Wouldn't a PP be two separate 4 cylinder engines, one running in reverse, coupled together via a gear box?
ok, HE Penn.., then se is a v6 and pp is a w12 🙂 .
Having recently completed my first very good PP amp, I honestly can't tell much difference between it and my SE amps.
Having recently completed my first very good PP amp, I honestly can't tell much difference between it and my SE amps.
IMHO, these are not my words, an article by Lynn Olson who presented an amplifier that I remember, called Amity, with DHT and trailer with transformer, Push pull by the way, at that time the panacea it was and talk about the PP was like cursing. The amplifier had no capacitors rather than in the power supply, not electrolytic and had power generators on each node voltage. I think that pressure nodes were Gary Pimm CSS, if I remember correctly. The analogy describing this author was, yes a good was a well-tuned four-cylinder engine, the DHT of its authorship, it was a V8.
So far, I think to have already found as many of you the expression of what we hear with what we measure, and in this article I will try to rescue for the common good, somehow was clear what we can refer today with as much paraphernalia, some expressing themselves in a way and others bullying is but at the end and at the end we all know that it is.
So far, I think to have already found as many of you the expression of what we hear with what we measure, and in this article I will try to rescue for the common good, somehow was clear what we can refer today with as much paraphernalia, some expressing themselves in a way and others bullying is but at the end and at the end we all know that it is.
what spice says.
it is interesting to look at it in spice with the RMS power being matched and everything else for the most part ideal.
PSE amp distortion
PP amp distortion
actual numbers for 1-9 for both.
dave
it is interesting to look at it in spice with the RMS power being matched and everything else for the most part ideal.
PSE amp distortion
PP amp distortion
actual numbers for 1-9 for both.
dave
I like the look of the first one.
I find it interesting that despite having 5% distortion in the SE vs the 1% in the PP, that the SE has physically less distortion. Look at it.
This is a perfect example of measurements not telling the whole story.
5% vs 1%, are misleading, dare I say an incorrect way of describing harmonic content.
Look at how well the harmonics integrate in the SE.
The SE amp actually has less overall harmonic content. If you could weigh those green lines, there would be more weight in the PP version.
If I had to choose an amplifier based on those charts, hands down it would be the SE. It has less and better sounding distortion then the PP
I find it interesting that despite having 5% distortion in the SE vs the 1% in the PP, that the SE has physically less distortion. Look at it.
This is a perfect example of measurements not telling the whole story.
5% vs 1%, are misleading, dare I say an incorrect way of describing harmonic content.
Look at how well the harmonics integrate in the SE.
The SE amp actually has less overall harmonic content. If you could weigh those green lines, there would be more weight in the PP version.
If I had to choose an amplifier based on those charts, hands down it would be the SE. It has less and better sounding distortion then the PP
Other peoples real world measurements don't support the simulation - so something is amiss here. It looks like the PP amp has not been optimized for lowest distortion. Valve choice or load maybe ? Is it at max power or at a more realistic level ?
Shoog
Are you saying that PP in real life measurement has higher distortion than PSE? The simulations above show PP has lower distortion...
What do you think about this circuit ? i intend to build it as soon i have all the parts...can make it 15W with 350V supply or 25W with 450V supply, but telefunken says it has 9,5% distortion, i think at full power...the only thing i have is the tubes, i need all the other parts...
Thanks
Thanks
Attachments
Hi EL156,
try this link: Volker Jeschkeit's Röhrenverstärker
One of the schemaics shows aEL156 SE-amp.
Its in german but the speach of the schematics is international🙂
Volkers circuits are allways fantastic.
Have Fun,
Hilmar
try this link: Volker Jeschkeit's Röhrenverstärker
One of the schemaics shows aEL156 SE-amp.
Its in german but the speach of the schematics is international🙂
Volkers circuits are allways fantastic.
Have Fun,
Hilmar
I have looked at enough spice distortion plots to recognise that the PP version is very close to clipping. That spectral plot is typical of an amp near clipping.
Cheers
Ian
Cheers
Ian
Real world experience shows a shorter tail of harmonics. The long tail is indicative of suboptimal operating conditions.
Shoog
Thanks jazbo8...i wonder if Joshua_G has completed his Amp...anyway he said in the thread that he would publish the results...
Why are we ignoring actual amp measurements? Karna vs a 300B SE. Posts 137 and 178. While the comparisons may not be ideal, it's a whole lot more real-world than simulations. I can tell you I have never made a PP amp that looks remotely close to Dave's simulation, so something is amiss.
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There's really no need to argue which one is better. After my friend listened to both SE and PP amp that I built, they all agreed that we need both for different kind of music.
It is really difficult to make a PP amp has the silky sound of SE. The SE does not has the punchy and power of PP.
Distortion doesn't mean too much.
Johnny
It is really difficult to make a PP amp has the silky sound of SE. The SE does not has the punchy and power of PP.
Distortion doesn't mean too much.
Johnny
Nothing is amiss. This represents the ideal PP with perfectly matched tubes ideal iron etc. Of course we never get this in practice but I feel the sim is the best way to take the variables between the two out of the picture.
The levels were indeed that of just before A2 operation on the peaks and I think it gives a clear view of the overload characteristics of the two topologies. Simply put SE amps overload with copious amounts of 2nd order distortion and PP amps overload with higher predominantly odd order distortion.
Simply reducing the drive by 6dB does indeed eliminate most of the harmonics above 5 or 7 in the PP case, but you also have to remember that this amp should put out 7W RMS but by looking at the peaks we really are only getting 7W peak which is 3.5W Rms. the case of another 6dB reduction of drive to eliminate the creation of the higher orders leaves you with a 7W amp that can only deliver 1.75W RMS power before it "gets ugly" (RMS power is a pointless measure)
I do have to admit that I am a SE guy and suspect it is the overload characteristics of PP that irritate me. I have yet to hear a PP amp that doesn't have a "solid state" character and by the time you reduce the drive to keep it behaving on dynamic peaks, you are in the territory where SE also has reasonable distortion levels.
dave
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