Hi
My only experience of valves was in a Croft Pre Amp so I am looking for advice.
I'm considering a valve power amp to run midrange and tweeters in a semi active 3-way and wondering how much power I will need to do this? Would something like a Puresound 2a3 (18w/channel) do the job? I like to crank things up to a reasonable level, but not ear splitting.
Details - I have a 3 way set up using the Yamaha NS-1000M midrange and tweeter which are both nominally 8ohm but dip to 6ohm in use. These are both around 93dB sensitivity. I'm using a passive crossover between mid/twt.The bass drivers are 4ohm 12" Scanspeak and powered by a 700w/channel class D amp. So masses of headroom there.
I am using Rod Elliott's active crossover (Analogue) to split for bass. This active circuit also acts as a HP pre-filter for the mid/twt combo. So there is no passive HP filter element for the midrange drivers.
With powerful class D covering bass duties, is something like the Puresound 2a3 going to run out of steam to early, or will it give me realistic levels when used purely for mids and highs? My musical taste is very broad, basically anything that is good of it's type, so anything from Metal to Classical.
Would I be better going for something like the PrimaLuna Prologue Premium and KT120 producing about 35w/channel? More grunt, but maybe less finesse. The auto bias with this model is useful for a newbie to valves as well.
I've done a bit of reading and I'm aware there is more to it than just watts. But without getting into the technicalities of transformers, bandwidth etc. Has anyone knowledge of the Puresound 2a3 in this type of application and how well it performed?
My only experience of valves was in a Croft Pre Amp so I am looking for advice.
I'm considering a valve power amp to run midrange and tweeters in a semi active 3-way and wondering how much power I will need to do this? Would something like a Puresound 2a3 (18w/channel) do the job? I like to crank things up to a reasonable level, but not ear splitting.
Details - I have a 3 way set up using the Yamaha NS-1000M midrange and tweeter which are both nominally 8ohm but dip to 6ohm in use. These are both around 93dB sensitivity. I'm using a passive crossover between mid/twt.The bass drivers are 4ohm 12" Scanspeak and powered by a 700w/channel class D amp. So masses of headroom there.
I am using Rod Elliott's active crossover (Analogue) to split for bass. This active circuit also acts as a HP pre-filter for the mid/twt combo. So there is no passive HP filter element for the midrange drivers.
With powerful class D covering bass duties, is something like the Puresound 2a3 going to run out of steam to early, or will it give me realistic levels when used purely for mids and highs? My musical taste is very broad, basically anything that is good of it's type, so anything from Metal to Classical.
Would I be better going for something like the PrimaLuna Prologue Premium and KT120 producing about 35w/channel? More grunt, but maybe less finesse. The auto bias with this model is useful for a newbie to valves as well.
I've done a bit of reading and I'm aware there is more to it than just watts. But without getting into the technicalities of transformers, bandwidth etc. Has anyone knowledge of the Puresound 2a3 in this type of application and how well it performed?
Considering that 8 WPC is enough for full range 93 dB. sensitive speakers, 18 WPC of 2A3 power will certainly work, in a mid-tweeter application.
Thanks for the reply Eli, gives me a bit of confidence.🙂
I just checked out Icon Audio's MFV3 Super MKIII Speakers, which they promote as suitable partners for some of their valve amps. They are a full range (multi driver) set of 92dB sensitivity and Icon say and I quote:
"This is a floor standing model capable of filling a large room with beautiful golden sound from 15 watts."
Confirms what you were saying, mids and tweeter should be a breeze. I'm used to modern solid state power amps, which tend to deal in big numbers for output, so was being a bit cautious, before dipping my toe in the water.
I just checked out Icon Audio's MFV3 Super MKIII Speakers, which they promote as suitable partners for some of their valve amps. They are a full range (multi driver) set of 92dB sensitivity and Icon say and I quote:
"This is a floor standing model capable of filling a large room with beautiful golden sound from 15 watts."
Confirms what you were saying, mids and tweeter should be a breeze. I'm used to modern solid state power amps, which tend to deal in big numbers for output, so was being a bit cautious, before dipping my toe in the water.
Don't mean nothing.
Another quote:
same as before: it don't mean nothing.
Re. full range 93 dB sensitive speakers: does it mean that the amp is able to drive a speaker's voice coil ? ANd what happens when it encounters a passive crossover net?
What is the target in deciBel SPL that is to be reached? What if my speakers are 84 dB/W/1m ? Am I suffering and I don't know?
this kind of sensivity needs somwhere between +10 watt (depending on the space) i think. So that amp should do the job.
you can use a 10 - 20w 70v line transformer ( $10) for the output.
frequency response 70hz - 80khz. class D for bass driver
frequency response 70hz - 80khz. class D for bass driver
Sorry, this reply may as well be in Greek, means nothing to me.
Are you saying connect this line transformer to the line level output from my active crossover to drive the mid/twt's ?
Sheesh… Qwin asked a perfectly reasonable question. PicoWallSpeaker sniped. Why?
The best answer so far was the composite one: for reasonably loud listening, let's say at 2 to 3 meters, from a speaker producing 93 dB nominal, by inverse-square law, and ignoring wall reflections (which substantially mitigate open-ended power requirement), you would need what?
Since — as others have indirectly cited — by sending the bass signal (let's say below 100 Hz?) to a separate amplifier and dedicated subwoofer, well … 50% of the Big Power is removed So, 7 W would be sufficient. Figuring back in the passive wall reflections as contributing at least ¼ if not ⅓ to ½ the power for a given perceived sound pressure level, then 7 × (1 - ⅓) = 5 W.
Meanwhile, your D-class subwoofer amplifier is going to output 'sweet' bass at only 10 W, but turned up for more oomph, 25, 50 or more W. Likewise, when a bunch of people are in the listening room, absorbing sound like crazy (and worse, if they're standing, and worse yet, drinking and quietly chatting…), then 5× the power will be required from both the main amplifier and the subwoofer deal.
The only mystery left open is “how did The Goat come up with 9.1 dB derating for 3 meters?”. Mystery solved:
Just saying,
GoatGuy ✓
The best answer so far was the composite one: for reasonably loud listening, let's say at 2 to 3 meters, from a speaker producing 93 dB nominal, by inverse-square law, and ignoring wall reflections (which substantially mitigate open-ended power requirement), you would need what?
95 dB "nice-and-loud" output level.
3 meters distance
93 dB/Wm² speakers
–6 dB/m² derating
dB factor = 95 dB - (93 dB/W ⊕ 6 dB/m²)
dB factor = 95 - (93 dB - 9.1 dB (3 m))
dB factor = +11.1 dB
x factor = 1011.1 ÷ 10
x factor = 101.11
x factor = 12.9×
So, 1 W sensitivity × 12.9 factor = 12.9 watts required, again nominally.3 meters distance
93 dB/Wm² speakers
–6 dB/m² derating
dB factor = 95 dB - (93 dB/W ⊕ 6 dB/m²)
dB factor = 95 - (93 dB - 9.1 dB (3 m))
dB factor = +11.1 dB
x factor = 1011.1 ÷ 10
x factor = 101.11
x factor = 12.9×
Since — as others have indirectly cited — by sending the bass signal (let's say below 100 Hz?) to a separate amplifier and dedicated subwoofer, well … 50% of the Big Power is removed So, 7 W would be sufficient. Figuring back in the passive wall reflections as contributing at least ¼ if not ⅓ to ½ the power for a given perceived sound pressure level, then 7 × (1 - ⅓) = 5 W.
Meanwhile, your D-class subwoofer amplifier is going to output 'sweet' bass at only 10 W, but turned up for more oomph, 25, 50 or more W. Likewise, when a bunch of people are in the listening room, absorbing sound like crazy (and worse, if they're standing, and worse yet, drinking and quietly chatting…), then 5× the power will be required from both the main amplifier and the subwoofer deal.
5× × 5 W = 25 W mid + treble, per channel.
5× × 20 W = 100 W for subwoofer.
This is a long way to setting a more concrete answer for you, by methods you can reproduce yourself per your listening space, likelihood of having booze soaked guests milling about 'listening' and so forth. 5× × 20 W = 100 W for subwoofer.
The only mystery left open is “how did The Goat come up with 9.1 dB derating for 3 meters?”. Mystery solved:
9.1 = 10log₁₀( 1 ÷ 3² )
Have fun! Don't over-worry … if you've got amplifiers of about 15 watts for the mids, and about 100 watts for the subwoofer, you're golden. Just saying,
GoatGuy ✓
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