Understanding Amps
Michael L Kankiewicz
I am considering buying a used Mesa B Dual Rectifier Maverick 1x12 combo.
I do not really understand tubes vs ss as far as watts/loudness goes. I am
mostly used to ss amps in the 60-100 watt range. The Maverick is only 35
watts. But, it is pure class A. I am wondering if 35W pure class A will have
enough headroom for a very clean, loud output. For example, to get a
nice clean sound over a big band. Or will it be distorted. Thanks much.
drthoma...@gmail.com
It will distort at that volume. There are mods that can reduce that
somewhat, but I would still expect it to be underpowered for very loud
and clean sound.
Kevin Van Sant
<drthoma...@gmail.com> wrote in message
<2c61cb04-a73d-4154...@u7g2000yqm.googlegroups.com> :
I'm no amp authority, but a long time ago I had a Mesa Boogie Mark IIc
which had both a class A 15w amp, and a 50w (class C?) amp. You could
use one or the other or combined. I only ever used the 15w class A
amp and it was LOUD and clean. Easily much louder and much more
headroom than my 150 Evans hybrid head.
________________________________________
Kevin Van Sant
Check out my brand new CD "Play the Music of Horace Silver"
http://www.kevinvansant.com
tomsalvojazz
> On Thu, 19 Nov 2009 06:43:51 -0800 (PST), "tombr...@jhu.edu"<drthomasfbr...@gmail.com> wrote in message
>
> <2c61cb04-a73d-4154-9352-524c460b1...@u7g2000yqm.googlegroups.com> :
Loudness has to do with a lot of variables including the size of the
output transformer, the efficiency of the speaker, and the types of
tubes, etc. Having said that, a 35 watt tube amp can be VERY loud and
clean. I have a Carr Rambler that, at 28 watts, is pretty loud and
stays fairly clean. I've had Koch Twintones that were too loud at 50
watts and had to be set to the 25 watt setting and were still
extremely loud and clean.
The Maverick may or may not be designed to break up. Can't comment on
that one. But, generally speaking, a solid state amp needs something
like 3 or 4 times the wattage to produce the same volume as a tube
amp, I think. I'm no expert on the technology and the physics,
though...
RickH
Tube watts are louder than solid state watts. Now let the fighting
begin. My job is done here.
Dave
For one thing, the Dual Rectos are not designed to be clean amps; they're
heavy duty rock amps, at least that's my understanding.
With regard to "tubes vs ss as far as watts/loudness goes", watts are watts,
whether they be produced by tubes or transistors, and regardless of the mode
(class) they're operating in. However, a wattage spec without an
accompanying distortion spec is actually sorta meaningless. So, an amp that
produces 50W at a low 1% total harmonic distortion will be loud and clean.
50W at 10% THD is very distorted, though just as loud. That same amp might
only be clean up to 35W or so.
Guitar amp wattage ratings never include a distortion spec, but with a tube
amp, it's safe to assume that the wattage figure given is with amp
distorting heavliy. While that Dual Recto produces 35W, the question is how
much power will it produce before beginning to distort to the point that
it's no longer useful to you? (Since you want a clean sound.) SS amps are
a lot less expensive to make, so most SS amps will be much cleaner at their
rated power output.
The issue becomes: what are your needs? If you're doing a rock/blues gig in
small venues, and you want an amp to break up without being too loud, a
smallish tube amp might be the answer. If you're looking for a very clean
sound at almost any volume, you'll need a fairly high-pwr tube amp or a
medium-pwr SS amp.
drthoma...@gmail.com
>
> Tube watts are louder than solid state watts. Now let the fighting
> begin. My job is done here.
There are also widely varying definitions of "clean".
Carl
> Michael L Kankiewicz wrote:
>> I am considering buying a used Mesa B Dual Rectifier Maverick 1x12
>> combo. I do not really understand tubes vs ss as far as
>> watts/loudness goes.
>> I am mostly used to ss amps in the 60-100 watt range. The Maverick
>> is only 35 watts. But, it is pure class A. I am wondering if 35W
>> pure class A will have enough headroom for a very clean, loud output.
>> For example, to get a nice clean sound over a big band. Or will it
>> be distorted. Thanks
>> much.
>
> For one thing, the Dual Rectos are not designed to be clean amps;
> they're heavy duty rock amps, at least that's my understanding.
>
> With regard to "tubes vs ss as far as watts/loudness goes", watts are
> watts, whether they be produced by tubes or transistors, and
> regardless of the mode (class) they're operating in. However, a
> wattage spec without an accompanying distortion spec is actually
> sorta meaningless. So, an amp that produces 50W at a low 1% total
> harmonic distortion will be loud and clean. 50W at 10% THD is very
> distorted, though just as loud. That same amp might only be clean up
> to 35W or so.
the system used to determine the output power. To me, RMS is the most
meaningful and probably what guitar amps are rated with. But some audio amps
are rated with systems such as "Peak Music Power" which tends to overly
inflate the power output.
The other variable(s) is speaker-related. One factor is speaker efficiency.
A high-efficiency speaker will sound louder given the same power, than a
lower efficiency speaker. And the other speaker-related variable is speaker
size. A 15" speaker will push more air and sound louder than a 12" speaker
hooked up to the same amp with the same power output rating, given that the
speakers are of the same efficiency.
All that said, my experience is that a 35W Class-A amp will stay clean
longer and will be very loud. I think the OP will be surprised at the
result. I had a Gibson 15W (switchable to 5W) Class A amp and could very
rarely use it in the 15W position.
Michael L Kankiewicz
>
> The other variable(s) is speaker-related. One factor is speaker efficiency.
> A high-efficiency speaker will sound louder given the same power, than a
> lower efficiency speaker. And the other speaker-related variable is speaker
> size. A 15" speaker will push more air and sound louder than a 12" speaker
> hooked up to the same amp with the same power output rating, given that the
> speakers are of the same efficiency.
>
> All that said, my experience is that a 35W Class-A amp will stay clean
> longer and will be very loud. I think the OP will be surprised at the
> result. I had a Gibson 15W (switchable to 5W) Class A amp and could very
> rarely use it in the 15W position.
OP here. I have a couple of very powerful/effficient speakers laying
around at home. Couple of JBL's and EV's. Maybe swapping out the
Celestion for one of those would help. But they are *heavy*!
rpjazzguitar
Generally, I don't think you can tell what an amp is going sound like
on a gig based on a test in a store. You have to buy it with a return
privilege and try it out in the situations you're buying it for.
That said, I'd be surprised if it wasn't loud enough to keep whoever
is closest from hearing the other instruments - which is all the
volume you can use.
Dave
> some audio amps are rated with systems such as "Peak Music Power"
> which tends to overly inflate the power output.
Didn't they do away with that in the 70s? I'm pretty sure RMS is a required
spec.
> The other variable(s) is speaker-related. One factor is speaker
> efficiency. A high-efficiency speaker will sound louder given the
> same power, than a lower efficiency speaker. And the other
> speaker-related variable is speaker size. A 15" speaker will push
> more air and sound louder than a 12" speaker hooked up to the same
> amp with the same power output rating, given that the speakers are of
> the same efficiency.
Of course speaker efficiency is a factor. But much less so than the
difference in amps, as I described. Besides, I think most guitar popular
speakers are pretty similar in efficiency. I mean, nobody's using JBLs. ;)
> All that said, my experience is that a 35W Class-A amp will stay clean
> longer and will be very loud. I think the OP will be surprised at the
> result. I had a Gibson 15W (switchable to 5W) Class A amp and could
> very rarely use it in the 15W position.
Depends on how clean a sound one is looking for. I've tried a few small
tube amps over the past few yrs; none was too clean, especially with a jazz
tone. (And I wasn't looking for crystal clean; I like a little grit.) Rock
guitar sounds have lots of highs. You roll off the highs, and a goodly
portion of the tone spectrum is gone, greatly reducing headroom.
And don't forget, the front end of most tube amps will break up regardless
of how hard the output stage is being driven.
Blues Fuse
If you can try it before buying, you'll probably have your answer.
Tonally, the Maverick should not be confused with higher powered Dual
Rectos. The Maverick is not a heavy metal shred machine. Lee
Ritenour has used the Maverick and I suspect it would work for your
purposes.
Dave
Yeah, that's the problem with those spkrs--the weight.
If you're able, you might try the amp in a loud situation to see how it
fares. If it's just about cutting it, a more efficient spkr *might* give
you the extra headroom. But if it's not making it at all, the slight
increase in vol from a more efficient spkr ain't gonna fix it.
Of course, you could first try the other spkrs to see how you like the sound
compared to the Celestion. The EVM-12L is a great spkr, so I'm sure you'd
like it. But is it "worth the weight?" I'm a longtime fan of the EV, but I
haven't even bothered to try one in my current amps, because I'm not willing
to deal with an add'l 10 lbs.
rpjazzguitar
era.
And yet, it also produces a gorgeous jazz tone. If it weighed several
hundred pounds less, jazz players would use it.
drthoma...@gmail.com
>
> And don't forget, the front end of most tube amps will break up regardless
> of how hard the output stage is being driven.
That front end break-up can be mitigated pretty easily, by rolling off
your guitar volume and/or using a lower mu preamp tube.
Tim McNamara
"Dave" <n...@spam.com> wrote:
> Carl wrote:
> > some audio amps are rated with systems such as "Peak Music Power"
> > which tends to overly inflate the power output.
>
> Didn't they do away with that in the 70s? I'm pretty sure RMS is a
> required spec.
>
> > The other variable(s) is speaker-related. One factor is speaker
> > efficiency. A high-efficiency speaker will sound louder given the
> > same power, than a lower efficiency speaker. And the other
> > speaker-related variable is speaker size. A 15" speaker will push
> > more air and sound louder than a 12" speaker hooked up to the same
> > amp with the same power output rating, given that the speakers are
> > of the same efficiency.
>
> Of course speaker efficiency is a factor. But much less so than the
> difference in amps, as I described. Besides, I think most guitar
> popular speakers are pretty similar in efficiency. I mean, nobody's
> using JBLs. ;)
Heh. I've got a pair of JBL K120s in my 35 year old Pro Reverb. Weighs
a blooming ton, loud as hell. Not especially clean cranked, but loud
enough that I never get it past about a 3 or 4 on the volume knob.
Great blues tone with a Strat, could probably shatter my carvetop at
full volume.
My Cube 60 is much louder than my Polytone MB-II with 90W. The Pro
Reverb is louder than either, although it has 2 speakers.
(Jerry Garcia used 3 JBL E120s pushed by a Macintosh 2300 power amp;
300W stereo bridged to 600W mono, fed by a blackface Twin Reverb
preamped out to the Macintosh. That'd get you heard over the drummer
and B-3...
The Dead's "Wall of Sound" PA had hundreds of JBL speakers driven by
26,400 watts RMS. FWIW. Nothing exceeds like excess.
Dave
It's also a 100W amp.
Dave
Yeah, I'm familiar with that.
Dave
> On Nov 19, 1:36 pm, "Dave" <n...@spam.com> wrote:
>>
>> And don't forget, the front end of most tube amps will break up
>> regardless of how hard the output stage is being driven.
>
> That front end break-up can be mitigated pretty easily, by rolling off
> your guitar volume
That's fine if you want to play that way, as it alters the tone.
> and/or using a lower mu preamp tube.
I guess the effectiveness of that would depend on how much gain was in that
part of the circuit.
Joey Goldstein
I had one of the early MKIII's that had the Simul-Class power section
with the outer two power tubes wired in "Class A" triode. It had 15
watts for the outer tubes and 60 watts from the inner power tubes
running in Class A/B.
In Simul-Class mode, with all 4 power tubes on, it was rated at 75 watts.
The first gig I tried to use it on, the day I bought it, was an outdoor
gig on the street at the Beaches Jazz Festival with a very loud drummer,
and it was breaking up way too early.
The Class A tubes are designed to break up early. People used to get
upset that Boogies couldn't get power amp distortion unless they were
played really loud so they came up with the Simul-Class idea.
Later versions of the Simul-Class MKIII's had the outer tubes in "Class
A" pentode for double the wattage (30 watts, when using 6L6 power tubes)
which brought the amp's total up to 90 watts.
My Simul-Satellite has the 90 watt Simul-Class power section and when
used at full power it's been pretty suitable for most loud jazz gigs
I've done with it.
I don't think that any tube amp with less than 100 watts, into a very
efficient speaker like an EVM-12L, is really suitable for loud clean
dark jazz especially when playing chords.
Tube amps have an especially hard time reproducing dark jazz tones at a
loud volume without breaking up.
--
Joey Goldstein
<http://www.joeygoldstein.com>
<http://homepage.mac.com/josephgoldstein/AudioClips/audio.htm>
joegold AT primus DOT ca
george4908
> hundred pounds less, jazz players would use it.
If it weighed several hundred pounds less, Balloon Boy would climb
into it and float away.
Carl
> Dave wrote:
>> rpjazzguitar wrote:
>>> I have a Boogie Mark III. It was the screaming distortion amp of
>>> its era.
>>>
>>> And yet, it also produces a gorgeous jazz tone. If it weighed
>>> several hundred pounds less, jazz players would use it.
>>
>> It's also a 100W amp.
>>
>>
>
> I had one of the early MKIII's that had the Simul-Class power section
> with the outer two power tubes wired in "Class A" triode. It had 15
> watts for the outer tubes and 60 watts from the inner power tubes
> running in Class A/B.
> In Simul-Class mode, with all 4 power tubes on, it was rated at 75
> watts. The first gig I tried to use it on, the day I bought it, was
> an outdoor gig on the street at the Beaches Jazz Festival with a very
> loud drummer, and it was breaking up way too early.
> The Class A tubes are designed to break up early.
>
perhaps getting too technical, but I believe that class A amps operate over
the most linear part of a signal and that amps operating as class A
introduce no clipping of the output signal at all, providing the most exact
reproduction of the input signal. If I understand this correctly, then class
A amps should provide the least amount of distortion, no matter what volume
you play them at. The most fanatical audiophiles desire class A operation
for their audio systems for this reason.
If I'm right, then the OP's 35 watt Class A amp should provide a lot of
volume with minimal clipping (ie. distortion) of the signal, certainly a lot
less distortion at high volume then the more common class AB design. As
someone else pointed out, any distortion would be introduced by the guitar's
volume being up too high and/or too high-gain tubes being used in the
pre-amp section. Lower the guitar's output in some way (ie. by either
lowering the volume control or changing the pre-amp tubes) and, if you turn
that class A amp all the way up, you should have a perfectly clean signal. I
am aware that many guitarists like to replace their 12AX7 pre-amp tubes with
12AT7s or 12AU7s for this very reason.
That all said, I'll confess that my electronics theory (once strong) is now
weak, though I did re-check some information before I posted this. I'm
certainly open to correction and re-education, so please don't hesitate to
enlighten me! :-)
Joey Goldstein
That may be true, but they're not driving their audiophile amps into
distortion like guitar players do.
I don't know the technical reasons for it, but Class A *tube* amps for
guitar players are generally designed for players who like the sound of
power amp distortion.
> If I'm right, then the OP's 35 watt Class A amp should provide a lot of
> volume with minimal clipping (ie. distortion) of the signal, certainly a lot
> less distortion at high volume then the more common class AB design. As
> someone else pointed out, any distortion would be introduced by the guitar's
> volume being up too high and/or too high-gain tubes being used in the
> pre-amp section. Lower the guitar's output in some way (ie. by either
> lowering the volume control or changing the pre-amp tubes) and, if you turn
> that class A amp all the way up, you should have a perfectly clean signal. I
> am aware that many guitarists like to replace their 12AX7 pre-amp tubes with
> 12AT7s or 12AU7s for this very reason.
>
> That all said, I'll confess that my electronics theory (once strong) is now
> weak, though I did re-check some information before I posted this. I'm
> certainly open to correction and re-education, so please don't hesitate to
> enlighten me! :-)
>
>
Dave
> Forgive me for questioning this last statement, and your experience,
> and for perhaps getting too technical, but I believe that class A
> amps operate over the most linear part of a signal and that amps
> operating as class A introduce no clipping of the output signal at
> all, providing the most exact reproduction of the input signal. If I
> understand this correctly, then class A amps should provide the least
> amount of distortion, no matter what volume you play them at. The
> most fanatical audiophiles desire class A operation for their audio
> systems for this reason.
Yes, Class A amps operate in the most linear part of a device's range (not
the signal's), but any amp will clip if driven hard enough, when its pwr
supply runs out of steam. When they do distort, it's typically a more
pleasing distortion. But the main thing that makes Class A desirable for
audiophile applications is the nature of Class A operation. Not only are
the output devices operating in their most linear range, since they're
always on (conducting), even when no signal is present, no distortion is
introduced as the devices turn on. But because the devices are always on,
and use a smaller part of their operating range, they have less headroom.
> If I'm right, then the OP's 35 watt Class A amp should provide a lot
> of volume with minimal clipping (ie. distortion) of the signal,
> certainly a lot less distortion at high volume then the more common
> class AB design.
The Class A amp might produce a "cleaner" signal when operating within its
range, but when it's out or power, it's out, and it will distort. Class AB
may have higher distortion (other than clipping) in general, but it will
have more headroom than a Class A design.
rpjazzguitar
volume in my applications, mostly clubs with quartet or quintet.
The difference in perceived sound level between 75 watts and 100
watts, all other things being equal (which they usually aren't), is
relatively minor.
Tim McNamara
"Carl" <crot...@NOSPAMoptonline.net> wrote:
> Forgive me for questioning this last statement, and your experience,
> and for perhaps getting too technical, but I believe that class A
> amps operate over the most linear part of a signal and that amps
> operating as class A introduce no clipping of the output signal at
> all, providing the most exact reproduction of the input signal. If I
> understand this correctly, then class A amps should provide the least
> amount of distortion, no matter what volume you play them at. The
> most fanatical audiophiles desire class A operation for their audio
> systems for this reason.
Here's a good summary of what is a class A versus class AB amp. It has
much less to do with the sound and everything to do with how the
amplifier operates electronically.
http://www.guitarplayer.com/story.aspx?id=34419&terms=class+a+amps
sheetsofsound
> I am considering buying a used Mesa B Dual Rectifier Maverick 1x12 combo.
> I do not really understand tubes vs ss as far as watts/loudness goes. I am
> mostly used to ss amps in the 60-100 watt range. The Maverick is only 35
> watts. But, it is pure class A. I am wondering if 35W pure class A will have
> enough headroom for a very clean, loud output. For example, to get a
> nice clean sound over a big band. Or will it be distorted. Thanks much.
that's a terrible amp for clean jazz sounds.
Dave
> Here's a good summary of what is a class A versus class AB amp. It
> has much less to do with the sound and everything to do with how the
> amplifier operates electronically.
>
> http://www.guitarplayer.com/story.aspx?id=34419&terms=class+a+amps
Pretty good. Thanks for posting.
Greger Hoel
<crot...@NOSPAMoptonline.net>:
> Forgive me for questioning this last statement, and your experience, and
> for
> perhaps getting too technical, but I believe that class A amps operate
> over
> the most linear part of a signal and that amps operating as class A
> introduce no clipping of the output signal at all, providing the most
> exact
> reproduction of the input signal. If I understand this correctly, then
> class
> A amps should provide the least amount of distortion, no matter what
> volume
> you play them at. The most fanatical audiophiles desire class A operation
> for their audio systems for this reason.
I read years ago, somewhere, that what's called class A in guitar amps
ain't really class A, it's a modification on the class A/B which saomebody
saw fit to call class A, probably for marketing purposes. I don't
understand this stuff myself, but the guy who claimed this convinced the
other posters on the board with a bit of explanation.
Don't know if this is helpful, but I guess you can check it out for
yourself if you know this stuff works.
--
Always cross a vampire; never moon a werewolf
sheetsofsound
the other factor that nobody's mentioned is speaker breakup.
Celestions break up very early.
Joey Goldstein
Mesa Boogies verion of "Class A" operation in many if not most of their
"Simul-Class" amps is not really true Class A operation of the power tubes.
Maybe that's what you heard.
But there are now and indeed were true Class A amps that are part of the
guitar amplification landscape.
Greger Hoel
<nos...@nowhere.net>:
> Mesa Boogies verion of "Class A" operation in many if not most of their
> "Simul-Class" amps is not really true Class A operation of the power
> tubes.
> Maybe that's what you heard.
> But there are now and indeed were true Class A amps that are part of the
> guitar amplification landscape.
I think it was something along the lines of this article that Tim posted
upthread, albeit much less detailed:
http://www.guitarplayer.com/story.aspx?id=34419&terms=class+a+amps