VOX Amplification Ltd AC4HW1 by radiospace
I'm fortunate to own both a Vox AC15 handwired and this Vox AC4 handwired. I wrote a (glowing) review of my AC15hw1x yesterday here, and I thought tonight I would add a review of the AC4hw1.
(As a side note my cat is walking all over the computer keyboard while I try to write this, so if there are typos please blame him...)
I had been saving up for quite awhile for the AC15 version of this series, but they were out of stock for around a year due to manufacturing issues of some sort; at some point in this process I played the AC4 in Nashville and fell in love with it, for the price, and ended up getting one to sate my appetite for a Vox amp. (A temporary solution, it turned out, as I now have the AC15 handwired as well).
Assuming that you have already read my AC15hw1x review, I will cut to the chase and say that, in comparison, the AC4 is very much of the same family of tone, but has a more limited palette. It is still capable of quite a lot of different sounds, from clean, to slightly overdriven (my favorite), to Brian May-like heavy distortion. But where the AC15hw amp has a normal and a top boost channel, as well as the classic vox Tone Cut circuit which rolls off the brightest high end, this AC4 only has one channel, with a two-band EQ, and a "cool/hot" mode switch that bypasses the EQ tonestack.
Like the AC15, this amp has a great master volume that allows you to play at any level you wish without seeming to negatively effect the tone. While one might be inclined to think that this smaller amp would be a better bedroom amp with its lower wattage, in practice I find that either amp is capable of sounding great at very low volumes, moreso than any other amps I have ever owned, and to some extent I tend to actually play the AC4 louder than the AC15 because I dig the je ne sais quois of a tiny amp being pushed really hard.
Tonally the AC4, while sharing the same overall vibe as the AC15, is quite different. It's less scooped and less "big" sounding, with a noticeable lack of bass -- I haven't measured it technically but I'd guess that it's not producing much below 120 Hz or so. It also has much less detail in the top end and is simply not as bright. Thus, it is a much more midrangey amp -- not in a 700 Hz kind of way, but more in the tenor range -- it's bright and warm but lacking in both deep bass and sparkling (or piercing, depending on your viewpoint) treble.
Additionally, whereas the AC15hw1x naturally fills the room up with sound due to its beautifully designed cabinet, the AC4 in comparison definitely sounds more boxy, or contained within its own cabinet. (This is one reason I tend to crank it up a little louder, because it cures this effect somewhat). As a result, I am more likely to reach for some reverb when using the AC4 (typically from a Strymon Flint set to the Spring reverb setting), than when playing the AC15. But not always -- the AC4 can sound magnificent completely dry when tuned just right for my Telecaster with touch-sensitive distortion, for example.
I put some of the sonic differences, particularly the lack of the incredible treble detail found in the AC15, down to the speaker differences. The Celestion Blue in the AC15 just delivers an incredible, hi fi but rock n' roll sound that can't be replicated by the Celestion Greenback in the AC4. Nevertheless, the Greenback has its own charms. To me the AC4 excels at a more vintage vibe -- think early Rolling Stones circa "Get Off My Cloud" -- a pumping, semi-distorted sound that you might also get with a Fender blackface amp, but only if you turned it up so loud that police helicopters would soon be circling your house.
I find that the AC15 has a much larger sweet spot than the AC4. Another way to put it is that you will have to spend a little more time with each guitar on the AC4 to bring out the best in the guitar. The AC15 is more forgiving, in particular it's clean sounds are, to me, more readily pleasing with increased chime but also a more jazzy, piano-like bass tone.
I have tried using the AC4 in a band practice situation and found it wholly inadequate. But, this band practices far too loudly in a very small space, so you might get better results. For me, the AC4 is primarily a recording amp, where, for instance, its lack of a big bass sound is hardly an issue since you often carve out those low frequencies from the electric guitars in a mix anyway. It really records very nicely for a classic early British invasion kind of sound.
If I could choose only one I'd definitely take the AC15 -- it's my desert island amp without a doubt. But, if you are on a budget and want an affordable but high end implementation of the classic Vox sound, I would personally rather have the AC4 handwired than one of the more fully featured run of the mill AC-family amps that Vox sells (the reasonably priced black amps, etc.)