ACM & ACMP Reviews by Nuemes

[dgatwood]

Unless you're trying to get distortion for some reason or unless your sources are so hot that they clip at your DAW with the input gain at the bottom, you should generally leave the output gain all the way up and use the input gain to set the level.

If the input gain isn't fine-grained enough, you can set the input gain a little high and tone it down a little with the output gain; just remember that your lowest noise level occurs when you minimize the input gain level as much as possible without compromising the resulting level.

 

[antichef]

OK - I plugged in my SM7b to an ACMP73. With the output gain all the way up, and the input gain at 11 o'clock (two notches back from maximum, which is at 1 o'clock), I'm pushing both the 73 and the interface into the red with some quiet humming about two inches from the mic. I think for recording, I'll probably have it at 9 o'clock at the most (for the SM7b - less for other mics, of course) - I've got a decent amount of headroom there (for quiet humming, anyway). I'll just punch in some digital gain to get it where I want if it's too low. I guess I do kinda like the sound of the 73 as it's close to redlining, but to pull that off will take some practice to set the level right for the source.

 

[MCI2424]

Here y'go:

ACVST

On time and under budget!

Functions:

Buzz: adds 60Hz hum with lots of harmonics! If there is demand, I will do an international version at 50Hz

Distort: adds distortion (duh). Mostly second harmonic up to about 1/3 the knob; above that higher order distortion grows rapidly.

Hiss: adds hiss!

Pop: does nothing unless in the midrange, where it will drop out all audio and replace with a constant stream of maximum values. WARNING! This control may cause a nasty pop if operated, and if left in the midrange, will cause illegal output to your converter, potentially destroying headphones, amplifiers, speakers, and your ears! USE AT YOUR OWN RISK!!!

Pretty cool except now I need the heads-out-of-alignment and azimuth out features. A wobbly capstan feature would be nice too.

 

[MCI2424]

1974 Ibanez lawsuit 335 > 1974 Fender Twin with gain mod > SM57 > Pre > Lynx Aurora 8 AD/DA

Amp was mildly distorted. Think CCR with both pickups engaged, Clash with bridge(?)

Keep in mind the mic has everything to do with this test. Used an SM57 because it's easy for everyone to reference.

Avalon M5: Sounds good, has clarity and detail but sort of dull with both pickups engaged. With bridge humbucker it really picks up the bark of the 335 nicely - really, really good on the bridge humbucker.

Pacifica (pad on): More vibe than the M5 with both pickups on, scooped, more highs than the M5, maybe a little too much when getting humbucker bite from a Twin. Tight sounding. I might use this for a thrash or funk band.

UA610: Sounds cheesy but it's more classic sounding than the Pacifica or M5. Loose, rugged. More depth, not as scooped, more realistic sounding than the Pacifica and more high end and all-around more fun sounding than the M5 with both pickups. Doesn't quite beat the M5 in bridge humbucker, though - too much high freq for that. This has always been my main preamp for recording elec guitar amps.

ACMP73 (no EQ): High freq is there but almost too much. Lacks the bass or depth of the UA610, doesn't even come close to the UA610 in fact. Not as good as the Pacifica either nor the M5. But not particularly bad, either; just not as good as the others. I'd use this on an amp that needed increased high end or with ribbon or dull mic that needed extra high freq push.

ACMP84 (no EQ): Pretty much the same as the 73 but with what sounds like a little more midrange. I like it better than the 73 for guitar but the 84 is still a far cry from the UA610.

ACMP73 (with EQ): No noise issues with EQ engaged. I only use EQ for cutting on Elec Guitar, seems to do this ok, nothing special. Will depend on the guitar within a mix.

ACMP84 (with EQ): Hiss was not a big issue with EQ engaged as the amp already had a bit of distortion. Sounds a little better than the 73 but again depends on the guitar within a mix.

Final thoughts...
Eh. This is tough. Which pre is most suitable is pretty dependent on amp/guitar/pickup/mic combination. I feel like the Avalon is the only pre that isn't hyping the high freqs. On that note, the UA610 has a depth I like on certain pickup combinations more than the Avalon. Considering the price point the ACMP's are very good but not quite up there with the other 3 in this case. I don't expect to use them on amps unless some serious EQ sculpting would be needed for a not-so-great amp.

You are probably coming to the truth about these ACMP pre-amps. I think too many are praising them in the heat of the excitement. They are cheap pre-amps and, really, how great could they be pitted against many other cheap pre-amps? I am not trying to put a damper on this, but I am pretty sure that time will tell on these pre-amps. Once the excitement dies down of coarse. Since Alan Hyatt passed on them, like him or not, he passed for good reason.

 

[redddog]

You are probably coming to the truth about these ACMP pre-amps. I think too many are praising them in the heat of the excitement. They are cheap pre-amps and, really, how great could they be pitted against many other cheap pre-amps? I am not trying to put a damper on this, but I am pretty sure that time will tell on these pre-amps. Once the excitement dies down of coarse. Since Alan Hyatt passed on them, like him or not, he passed for good reason.

That's what I was thinking. The Alan Hyatt thing.

If these things were the greatest sounding, value pres around, I'm thinking that Alan would have been all over these as well. I think it sounded, at first, like these were designed just for us, but Alan had proved that he had seen these and realized some issues. I think he tried to warn us and preserve some professional integrity but that proved impossible and was run outta town.

Like I've been saying, I think these will be great someday. But in their current incarnation, they need a lot of work to be that professional, high-end pre we were hoping they would be out of the box.

And as the average user who may not have any EE experience will soon realize, these things may require too much knowledge and skill to get them to that level.

I know my eyes were too big for my own good. And I'm sure that I will be unloading some at some point when this all shakes out.

 

[nuemes]

Keep in mind the 73 appears to be very solid as a bass DI and they sound good on vocals for mics that don't require a tremendous amount of gain. They're certainly worth the cost we paid.

I'm curious how they'd do on a shoot-out with the Art Digital MPA. Similar price per channel. Anybody have an MPA and an ACMP they could compare?

 

[WhiteStrat]

Keep in mind the 73 appears to be very solid as a bass DI and they sound good on vocals for mics that don't require a tremendous amount of gain. They're certainly worth the cost we paid.

I'm curious how they'd do on a shoot-out with the Art Digital MPA. Similar price per channel. Anybody have an MPA and an ACMP they could compare?

I've got both (MPA & 73) but a comparison might be a couple/few days off...

 

[antichef]

I've got both, too -- I can probably do a comparison soon (the more the merrier!)

I'm having some issues with high frequency distortion on the 73 (crash cymbal and high hat), and DI guitar sounds nasally, maybe due to the same problem, but haven't had a chance to do a pretend-scientific analysis.

I did a vocal track with the 73 that I like - nice and clear, and more in your face than other tracks I've done with the Digital MPA (but note that I like the MPA because it's *not* in your face).

I have two well matched Shure SM-81 mics - I could point those both at the hi-hat and run one into the 73 and the other into the Digital MPA. I had planned to do the same thing, but using my BlackLion MOTU Traveler (which is what I prefer for drums/cymbals) instead of the MPA. I guess I could do both

 

[thajeremy]

I have an ART MPA but not the digital model.....

 

[WhiteStrat]

I have an ART MPA but not the digital model.....

That's fine. The 73's not digital either. Just send 'em both to your DAW via the same converter/interface to make the comparison useful.

 

[antichef]

That's fine. The 73's not digital either. Just send 'em both to your DAW via the same converter/interface to make the comparison useful.

That's a good point -- I should probably use the analog outs on my Digital MPA (for the first time) for that reason, as well. I don't *think* it would make a noticeable difference, given the various converters I have, but it'll be one less thing to distract away from a comparison of the results. I did do a quick check of the analog versus the digital output of the Digital MPA once, and the digital is quieter (provided the clocking is set up correctly), but whatever.

 

[mshilarious]

You are probably coming to the truth about these ACMP pre-amps. I think too many are praising them in the heat of the excitement. They are cheap pre-amps and, really, how great could they be pitted against many other cheap pre-amps? I am not trying to put a damper on this, but I am pretty sure that time will tell on these pre-amps. Once the excitement dies down of coarse. Since Alan Hyatt passed on them, like him or not, he passed for good reason.

One of zmix's early comments on PSW was very telling, in that he noted the units had a fair amount of second order distortion. That accounts for many, many of the observed comments about thickness and use as a bass DI, and so forth. For example, if you have a VST that allows you to add harmonics, try a bit of second on a bass track. One thing you will notice is the bass track suddenly becomes thicker and punchier. That's because you have now essentially doubled the low-frequency bass line an octave higher, where your ear can more easily directly hear it. It's like doubling it on a guitar, or more accurately, an octave higher on bass, and back in the mix 12dB or more.

This is also why the little tewb pres like the ART MP are popular for the same task, but aren't valued for acoustic instruments. The ART is at a big disadvantage to the ACMP, because it has IC stages that will run out of headroom rather nastily, and the ACMP's design shouldn't do that. But the cost and time difference between an MP and ACMP is rather large as well . . .

I would bet Hyatt passed due to QC issues--this level of initial defects would be quickly fatal to an importer.

There is also the open question of the mis-specified transistors. It was never resolved whose design this was. Hyatt made it sound like it was a Chinese design; I would think he wouldn't have specified transistors that were underrated. But we don't really know. Chance said the Chinese weren't at fault because they built to the schematic. Whose schematic?

 

[mshilarious]

That's a good point -- I should probably use the analog outs on my Digital MPA (for the first time) for that reason, as well. I don't *think* it would make a noticeable difference, given the various converters I have, but it'll be one less thing to distract away from a comparison of the results. I did do a quick check of the analog versus the digital output of the Digital MPA once, and the digital is quieter (provided the clocking is set up correctly), but whatever.

That's not because the ART's analog output is noisier, but rather its internal converter is quieter than whatever you were comparing--which might not be a fair comparison if both units do not have the same dBV=0dBFS level.

 

[antichef]

OK - I set up my crappy hihat and pointed my two SM-81s at it about a foot away, each pointing straight at the center, and about an inch above the top hat -- not going for optimum placement, just "equivalent" placement. I ran one into the Digital MPA with high voltage=on, and one into a ACMP-73. I ran analog outs on both pres into an Echo AudioFire 12. I very unscientifically set the pres with the output gain all the way up and the input gain to the point where they wouldn't clip the Echo (surprisingly, both the fourth detent from off for the 73 and the fourth little line from off on the MPA)

Plenty of room noise, including some noise several rooms away where my daughter and her friend are watching videos on theonion.com - sorry about that, but you do what you can.

here are the files:

http://www.recursor.net/DigitalMPA-hihat1.wav

http://www.recursor.net/ACMP73-hihat2.wav

the wav files are about 4 megs. [edit: I've secretly replaced the links above with other links to files with lower peaks, in response to MSHilarious's subsequent post]

MSHilarious - now that you mention it, I think I was running the analog out of the MPA into a noisy line in before, as you suggested. This time it seems pretty quiet - you hear some hiss at the beginning of each recording, but I think that's actually room noise - it subsides in both right before I hit the hihat the first time.

 

[mshilarious]

I hate to be a killjoy, but how did you set the gain on the ACMP? It's quite obviously distorted compared with the ART, and given that peak on each sample is 0dBFS, did you have to normalize to get these files? Try shooting for peak at -6dBFS or a bit less, and then normalize.

If that's what you did . . . well . . . I hope that's not what you did . . . in fact, it can't be. Compare the peak at 3s and 2s. I think you clipped the converter on the ACMP sample.

Also on the ART, I think you want to take more gain at the first stage as it feeds the tube, which is a potential noise source. I don't get why it shows up noisier here. Try setting the output gain at 12:00, and make up the difference with input gain.

 

[antichef]

OK - I redid them with lower peaks. I also did what you said about the output gain (on both - 12 o'clock). There was never any intentional normalization, and I'm sure there was none on the .wav files -- to anyone who wants to hear the original samples that mshilarious is talking about, use the links in my previous post, but delete the "1" at the end of the filename before the extension.

 

[mshilarious]

OK, now the ACMP .wav doesn't contain any audio . . . . . . the .mp3 is OK, but I'd prefer to compare .wav to .wav

 

[drBill]

You are probably coming to the truth about these ACMP pre-amps. I think too many are praising them in the heat of the excitement. They are cheap pre-amps and, really, how great could they be pitted against many other cheap pre-amps? I am not trying to put a damper on this, but I am pretty sure that time will tell on these pre-amps. Once the excitement dies down of coarse. Since Alan Hyatt passed on them, like him or not, he passed for good reason.

Total BS. Are you just grouchy because you never got around to ordering any??? LOL I'm not sure how you can be dissing them without actually using them yourself.

I've been doing this recording thing for awhile - (20+ years professionally full time) - and have been putting them up against my API's, Shadow Hills GAMA's, Biz and D&R's with a variety of mics and they are more than holding their own. Money aside, they are holding their own, and exceeding all of those listed pre's in various situations. If you want to add the price into the equation, they are unFREAKINGbelieveable.

No pre is perfect and #1 in every situation. My most noteable moment of joy with these pre's was on Kick drum. OMG, I was totally blown away and estatic. Giddy in fact. No need for a subkick ever IMO. E. Guitars were also a stunner. Beat out the API's two days ago, but that's not saying the API's were not great, the 73's were just a bit rounder which was just the ticket.

As for Alan Hyatt, he either didn't have the juice or the saavy to get these pre's in his lineup. He could have sold as many as he could have gotten his hands on if he had priced them fairly, which would have seemed to be easy considering the price. Fine with me though. His loss is our GAIN!!! (I'm giggling at the very thought........)

 

[drBill]

Like I've been saying, I think these will be great someday. But in their current incarnation, they need a lot of work to be that professional, high-end pre we were hoping they would be out of the box.

And as the average user who may not have any EE experience will soon realize, these things may require too much knowledge and skill to get them to that level.

I know my eyes were too big for my own good. And I'm sure that I will be unloading some at some point when this all shakes out.

Have you used them yet?!?!?! If not, take all the BS whining and naysaying with a grain of salt. If you really want to off-load them, sign me up. I want more as do every person I ordered them for. I know 2 guys for sure, and probably 3 more. I'm good for them, please contact me via PM asap. Thanks!

Bill

 

[drBill]

I would bet Hyatt passed due to QC issues--this level of initial defects would be quickly fatal to an importer.

Logical on first look, but AH stated that he has done much businiess with this manufacturer in the past (and into the future). QC is QC. Doesn't matter what the product is. Either the company is good about it or not. He seems to have found a way to work around it on the other products they make for him. No, he passed for other reasons altogether.