I bought this preamp and amp (T-100) as a pair in April, 1994 (I think). The T-100 stb during a rehearsal. The Quad X has remained a highly-valued part of my rack simply for the sounds it brings to the table.
Channel 1 is a twangy Fender Tweed feel to it (even with a LP). It can be completely sparkling clean with the right EQ (knobs) and touch on the guitar. At some points, it can rival (operative word can) an AC 15 with good technique and the right pickups.
Channel 2 is useless...NEXT....
Channel 3 can really be the end all to preamp high gain and nasal at the same time if you play with the EQ (and yes) Cloaking enough. From Pete Townshend to Angus Young to Early Page to High Gain Adrian Smith, this channel CAN do it all. It can't do them all simultaneously, but it can make every one of those sounds whether you're beating on the strings like the Clash or picking them quietly with a ten pence like Brian May. Best Channel on this preamp.
Channel 4: Like Randy Rhoads, this is your channel. Big loud and totally in your face. Boasting a "Cascade Tube" circuit, Carvin pulls this one out with Over The Top Gain. Big Noise.
4-channel tube preamp (9 12ax7):
Channel 1: Clean (1 preamp stage, 1st stage of tube 1), volume, low, mid, high
Channel 2: Clean (1 preamp stage, 2nd stage of tube 1), volume, and low, high EQ, cloak shared with channel 3
Channel 3: Clean (5 preamp stages, tubes 2, 3 and 1st stage of tube 4), volume, crunch and low, high EQ, cloak shared with channel 2
Channel 4: called Sustain (and rightly so) (11 preamp stages, 2nd stage of tube 4, and tubes 5, 6, 7, 8, 9), volume, gain, low, mid, high
Boost switch, bright, separate EQ for the master.
Effects loop on the master and specific loops for each channel.
True reverb that simply sounds.
Good quality noise gate circuit.
Ultra-comprehensive connection options (jack, xlr, stereo, mono outputs with separate volume controls), inputs on the front and rear, footswitch jack for each channel (on the non-MIDI version).
The settings on each channel are fairly simple (volume, eq).
Knobs are very responsive, you can get interesting sounds right away.
The manual is very well-made and not mandatory.
Do note that the status of the master graphical EQ is activated by channel, so you can activate it for channel 1 but not the rest and these settings will be saved.
Channel 1, wonderful clean sound, crystal-clear, easily shapeable with the EQs
Channel 2, clean sound, crystal-clear, EQ shared with channel 3, very handy to have a "clean" version of channel 3
Channel 3, it goes from a warm clean to a downright rock sound with a good amount of distortion (with boost engaged if necessary and depending on the pickups you use). Among the most beautiful crunch sounds (from smooth to really driven).
Channel 4, from crunch to fat distortion. Ideal for lead sounds, as its name implies it has a huge sustain.
Probably among the most versatile preamps I know.
On the same level as a Soldano (X88), Mesa (quad or triaxis) or Bogner (fish, for example)
I use it mainly within a studio setup and record it via the direct output into a soundcard input, I then add a speaker emulation (like a Torpedo), and the sound is wonderful.
Unbeatable value for money secondhand.
Its only negative point is that it depends a lot on the quality of the tubes used and when you need to replace them, you need to break the piggy bank. I opted for a cabling mod that allows me to use Russian 6N2P-EV tubes of excellent quality, which only cost a couple of bucks (and sound way better than some $50 NOS ones).
This preamp is very very versatile. The cleans are very Fendery, maybe a little bit too bright at times, but you can always turn down the treble! Channel one and two are clean, channel 3 and 4 are dirty. They all sound great. I like all of them equally, for their own reasons. A lot of people say they don't like Channel 3, but I use it for my solo sound and I think it is very smooth. (depends a lot on the tubes you are using though.) I have just been using it with the stock tubes and it sounds great, so new EH or groove tubes would probably make it sound fantatstic! The tone controls are active, so you can take any eq possibility to the extreme, and, more importantly anywhere in between. The thing I like the best about this is it's degree of control. There is an eq for 1, 2&3 share,and 4, and an assignable 5 band graphic eq. There are effects loops on each channel (always on) plus two master effects loops (a serial AND a parallel) that you can turn on and off via the footswitch. Full stereo capability on these effects loops. Many more features I like, read the manual at www.carvin.com/manuals/quadx.pdf
I use this for prog rock with fairly complex chord inversions, and the distortion lets every not come out clearly. Try playing a Bbmaj9b5 with your distortion sound and see how clear it sounds. The quad-x makes it clear. I use the gain on channel four at about 3.5 or 4 and it is a perfect sound for me.
The only thing I don't really like about this is that the reverb has some 60 cycle hum when you turn it up, but I use an external reverb when I need it. The midi capability is there, but you can only change channels, and the midi patches are preset in the unit; you have like four options in how to lay it out. But I still think that it's usable. The distortion could probably be a little bit tighter at times, but that would probably change with tube selection.
This thing is built pretty well from what I can tell. In mine, the circuit the tube sockets are on is a little loose, but I don't think that is a problem in any way, I've changed some tubes just to experiment a couple of times, no problems. It looks and feels like a quality piece of gear.
This thing sounds great and gives you a lot of control over all it's aspects.
You can get almost any sound I can think of with this thing. I have gotten good distortion tones from blues to scooped mid metal distortions (which, in my opinion, are kinda dumb anyways) and it does it all well, not excellent, mind you, but very good. If you want one particular tone to be excellent get a specialized amp, but if you want a flexible, versatile unit that sounds really good, get this. It is a really good value for the money, comparable to the mesa quad, but the mesa obviously has some advantages (again I reference price)If this were a value for the dollar rating, I would give it a 5, but this is an overall rating. I give it four. Very good unit! If you want any questions answered that you can't find elsewhere, feel free to email me!
This is basically a huge 4 channel preamp. Similar i believe, to that of a boogie mark IV in a rack style preamp.
HUGe in size! Gigantic!! Heavy and tons of tubes too!!
Ok it gets a little bit confusing especially since the 5 band EQ can be assigned to nearly any channel so you have to set that.
The clean channels are easy to use and have gain knows so you can crank them to get any bit of dirt if you want a sort of mild crunch.
It's slightly difficult at first, you should most likely read the manual to get started if you haven't dealt with multi channel amps before. The manual is quite easy to read and understand each setting etc.
Though it is generally easy to get the ball rolling and get some decent sounds to start.
I like carvin clean sounds. They are completely underrated and suit for any type of genre doesn't matter what, blues funk, jazz etc. It works all the time for anything! It's so crisp, clear and shimmers!! There isn't much else a clean channel can really do for you but now with the quad X you have TWO? What?! So now you can make one super clean, and one dirt up a bit to get those bluesy sounds all in one? And just switch between them if you feel? How perfect is that?
Let's not mention the dirt, it stays true to the hot rodded vintage sound that can range anywhere from classic rock to modern heavy metal depending on the rest of your gear of course. The poweramp you have plays an important part in this. The 3rd channel has the super hot rodded vintage sound while the 4th channel is very reminiscent of a lead boogie mark series, thick and creamy! Very cool!
Another thing to note is the speaker sim it was unfortunate that I didn't have enough recording equipment at the time to try this but the fact that it's tonally adjustable means that the speaker sim was not an afterthought and must have some potential in some way.
The added noise gate is a good feature too I wouldn't say it's completely transparent but it does a half decent job and stopping squeaks and whatnot depending on how you set it, try not to set it it too high and stay a good distance from the speaker to avoid any unnecessary noise.
Overall, I think this is carvin's response to the boogie preamps that came out during the same era and I gotta say it's held up quite well in terms of tone. In terms of popularity it hasn't gotten as big, but that's ok, it keeps the costs low for players who know about this amp! It's the price point that really gets me, it's so cheap yet it's amazing. How is this possible in today's world? It's not really, I think I'm just lucky! Super lucky!
I could imagine pairing this up with a VHT poweramp and just going balls to the wall crazy!! Good buy good price, if you can find one with the footswitch you'll be in tonal heaven!!