How much headroom should I expect out of my Silverface Vibrolux?

Muttlyboy

Gold Supporting Member
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3,093
A Vibrolux is a pretty loud amp (especially these days when people are being told to turn down their Princetons).

Like everybody already said, Speakers will probably get you there.

I pretty sure that the 70s Vibroluxes use a 5U4 rectifier tube. A GZ34 rectifier will raise voltage across the circuit and will make the amp cleaner and louder with a somewhat punchier pick attack.

A solid state rectifier will move the amp even more in that direction.

JJ 6L6 tubes are pretty big and loud versions of 6L6 tubes but yours might be spent.

Also for higher volume and output, it's better to not bias the tubes too hot (hotter bias tends to make for easier distortion).
 

Dontchaknow

Silver Supporting Member
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1,478
4 years on power tubes is awhile. I would start by changing those (JJs are fine for what you want). Then look at more sensitive speakers as others have mentioned. Will give you more volume at the same level of clean/breakup which is what most of us mean when we say headroom. Sounds like worn power tubes to me though, especially if it has worked well in the past without you noticing anything.
 

Freedom35

Member
Messages
52
Ok, the consensus seems to be that the amp isn't malfunctioning, but the power tubes could be tired, and that a change of speakers will help me accomplish what I want out of this amp. Now for the plan: I shall call my amp tech and see about getting new power tubes, and I will shop the internet for a suitable pair of replacement speakers.
The question is, can the community recommend some speakers? I don't want to change the amp's overall character too much, so maybe even a new pair of something similar to what's in there will be cleaner? I currently have the original blue Fender labled speakers. What is similar to those with just a bit more "sensitivity?"
 

Freedom35

Member
Messages
52
Here are the contenders for speakers based on just reading online reviews. To reiterate, I'm looking for [slightly] more clean headroom from my Vibrolux Reverb, especially for rhythm playing, hopefully without sacrificing dynamics or clarity. I play a bright semi hollow and I like clean, jazzy and funky rhythms, and my solos are usually played with a Jetter (kinda dumblesque) overdrive.

Alessandro GA10-64SC
Warehouse G10C
Emi 1028K
Weber 10F150
Weber something else? They make a million models....

Am I looking in the right direction for what I want?
 

ToneGrail

Member
Messages
1,845
I have a 68 Silverface and it breaks up around 4.5 with humbuckers, but it's deafeningly loud by that point. I usually never go past 2.5 or 3 on the volume knob.
 

stratzrus

Philadelphia Jazz, Funk, and R&B
Gold Supporting Member
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23,795
Plugged into input 2, I can get some breakup with the volume on 4 or 5, and 6 gets downright crunchy if I play hard chords...Let me know what you all think!

If you need more headroom, the best fix is a pair of very efficient speakers.

Put 2x EV 10"s in there :)

If you're committed to gigging with that amp the "more efficient speakers" suggestions make sense.

The "Put 2x EV 10s in there" suggestion would be ideal but the increase in weight may prove to be impractical.

I have blackface Deluxe Reverb, Vibrolux Reverb, and Super Reverb amps and a Prosonic combo.

Both the Vibrolux Reverb and Prosonic on the clean channel breakup earlier than I'd prefer for my Jazz gigs in medium sized venues with no sound reinforcement. I put a pair of EVs in the Prosonic and it sounds great now. No headroom shortage and for once the bottom end is solid and tight.

It is however a back breaker and if you have to carry it up a flight of stairs it will ruin your evening.

For my money, getting a Super Reverb is the answer and that's what I ended up gigging with for a long time. While heavy it's not as heavy as the Prosonic with the EVs and the sound is nice and full with more headroom.

They are still quite reasonably priced. Well worth considering.

Edit: I just checked the prices and holy cow! I got my '65 BFSR for a little over $800. Apparently those days are long gone.
 

HeavyCream

Silver Supporting Member
Messages
6,085
Ok, the consensus seems to be that the amp isn't malfunctioning, but the power tubes could be tired, and that a change of speakers will help me accomplish what I want out of this amp. Now for the plan: I shall call my amp tech and see about getting new power tubes, and I will shop the internet for a suitable pair of replacement speakers.
The question is, can the community recommend some speakers? I don't want to change the amp's overall character too much, so maybe even a new pair of something similar to what's in there will be cleaner? I currently have the original blue Fender labled speakers. What is similar to those with just a bit more "sensitivity?"

Considering you’ve noticed a reduction in headroom, something has changed. Yes, more efficient speakers will increase clean volume capacity. With 4yo heavily gigged power tubes, that would be my first priority. Get the amp back to square before replacing speakers. If new power tubes don’t get your headroom back to where it was, it might be time for a cap job. Considering the age of the amp, if it has it’s original filter caps, I’d replace them.
 

AintNoEddie

Member
Messages
955
Here are the contenders for speakers based on just reading online reviews. To reiterate, I'm looking for [slightly] more clean headroom from my Vibrolux Reverb, especially for rhythm playing, hopefully without sacrificing dynamics or clarity. I play a bright semi hollow and I like clean, jazzy and funky rhythms, and my solos are usually played with a Jetter (kinda dumblesque) overdrive.

Alessandro GA10-64SC
Warehouse G10C
Emi 1028K
Weber 10F150
Weber something else? They make a million models....

Am I looking in the right direction for what I want?
I would hesitate to put in Alessandros: they are 20W, so 40W in total. The Vibrolux has 35? W clean, so if you are at the edge of breakup it will be likely more than 40W. For playing at home I wouldn't sweat it, but as you are saying you are competing with a loud drummer I'd be worried.

Emi 1028k would be fine, or better 1058 as they have better sensitivity (= louder cleans for you).

Oh, and I agree with the majority of the comments, so that a speaker swap would help you most. Maybe power tubes are worn, if you get replacements and it doesn't change the situation, you have at least some backup ones. Other than that there is not a lot to do, your headroom will be limited by the transformer so even if the power tubes would provide more headroom it wouldn't help with another bottleneck.
 

WillLane

Member
Messages
2,577
The question is, can the community recommend some speakers? I don't want to change the amp's overall character too much, so maybe even a new pair of something similar to what's in there will be cleaner?
Ragin Cajuns would be louder than the Emi 1028Ks or even the 1058s.

Another vote for the Ragin Cajun's. They are what is installed in my '68 Custom Vibrolux Reverb. Percussive, full, glassy, round, etc... Great for funk, jazz, R&B, hip hop.

I have a Jupiter 10LC installed in a '68 Custom Vibro Champ. That would also be a great choice. It's a bit softer and a more vintage sound than the Ragin Cajun. Not as much sensitivity increase with the 10LC.
 

Khromo

Silver Supporting Member
Messages
1,448
In addition to changing out the speakers, the V2 preamp tube can sometimes provide more headroom. Depending on what's in there now!

I have found a good 5751 can sometimes settle an amp down just enough. You could try it with input #1 and see if it sounds better.

Not long ago you could get true NOS 5751's for very reasonable prices. Not sure about the current state of affairs!

I strongly agree that this is a near perfect amp for low to pretty loud volumes. If you lose the first channel (and the vibrato for most of us) and vertically align the speakers, you are getting close to perfect.
 

MoBigBro

Gold Supporting Member
Messages
1,097
Here are the contenders for speakers based on just reading online reviews. To reiterate, I'm looking for [slightly] more clean headroom from my Vibrolux Reverb, especially for rhythm playing, hopefully without sacrificing dynamics or clarity. I play a bright semi hollow and I like clean, jazzy and funky rhythms, and my solos are usually played with a Jetter (kinda dumblesque) overdrive.

Alessandro GA10-64SC
Warehouse G10C
Emi 1028K
Weber 10F150
Weber something else? They make a million models....

Am I looking in the right direction for what I want?
@Freedom35 :
Trying to give you the best possible advice, I re-read the original and subsequent posts:
You're in a new (Louder) band and your SF Vibrolux Reverb is breaking up before you are at the volume that you need to keep up.
I wish I had a Vibrolux Reverb too, but I've got BF Bandmasters and Super Reverb: It's normal to get some break-up Starting between 4 and 6 and to be getting pretty crunchy at 7 to 8.

First: Since you're gigging with this amp, it totally makes sense (as @HeavyCream and @Khromo suggested) to have your SF Amp checked out to be sure that it is running perfectly, but I don't think that is going to get you the increased sound pressure that you need to keep up with the loud band.

Given your situation, highest possible speaker sensitivity is the first priority, (obviously they must sound really good as well). As @AintNoEddie pointed out, you also need to take the speaker Wattage into consideration and you probably want to have at least 60 to 70 Watts of power handling capacity from your combination of two speakers. Some of the speakers on your list are lacking in these attributes.

I've been looking at a lot of 10" speakers and the sensitivity ratings are generally lower than for 12" speakers on average. Of the speakers that I know sound really good, the highest sensitivity rating I could find is the Ragin' Cajun at 100.5. Luckily, these are really great sounding speakers! They will sound slightly different from your 70's era CTS Ceramic speakers, but they will be very good for R&B, Funk, Jazz and Rock and they will retain the glassy, sparkly Fender sound that you would expect from a Silver Face Fender amp. (Obviously, save the CTS speakers that you like for lower volume work). I like the Ragin Cajun well enough that I have 3: (2X10 Extension cab, 1X10 Extension cab and a Valve Special). I think you will like the tones and As @Steppin' Wolfe pointed out, they will give you significantly more sound pressure (Volume) from your amp.


As I mentioned before, I think a Vibrolux is a nearly perfect gigging amp. If you are still lacking the volume to keep up, maybe your new Band is louder than it needs to be (Starting with the drummer)?

Cheers,
MoBigBro
 
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Muttlyboy

Gold Supporting Member
Messages
3,093
If you're looking to get loud and punchy out of a Vibrolux reverb, the loudest 10s that I've experienced are Weber 10F150s. They were too loud and punchy for me.

Another fairly loud 10 is the Eminence Copperhead. People say the Rajun Cajun is a loud one, but I've never tried one.

I like the GA10SC64s because they have a sweet smoothness to them ( but that might be the enemy of loud enough for you?)

I have tried the small magnet Jupiter 10 in an amp, and the GA10SC64 was bigger and stronger sounding. I haven't tried the large magnet Jupiter 10, but when comparing the Large magnet Jupiter 12 to the 12" GASC64, the Jupiter seemed louder and punchier than the GASC64.
 

Jack Luminous

Member
Messages
1,054
I have a Silverface Vibrolux Reverb with pull volume knob, I believe from 1975, in top shape. What you describe sounds perfectly normal to me. Mine is exactly like that. You could add an external 2x12 speaker for more headroom. But I think the perception of breakup is different when you pay attention to your own tone and in the context of the mix with foreign ears. Did someone else tell you about it ? Did you hear a recording of the whole band ? Maybe it sounds just fine as it is despite you hearing some breakup in your tone.
 

deadflowers85

Silver Supporting Member
Messages
39
I have the very same amp from the 70's and had breakup at about 5 until I put in Weber 50 watt 10F-150T ceramic speakers. Then it got way louder and less breakup. In fact, I eventually switched to Jupiter 25 watt alnico because I missed the earlier sweet breakup and got tired of soundmen telling me to turn down. I put a set of TAD STR 6L6 tubes which also helped headroom a bit. That SV Vibrolux is no twin and will breakup about 6 no matter what you do but it sounds good to me but its loud at 6! Been a love- hate relationship but mostly love. good luck!

I honestly doubt the issue lies with the tubes or the amp - breakup between 4-6 sounds pretty normal to me for most of the BF/SF "reverb" amps I've played with the exception of the Twins. JJ 6L6s are perfectly fine for current production, and it sounds like they haven't been particularly stressed over the past four years. They're probably fine.

A pair of Weber 10F150Ts will definitely get you loud and clean - these have got to be around 100db, and it'll make your V-lux sound like a 2x12. I've compared them to some of the Eminence speakers known for high sensitivity and the Webers were louder. As others have alluded to, it's possible you'll find the change overkill, but that's something you'll have to find out for yourself.

Personally, I'd try the Eminence 1058. There's a pair of them for a great price in the TDPRI classifieds at the moment (no affiliation with the seller). They'll be more robust than your stock speakers without sacrificing the liveliness and sparkle. Less weight, too.
 

HotBluePlates

Member
Messages
14,036
... mid-late 70s Vibrolux Reverb ... Plugged into input 2, I can get some breakup with the volume on 4 or 5, and 6 gets downright crunchy if I play hard chords. ...

That sounds 100% normal for the average 60s-70s Fender with reverb.

... I have a mid-late 70s Vibrolux Reverb ... and lately have been using it in a band doing funky, jazzy, R&B and hip hop, with a rather loud drummer. I'm finding myself wanting more clean headroom for rhythm playing. ...

This is what Twin Reverbs were made for. If your Vibrolux isn't enough, you should step up to the next-bigger amp. Or use more-sensitive speakers as folks noted below:
... If you increase the sensitivity of your speakers from around 95Db to 100Db, that will increase sound pressure (volume) about the same as doubling your amp's wattage. ...
A 6db increase in speaker efficiency will double the apparent volume, ime and as I have read. That increase 8n efficiency would be akin to increasing amplifier output power by a factor of 10. ...

10x Power = +10dB = Double-Loud

2x Power = +3dB = Louder, but not Double-Loud

"Double-Loud" is dependent on perception, so it's "generally accepted" vs being a concrete fact.
 
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