• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

advice for a novice (which power)

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Hello,
I would like to approach the world of tube amplifiers, and I would be about to buy my first amplifier to use with a turntable.

I would also combine a couple of speakers that I already have with these characteristics

Type: 2 way, 2 driver loudspeaker system.
Frequency response: 50Hz to 20kHz
Recommended Amplifier: 75W (maximum)
Crossover Frequency: 3600Hz
Impedance: 8Ω.
Sensitivity: 89dB.
Bass: 1 x 165 mm polymer laminate cone
Tweeter: 1 x 25 mm titanium dome.
Enclosure: bass reflex
Dimensions: 375 x 274 x 235 mm
Weight: 17.7 kg
Year: 1987

my doubt is about the power of the amplifier I should focus on.

I have seen a model based on PSVANE HIFI KT88-K3 series of about 45W x 2 (RMS 8Ω) and a model based on PSVANE HIFI EL34 of 8Wx2 (ultra-linear connection).

the environment is a room of about 6x5 square meters.

Can the 8W amplifier be enough or should I focus more on the 45W? it is not my habit to listen at high volume, but it is also true that I would not like to have an amplifier that can only make background music.

Please be patient if my request is a bit too trivial and a bit subjective.

Kind Regards,
Luigi
 
Paul Joppa has provided the audiophile community with a rule of thumb for mating amps and speakers. Joppa's Rule states that for a "typical" listening space an amp/speaker combination should be capable of 102 dB. SPL peaks at a 1 M. distance. Applying the rule to an 89 dB. sensitivity yields upwards of 30 WPC being appropriate.

However, we are not done. Tube amps don't exhibit the gargantuan damping factors SS amps do. They "dislike" speakers with significant dips in the impedance curve, particularly in the power "hungry" deep bass. The target speakers are 8 Ω nominal. If there are impedance dips below 6 Ω, the speakers should be connected to 4 Ω taps and their sensitivity derated. Remember, 2.83 V. is 1 W. into 8 Ω, but it's 2 W. into 4 Ω. Speaker manufacturers enumerate specifications in a manner that favors marketing. A nominal 8 Ω speaker that dips down to 4 Ω has to be regarded as 4 Ω, when mated to tube power amplification, and the claimed sensitivity derated by 3 dB.

CAVEAT EMPTOR!
 
Hi MarcelvdG,
thank you for sharing the test, for sure I'll try it.

about your question....the answer is only one world "time" :(

by my nature, I have always tried to build myself as much as possible, the satisfaction is immense.

In 2004, with a lot of effort, I made one of the first car PC for my car, which today is standard in almost all new cars ...

Now, however, in this period I have two "projects" in progress, one of 7 years old and the other of 2 years old that devour me all my free time, and time to devote to my passions is alas now minimal .. from here the choice to buy ...

anyway thank you for stimulating my DIY nature again.

Luigi
 

45

Member
Joined 2008
Hello,
I would like to approach the world of tube amplifiers, and I would be about to buy my first amplifier to use with a turntable.

I would also combine a couple of speakers that I already have with these characteristics

Type: 2 way, 2 driver loudspeaker system.
Frequency response: 50Hz to 20kHz
Recommended Amplifier: 75W (maximum)
Crossover Frequency: 3600Hz
Impedance: 8Ω.
Sensitivity: 89dB.
Bass: 1 x 165 mm polymer laminate cone
Tweeter: 1 x 25 mm titanium dome.
Enclosure: bass reflex
Dimensions: 375 x 274 x 235 mm
Weight: 17.7 kg
Year: 1987

my doubt is about the power of the amplifier I should focus on.

I have seen a model based on PSVANE HIFI KT88-K3 series of about 45W x 2 (RMS 8Ω) and a model based on PSVANE HIFI EL34 of 8Wx2 (ultra-linear connection).

the environment is a room of about 6x5 square meters.

Can the 8W amplifier be enough or should I focus more on the 45W? it is not my habit to listen at high volume, but it is also true that I would not like to have an amplifier that can only make background music.

Please be patient if my request is a bit too trivial and a bit subjective.

Kind Regards,
Luigi

I would just buy a classic EL84 PP amplifier. 12-15W power will be enough, IMHO...spend your time and efforts on room acoustics and isolating your turntable and tubes from vibrations (don't use spikes!!).

If you are in Italy I have seen a nice Synthesis NIMIS in like-new condition for sale at a popular HiFi shop for just 480 eu. It uses EL84's for 15W. It only has one secondary for 6R which is a clever choice with a single output.
Nice little amp at modest price. That's a my advice for first experience. It also has some value there and you can always re-sell and get some money back if want to upgrade.
 

45

Member
Joined 2008
This is the amplifier:
 

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Hello,
thank you for your advise.

I've performed the Pano test, and I've measured a voltage between 3 and 4 Volts, so I think that the suggestion of 12-15W is quite good for me.

About the budget, thank you Lampie519, but the suggested site, to start is it too much for me, I'm looking for something more cheap.

Cheers,
Luigi
 
I don't know Hi-Fi amplifiers but I have a mesa-boogie Express 25 for guitar. There is a Class A mode with a power output of 5W. It seems low ... but not, it does a lot of noise in a middle room. I can play with a drummer @ 5W ;)

So OK it depends on efficiency of speakers but I would like to say that the 8W should be enough and less expensive. If cost is not a problem, buy the 45W amplifier, then you have the volume pot to have normal and louder sounds ;)
 
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