I don't know how you would rate your constructional skills, but have you thought about assembling a pre-amp from a kit? People such as Seventh-Circle Audio have very respectable transformer-based designs, and your money goes a long way. If you don't fancy construction, maybe you should start saving your pennies towards an API 3124+.

I'm not clear what your signal chain is after the pre-amps. How do these signals get into the computer? You are surely not feeding them into the line inputs of the Mackie mixer? If you don't yet have a high-quality audio interface, you might look at investing in that end of the signal chain before shelling out for more boutique pre-amps. Mixers have a role in recording rigs for generating headphone mixes and the like, but they should not really be in the recording signal chain unless they are of better quality than the pre-amps and converters you would otherwise use.

Alright, I'll tackle those questions/comments in order. I would feel totally confident putting together a kit, I wasn't aware that anything higher end was even available in that form. I'm no pro, but I used to work in a service shop and did some odd repair jobs to circutboards and such (I'm assuming such a kit would be point to point though, I'll have to look those up). API 3124+ looks like great value actually, but a LOT of penny saving will be needed for something like that!

My (this is going to make you cringe) signal chain is thus: Mic into preamp (99% of the time I'm just using the Mackie's channel pre's, trying to get away from that as time goes by) and then yes, into the line-in on my mackie. I've read around here that this should be fine (Remy) and should essentially bypass the pre's, but I'm going to do some A/B tests with the line-in and using the insert instead to see if there's a better option. My Onyx has firewire out which obviously is fed into my computer. The reason I chose the Onyx is because the pre's are supposed to be about as decent as is humanly possible when trying to get 16 channels into my computer at once for under $2000.

I realize that this is far from where I need to be, and the mixer is slated to be replaced by dedicated preamps and converters as soon as possible, but if I swapped it for another interface right now then I'd need to buy another 15 preamps to get back to where I started for tracking abilities... you can see my concern.

My plan was to add more and more preamps and bypass the mackie pre's up until I have around 16 of them, and at that time replace it for a proper AD/DA. From all the research I've done so far I am under the impression that while hugely important, A/D conversion is not where my money is best spent in the short term. (For example, if I drop $___ on converters and then have to use cheap pre's, or can reverse that and spend the money on pre's in the short term - my impression is that in the short term I'm getting more signal chain improvement for my $ on microphones and preamps than with the AD/DA).

If I'm off base on that please let me know, I'm not stubborn and just want to do as much for my signal chain as possible, within the limitation that I only have certain amounts of money at a time (willing to spend endless amounts in the long term as needed, but I dislike going into debt for gear).

Thanks for helping me think this through.

I think that you have made a good choice with the Mackie. Some of the best "mixer level" pres on the market (at least in that price range). IMHO the preamps you are considering will only be marginal improvements over the Mackies. (I own the Brick, have use the Mackie Onyx on several occasions and I'm just guessing on the ISA.) I'm with Boswell (especially since he picked my favorite pre - the 3124+). Make the most of the Mackie Pres until you can make a bigger jump. If you are itching to make a move now, buy something where you can afford top quality - like dynamic mics SM57,58s, SM7, EV RE20, Senn421s, etc.

Thanks Bob, I'll load up on mics for the time being (I do need a pile of 421s... need a SM7B too), and maybe what I'll do it put away some money at a time and try to save up for higher end hardware bit by bit as I can. That 3124+ is a lot of cash at once, but for 4 channels it's really not much more expensive per channel than what I was thinking anyways... I'm just half-broke right now (just blew more money than my car is worth on some Genelecs).

I have to say though, that Seventh Circle stuff looks like a lot of fun, thanks for pointing me towards that Boswell, I'll definitely put a good 8 channels of that on my short list of things to buy.

Thanks everyone for the advice, I was suspicious that I was maybe developing a premature case of GAS, looks like I was right.

For a mobile rig there is nothing quite like a lunch-box set up with good pres for space and portability. The Seventh Circle stuff will serve you well. A short term higher end move would be Sebatron. Singles duals, and fours. Very colorful in a sweet sounding way. API ....yah cant go wrong. True systems....very clean and three dimensional...also in several configurations.

I dont really think you'll ever get rid of the Mackie. The pres are just too good and the ease of use and the routing precludes any reason to get rid of it. Just add to the mix......you'll be surprised at the quality you're getting even when you put it up against the 'big' guys stuff.

If I start replacing pre's I definitely want colourful, there's lots of clean (or close) stuff I can get for cheap.

I appreciate all the feedback on the Onyx, I bought it because it sounded good to me (I've GOT to get it modded so that the EQs are included in the AD feed, they're half the reason I got the thing...) and because I figured it was the best stuff I could get in the range. I didn't realize that the thing "really does" sound good - I mean, it sounds good to me, but I'm far from pro, and I haven't exactly A/B'd it against much else. It's good to hear that people with a lot more experience than me think it's decent, I thought I was doing my signals a disservice!

My only gripe is that it's big, 80lbs when in it's hardcase (which I stopped lugging around).

I'll start putting money aside for all Seventh Circle and API (maybe sebatron, I'd like to check it out in person), and until then I'm loading up on mics. Thanks again everyone for the advice.

Fine, and I agree that the Onyx-series pre-amps are some of the best in the business at that price point, but remember that the line inputs of the Onyx 1640 are attenuated and put through the mic pre-amps. When you connect external pre-amps to the line inputs, you get the convolution of the external pre's characteristics with those of the 1640's pre-amps. In a studio-quality audio interface such as the RME FireFace800, the line inputs by-pass the pre-amps and feed the A-D converters directly, so you get more of the unadulterated sonic quality of the external pre-amps.

That's good to know (and I didn't), thanks. That seems like a dumb way to design it, but I'm sure they have their reasons.

What I'll do is sneak the pre's into the return on the inserts then (I'll do some A/B recordings just for my own education, though I know the insert way should sound better).

The input section of the block diagram on page 31 of the [[url=http://[/URL]="http://www.mackie.c…"]Mackie Onyx 1640 manual[/]="http://www.mackie.c…"]Mackie Onyx 1640 manual[/] is worth studying. You say you've had the mod done that alters the take-off points of the recording (+ADC) outs to post-EQ, which is just as well if you intend to try using the insert returns for your pre-amp connection.

Talking of which, check what the output configuration is of your pre-amps. For dual op-amp or for centre-tapped transformer output, just take XLR pins 2 (signal+) and 1 (ground) (or tip and sleeve if TRS), leaving pin 3 (or ring) unconnected. These should go to ring and sleeve respectively on the insert jack, leaving tip unconnected. You lose 6dB of signal, but that's no big deal with the output swing available on most pre-amps. If the pre-amp has floating transformer or electronic transformer outputs, do the same, but ground pin 3 (or ring) on the pre-amp output, and you don't lose 6dB.

I wouldn't have thought of doing that, thanks. I will study that diagram as well for my own education.

Also I should have been clearer, I haven't gotten the mod for the EQ done yet, but because I'll be sticking with this thing for a while I'm going to get it done soon. I just have to find what the closest place is that does the mod and find a block of time when I can be without it for however long their turnaround is.

I'm in much the same position as you (focus-wise), w/ the exception of the aforementioned FF800 vs the mixer. While its cost was a good way towards the 3124+ I've been lusting after for awhile now, it was worth the setback.
You're going to want an interface that isn't going to compromise/alter the sound of those expensive preamps, first.

Otherwise, Bob hit it on the head for me, and perhaps for you as well.
Invest in lifetime mics worthy of the expensive preamps you're looking at.
I own some of those dynamics he mentioned, and have my eye on the rest.
I would also suggest in investing in a good pair of ribbon mics, and a pair of good SDCs and LDCs. That's a pretty complete mic locker, especially if you're doing rock-oriented stuff - and you'll have the range to do acoustic music and horns.

Unless you're trying to record 16 channels of superior audio at once, you can cheat and get by w/ half that for the important stuff, leaving the cheaper Mackie (or whatever eventually replaces it) pres for the scratch / less important sources.
I hate to call any source "less important", but sometimes compromises must be made.
At least you'll have quality mics (well-placed!) through clean digital pres w/ good ADC from a proper interface for the last 8 channels.

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They are both great pres......Highly recommended !!

DB