Flubby bass in a '65 DRRI

[Jericfos]

Hi,

Deluxe Reverb Reissue seems to fall apart in the low end at the volume i want to use. But at slightly less volume it's perfect for me.

Here's what i think i should try as the easiest fix...a high sensitivity and high wattage speaker, and a weber copper cap rectifier replacement.

Does this sound like the right call to tighten up the low end? Is there anything wrong with using the copper cap in the DRRI?

Thanks!

 

[Roe]

1, turn down bass when volume is high
2 up filtering on mains and screens
3 reduce coupling caps
4 try ab769 phase inverter
but yes a speaker and ss rectifier can help

 

[Blue Strat]

What volume is beyond the point of being usable? If over 5, that's pretty normal.

A 5AR4 type copper cap (the highest rating advisable to use in that amp) won't improve low end because it's virtually the same as a 5AR4 tube.

A "pure solid state" rectifier is completely unadvisable unless you switch to 6L6s or JJ 6V6s.

The power supply filtering in RI's is already higher than in vintage DRs.

 

[TweeDLX]

What Roe said...

 

[Roe]

What volume is beyond the point of being usable? If over 5, that's pretty normal.

A 5AR4 type copper cap (the highest rating advisable to use in that amp) won't improve low end because it's virtually the same as a 5AR4 tube.

yes, this is important

 

[Jericfos]

Yeah, i guess it's above "5" when it starts falling apart. Right, turning down the bass helps. But it's not less bass i want, just tighter bass.

So a 5AR4 copper cap is safe but won't help?

I'm not against buying a different amp... but i like 6v6 blackface type sounds, and i'd like to find a 20ish watt fixed bias combo that can stay a bit tighter at high volume, and at least as much headroom as the DRRI (slightly more is welcome too). Because i haven't found that i'm looking into some easy mods for the DRRI.

Interested in the ab769 PI thing too.

 

[hasserl]

In that amp tightening the bass usually requires reducing the bass. What happens is the power supply rail drops when you dig in to it or hit chords. Bass frequencies require more power to produce, so when you hit a chord the voltage level sags and the tubes go non-linear and distort. Adding filtering can help with this, but with a tube rectifier you are limited to how much filtering you can use. This is where a copper cap can help, because with a copper cap you are not limited in filtering, you can add as much as you want.

But this is not the only area of the circuit that causes the flubby sound. Part of it is due to blocking distortion. Go to Aikenamps.com and search the tech section for "what is Blocking Distortion?" and if you read that he explains another significant reason DR's sound the way they do when pushed. He also offers some means to reduce the effect. (note: this is one reason for Roe's point 3 & 4).

 

[Blue Strat]

A lower bass control setting isn't necessarily "less bass". Try it, it takes 2 seconds.

 

[tommytomcat]

(Side note.. It's important to mention what kind of pickups you're using..) I'm guessing you're using humbuckers or hot P90's..? FWIW, vintage Fender amp's were designed around the guitars of the time... In this case, stratocasters and telecaster with low output pickups. If you're using humbuckers or P90's you're hitting the first preamp with 50 to 100+% more signal.. h/b's tend to be bassy anyway, easily flubbing out the bass. That's why your fender amp has that #2 hole. It's there for humbuckers. Plug into it and turn the volume up and the bass down a little.

The DRRI is a PCB amp.. a total PITA to mod compared to a vintage hardwired amp. So.. Modding the circuit would be my last resort.

A better speaker will help. I'd suggest the Weber Signature Series 12B or Eminence Legend 1258 (both cost around $50). If $$ is no object, check out Weber's Vintage series for the model's that pair up with DR's the best... or maybe a Emi RW&B.

 

[phsyconoodler]

I agree with the speaker swap.I was not liking my Custom Vibrolux's flubby breakup so I swapped the Alnico's for an Eminence Ramrod and a Celestion Vintage 10.The bottom end tightened up considerably and it overdrives much nicer now.The cleans are darker too and that's not a bad thing with a bright amp like the Vibrolux.
A speaker can make or break your sound.

 

[Roe]

lower bass means clearer bass rather than less bass. improving speaker doesnt help if the amp struggles

 

[TimmyP]

The trouble with reducing bass via the bass control is the wide frequency range it covers.

If you reduce bass by reducing the coupling caps (or the cathode bypass cap(s) you'll reduce only the lowest frequencies, leaving in more of the fatness.

 

[phsyconoodler]

Speaker changes can make huge differences in bass handling.Yes,it's limited by the circuit too,and some people's idea of how 'much' bottom end they really need.
Fender's use of .1uf coupling caps makes them fat and full sounding at the expense of tighter distortion characteristics like Marshall's have.They typically use .02uf caps.
The cathode bypass caps have a lot to do with it too.Fender's use 25uf while Marshall's can use anything from .68uf and up.
But......beware of having an amp that's too trebly when playing clean with a strat with low output pickups.
That's the reason many people go to a two channel amp like a Dumble style or a Marshall for the dirt and leave the Fender alone for the clean and slightly overdriven blues tones.
Trying to get all sounds from one amp gets you into Messy Booger territory with bells and whistles and less than stellar tones.
a speaker will do more than you can imagine if you aren't looking for too much more than the amp was designed for.
I was experiencing exactly what the OP was and a speaker change did it for me perfectly.The circuit is not struggling at all.It just needed some support.

 

[parkhead]

change the Bass and Mid caps to .02

this shifts the frequencies up and out of the problem range

this is an old Ken Fischer mod

P

 

[Roe]

yes, diaz even used .015

 

[GearHeadFred]

To paraphrase sheriff Brody (from Jaws): "We need a bigger amp".

Perhaps you are asking too much from a DR (22 watts, single 12 open-back combo)?