Plugging guitar directly into power amp

[clintonb]

I don't have a question, just an observation.

I have a Crate Vintage Club 50 2x12 combo (4xEL84) that I think sounds really bright. At gig volumes, I often have to turn the treble all the way down. It uses Crate speakers that are supposedly relabeled Eminence GB12 (one of their greenback-like speakers). It sounds better when I replaced the speakers with an old Fender speaker from my Twin Reverb, I could actually use the treble knob.

But if I plug directly into the power amp via the effects return (still using the Crate speakers) the tone is almost perfect. It is fat, warm, and surprisingly clear. It sounds great with single coils and a little less great with humbuckers. My only complaint would be about the boominess when playing the low E-string. The volume also seems like it is almost loud enough for gigging.

I'm curious why Crate took a beautiful power amp tone and created an overly bright preamp and then paired it up with overly bright speakers. It seems like the only tweaks it would really need is a little sculpting on the low end.

I also tried plugging directly into a Peavey Classic Series 60 Power amp (2x6L6) but that sounded muddy.

So it appears that perhaps EL84s have a baseline tone that sounds better than 6L6 to my ears. Yet I find most 6L6 amps to be warmer than most EL84 amps.

[guitician]

That amp sounds like it could have a factory defect, like a wrong capacitor value, or resistor. Yeah, how the speaker and the power amp work together are the key to great tone. The pre-amp is just for added flexablity in tone control.

[clintonb]

That amp sounds like it could have a factory defect, like a wrong capacitor value, or resistor.

Actually, it seems like all the Crate vintage club amps I've tried are bright. I wonder if they were designed to sound good at music store volume levels?

There is a 220pF treble bypass cap on the clean channel volume control. Taking that out helps a lot. But the clean tone still doesn't sound as warm and full as plugging directly into the power amp.

Perhaps less is more. One of the best sounding amps I've ever played was a tweed champ, and that circuit really doesn't have any tone shaping at all in the preamp. It just has .02uF coupling caps. However, I tried modding my Electar Tube 10 amp (1-12AX7, 1-6L6) to be the same and it didn't sound as nice as the Champ. However, it sounded a lot better than the stock circuit. Changing to a larger transformer really opened up the bandwidth too.

[pdf64]

The tone you get from doing this will depend on the input impedence of the effect loop return, which will vary far more from one design to another than the normal guitar input. If it's only 10k then the guitar tone straight into it will be really muddy as the pickup resonance will get damped out. Peter.

[Enzo]

How well do they make that scooped away middle sound, where there is nothing BUT high end and bottom? That sound the death metal kids all savor? Nothing against Crate really, but I don;t think Crate is marketing to the experienced touring pro. I think they are marketing to the entry player. So tonal extremes speak louder.

[clintonb]

Well I tried my amp again today, but turned the bass down and the treble down which, according to the Tonestack calculator at Duncan amps, should make the frequency response flat. I guess it does sound pretty close to the sound when plugging into the effects return, just not as sweet.

The real key was getting rid of the treble bypass cap on the volume control.