Strange Bass Resonance on both DR and Rectoverb

[cyber104]

Hi Guys:

Let me say upfront that I realize this is a vague question....

On both my Rectoverb with a custom 1x12 (v30) and my sons Dual Rec with a 2x12 Rectifier cabinet we are getting a strange bass resonance when hitting a muted "A" (low). Only on the "Modern Setting"

At moderate volumes (band practice levels) it can be quite distracting if you hang on it.

It's almost like a bass spike verging on a farting sound.

The Rectoverb with 1x12 does it worse but the DR does it too.

If you palm mute all the strings and compare the relative volumes - the 'A' string produced a much louder resonance and thump that even the low 'E'.

We tried several guitars and they all produce the same results.

Dialing the bass back to 09:00 helps but then you lose a lot of bottom end. Normally we both run our bass between 12:00 and 2:00.

Gain setting doesn't seem to matter but we both run our gain at about 01:00.

Any thoughts? Is this characteristic of a v30?

Thanks,
Chris

 

[UnderJollyRoger]

Well, DR's for example are bassy. I noticed the other day, even with a boost in front to clean things up, my C (not too far from your A, eh ?) still is mighty powerful, so to say, especially with more gain than less gain. however, it's hard to get with the bass control because the note seems a little too high for the control to really get it ...

Depending on your guitar and pickups this might move a note or so ... have you tried a different guitar ?

 

[cyber104]

I think things are probably OK - just a resonance inherent to the cabinets.

Yes - we tried 3 different guitars - a Les Paul, a PRS Tremonti and a PRS SE. They all reproduced the resonance to some degree - the PRS Tremonti least and the Les Paul the most.

Thanks for the reply!
Chris

 

[caterplotheawful]

have you moved the amps into a different room? Sometimes you can get some resonance from a room on certain notes

 

[94Tremoverb]

It's a characteristic of the Modern mode on these amps, because the power amp Negative Feedback (NFB) is turned off, only in this mode. This is a sort of 'damping' that most higher-power amps have, and turning it off is what gives the huge, open and dynamic tone these amps are famous for... but it also allows the circuit to resonate slightly when it's pushed into it at certain frequencies. Palm-muting on an A seems to be the best way to trigger it. The fatter the guitar tone, the more easily it happens.

A friend of mine has a Rectoverb that does exactly the same thing - we looked at fixing it by bypassing the NFB switch to allow a little damping to control it - which worked, but this also takes the tone back in the direction of the Vintage mode, which he didn't like. In the end he's just learned to 'play around' the problem for the sake of getting that tone.

 

[YellowJacket]

Interesting. I noticed this problem too, but when using my Dual Recto as a bass amp. I noticed that at the octave E down to about the B or A, there was a weird bass woof on the clean channel. I got around it by diming the mids, rolling down the bass considerably, and turning up the presence. In my opinion, the best thing to do with rectos is to match a suitable pickup. Something that puts out most of the power in the midrange and highs is best. Given the scooped nature of the tone, the amp will still sound huge but it will be MUCH tighter! In the end, I ended up building a close back cab with an interior ported baffle that reduces standing waves and mud. It is very tight!!

Apparently, with an Electra Dyne, turning up the presence reduces the negative feedback in the amp so by diming the presence, you can get very open modern type tones. At least this is what the manual says... The dyne is a really weird amp though. I find it absolutely does not like my thiele cab because it has these sub lows that become painfully amplified with a bass reflex design. I have never had this problem with the Recto.

 

[cyber104]

Thanks guys - I suspected that it was something inherent to the amp but the explanation given above is quite interesting.

I'll deal with it - it's just a little distracting at times - I like the amp too much to let a small issue like this discourage me

The notion of a matched pickup explains why the PRS Tremonti USA does not do it as bad as the Les Paul.

Thanks again!
Chris

 

[cheameup]

have you moved the amps into a different room? Sometimes you can get some resonance from a room on certain notes

+1

My music room at home vibes like hell at any f#. Doors and windows rumble. Low or high it doesn't matter

The pickups voicing is a reall good point too. Before my dual my pickups were pretty light on the mids and big on lows but they sounded muddy through the recto at times Both guitars have much more mid focused pick ups now