Two questions about tubes in my SF Vibrolux Reverb

[Blue Furry Monster]

Hi all,

My main amp is a silverface vibrolux reverb -- it's a '78 or a '79 i believe. i play in a indie band and usually i'm playing clean with a little slapback or slightly crunchy with a little slapback. :) lately i've wondering:

- is there any way to get a little more clean headroom from the amp? would i be looking at swapping out the preamp tubes?

- the tremelo on my VR seems much less "deep" than the trem on my SF Vibrochamp. Is this also a function of the tube, or is it simply the way the VR is designed vs. the champ?

Any help/advice would be much appreciated!

cheers,
han

[Ringo]

I doubt that changing preamp tubes would get you much more clean headroom, but if you were to try some different power tubes possibly that would help , along with a solid state rectifier.
IMO the biggest improvement would be to get some efficient speakers, if the amp has the stock speakers, then changing speakers could make a dramatic improvement.
If you aren't familiar with the Weber BB's, check over there http://www.webervst.com/vstbbs/bbs.html
You can ask on the amp board and on the speaker board, bet you'll get some good advice.

[tlpruitt]

The tremolo in the VC is the output stage bias based type and the VR type is the preamp opto-oscillator type. They will sound different. Many prefer the output bias type. The Princeton and the brownface amps also used the output stage bias type of tremolo.

-Tim Pruitt

[jjmantele]

The VC's trem signal modulates the bias of the 2nd pre-amp stage via the cathode. The VR's trem circuit modulates a light to flash which modulates a resistor that grounds out some of the pre-amp signal. The Brown amps with 2 output tubes have output tube bias modulation via their grids.

[Blue Furry Monster]

Thanks for all the help, everyone!

[JoeyV]

I got a stock Vibrolux Reverb too, 79

Get a pair of RCA 6L6GC's or the new JJTeslas are good too..
Instead of a 12Ax7 in the second tube socket put in a Sylvania 12AYT or a 12AU7 ( I think thats what I did?) ..I set the volume on about 5, amp up on a stool and its still nice and clean, I use a Bad Bob booster for even louder punchy clean with it...I had another Vibrolux Reverb that I completely modded out with a 50 Watt transformer and some funky power tubes 5879A's or something like that and it was ehhh just ok , sounded more like a twin ...it eventually went on the road with touring act and blew up but hey..the stock models can be cleaned up to sound nice and clean and loud...making sure that the amp is the best it can be stock is a start so, some good tubes, a bias and new caps would be a starting place and then go from there......as far as the vibrato goes ..that always baffles me...some silver face models i have had , the trem was great others not so great no matter what i did..also to emphasize the tremolo more..I usually turn the reverb off or at least down..that can eat up the trem effect alot..