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Sansui SP-150 Speakers : What power needed and amp style (SE vs PP)
Sansui SP-150 Speakers : What power needed and amp style (SE vs PP)
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Old 17th May 2018, 12:31 AM   #11
Lingwendil is offline Lingwendil  United States
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Sansui SP-150 Speakers : What power needed and amp style (SE vs PP)
SE is a waste of a good 300B if you expect it to provide decent bass response out of anything other than some physically large horns with very efficient drivers, been there, done that. Push pull AB1 or AB2 300B, tetrode connected 6L6, or a triode connected KT88 AB amplifier would be pretty much spot on if you want a good all-around amplifier capable of most anything you ask of it at that sort of power. Bass requires power and decent output impedance to sound accurate.

Leave poor performing SE to the golden ears that drink expired wine while listening to LPs by candlelight. That, or run a separate subwoofer

( I better board my windows, deadbolt my doors, and keep a rifle handy tonight, I fear what I spoke may be heresy to some of the members here! )
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Old 17th May 2018, 10:05 AM   #12
gug42 is offline gug42
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Hello,

Thank you, It seems that somes points goes in this direction ...

I tried to evaluate needed power with SPL and sensitivity .... but I'm really not comfortable to handle thoses data ...

- Let's start with with a SPL of : 80 dB
- I will be at 1,5 or 2m.
- Power peak seems to be at +10 or 20 dB from the average... so let's say 95 db @ 1,5 m
- Let's says my room is not treated ... so very little absorption, well so max 100 dB @ 1m
- With speaker of 95 dB / w / m, I need + 5 dB hum ... that's the point ... : to convert 5 dB in Watt ?!?

Ok I have read : to have +3 dB, the must be double. So for speaker with efficiency of 95 dB / W / m ... onyl two watts ?

And 80 dB SPL seems to be prety loud : Sound pressure - Wikipedia

Thank you in advance !
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Old 17th May 2018, 11:08 AM   #13
azazello is offline azazello  Bulgaria
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1-2 W from amp 3-4 W sounds better than 1-2 W from amp 30 W....except If You want to break the furniture, windows....
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Old 17th May 2018, 01:31 PM   #14
gug42 is offline gug42
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Well indeed for sure ... lot's of people says (and some on this thread), says that a SE 300B can't have good bass with thoses types of speaker (ie not high efficiency huge boxes).

I have done other calculation.

If I'd like to listen louder, well 85 dB SPL at the listen position. It could be 105 dB at one meter.

- With efficiency of 95 dB / W / m, I will need +10 dB. So 10 watts power.
- With efficiency of 90 dB / W / m, I will need +15 dB. So 30 watts power


More over, I have some doubt about the datasheets of the loudspeaker .... at least I doubt than the annonced efficiency could be for all frequencies ... from 20 Hz to 20 kHz ...

Did you think than Davis stentaure have 95 dB / W / m at 40 Hz with two 17cm woofers ?
And for the sansui, same question 98 dB / W / m at 40 Hz with the woofer and thoses boxes ?

And well is a "classical" 300B SE can really produce the needed powers at 40 Hz ? At least 5 Watts (10 watts will be better of course) at 40 Hz ?

Thank you in advance.
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Old 17th May 2018, 07:49 PM   #15
Wavebourn is offline Wavebourn  United States
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Sansui SP-150 Speakers : What power needed and amp style (SE vs PP)
Quote:
Originally Posted by azazello View Post
1-2 W from amp 3-4 W sounds better than 1-2 W from amp 30 W....except If You want to break the furniture, windows....
Not at all, if you are listening to good recordings. You are right, if you play a solo guitar.

However, when you play highly compressed music, you do not need headroom, but what's the point in tube amps for such a music? Class D amps do it better.

Quote:
Originally Posted by gug42 View Post
More over, I have some doubt about the datasheets of the loudspeaker .... at least I doubt than the annonced efficiency could be for all frequencies ... from 20 Hz to 20 kHz ...
According to the graph on the datasheet above, your Sansui has -20 dB on 40 Hz. How much power do you need to boost 20 dB on 40 Hz?
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Old 17th May 2018, 09:20 PM   #16
gug42 is offline gug42
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Wavebourn, you are right ! Damm too much will be the answer .... So 30 Watts could not be enough ... and PP UL .... thx

Thank you evryone.

Regards,
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Old 18th May 2018, 11:32 AM   #17
azazello is offline azazello  Bulgaria
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Quote:
Originally Posted by Wavebourn View Post
Not at all, if you are listening to good recordings. You are right, if you play a solo guitar.

However, when you play highly compressed music, you do not need headroom, but what's the point in tube amps for such a music? Class D amps do it better.
Mmm, solo guitar sounds better on big power /You are musician/! But for good simph., string, soul, jazz music, IMO, is enough about 2 x 2 W - quality SE with good freeq. band is for listening for a much hours. And these Sansui have posibility for big bas sounding. High sensitivity speakers are for this goal! Small power for big rooms. Do people need big power, that never will use more 5-10 min and damage ears? /I have PP KT88 and SE 2A3 RCA and +++ are for second, acc. my frends opinion, but alwais I use 1 W SE EL11 Telefunken in triod with cool OTs, that is the best tube for all the times, IMO....I like SE, but this is another beer...PP is for breaking the sinks.../.
If You need a big power, You can make SE GU, GK,GM....Doesnt enough to be technician, can be meloman and audiophil!
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Last edited by azazello; 18th May 2018 at 11:57 AM.
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