Tube power amp into cab?

[jeremiahzellers]

Has anyone tried that? I have a full a full hollow solid wood archtop with a floating pickup. I love the guitars sound, but when I plug it is it seems to lack something. Note bloom? Warmth? (I hate that vague descriptor).

I didn’t want to plug into a preamp that will drastically alter the sound, but would like the tube goodness I’m used to.

Would love to know if that’s a thing people do/have done.

[EastwoodMike]

Hey Jeremiah
Not sure how familiar you are with amps and arch tops in general, so I don’t want to sound too simplistic towards you here:

Archtops plugged in will at a certain volume sound like a pickup amplified. After a while you will not hear the guitars resonance. Depending on the construction of that archtop you will probably hear feedback as well.

If you are recording direct you will not hear the resonance of the guitar in the recording the same way the player was hearing it- unless the guitar body is also mic’d and recorded in parallel to the direct signal. The tone of the direct signal will be a bit different to a solid body though.

As to plugging into the power section of an amp direct, your signal will be too weak. You need some form of preamp to lift that signal strength to the point the power tubes can use it. I think that is what you are referring to?

If by cab you mean a powered speaker then you will probably damage or at the least overload your cab input and possibly damage the output transformer of your tube amp. Don’t do this unless you are supremely confident of the outcome.

If by cab you mean just a speaker- that is how every tube amp operates anyway. The speaker is providing a load the Output transformer can dump all that scaled power into.

Now if you do want warmth of tubes but into a powered speaker, consider either a tube boost pedal, tube preamp pedal or if you can take a line pre-out (or effects send) from your tube amp.

But just note that bloom is a function of power supply starvation in a tube amp recovering. I’ve never come across a preamp that causes that. Pedals may try to emulate that. And warmth is a function of distortion setting in- the tube starting to exceed its design linear operating range. It by definition is colouring your sound but in a nice way. The further you go the more it sounds like ‘rock’ distortion.

Also remember a typical guitar cab speaker will colour your tone. That’s a whole different rabbit hole.

Again, if you know all this already my apologies- just the wording of your question suggested you may be new to this part of the world….

Hope that helps your quest. Good luck!

Emike.

[JazzNote]

Has anyone tried that? I have a full a full hollow solid wood archtop with a floating pickup. I love the guitars sound, but when I plug it is it seems to lack something. Note bloom? Warmth? (I hate that vague descriptor).

I didn’t want to plug into a preamp that will drastically alter the sound, but would like the tube goodness I’m used to.

Would love to know if that’s a thing people do/have done.

I find that much of the change of tone is dependent on the volume and how this volume is produced. E.g. plugging into a small miked amp at low volume over a PA with one or better two speakers, provides me with a much more acoustic sound than just the amp which i might have to crank up to get the same volume. And btw: every amp which is designed with a guitar input has a preamp stage which will be responsible for shaping the tone. If your amp does not give you the desired sound you may need to look for another. In order to find out you may need to try at different volumes with different tone control settings.

[jorgemg1984]

A good alternative to that would be a flat eq tube amp, which is not that easy.

Old Ampegs do that - they use a Baxandal EQ (flat with all knobs at 5) and they are full tube, plus they have plenty of clean headroom. Cheap and easy to find in the US.

Henriksen had an hybrid design, the Forte, which has a tube preamp and a ss power amp. Again, flat at 5.

Blackface amps can be made "flat" by lowering the bass and the treble to close to 0.

Some combo amps have what is called a "tone stack lift", which basically means you "bypass" the preamp. Here you just have to be careful because sometimes that means flat but also a lot od distortion.

Also, I wouldn't be too much worried about the preamp "coloring" my sound. Guitar pickups are not, by all means, flat or high fidelity reproducers. An open-back cab with say, a Jensen or a Celestion, will also not be flat at all. I've found a good blackface amp, with enough headroom, can be "flat" enough, even with other eq settings than the ones I suggested, for an archtop with an humbucker.
If fidelity and tubes are your ultimate goal, a good mic and a mic tube preamp, plus some good FRFR speakers, would be your ultimatr solution.

[marcwhy]

@jeremiah, I'm kinda confused about your post... Are you simply using a tube power amp (i.e., Mesa, Carvin, etc) into a cab, with nothing in front of it (i.e., pre-amp, pedals, etc)? If so, that's a fairly unusual rig. The "tube amp sound" that many of us enjoy - including the "blooming notes" that arise - typically comes from a "regular" tube amp, which has a tube pre-amp and a tube power amp. What's the concern about this normal setup??
[Maybe show a pic of your rig so we know what you're doing? Thx!]

[sgosnell]

A decent power amp won't color the sound at all, it should just make whatever signal it gets at its input and make it louder. That's a power amp's job. Coloring the sound is the job of the preamp.