Odd Preamp vs Amp Differences

[neutron619]

Hello Chaps,

 

I've had a bit of an odd encounter - and this is with an HX Stomp as opposed to a lady of the night (!) - and I'm hoping someone might be able to explain what's going on.

 

Having read lots of threads like this one recently - https://line6.com/support/topic/27397-preamp-vs-amp-block/ - I've been playing around with the preamp blocks as a way of creating some nice overdriven tones. It's worked pretty well. Most recently I've been trying some of the older preamp models - the Fender Champ, the Gibson 185 (can't remember the Helix names) - and getting some really good results.

 

Most recently, I tried a simillar experiment with the Vox AC15 (which I think is called the "Essex A15" on the Helix). I expected simillarly positive results. In this case however, the pre-amp doesn't sound or behave in any way resembling what I'd expect. Running the gain all the way up increases the volume but doesn't really introduce any overdrive / clipping / distortion into the tone. This is not the same with the equivalent amp model, which produces lots of crunch quite early on, which makes me think that the power amp part of the model is contributing significantly to the tone.

 

Can anyone confirm that that is the case (or add some background)?

 

Thanks in advance.

 

[Schmalle]

The AC30's overdrive comes from it's power amp. You won't get overdrive from the preamp unless you hit it hard with a boost - it is just one tube stage and a bit of filtering. The overdrive happens after the preamp in the phase inverter and the power tubes.

 

You could try the Carillon preamp for this.

The best preamp imho is the Cali Texas CH2 - very versatile. Give it a try!

 

[codamedia]

On 2/13/2024 at 3:48 PM, neutron619 said:

I tried a simillar experiment with the Vox AC15 (which I think is called the "Essex A15" on the Helix). I expected simillarly positive results. In this case however, the pre-amp doesn't sound or behave in any way resembling what I'd expect. Running the gain all the way up increases the volume but doesn't really introduce any overdrive / clipping / distortion into the tone.

 

As stated above already... a real VOX gets it's dirt/drive/character from the power amp section... therefore the pre-amp alone will not give you that tone. 

 

Some amps get their character from the pre-amp, some from the power-amp, some from a combination of both. To complicate matters further, the "standard" speaker option is often another huge factor in an amps tone. EG: Place a bluebell/silverbell cabinet on a Fender Deluxe... the deluxe starts to sound surprisingly like a VOX. 

[neutron619]

Thank you both for your responses - they are appreciated.

 

So it seems that in this case, I need to play around with the full amp model, rather than the pre-amp. I'll give that a try.

 

More generally, playing with these different preamp / amp blocks is forcing me to learn interesting stuff about amps etc. of the sort that you two have just taught me and I'm really enjoying it. Thanks again.

 

(If I could work out how to make this editor do a thumbs-up emoji, I would... :-S )