wattage for valve heads- whats good enough?

[matt_citizenbass]

i'm currently selling my head and have about £250 or so to spend on a old valve head.

i'm worried about power though cause i've heard mixed views.

some people say 50 watts is more than enough, and others say (well Ant) that 300 watts (all valve) isn't enough.


what are your experiences?

[Dubs]

IME of valve heads, 50W wouldn’t be enough for a lot of gigs, and 300W is excessive for a lot of gigs. Personally I wouldn’t bother with anything smaller than 100W, and I wouldn’t feel the need for anything more than 200W. Hope that helps, but there are others here with a lot more experience of valve amps than me so I’m sure you’ll get some sound advice.

[thisnameistaken]

Get the same power you'd get with a solid-state head. With the same speakers the output ought to be the same, unless something is broken somewhere.

Personally I'd be after 300W if I was intending to gig it.

[Dubs]

[quote name='thisnameistaken' post='450151' date='Mar 31 2009, 12:14 AM']Get the same power you'd get with a solid-state head. With the same speakers the output ought to be the same, unless something is broken somewhere.

Personally I'd be after 300W if I was intending to gig it.[/quote]

With a good 300W valve head you won’t get the master volume above about 2 or 3 until you’re playing 750+ capacity venues. When I gigged my SVT-CL the few times that I did I only had the master volume on 3 in a 300 capacity venue and I didn’t have any bass through the monitors because the volume from the backline was insane. For some reason you seem to get more volume with valve heads; that’s my experience anyway.

[Mr. Foxen]

[quote name='thisnameistaken' post='450151' date='Mar 31 2009, 12:14 AM']Get the same power you'd get with a solid-state head. With the same speakers the output ought to be the same, unless something is broken somewhere.

Personally I'd be after 300W if I was intending to gig it.[/quote]

Not really true, you can get more percieved volume from a valve head, and you can run a valve head in clipping and it sounds awesome whereas a SS will sound terrible. Running my Peavey firebass into an Aguilar GS412 at 475 watts was loud, but the limiter light was on quite a lot which is not ideal, the 400W Laney Nexus into the same cab, dub lows and awesome sound. The traynor at 200w seems quite sufficient for most purposes, and I supplement it with another 120W head also.

If you have a decent cab, an old 100w valve amp will be ideal if you don't mind a bit of grind in your sound, budget half for the head and half for a service and revalve.

Plug: Listen to myspace recordings, the clean bass is the Laney nexus 400w valve head, the distortion is that plus 120w head driving its nuts off, both into decent modern cabs.

[matt_citizenbass]

[quote]if you don't mind a bit of grind in your sound[/quote]

thats exactly what i want for the clean channel then the distortion channel will be face ripping

[Mr. Foxen]

[quote name='matt_citizenbass' post='450161' date='Mar 31 2009, 12:26 AM']thats exactly what i want for the clean channel then the distortion channel will be face ripping [/quote]

Other thing to bear in mind old valve amps are wicked dodge for electrocuting you, so get it tech before you play with it if it hasn't been used in a while.

[umph]

[quote name='thisnameistaken' post='450151' date='Mar 31 2009, 12:14 AM']Get the same power you'd get with a solid-state head. With the same speakers the output ought to be the same, unless something is broken somewhere.

Personally I'd be after 300W if I was intending to gig it.[/quote]
have you ever cranked a 300watt valve amp? they put out 300 CLEAN watts about half way and will go up to around 600 DISTORTED watts fully cranked.

if you crank a 300watt valve amp you'll end up killing any small children and animals unlucky enough to stroll into the venue

to the original poster above 100watts is ideal but 50watts should be enough as long as it has a decent power supply / rectifier

[thisnameistaken]

[quote name='umph' post='450189' date='Mar 31 2009, 01:15 AM']have you ever cranked a 300watt valve amp? they put out 300 CLEAN watts about half way and will go up to around 600 DISTORTED watts fully cranked.[/quote]

Eh?

I gigged an SVT Classic for a while and - while I didn't deliberately overdrive it - I didn't think it was that loud.

I suppose you're talking about a higher perceived volume due to all the harmonics from the distortion? Just stick a distortion pedal before your solid-state amp. Same result.

[umph]

[quote name='thisnameistaken' post='450203' date='Mar 31 2009, 01:55 AM']Eh?

I gigged an SVT Classic for a while and - while I didn't deliberately overdrive it - I didn't think it was that loud.

I suppose you're talking about a higher perceived volume due to all the harmonics from the distortion? Just stick a distortion pedal before your solid-state amp. Same result.[/quote]
;<

the power rating on valve amps is the clean power i.e before the wave form starts to distort, they will continue to amplify beyond this point putting out considerably more distorted watts, solid state does the same but sounds terrible if you do it.

[matt_citizenbass]

^^ listen to him, he makes pedals, he knows whats going down man...

i've just placed a bid on a selmer 100 watt PA Head, lets see how that goes.

thanks guys!

[thisnameistaken]

[quote name='umph' post='450205' date='Mar 31 2009, 02:11 AM']the power rating on valve amps is the clean power i.e before the wave form starts to distort, they will continue to amplify beyond this point putting out considerably more distorted watts, solid state does the same but sounds terrible if you do it.[/quote]

Really?

So a 100W solid state amp can actually produce around 200W of power?

[rodl2005]

Geeeeezz!!!! Look into the ol' S.S. Vs valve power.......

IMO 100w into a GOOD, efficient cab(4x10" at least- 2x15" or 6x10" - I use a Bergantino NV610 & the Ampeg V4BH-100w is fine for MOST gigs.) is fine. Tho at a lotta gigs you'll need to run a DI ir mic yr cab to the FOH PA system- as U do with any large-ish gig. I too find 300w SVT- lovely, but usually run the MAster on 9 oclock or 3/10. Where I use a 300w s.s. amp & for the same volume ONSTAGE, she nees to be running at 8/10. Thats MY experience!

[Noisyjon]

[quote name='matt_citizenbass' post='450138' date='Mar 31 2009, 12:00 AM']i'm currently selling my head and have about £250 or so to spend on a old valve head...
...what are your experiences?[/quote]

I would recommend saving up and then looking for a decent used Ampeg, Mesa Boogie, Orange, Hiwatt, etc.

There's a lot of love for the Orange AD200B Mk.3 here on Basschat and that's a 200W valve head.
I personally use a Mesa Boogie Bass 400+ and it's a real beast of an amp but a Mate has an Ampeg SVT 2 Pro and that is really nice too...

Good luck,
JTB

[alexclaber]

The amount of power needed is hugely dependant on your choice of cabs and the context you're in. Basically the bigger your cabs and the more overdriven you like your tone, the less power you need.

Alex

[henry norton]

I used to use a marshall 100 watt head (one of the old pre master volume versions), and it was plenty loud enough to compete with drums, guitar and keyboards. I'd be wary of 'saving up' for something like a MESA 400 or an Ampeg - they'll cost you way over your £250 budget and if something goes wrong they can be very expensive to fix, especially the MESA, which uses particularly expensive valves (something to do with having a fixed bias). Having said that, if you do decide to go for a big bass valve head, (ie. you up your budget for the head, the servicing and the roadie to carry it around for you), there ain't nothing cooler than a massive 3-400watt valve amp stacked behind you. It'll make your MarkBass combo look like something from Noddy

[alexclaber]

For instance a 50W valve head into this would reach serious SPL (like upsetting many guitarists) before you started getting dirt:



Whilst if you only used one cab you'd need 200W to reach the same SPL before overdrive.

Alex

Edited March 31, 2009 by alexclaber

[mcgraham]

Does adding four cabs together like the above picture increase the overall sensitivity of the setup?

Mark

[alexclaber]

[quote name='mcgraham' post='450300' date='Mar 31 2009, 09:42 AM']Does adding four cabs together like the above picture increase the overall sensitivity of the setup?[/quote]

Yes, absolutely! What happens is that at all wavelengths greater than the centre to centre distance of the speakers the speakers perfectly couple acoustically. At higher frequencies the coupling diminishes but as most of the energy in music is in the lower frequencies (for typical program material energy drops by 3dB for every octave above 100Hz) and for bass guitar even more so the loss of coupling as you go higher is not significant.

The sensitivity of one Compact is about 100dB @ 1W1m. The sensitivity of four is about 106dB @ 1W1m. 50W will thus get you cleanly to 122dB. For comparison absolute full volume on your Berg IP112 will be about 120dB.

Alex

[mcgraham]

Ouch! That sounds painful!

Sounds great though Alex. Good job!

Mark

[escholl]

[quote name='alexclaber' post='450310' date='Mar 31 2009, 10:06 AM']The sensitivity of one Compact is about 100dB @ 1W1m. The sensitivity of four is about 106dB @ 1W1m.[/quote]

You'll have to forgive me if this is a stupid question, I'm still trying to learn about all of this stuff.

But my understanding is that in the sub-200Hz range, the benefit for just two cabs would be 6dB, as not only has the number of drivers doubled (+3dB) but also the bottom cab has gone from half-space (assuming it's not against a wall or in a corner) to effectively quarter-space (another +3dB below 200Hz -- the coupling effect you talk about is the change from half to quarter space).

So then adding another two more cabs would be....loud. >.<

[alexclaber]

[quote name='escholl' post='450390' date='Mar 31 2009, 11:30 AM']But my understanding is that in the sub-200Hz range, the benefit for just two cabs would be 6dB, as not only has the number of drivers doubled (+3dB) but also the bottom cab has gone from half-space (assuming it's not against a wall or in a corner) to effectively quarter-space (another +3dB below 200Hz -- the coupling effect you talk about is the change from half to quarter space).[/quote]

It is really complicated, I've spent years puzzling over this and still so much to learn. The benefit from doubling the number of cabs is 3dB wattage sensitivity or 6dB voltage sensitivity (for parallel wiring) or 6dB maximum output (3dB sensitivity plus doubled power handling). I believe the reason for this improvement in sensitivity (and thus efficiency) is due to increasing the radiation impedance by increasing the radiating area - I'm not 100% sure on this though.

There is a change due to the space they're firing into but it's only within a small frequency range - basically it's like lowering the baffle step frequency slightly (that's the frequency where output shifts from just forwards (180 deg) to wrapping around the whole cab. If you go from one cab to four in this arrangement you'll lower the baffle step frequency by an octave, in this case from ~220Hz down to ~110Hz. If you stack two cabs vertically there won't be much change in baffle step.

[url="http://www.t-linespeakers.org/tech/bafflestep/index.html"]http://www.t-linespeakers.org/tech/bafflestep/index.html[/url]

Alex

[escholl]

[quote name='alexclaber' post='450401' date='Mar 31 2009, 11:40 AM']It is really complicated, I've spent years puzzling over this and still so much to learn. The benefit from doubling the number of cabs is 3dB wattage sensitivity or 6dB voltage sensitivity (for parallel wiring) or 6dB maximum output (3dB sensitivity plus doubled power handling). I believe the reason for this improvement in sensitivity (and thus efficiency) is due to increasing the radiation impedance by increasing the radiating area - I'm not 100% sure on this though.

There is a change due to the space they're firing into but it's only within a small frequency range - basically it's like lowering the baffle step frequency slightly (that's the frequency where output shifts from just forwards (180 deg) to wrapping around the whole cab. If you go from one cab to four in this arrangement you'll lower the baffle step frequency by an octave, in this case from ~220Hz down to ~110Hz. If you stack two cabs vertically there won't be much change in baffle step.

[url="http://www.t-linespeakers.org/tech/bafflestep/index.html"]http://www.t-linespeakers.org/tech/bafflestep/index.html[/url]

Alex[/quote]

The first part makes sense, that would be my guess too.

The second part, I wasn't referring to the baffle step, but rather the "space" the speaker is in as defined by the acoustic boundaries, or something like that. I've read about it in a few books recently, although I can't really explain it without an image, and i can't find an image on the net. fail. but it's the same thing as when speakers are defined as being measured in either half space or free air (whole space), and why some studio monitors have adjustments for half, quarter, or eighth space. this probably isn't explaining it any better -- but it's basically what causes the acoustic coupling effect you were talking about, i think.

[alexclaber]

[quote name='escholl' post='450413' date='Mar 31 2009, 11:54 AM']The second part, I wasn't referring to the baffle step, but rather the "space" the speaker is in as defined by the acoustic boundaries, or something like that. I've read about it in a few books recently, although I can't really explain it without an image, and i can't find an image on the net. fail. but it's the same thing as when speakers are defined as being measured in either half space or free air (whole space), and why some studio monitors have adjustments for half, quarter, or eighth space. this probably isn't explaining it any better -- but it's basically what causes the acoustic coupling effect you were talking about, i think.[/quote]

That's exactly what the baffle step is. With the speaker on the floor below the baffle step it radiates into half space and above the baffle step it radiates into quarter space. Linearly double the size of the baffle (i.e. use four cabs) and you lower the frequency where you shift from half space to quarter space radiation by an octave.

Alex

[ben604]

Yeah...but dont valve amps sound lovely.