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Old 10th December 2001, 11:42 AM   #1
stigla is offline stigla  Norway
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Hey.

I am wondering; what is really the sonic difference between a triode SE amp. and a triode PP amp. More or less bass? Details and perspective etc...?

I am considering to buy the Klipch KF-3 (or whatever it was named) with a sensitivity av 98dB at 1W/1m! This will allow me to use a SE amp with 8-10W. I am just conidering what to build. A SE amp would be cheaper...(relatively...)


- Stig
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Old 11th December 2001, 08:03 PM   #2
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Default SE VS PP

In my opinion, a pp triode connected amp will give you a taste of what se triode has to offer. I have a narrow point of reference, having only used a Dynaco st-70 wired in triode mode, compared to a full fledged 2a3 se triode amp.
Before I bought my 2a3 set's, I wired up my Dynaco into triode mode to see what the fuss was all about, I was impressed. First off, I would have thought bass would be lessened due to the lower power; Just the opposite occurred. The bass was full and detailed, and seemed to "bloom" out into the room better than before. Instruments sounded more like there live counterparts, and it was as though the were almost in the room. As I heard it described once; "There was more "there" there". Imaging was better, and the slight bit of "softness" to the upper treblemade you relax and listen to the music.
As for my se 2a3's, they have all of the above to a much larger degree. Your choice of speakers is limited which can be a drawback, or a blessing depends on how you look at it. I am very happy with my 104 db/1w/1m Klipsch Lascalas and 2a3 triodes.
I will never go back to inneficient speakers and 200 wpc solid state amps.
mg16
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Old 11th December 2001, 09:57 PM   #3
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The sound of SE is more natural, but the design of the output transformer is difficult, specially for low frequencies, because of core saturation. In multi-amplification systems, PP is used for woofers, and SE for medium and tweeters.

Regards, P.Lacombe.
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Old 12th December 2001, 01:58 PM   #4
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Default PP vs SE

If you are getting 98db efficiant speakers you can easily use a 3 watt SE amp. I have used SE 3.5 watt amps with 92db speakers with great results. PP can sound very good and often will have a greater dynamic range than SE in the lows but our ears are tuned the best to the range of the human voice and in that area nothing can touch SE for clarity. With good speakers your system will disappear and you will be listening to the performance. You will also find yourself sitting in the dark because the soundstage seems better. Get some of those great old tube analog recordings of Ella, Frank etc and you can tell your friends "I see dead people."
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Old 12th December 2001, 06:21 PM   #5
stigla is offline stigla  Norway
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Hmmm, so SE is the way then... thats just wonderful! I have found that Andrea Ciuffoli's SV572-3 amp suits just fine for me! I've heard many great impressions of this tube. 13W will give me some headroom too.
I have read about the Amithy amplifier by Lynn Olson... This was the article that got me going into tube amps in the first place, and realy got me wondering about PP vs SE.
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Old 12th December 2001, 06:31 PM   #6
stigla is offline stigla  Norway
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What about Paralell output tubs in SE? Any impressions?
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Old 13th December 2001, 11:36 PM   #7
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SE vs PP

Single Ended amps are for those who are pure in heart and mind. For they shall listen to heavenly music.

A properly designed and built SE amp will be more musical than a Class A PP amp.

The difference to my ears is mainly in terms of tonal purity, real dynamics as opposed to the ‘slam’ of most PP amps and the ability to present a wealth of low level information that is simply not there with PP amps.

To enjoy the maximum benefits that Single Ended amps are capable of, we need speakers without crossovers. This means that the voice coil of the driver should be connected to the output transformer. In the old days, Philips made 600 ohm voice coils to suit their OTL amps. I wish a few of the present manufacturers would consider making full range (well, almost full range should be adequate for 90% of recorded music) drivers with 600 ohm voice coils. Some 5 years ago, I did take up the matter with Lowther and when I replied that I am willing to purchase 10 pairs, there was a brief silence at the other end of the telephone line and the discussion topic changed!

A less puristic approach will be to engineer the front end and output transformers of SE amps to roll off at frequencies appropriate for a selected driver. This means that we need separate amps for each driver and the drivers should be capable of operating over a wide frequency range to suit 6dB/octave roll off. This is going to be an expensive affair and could be outside the domain of most DIY enthusiasts. Besides, the wife would not like all those wires and ugly cases taking up more than their deserving share of the room. I hope that I have not offended some of our members.

Yes, paralleling output tubes and increasing the current drive to these tubes is an option to increase power output at the expense of loosing a puristic approach. Bottom line is that no two tubes would act alike. Full stop. We will need to match the tubes regularly and adjust the bias at each listening session. This is the story of PP amps.

Yes, there are ways of forcing the tubes (shared cathode resistors is a simplistic and effective approach) to be more consistent and follow each other more closely under signal conditions. The tubes then become rather restricted in their voltage and current swings because one tube may not exactly like what its neighbour is forcing it to do. The net result is somewhat diminished transient response (pulse rise time) than otherwise would have been possible with a single tube.

My opinion is that SE is for purists and single driver systems. PP is a more practical approach for systems with multiple drive unit systems. Yet again, some of my friends with ESL 57 say that parallel SE is more musically satisfying than their PP amps.

Mohan
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Old 18th December 2001, 03:41 AM   #8
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Default PP vs SE

This big tube will handle 2 channels? My question is why would you want to stray off the beaten path for enjoyment? Wattage is not worth it. Your SE tube amp can't take it? You bi-amp and increase your power more tham 2 fold. If your speakers can't get it for you then, well, it is you or your speakers. One or the other aint working right.
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Old 19th January 2002, 10:38 PM   #9
dice45 is offline dice45  Germany
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Default PP and SE sonics can be married ...

Hello all,







if the PP amp is built fully differential including the output stage, then the beauty of the SE is combined with the utter control and clarity in the low end a good PP amp can deliver. Yes and with the slam other posters mentioned.

With fully differntial I mean the sort of circuitry Tektronix and HP used to use in their tube oscillioscopes: long-tailed pairs with a huge reistor looking to -150V or a constant current source looking at -whatyouhave and behaving like a MegOhm resitor looking at -1000V.







I had the extended opportunity to listen to Allen Wright's EL 34 PP amp using this topology. At one of the occasions, we compared Allen EL34 with a gorgeous BorderPatrol 300B SE amp., the best classic WE300B amp I ever heard.



Allen's shitty lil'experimental thing was easily as good as the Border Patrol and it outperformed it in the low end. Speaker was Peter Bahnsens Maximator horn which is a 3way tractrix horn with passive XO and should not be a difficult load at all (SPL >100dB/W/m). And Allen had not taken care of any component choice, in the amp was what he had at hand.







For the record, I do like SE sound very much. But diff.PP is equivalent to SE, it has the same sonic beauty, maybe not the same glamour but more accuracy.



What I heard from the differential PP topology with THAT components, I decided I have to give this PP a tryout which can be called serious. AD1 output tubes, E80CC drivers, Tango XE-45-5 OPT.



I come back with results as soon as the amp is running.







Greets,
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Old 23rd January 2002, 05:27 AM   #10
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Default Re: PP and SE sonics can be married ...

Quote:
Originally posted by dice45
bernhard.

Allen's shitty lil'experimental thing was easily as good as the Border Patrol and it outperformed it in the low end.
Good to hear. I have least a couple PP amps (EL95/EL84/EL34) i want to give Allen's treatment to.

dave
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