Newbie guide to SE Vs PP

[Dave the bass]

After browsing through Jerry T's ebay SE 3.5 watt amp discovery... and the funny lampooning he's recieved I just wondered...

For me and any other Valve Virgins lurking in Cyberland what are the Pros and Con's of both SE and PP?

I've never heard a SE amp in a Hi Fi scenario ('cos I'm a newbie like I said) but my understanding from reading informative posts both here and in HFW is that SE's are generally low powered using 300B's or 2A3's and are 'fussy' at what impedances they drive into, hence high sensitivity speakers are required but on the upside they sound 'nice'. (I should work on a Hi Fi magazine, my descriptive vocabulary is amazing )

PP on the other hand are fairly common, more powerful, less fussy about loads but lacks that SE sound.

Sorry if this has all been done before but I'm sure theres a few others like me out there (ie- clueless ).

Dave the bass.

P.S The E-bay Audio-lite Phono Stage project is still at the bread board stage, as soon as the good weather comes I transform into an 'outdoor' guy i'll finish the build when winter comes around and I'm stuck indoors and can't go out to play on my Skateboard (boo!).

[Darren D]

Hi Dave,

Describing the difference between PP & SE is very difficult to put into words.

I have heard plenty of both, from simple to some amaizingly complex, including one off Hi-fi diy's to comercial.

The answer is, you need to listen to both and decide for yourself. There are certainly merits of both types and although I personaly prefer SE I wouldn't knock PP at all.

Speakers have a large part to play in the deciding factor. I often wonder if it's the speaker that makes the decision for you....

Ask around and see if you can't get invited for some friendly demonstations, It's prob the best way. Not much help to you now I know, sorry.

Darren

[andrew ivimey]

You've got the basics there Dave but yes it is a bit more complex.

You will have to listen to a few. There must eb someone around / nearby.

Isn't 'The Matrix' down near you? - A HiFi shop which specialises in valve amplifiers.

[Greg.]

Hi Dave,

Come to Eggfest on 3rd June and you'll hear both.

Best wishes,

Greg

[Dave the bass]

Originally Posted by andrew ivimey

Isn't 'The Matrix' down near you? - A HiFi shop which specialises in valve amplifiers.

Yeah, its in my home town (Dartford) but I feel its a bit cheeky going in and asking for a demo between PP and SE and then telling them I want to build a WD amp any way S'funny actually, I went out on the town last Friday and had a meal and a few Ales with my (long-sufferin') partner and we used the new Fastrack Bus system that stops outside Matrix (great for when i'm old and wrinkly but need a new valve). While waiting for the bus I toddled over to their their shop was droolin' down the window at all the TT and glassy loveliness and nearly missed my bus They had a VAA EL34 PP amp for sale up on ebay for £199 a while back, I was sorely tempted. In the end I decided to wait to see the results of WD's new line up.

DTB

[Dave the bass]

Originally Posted by Greg.

Hi Dave,

Come to Eggfest on 3rd June and you'll hear both.

Best wishes,

Greg

Thanks for the invite Greg, its a fair ol' trek up to Eggborough, I've just looked it up Bum.

I'll see how we're fixed, it means leaving familly behind without a car for the weekend (again).

Thanks again for the invite, one day I'll meet up with you guys.

DTB

I recently got my first taste of Push-Pull vs Single-Ended, and it was 'interesting'.

PP amplifier: 300B Directly Heated Triodes, Solid State rectified with 600v power supply and an interstage transformer instead of a valve phase-splitter. It has no feedback and a Class A output of nearly 20W, but it did have to be used with an average valve pre-amplifier.

SE amplifier: 211 Directly Heated Triodes, Valve rectified with 1200v power supply. It too has an output of about 20W but is an integrated amplifier.

The source CD player was an expensive valve output model, and the loudspeakers were medium/high sensitivity two-ways designed with SE amplifiers in mind.

To my mind this was a better PP vs SE contest than most, as both amplifiers have similar output power of 20W (unusual for SE) and use DHTs without feedback (both unusual for PP). Ideally the PP would also be Valve rectified and similar pre-amplification stages used for both, the PP would also welcome some of the boutique components used in the SE!

My host, the chap used to using the SE amplifier was astonished at the quality of the 300B amplifier, and further so when informed that it was a PP (he'd assumed PSE) and that it used SS rectification. I was surprised at the presentation of the 211 amplifier but not at the excellent quality!

We both agreed that the PP amplifier had slightly more 'drive' especially from the mid-range down. We also both agreed that the SE amplifier removed a hint of 'grain' in the upper-mid, he blamed this grain partly on the pre-amplifier and I think it may also have something to do with the cheapish diodes in the PP. I found the high frequencies hard to judge as they were coloured by the omnipresent splash of a dome tweeter. The tone and sound quality of the amplifiers were similar with the SE having the edge, most differences here could be attributed to component differences. What was most noticeable was the difference in presentation ...

Both amplifiers imaged beautifully, with the SE amplifier having the slight edge with a little more forward projection. Chap admired the "cohesive" qualities of the PP amplifier which encouraged listening to the whole piece, I found that the SE amplifier seemed to "spotlight" elements encouraging dissection of a piece. I know that it is possible to dissect with the PP amplifier, and I'm sure that with familiarality the spotlighting of the SE would have seemed less obvious. I liked the effect, I just wished it was spread more around the soundstage and not restricted to the midrange instruments.

I found the 'pace' of both amplifier types different too, the PP had those qualities of drive and grip that could handle any type of music. I tried to trip the SE up in this regard but, being a very good one, it too could handle anything, but quite differently! I know that the following is going to sound weird, but "weird" was my initial comment when feeding the SE some very busy grooves: Whereas the PP pushed out anything given to it without hesitation, the SE seemed to create itself more time to play what it was given. I'll try that differently: The SE didn't sound slow or bad in any way, and although it didn't have the slam of the PP it did give the demanding passages all the attention they needed - it was very weird to hear a slamming piece of music sound great without it having a lot of slam!

To my ears neither SE or PP was wrong - they just had different presentations.
Please note that I was listening to better types of each topology which must have minimised the weaknesses of both. Indeed, I've heard more objectionable differences with Triode PP vs Pentode+Feedback PP than with 300B PP vs 211 SE!

I am not ready to jump into the SE or PP camps with both feet just yet, I'd like a mixture of what they both do well.
So I'll vote for well designed Triode amplifiers implemented beautifully! :p

[Paul Barker]

Matt, reading down I was just saying yes yes yes, I recognise all those things.

I too think when it comes to amps of that quality it is simply down to preference.

For my money you can build a cheap 6em7 SE amp and get loads of enjoyment, great imaging, some distortion, and masses of distortion overdriven.

Out of interest the 211's were probably gevt4c's. Though these are very solid performers with a silken sound they are rubbish compared to WE Oxide coated 211. Chinease 211's are just wheely bin fodder.

First eggborough I demonstarted the difference in sound between a straight sides px4 a straight sides px25 and a balloon px25. Though not unanimous it was majority approved that each stage was an improvement.

This ytime, though in mono, I shall show the progression from gevt4c to WE211. If someone could bring a chinease 211 we could start with that one (if it doesn't blow up).

Thanks Paul,

I thought mine was quite an ambititous write-up given it was my first (3 hour long) experience of SE! This thread coincided nicely with my memory still being fresh, so that was my excuse for writing the above.


And yes, I'm pretty sure that the 211 valves were as you say.

What I left with at the end of the night was a determination to try and play with a wider range of components inside and on top of my amplifier (and a renewed dislike of dome tweeters!)

[andrew ivimey]

Paul, 'as any fule no' the difference between shuguang 211 and GE vt4c is barkingly obvious but as the dusbin operatives have not yet arrived here this morning I have fished around and found a used but cheerful chinese 211 and am happy to bring it along to help demonstrate 'the progression'.