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Fender Vibroverb 63 Re-issue
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AlanN
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PostPosted: Thu Jan 15, 2009 7:16 am    Post subject: Reply with quote

It's not even an issue on 50W speakers. The rating is a guide to the peak load the speaker can handle, not what it should be matched to.

Only high-powered speakers (think bass amp) will state minimum power levels (around 50W on the last 300W speaker I saw), and that's just to ensure the drivers will be safe. A pair of 4x12 guitar cabs can be powered by a Blackheart 1/4W(!) Killer Ant without sounding like a bass guitar

http://www.youtube.com/watch?v=5FZsFWO_0IE
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stratman323
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PostPosted: Thu Jan 15, 2009 7:48 am    Post subject: Reply with quote

AlanN wrote:
It's not even an issue on 50W speakers. The rating is a guide to the peak load the speaker can handle, not what it should be matched to.



Thanks, so are you saying I should get the 25w or 70w rated speakers? You know I'm a bit slow on this stuff, I need it spelled out for me.

Marcus - if this works out with the VV, I have already thought about trying to improve the Blues Junior. I don't need to improve the sound of the VV (that would just be a bonus), but the Junior either needs improving or selling!
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AlanN
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PostPosted: Thu Jan 15, 2009 7:50 am    Post subject: Reply with quote

Sorry, let me read back a bit and see what amp you're talking about.
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Dave_Mc
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PostPosted: Thu Jan 15, 2009 2:32 pm    Post subject: Reply with quote

mega-post... sorry

stratman323 wrote:
(a) Thanks Marcus, that's good to know. One more thing was that I checked the speaker in my Blues Junior, which I don't rate at all - thin, scratchy tone. It has a Fender speaker - made by Eminence!


(b) The amp is 35w or 40w (depends what you read), & as there are two speakers, I understand that I need to divide the power by 2 - so I need each speaker to handle 20w. Is that right?

(c) So that means I should be OK with the C10R, which can handle 25w. Am I right in thinking that using a speaker with a higher wattage than the amp would lower the overall amp output, but may increase the low frequency response?


(a) i don't think it's fair to judge eminence based on its oem models. I mean, celestion do the same thing and have plenty of terrible oem models, and i've tried a few oem jensens too which weren't great either.

not saying you shouldn't go for the italian jensens, just saying you shouldn't discount the eminences because the oem ones you've tried sucked (i'd agree, the oem eminence in the hot rod deluxe, for example, is horrible).

(b) yeah, i think so. at a minimum, anyway. valve amps can put out more than their rated wattage... but then presumably speaker manufacturers know that too. depends on the speaker, i guess, and how much speaker breakup etc. you want. also bear in mind, if you go for two differently rated speakers, it's the lower power-handling speaker's wattage multiplied by 2, i think. for example, if you combine a vintage 30 (60 watts) with a g12h30 (30 watts), the combined wattage handling is 60 watts, not 90, as the output is split evenly between the two speakers. I think. mixing speakers might be cool to get a slightly more complex tone... but then you can go wrong too, if you aren't careful...

(c) i don't think it's going to lower the amp's output, the sensitivity/efficiency is what matters there (i think so, anyway). the higher the wattage you go for, the less chance you have of a blown speaker, and speaker distortion, but if you go too high (say a 500 watt rated speaker coupled with a 1 watt amp), things can start to sound a little sterile, bit like running a 100 watt valve amp on 1 versus running a 5 watter on 7...

I think so, anyway. again, it depends on the tone you're going for, the specific speaker, etc. etc. etc. i'm giving you more questions than answers, unfortunately.

marcusnieman wrote:

I pulled and stored the original speakers from all of my 60's Fender blackface amps (Super Reverb, Pro Reverb and Princeton Reverb) and put Italian Jensens in all of them. They sound fantastic and don't cost an arm and a leg.


ah, sweet. like someone else posted in this thread, i've heard bad things about the chinese jensens, but if the italian ones are good, that's definitely another option (i'm sort of considering a speaker swap myself into my valve junior cab, it needs to be a pretty high wattage though).

is there any way to tell if they're italian or not, other than reading the back of the speaker?

EDIT:

stratman323 wrote:

Thanks, so are you saying I should get the 25w or 70w rated speakers? You know I'm a bit slow on this stuff, I need it spelled out for me.


just to spell it out, all in the one place, the 3 main quoted specs about speakers are:

1) the impedance. this needs to be matched to the impedance of the output transformer.

if you're replacing speakers, unless the amp has an impedance selector, replace speakers with the same impedance as the old ones.

2) the wattage- this is how many watts the speaker can take (more or less- they're often rated conservatively) before blowing up. It doesn't say anything about how loud the speaker will be, but generally you'll get more speaker distortion if you use a lower wattage of speaker with the same wattage of amp (though some speakers break up more than others, etc. etc.).

you want, at minimum, the same wattage as the wattage of the amp. some people/manufacturers suggest double the wattage (to cover for valve amps putting out more than their rated wattage), some don't... not certain which is best, to be honest. i know when i emailed eminence, their rep said that its speakers were rated pretty conservatively, and if i were willing to take a chance, could even go slightly lower than the amp's rated wattage, as long as i wasn't cranking the amp to 10 all the time.

3) the sensitivity/efficiency, rated in decibels. This is the amount of decibels the amp puts out for a given wattage from an amp- the higher, the louder.

often you can make a lower wattage amp louder than a higher wattage by using a much more efficient speaker, as the sensitivity can range from low 90s to 103, or even more, decibels. Some different companies rate the efficiencies slightly differently, so it's not always a direct comparison.

other specs too, like whether it's a ceramic/ferrite, alnico or neodymium magnet, the graph of the frequencies it outputs, size of the voice coil etc. can tell you about the tone etc., but those three are the main ones for determining the basic specs- how loud it's likely to be, and whether it'll work with your amp without destroying either the speaker or the output transformer. i should add that i'm far from a speaker expert, i can't understand all those graphs etc. regarding the tone, but those should keep you right and at least make sure you don't blow anything up.

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JohnA
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PostPosted: Thu Jan 15, 2009 3:00 pm    Post subject: Reply with quote

If you are set on the Jensens than from the link Marcus posted earlier Jensen recommend either P10R, C10R, or C10Q for a 40w vibroverb, the fact that you've managed to pop 2 speakers makes me think you should go for the ones with the highest power rating to minimise the chance of that happening again.

I definetely think you are pushing your luck running 2 25W rates speakers in a 40W valve amp.
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stratman323
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PostPosted: Thu Jan 15, 2009 3:19 pm    Post subject: Reply with quote

Yes I was thinking the same thing John, I just wanted to make sure that there wasn't a down side to using two 70w rated speakers. As the voice coil is larger, I thought that meant increased bass response?
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JohnA
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PostPosted: Thu Jan 15, 2009 3:26 pm    Post subject: Reply with quote

The only downside to using an overpowered speaker is it might not sound as 'alive' at very low volumes, but a standard marshall cab is rated at 300W (4 75W speakers) and they are designed to be used with 50W heads.

I use 4 greenbacks with a total rating of 100W with a JTM45 rated at 30W output and they sound fine. Much better to give yourself a bit of headroom.

Marcus says the pro juniors come with a 50W speaker, and also Jensen recommend the Q's for the vibroverb so they must be OK, you would assume.
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Dave_Mc
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PostPosted: Thu Jan 15, 2009 4:59 pm    Post subject: Reply with quote

yeah, considering you blew speakers before, erring on the side of caution is probably best. it's only really going to sound a bit flat if you've got a ridiculous mismatch...
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AlanN
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PostPosted: Fri Jan 16, 2009 3:00 am    Post subject: Reply with quote

Sorry Mike, we had a massive virus outbreak at work and IT decided to drag me into helping them.

You're fine with overrated speakers (just don't go for 300W'ers). John's answer is spot on - all you'll lose is that bedroom-volume sparkle; hopefully you've got something a bit smaller than a 40W tube amp for practice

My rigs:

RAT modified 5W Blackheart Little Giant head
18W Ceriatone TMB Marshall
Fender Hotrod Deluxe

For more oomph I feed all 3 into an Orange 2x12 120W cab. Even with the power scaling right down, the Little Giant is perfectly at ease with driving 120W.
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stratman323
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PostPosted: Fri Jan 16, 2009 5:18 am    Post subject: Reply with quote

JohnA wrote:
also Jensen recommend the Q's for the vibroverb so they must be OK, you would assume.


Yes, but Jensen recommend the P10R, C10R or C10Q, all apparently equally. From what everyone has said, it looks as though the C10Q is the safest bet. So, thanks guys.

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stratman323
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PostPosted: Fri Jan 16, 2009 5:20 am    Post subject: Reply with quote

AlanN wrote:
hopefully you've got something a bit smaller than a 40W tube amp for practice


Yes, but the BJ sounds awful in comparison, so I've been using the VV at home. Hopefully I'll still be able to do that - we'll see.
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AlanN
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PostPosted: Fri Jan 16, 2009 8:49 am    Post subject: Reply with quote

You won't see that much difference with 70W drivers (in fact, if the speakers are a league above what you had, you'll see an improvement!).
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JohnA
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PostPosted: Fri Jan 16, 2009 8:50 am    Post subject: Reply with quote

stratman323 wrote:

Yes, but the BJ sounds awful in comparison, so I've been using the VV at home. Hopefully I'll still be able to do that - we'll see.


I often take along a Tokai TA-35 combo with an 8" speaker to reahearsals, at home I use a Marshall JTM45 and a 4x12 cab

I really don't think you would notice the difference between the R's and Q's at low level, I think the Q's are the right choice.
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Dave_Mc
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PostPosted: Fri Jan 16, 2009 2:25 pm    Post subject: Reply with quote

why not p10q? that'd let you get the alnico magnet with increased wattage handling... unless it's not recommended for your amp...

oh, just checked the jensen site, apparently it is made in italy, you can zoom over the sticker on the back and it says it's made in italy... as are the other ones you're looking at.

i think it probably boils down to: are you willing to risk slightly more chance of a blown speaker for possible slightly better tone? i mean, jensen recommends (in that link marcus posted) speakers without too much more rated wattage than your amp puts out, so you'd assume it's ok... unless it's some evil scheme to sell more speakers...


Last edited by Dave_Mc on Fri Jan 16, 2009 2:33 pm; edited 1 time in total
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stratman323
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PostPosted: Fri Jan 16, 2009 2:32 pm    Post subject: Reply with quote

I wondered why the P10R but not the P10Q were recommended, but I've ordered 2 C10Qs now. Might have them on Monday, with a bit of luck.

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