Question for guitarists

[seekir]

I'm contemplating replacing the 8ohm 12" speaker in my 25 watt Peavey Bravo due to deterioration in the distortion "ceiling" (can't get a LOUD clean sound anymore, though I seem to remember the amp was capable of a quite loud clean sound when it was new.) The celestions in my Am. Musical Supply catalog are listed with a wattage no., but I'm not sure if this should match, exceed, or is not relevant to the wattage of the amp. Anyone know how to choose an appropriate speaker for a particular amp? I'd prefer a hardy unit that can tolerate performance volumes and low notes without distorting on the clean side, so I'm thinking a tougher, and perhaps pricier 12" model than the stock speaker may be a better choice.

<small>[ May 21, 2005, 05:06 PM: Message edited by: seekir ]</small>

[David Jones]

How old are the tubes in the amp?

[jackorhythm]

the 25 watts rating is rms or average. it peaks much higher. you should get a speaker w/a higher rating but not so high that it doesn't move(distort) when you want it to. i replaced the speakers in my 60's fender deluxe(22 watts approx) and workhorse peavey vintage 30(loud 30 watts) with reissue jensen c12n for a little extra headroom. if i wanted more bluesy breakup all the time then i'd maybe try a c12q.

for a celestion, i'd try a greenback or vintage 30.

and check the tubes. tubes like el84's should be replaced yearly with heavy use. 6v6's also have a fairly short life.

p.s.-i just looked up the amp. definitely change the power tubes-the ei's are the best i've found these days. try the greenback if you want a marshall tone or the jensen for a more american tone.

<small>[ May 21, 2005, 10:07 AM: Message edited by: jackorhythm ]</small>

[seekir]

The amp died some years back and a shop replaced the tubes (or at least some of them) once. I recently opened it up when a fuse blew and noticed that the tubes were not all the same: two 12AX7's wore a Peavey label, one had none. I replaced the two EL84 power amp tubes with Groove Tubes and the three 12AX7 preamp tubes with mesaboogie 12AX7A/7025 tubes. I'm not sure if the speaker is the source of the unwanted distortion, but I have a feeling it may be - when the clean channel and guitar are maxed, the distortion is most noticeable when I play low notes, and my impression is that the speaker is just too flimsy (or worn out) for this treatment. However, I suppose the tubes could be a factor. I noticed that the GT Sovtek 12AX7A/7025's in my catalogs are described as "high gain" - which suggests that they might be capable of overdriving the power amp even on the clean channel. Sound likely?

I guess the preamp tubes I bought are the Sovtek high gain tubes with a GT logo painted on the glass and a Mesa logo outside on the box (what a confusing practice if so). Anyway, I feel like the amp is putting out a distorted overdriven sound I would prefer to be able to select on the dirty channel rather than accept as the default loud tone on both sides. I want the amp to sound more like the great amp it did when it was new, I'm not sure whether that would be considered an American (Fender?) sound, or Marshall tone, though I believe Peavey was shooting for something more like the latter with the Bravo.

<small>[ May 22, 2005, 01:16 AM: Message edited by: seekir ]</small>

[jackorhythm]

the el84 style amp is based on a vox which is a british style. like i said-in my classic 30 which is a big brother version of your amp, i use a jensen. if you are playing mostly rock then i'd say to get the celestion. how long ago were the tubes changed? the preamp tubes will last much longer in this style amp/ raplace the power tubes which are the el84's.

[seekir]

I think I changed the tubes about a year ago. And I use the electric mostly for various kinds of bluesrock/classic rock with some other stuff mixed in. I've been interested in the Peavey Classic line for awhile after finding the Bravo and seeing the ads for the Peavey Classic amps. I strolled into a store over on Oahu and heard an instructor/club player trying out a new Bravo back in the 90's. He loved it and so did I. My previous amp was an 80's era Fender Montreaux solid-state that had a nice clean side but (for me at least) an unexciting dirty channel. The Bravo cost $200.00 less and seemed to sound much richer to me.Too bad there aren't any Peavey dealers on this island. Thanks for the help.

Mike

[jackorhythm]

y'know, the type of "low end" distortion you described could well be a blown speaker but could also be other things besides speaker or tubes. i am not an amp expert but there are people who are. there must be a good repairman near you. ask some of your favorite guitarists who the y use to maintain their tube amps. remember that it's a skill that takes an understanding of music and guitar playing because the amp is part of the instrument. there are guys who fix amps and guys who make amps sound as good as they can and you should find someone like the latter.

as far as the tubes not matching, that only is an issue for the power tubes-they work in tandem and therefore sound/work best when they are a "matched set". preamp tubes (12ax7's, etc) do not. i guess that sovtec preamp tubes are probably okay but i'd get the highest quality line. the sound of el84's can vary considerably and i've found that "e.i.'s" sound the best of the new ones. like i said, el84's wear out because they run so haot and should be replaced every year under moderate to heavy use.

the new speaker will be an upgrade whether your present speaker is blown or not. considering the styles that you mentioned, i'd get the jensen reissue. that little amp may not move the celestion enough and it might sound thing and scratchy. if your amp is an 8 ohm output then i'd even consider a smaller jensen than the c12n-maybe the c12q.if it is 16 ohm like my classic 30 then you'll need to get the c12n16. i think you'll find it warm and vocally sounding.....sort of in the world of old clapton or stevie ray vaughn. you can still rock in a stonesy or even acdc manner.

try www.VintageSpeaker.com

[tfillingi]

HI,
I have a Fender Deluxe reverb also.
I use JBL 12 in it, the best sounding speaker
I've ever heard.
The JBL's are pricey, but worth every penny.

[markwayne]

I'd try swapping out all the tubes and also try changing out the first preamp tube (probably the one closest to the input jack) for a 12at7. This will reduce the gain for the clean channel. Keep in mind that this will also effect the dirty channel as the clean channel preamp tubes are cascaded into the following tubes to generate the dirt. Also try gently moving the speaker cone in and out and listen for any noise. If you hear any scratching, you need a re-cone or a new speaker. If possible, I would strongly suggest you try the speakers in question with your amp before you buy. Your amp will sound radically different with each speaker.

[jackorhythm]

Originally posted by tfillingi:
HI,
I have a Fender Deluxe reverb also.
I use JBL 12 in it, the best sounding speaker
I've ever heard.
The JBL's are pricey, but worth every penny.

i used jbls for awhile. they are very clean and not really suited to classic/bluesy rock in my opinion.

and i'm not sure that trying lower gain input tubes is the answer. i think this guy liked the original tone and gain structure of his amp but has begun to hear an unpleasant and unwanted distortion.

really, it's hard to know exactly without hearing the amp. if the amp is important to you, why not just take it to a repaiman.

[seekir]

Went to the Peavey site and their support page lists their 8 ohm Blue Marvel Classic for the Bravo as a replacement - I suppose it's the original equipment. Specs: 300W peak, 150W prog., 75W continuous. Sensitivity; 96.5 db 1watt/meter, freq. range - 79Hz~6.5 Khz. The only trouble with using the original unit is that I worry that it may tend to give out under heavy use (assuming the speaker is the problem now). It's a little amp, and I turn it up for performances/rehearsals. I do want that original sound back though.

I wish there was a repairman I could trust here. When it came back from the shop after it died the first time, it seemed to have lost some of its superlative quality, and now I don't feel really confident in their skills.

[jackorhythm]

Originally posted by seekir:
Went to the Peavey site and their support page lists their 8 ohm Blue Marvel Classic for the Bravo as a replacement - I suppose it's the original equipment. Specs: 300W peak, 150W prog., 75W continuous. Sensitivity; 96.5 db 1watt/meter, freq. range - 79Hz~6.5 Khz. The only trouble with using the original unit is that I worry that it may tend to give out under heavy use (assuming the speaker is the problem now). It's a little amp, and I turn it up for performances/rehearsals. I do want that original sound back though.

I wish there was a repairman I could trust here. When it came back from the shop after it died the first time, it seemed to have lost some of its superlative quality, and now I don't feel really confident in their skills.

i doubt the replacement original speaker will give out for a long time. sometimes speakers just blow, especially after they get older.

i still like the jensen way better.

good repairmen are hard to find. there must be somone there. ask every guitarist you see who uses a tube amp and has good tone. you could always ship it to someone in l.a. or nyc.

<small>[ May 25, 2005, 03:48 PM: Message edited by: jackorhythm ]</small>

[shankyboy]

Unless the voice coil is rubbing or the speaker cone has deteriorated, I seriously doubt that replacing the speaker will solve your problem. If the sound you had (and liked) was there before, then your problem is most likely in your tubes and the bias setting. You could change out the speaker and still end up with the same problem. My advice would be to seek out that good (and honest) amp repairman and get the amp right before I would replace the speaker. Once the amp is set properly, then look into a new speaker if you're not getting the sound that you like.

[seekir]

The Bravo is a pretty basic unit. I understand that it can't be biased. I bought it for $375.00 if I remember right. Though I loved its original tone, I don't think its value would justify sending it off to a mainland repair facility. The Blue Marvel speaker costs around eighty bucks and ships for about forty. I'll take a chance and go with a third set of tubes next if the new speaker doesn't improve the tone. Thanks again.

<small>[ May 26, 2005, 01:39 AM: Message edited by: seekir ]</small>

[jackorhythm]

the bravo is most likely like other vox/el84 amps and has a biasing circuitry caleed "cathode bias". the bias doesn't need adjustment.

in all reality though, you might want to check the speaker by plugging a different amp into it 1st or for that matter, plugging your amp into a different spkr. any of your friends have anything that has an 8 ohm output/speaker that you could do this with?

$120 is a bit much to shell out just to see if that's the problem. a good repairman, even in nyc, costs about $80 an hour and any one worth his salt can diagnose and even repair the problem within that time.

<small>[ May 26, 2005, 03:55 PM: Message edited by: jackorhythm ]</small>