, we’ve increased the cut/boost amount from 8dB to 12dB on each band, added two position HP and LP filters (50hz, 150hz & 5k, 10k respectively) along with a trim/gain stage for boosting or cutting the overall EQ signal. pan60: So many will be familiar with this beauty. We have had some really cool chats about the EQ prior to getting my hands on one, so I am very excited to see it here, at last : )~ Scott: For sure! It’s always good to talk shop with “Pan”. I know you’ve been trying to get this little guy out of me for a while, now, as was mentioned during our first interview with the 583S. I knew we would at some point (it made too much sense) but, I wanted to see what kind of response it would receive serving on-board the 583E first before committing to it as a solo module. As it turns out, more than enough people liked our little solid state EQ for me to feel comfortable releasing it as a solo module. That period of time also proved valuable as I was able to take note and implement a few feature suggestions. pan60: Aside from guys like me hounding you to do the EQ in a single slot, what made you want to do this the 503 EQ? Scott: Again, it made too much sense. Since the EQ was already being successfully used, we were only a few minor design additions away from having an affordable, working unit. It was also important to let folks know that LaChapell Audio can move beyond the preamp world, even if that statement came in the form of a relatively small module. Allowing individuals an opportunity to get to know the LaChapell line without having to invest in one of our preamps was attractive too. pan60: Before we get too far here, you are really known for your tube gear, but, the 503 EQ is not a tube unit. Would you care to chat about that a bit? Scott: Yes, this is a solid state EQ and… transformer-less (gasp!). pan60: Transformer-less! Scott: I was already committed to this topology per the 583E and our desire to offer up a solo version of THAT EQ. So, adding anything to it (beyond features that would add to its performance) that would deviate from the current identity of the EQ might be little confusing and inconsistent. pan60: I recall you telling me this was an EQ you wanted to be as transparent as you could make it. The thought being you did not want the EQ to color other gear choices.   So, solid state and transformer-less would be the way to go? Scott: That’s right. Originally, this EQ was intended first to compliment the 583’s preamp signal. As you know, the 583 (and 992) are preamps that intentionally allow the user great swings in harmonic tone control. Tracking engineers spend lots of time finding the right “sound” via mic placement, position, gain structure, etc… So, when/if there’s a need to tailor the established sound a bit (especially at the front-end) by way of using an EQ, I believe that EQ should introduce as little “new” character to the sound as possible. That’s just my own engineering philosophy with EQ’s. This EQ is meant to fulfill that criteria by being very clear and transparent - allowing users to cut and boost frequencies without significantly deviating from phase alignment or adding a new layer of distortion. This is NOT to say that I dislike EQ’s that serve up tons of harmonic character when pushed hard. This EQ, however, was designed to service the 583’s amplifier as discretely as possible while preserving the amplifier’s own character when used. As a result, this solo 503 EQ possesses that same function. That’s not to suggest this EQ sounds sterile or ordinary. It doesn’t dull or flatten sounds at all… On the contrary, it preserves and allows enhancement of any signal no matter how full, thin or mid-dominant that signal may be. pan60: For the new kids on the block, give a brief description on just what the ''Q'' is. Scott: Well, “Q” is a way of qualifying the character of the bell curve of an EQ as it relates to bandwidth. A fairly common “Q” value is 1 (one). The difference between the -3dB points of a curve is divided into the source frequency resulting in a number or, Q value. The smaller the value, the wider the bandwidth of the bell curve, the higher the value, the more narrow. pan60: Tell me about the ''Q'' and why you chose this over some that are more surgical. Scott: Actually, the 503 features a semi-proportional Q. It’s at about .85 @ +8dB and narrows to about 1.5 at full boost. This provides a nice standard peak curve that just about every engineer is familiar with. The 503 was not designed to be called up for precision post work, nor did I desire it to be too broad in cutting/boosting. This EQ was designed to allow users the ability to shape and mold versus target and eliminate.  pan60: 12db of boost and cut: )~ Scott: Although 8dB is typically more than enough swing for the average session, the fact is plenty of people DO use this EQ for more drastic tone shaping. And, because the 503 does a great job of maintaining phase alignment, pushing beyond 8dB still sounds nice and natural. *Those of you that saw Ronan’s video review of the 583E might remember him mentioning a desire to push the EQ even more so… Ronan, I got one comin’ to ya to try! pan60: Trim pot sweet! Do you care to comment? Scott: We’ve all been there - cutting frequencies to the point where overall signal level is now too low. The 503 offers a very clean trim stage (+/- 6dB) allowing users the ability to maintain strong line level(s). pan60: Why the toggles for the 10K & 5k and the 150hz & 50hz? Scott: I went back and forth with this and finally settled on these values. I knew plenty of people would rather have 60 instead of 50 or 12K instead of 10K and for whatever legitimate reason. In the end though, I knew these would be good and useful. pan60: What are the specs on this beast? Scott: Noise: Quiet EQ type: Clean Price: Affordable …that’s pretty much all we know at this point. pan60: LOL Scott: Seriously, the 503 has a self noise of -92dB with the trim set to unity. The Q factor is actually slightly proportional but averages 1. It features a 48kOhm input impedance and a less than 25ohm output impedance. As a result, it can handle a 24dBu input signal with ease driving an extremely long output cable without significant loss in performance. And, of course, it is built solid. It features a fully enclosed/shielded chassis, solid custom milled aluminum knobs, very accurate custom noble and bourns pots (for sweep and cut/boost function) and ultra quiet high-end resistors and caps inside. pan60: We hear the term fixed "Q" or variable "Q". Can you chat a bit about why one would be more desirable for a given task as opposed to the other? What are the differences between the two? Scott: Sure. And to lessen confusion with terms for those that may not know - "Fixed Q" and "Constant Q" mean the same thing and "variable Q" and "Proportional Q" might mean the same thing ;) ... Most of the time, when people refer to "variable Q," they're really talking about proportional Q. The actual term "Variable Q" would refer to the specific adjustment of the Q/width of the curve itself (a separate control) versus the narrowing effects brought on by adjusting the cut/boost pot alone. With that said, I'm sure there are many reasons/opinions out there, but generally speaking, proportional Q is more friendly for mixing. Since the specific frequency being boost or cut narrows as more aggressive boost/cut amounts are applied, less intrusion into neighboring frequencies is experienced. The more one boosts or cuts into 12k, the more focused and sharp the curve at 12k becomes. But, not every proportional EQ is the same. Each EQ has its own unique curve determined by the designer. This is another area of critical listening that needs to take place when you're considering an EQ IMO... Some EQ's get real narrow the more you push select frequencies, others not so much... you get the idea. pan60: Are the high and low pass or shelving? Scott: The high and low bands are peak only, just as they are on the 583E. We will probably offer peak/shelve switching if we ever release a 2-channel rack version of this EQ... you never know ;). Pan60: So, to the point! Do I like this EQ? yes I do: )~ i love Scott's work and the 503 is no exception to his talent! The LaChapell Audio is another awesome tool any engineer could use in a heartbeat. This is not a surgical EQ, but isn’t heavy-handed with coloration, but it sure is smoking sweet! A big double thumbs up from the pan man EQ! Scott LaChapell LaChapell Audio 615-837-4598 www.lachapellaudio.com


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