how do u really warm up a bright tube amp

[Lewguitar]

Re: how do u really warm up a bright tube amp

Yeah, like Scott said, Get that bright cap off! Did a lot for my DRRI.

1. The Super Reverb doesn't have a hardwired bright cap to remove...it has a bright switch. Leaving the bright switch in the off position eliminates the cap.

2. Sure Jeremy, just pull the normal channel pre-amp tube. Shouldn't be a problem. No guarantee it'll be the tone you're looking for but it will give more gain and the remaining channel will overdrive more easily.

3. Jumping the channels will get a thinner tone because the normal channel does not have reverb and so the the two channels are out of phase. I always put reverb on both channels and then revoice each channel: one for humbuckers and one for single coils.

So MANY, MANY things that can be done to tweak Fender amps to your personal tone.

 

[jeremy]

Re: how do u really warm up a bright tube amp

yup, simple circuts

im about to dig into my bassman and change a 100k slope resistor to 56k and put a 25uf-25v bypass cap across the 820 ohm cathode resistor on the 2nd tube. supposedly a little more gain, fuller tone and a little earlier breakup

 

[Lewguitar]

Re: how do u really warm up a bright tube amp

yup, simple circuts

im about to dig into my bassman and change a 100k slope resistor to 56k and put a 25uf-25v bypass cap across the 820 ohm cathode resistor on the 2nd tube. supposedly a little more gain, fuller tone and a little earlier breakup

56K is the Fender tweed Bassman value. 100K is the blackface Fender value. But I think 56K sounds muddy in a blackface Fender...the two circuits are so differant that 56K sounds "right" in the '59 Bassman but 100K sounds better to me in '65 blackface Fenders.

Try 90K or 91K or whatever value is readily available in that range. A little lower than 100K brings up the mids just enough to satisfy me, but 56K is to much for me in a blackface or silverface Fender.

Another way to bring up the mids and, one that I like better, is to change the fixed 6.8K midrange resistor to 10K, or 15K or higher. In a amp with a 10K midrange pot, the pot is there instead of the 6.8K resistor...change that pot to 25K to increase mids. Also changing to a pair of .02 caps (Sprague Orange Drops or Mallory 150) in the tone stack will result in more of a plucky Marshall midrange tonality.

Lew

 

[Thames]

Re: how do u really warm up a bright tube amp

I'd really go with the preamp tubes first, then the power tubes, then the speaker... and if you still havent got the results (!!!), trying tweaking the circuit. But you shouldnt have to go there.

Put a JJ 12AT7 in V1 (or V2, depending on which channel you mostly use). It will calm things down (highs). Make sure you have a 12AT7 in the PI (V6). Make sure also you dont have any Sovtek/EHx tubes in there... they are usually bright and harsh. JJ are thicker, and a tad darker/warmer.

Is it a brand-new amp ? Do you think the speakers have broken-in enough ? If no, you can "loosen" them a bit by applying acetone with a paintbrush on the surround, while playing thru it (plug it to any stereo-amp and run some groovy/bassy tunes on CD). It should help

 

[seafoamer]

Re: how do u really warm up a bright tube amp

1. The Super Reverb doesn't have a hardwired bright cap to remove...it has a bright switch. Leaving the bright switch in the off position eliminates the cap.

My bad.

 

[Benjy_26]

Re: how do u really warm up a bright tube amp

Both tubes and speakers are a good try...some pre-amp tubes seem to be real "toppy" as well as power tubes...If you wanted to stay with 6L6/5881 powe tubes, try the new Electro Harmonix...they are made just like the opl RCA "Blackplates" and sound great...that said, I think the Speakers are the worst part of reissue Fender amps...they have the strange edginess that can't be eq'ed out no matter what guitar is used and I for hate it...I changed speakers to reissue Jensons and it was gone! That is what I would do first, just keep the old ones and if you ever wannt sell it...you have options.

+1. The EH blackplate replicas rock! :headbang:

 

[lastwinj]

Re: how do u really warm up a bright tube amp

the first thing I'd check would be the bias point on the tubes

Fenders often come biased a little cold from the factory, in order to extend tube life

while it is true they bias them up cold, this wont affect the brightness of the amp. underbiased amps sound lifeless and sterile.

germ