A4 Amplification Morph Preamp

Bought 1997. This is an all-valve (well, signal path anyway) kit-build pre-amp. The circuit is based around 4x 12AX7 dual triodes. The unit is two channel, Clean channel has three band EQ, volume and a Crunch mode which adds a gain control. The EQ has two switchable networks, one "Fender", the other "Marshall". The switch assigns one network to Clean, the other to Crunch, or vice versa. The separate Lead channel has its own 3-band "Marshall" type EQ, with a mid-boost switch. Overall output level is presettable internally to suit different power amplifiers. A major feature of this unit is the interchangeable "soundcard", a plug-in daughterboard which allows for a complete re-configuration of the gain stages, for different playing styles. My unit was bought with just the standard card ("Vintage" and "USA Hot-Rod" cards were options).

Since the unit accepts a double TRS type footswitch, Clean/Crunch and Channel 1/2 switching is possible remotely.

I have three minor criticisms of the facilities: a dedicated Crunch master volume would turn the unit into a versatile 3 channel device; as it is, the volume drop when engaging crunch mode from clean makes this impractical. The other problem is switching noise on the Clean/Crunch EQ selector (especially silly since there is a noise suppression circuit for all the other switching functions). Thirdly, the output socket would be better off at the back.

There is no effects loop; this is hardly necessary since an effects unit can be inserted between the pre-amp and the power amp.

I use a 1996 Fender USA Strat with Seymour Duncan Little '59 pickups in the neck and bridge. I have also just bought a Gibson Les Paul Studio+, with the stock 490R/498T humbuckers.

I play a variety of styles, mainly blues/rock. I find the Morph to be very versatile, although finding the required sound across the channels can take a bit of fiddling around. The clean channel has a lot of headroom when connected to a big power amp, but can be made to dirty up a bit if the channel volume is wound past 8 or so. It doesn't quite have the crystal clarity of a big Fender, but is very responsive and useable. The lead channel is fantastic, especially with the mid-boost in. This channel has 5 gain stages, and at full tilt sounds a lot like a Boogie, although lesser gain settings can give very nice bluesy tones with terrific touch sensitivity. There are settings that can range from a cranked Champ right through mega gain scoopy stuff (if you know where to look). Guitar character is well preserved, the Gibson sounds amazing through this.

The one mode I don't use much is the Crunch mode; it's a bit too mushy and the bass control is kind of all or nothing. There's too much gain (not much less than the lead channel) and it's a bit uninspired at lower gain settings. I find the lead channel covers everything this is supposed to do, but with more definition.

One nice thing in general is that the unit provides an almost fully formed tone, which doesn't require much help from the power stage. That said, a good valve power amp definitely warms everything up.

There's no real noise issue; the valves all have DC heater feeds to prevent hum, and hiss is fairly well suppressed, even at high gain settings.

Totally reliable, although having built it myself, it would be more my fault than the vendor's. To be fair I have only gigged occasionally, so it's not had a hard life. The components supplied were generally good quality, although the original valves were some rough looking (and sounding) Chinese items. A change to Electro-Harmonix 12AX7EHs made a vast improvement to the tone.

Now the bad news. The A4/Bradley organisation seems to have disappeared off the face of the earth, sometime in the two years after I bought my Morph. I was about to buy some alternative soundcards, only to find that the website had gone and neither the e-mail or phone were being answered. Luckily I'm quite handy with electronics so I can provide my own technical support.

I haven't owned much other valve gear, although a gigging friend has lent me 3 Rivera-era Fenders, a Boogie MkIII and a Marshall TSL at various times. The Morph compares favourably to all of them, maybe being more of a "jack of all trades" than an absolute master.

Replacement is not an option as mentioned above, unless I could find one used.

I bought the Morph mainly for economy; getting into valves would have cost twice as much otherwise. The build was a good challenge, so that was another factor.

The main reason for me writing this review is to compensate for the complete lack of internet information, and to try and get in touch with anyone who may own another Morph. Any links I've found have been dead ones pointing at the A4 site.

I have the schematic and build instructions, covering the standard soundcard. If anyone has schematics for the other cards, or information on what happened to the company, PLEASE let me know. Equally, if anyone wants copies of my stuff, please contact me. I also have a photocopy of a review published in The Guitar Magazine, November 1997.