Pro Audio

Warm Audio WA-2MPX: a Very, Very Close Recreation of Revered Vintage Preamps

We’ve been wanting to play with these for a while: the Warm Audio WA-2MPX, their recreation of Ampex 351 preamps.

We took a look at the brand new WA-2MPX. Now, I’ve recorded full albums through modified Ampex 351s, so I feel pretty familiar with how they’re supposed to sound.

Warm Audio is a company out of the USA founded by Bryce Young in 2011 – at that time they were at the forefront of bringing reasonably priced hardware clones of classic audio pieces into the reach of people who didn’t wanna pay the price for vintage equipment, or DIY it. Since then they’ve established a worldwide reputation for their equipment, and have cloned items from their first big piece, the 1176, the Neve 1073, a whole handful of Neumann mics, and much much more.

I’ve recorded full albums through modified Ampex 351s, so I feel pretty familiar with how they’re supposed to sound. Let’s quickly take a look at the interesting history behind these units.

Ampex was originally a reel to reel company founded on wire recording technology snatched from voided German copyrights, post World War II. Bing Crosby was in fact a large proponent of the company – he decided he’d like to be able to pre-record his popular radio show rather than always do it live, and cutting it to enormous discs for playback just wasn’t doing it for him. Crosby was so impressed with the Ampex tape recording of his show he made $50,000 worth of pre orders with the company, pretty much as an advance to develop their own technological approach.

The 351 unit was originally released in 1958 and came attached to a full range mono tape transport for recording with. Soon after you could pick these up with a pair or preamplifiers for an exciting new world of stereo recording too.

The 351s seemed to be largely forgotten for about 30 years after that, getting phased out by studios chasing more modern sounds, and a greater number of recording channels. And even at the time was criticised by engineers for what they saw as having underperforming pre-amps, which were often hardwired to have the preamp bypassed!

warm audio mpx

It wasn’t until a couple of decades later when people started pulling these units out of garbage bins and estate sales and began modifying them, to the dismay of many purists, that their full sound potential was unlocked.

So, looking over to the WA-2MPX we’ve got a stereo Ampex 351 that’s ready for recording with. No need to mess around with modifications, or replacing temperamental selenium rectifiers – here we’ve got a full voltage (no starved plate tube garbage) 300V preamp with up to 90db of gain.

And how does this thing sound? Surprisingly good. Thick and rich with a soft, tubey top end, and plenty of space to mash sounds into distortion. I ran this thing over drums, guitar and vocals separately to see what it can do.

ampex clone

 I went in with a little scepticism because I use a lot of vintage tube preamps in my own recording set up, but I feel like this piece can pretty much hold its own amongst them.

It’s rich and full with a top end that seems to round off any harsh frequencies. It’s maybe not as extreme in character as some of the tube front end stuff I run, but it’s reliable, and it’s got a whole lot of headroom, plenty for even the oldest ribbon mic.

I wouldn’t have specifically asked for a high pass and low pass filter tube front end, and so many switches do make the front panel feel a little crowded, but you can definitely pull some very good sounds out of it. The tape saturation is maybe towards the harsh side of things, but if you want to ram something with a crispy, extreme crunch this switch will indeed do it.

warm audio 2mpx

And with modern Cinemag transformers it’ll be a long time before windings go bad on this thing, so it won’t be like chasing vintage transformers to make replacements like I’ve had to a few times with older pieces. Plus the tubes are standard and easy to replace too, it comes stock with a tube amp doctor 12ax7, and a couple of modern Chinese factory 12au7s.

Whilst I feel like the WA-2MPX doesn’t 100% nail the absolute richness of an Ampex 351, especially when it’s pushed hard, but it’s very close, and will probably get you to the right place most of the time.

Right now you can pick up an original mono 351 for around $1500 and spend at least another grand to get it modified, OR you could pick up the Warm Audio WA-2MPX for around $2400 AUD and get a stereo version. And there’s also a mono version called the WA-MPX.

For more info head over to Warmaudio.com