Kofi Annan in: "Push and Pull with Me"

[SY]

Of course. It couldn't possibly be a result of listening, it has to be a defective Weltanschauung. I can only aspire to one day have the sort of objectivity that you do.

 

[Gluca]

Mr Annan you have the answers (well you could have ...)

Dear Mr Annan,

as far as I understand you built a pair of SET 2A3 and you seem to be quite happy with them. Now you would like to experiment something new.

I also believe that the struggle between PP and SET can last as long as the last tube is blown. As a matter of facts your decision depends on your own personal taste, that's why no instrument or measure can give a definitive answer.

Latins say "de gustibus disputandum non est" (don't waste your time talking about your preferences).

So there is no answer to your doubt "PP or SET" but the very answer is in your ears and mind.

There is a solution.

Just build a 2A3 PP using the same driver (as applicable) and components of the same quality.

Everyone here would be happy to hear from you what differences you will find out. Moreover this will kill your doubts once and forever (maybe?).

Gianluca

 

[Kofi Annan]

For my tastes, most SEs have a distinctive coloration, a sort of honeyed brightness that makes music sound much more "real" than real. Sort of the MSG of audio. And they change the sound quite dramatically, not surprising given that with real speakers, the frequency response will be anything but flat. Expensive tone controls which cannot be easily adjusted. If that EQ happens to suit your speakers and your tastes, and you like the honey glaze, you'll become a raving SE fan. For me, it doesn't, I don't, so they are banished from my listening rooms.

I hear this argument about "tone controls" again and again. And guess what, it is about as valid as it was when it was first advanced, namly absolutely invalid.

On average the worst deviations you get with a competently implemented feedbackless SE Amplifier are in the region of +/-2db and these in the LF region where the speaker has great impedance swings due to the fundamental driver resonance. Given that this invariably happens in the modal region of the room any frequency response linearity is long history anyway.

So, SET's MAY change the sound dramatically in subjective terms, but in objective terms they change the frequency response less than moving your head a few inch or your speakers.

Not this is the kind of discourse I was expecting. I can't believe it took so long.

Now fellas, fellas... can't we all just agree that there are some people that like the SETs and some that like push-pull? Can't we say that both have their advantages and disadvantages and, even though we wouldn't like to admit it, we really love both topologies and... yes... each other.

I propose we design an amp. Not just any amp-- a push-pull amp with an SET personality. Or an SET amp with push-pull heart. And we'll call it:

Together: The Amp of Love

Juuuuuuust kidding!!!

You can appreciate that I'm somewhat conflicted here. I really like the SET sound and I'm willing to admit that even if its honey-glazed, I still like it. Remember, you're talking to a guy who only a year and a half ago was listening to a Sears amplfiier with a built-in 8-track. Hi fi is new to me.

I think I will be bulding a 300b to be my main listening amp, but first, I'd like build an EL-84 PP. So, from you, the community, I'd like two things. Well, I'd like eight things, but I'll settle for two:

First, can you recommend an EL-84 PP that is reasonably cheap and easy that will get my feet wet with the push-pull topology?

Second, I would like recommendations for a 300b SET that I will likely build following the PP unless, of course, I fall in love with PP (heh, heh. PP). I am interested in the DRD Monkey thingee that Thorsten mentioned, mostly because I think anything involving monkeys is cool, but also because I looked at a DRD 300b design and it looked interesting.

Gluca, I know you'd like me to take on a PP 2A3, but I'm afraid the tube expense may push this out of my league.

Sy, any inclusion of the word Weltanschauung into a conversation is OK in my book. Try "schadenfreude" once in a while. I like that one too.

Thanks for all the replies. Just need a few more. Then a few more after that.

Yeah, I know.

Kofi

 

[SY]

First, can you recommend an EL-84 PP that is reasonably cheap and easy that will get my feet wet with the push-pull topology?

Like I said before, a Bevois Valley amp is an ideal way for you to take the plunge and be able to make up your own mind.

Sy, any inclusion of the word Weltanschauung into a conversation is OK in my book. Try "schadenfreude" once in a while. I like that one too.

It's all part of the Zeitgeist.

 

[gingertube]

Gingertubes 2c worth

I have too bloody many power amps for the HiFi. I routinely swap between:
1) 845 SET
2) "Bervois Valley EL84 Ultralinear Push Pull
3) AKSA 55 Nivarna+ Solid State Amp.
4) What ever I'm working on at the time from ECL86 to 4 x KT88.

So which is the best? None of them do everything well.

The 845 SET is lovely with jazz (female vocals in particular) but is subjectively slow and is a second harmonic generator on complex rock music and can sound "bloated" on some music selections AND at some listening levels - sonics change dramatically with listening level ( I'm of the same opinion as SY regarding SETs BUT I would miss it if I no longer had it)

The "Bervois Valley" is lightening fast, dynamic and exciting but probably is not quite as smooth in the very tops as the 845 SET. Respectable Bass punch for a 10W /Chan amp.

AKSSA 55N+ does everything well but not quite enough valve warmth (actually since its solid state its amazing how much valve warmth it does have). I use it as a reference amp. If the sound of the latest valve amp project is better than this SS job then I know I've done a very good job indeed.

I change amps according to my mood and what I want to listen to on a particular day AND on the sound level at which I want to listen.

If you're a Rock freak then a push pull amp will better suit tham the SET.

If your a Jazz freak then the SET will better suit than the Push Pull.

If you like a bit of every type of music then you need every type of amp.

Oh! and my clock/radio which wakes me up each morning is an elctronic timer with an old Philips FM Tuner into a Rogers Cadet III and Vintage Warfdales.

In short there is no topology that is inherently better at all things.

The way to live with this is to not get too stuck on defending any one style of amp. Experiment and enjoy each for what it is and what it can do.

Cheers,
Ian

 

[SY]

If your a Jazz freak then the SET will better suit than the Push Pull.

Hmmmm, I'm a jazz freak.

 

[arnoldc]

If you're a Rock freak then a push pull amp will better suit tham the SET.

Hmmmm, i'm a rock freak

 

[Jaap]

weltanschauung

It is of course selbstverständlich that an amp that only plays one kind of music satisfactory is a handicapped piece of machinery. Kind of like an oven that only bakes white bread. Kofi would stick his head in such an apparatus I presume. At least that is my Weltanschauung.
I have built an E810F (or D3a) => IT => TJmesh300B amp with the best transformers on earth and a 90 dB loudspeaker of good quality. I like that amp but it is not good enough.

I think Kofi is also missing something in his life. In such circumstances you have to go to a new source of inspiration or ideology. I would say do not lend your ear to Unified Iraq or Kurdish, Sunni and Shiite sections, ask Mr. Bush for advice on these complicate matters. If he can't give satisfaction in this case why not listen to gurus as Lyn Olson, Gary Pimm, and Allen Wright who once where on the SET-belief but who all have discovered new truths. I am now on the verge of trying PP and I believe strongly that mr. Kofi Anal also should try this receipt for more fullfillment in the area around and between his good developed ears.
For a first try I would say that the humble EL84 is an excellent choice but for the sake of a better world put current sources everywhere !!
Amen and look again at the schematic of mr. Huber you can find up stream in this thread of audiolove.

 

[ThorstenL]

Re: weltanschauung

Konnichiwa,

If he can't give satisfaction in this case why not listen to gurus as Lyn Olson, Gary Pimm, and Allen Wright who once where on the SET-belief but who all have discovered new truths.

Hmmm, I EVER SO MUCH hate it when people do shoddy research.

1) Allen Wright was NEVER into SET Amplifiers at all.
2) Lynn Olson from the very beginning was designing PP Amplifiers, not SE, though he encountered SE Amp's in his time as reviewer.
3) Gary most notably still retains a 300B SE Amp in his system.

So to portay any of these three as recent converst to PP from SE is taking more liberties than I think are proper.

For the rest of the discussion, you can make very good (but not identical) sounding amplifiers with solid state components, you can make them with valves, you can make them SE and PP. Which of these a given person prefers is a matter of preference.

Sayonara

 

[ThorstenL]

Konnichiwa,

First, can you recommend an EL-84 PP that is reasonably cheap and easy that will get my feet wet with the push-pull topology?

I would suggest that the absolutely classic ECC83 (first valve as voltage amplifier, second as phasesplitter) driven circuit similar to the Sansui 500 Circuit using ECL82.

Second, I would like recommendations for a 300b SET that I will likely build following the PP unless, of course, I fall in love with PP (heh, heh. PP). I am interested in the DRD Monkey thingee that Thorsten mentioned, mostly because I think anything involving monkeys is cool, but also because I looked at a DRD 300b design and it looked interesting.

Well, the "Monkey" may be also called a "signal loop optimised DRD". There where several people messing with DRD style circuits at the time, the DRD is the most famous of the resulting, the "Monkey" is my own take.

Among the Amplifiers I have build I am again and again pulled back to 2-Stage circuits.

To give an idea, the 91 Style (Pentode driver) Ampliifers tend to be a little better in immediacy and tonal colours, but loose a little in large scale dynamics, Amplifiers with high transconductance triodes as driver and cokes or interstage transformers in there (mainly gridchokes, IT & DRD Style) all tend to sound a little more delinated but tend towards a slight touch of what I call "whitness" of sound, as if tonal colours are slightly bleached out, but they tend to have a better low frequency impact and handle large scale dynamics better.

I have never really got to like any of the 3-Stage Amplifiers, my favourite "pet hate" is the kind of circuit with 2 sections of a 6SN7 in a cascaded cicuit (DC coupled known as JE Labs, AC Coupled most well known is reichers F&B).

Sayonara

 

[Raj1]

Konnichiwa,






Among the Amplifiers I have build I am again and again pulled back to 2-Stage circuits.

To give an idea, the 91 Style (Pentode driver) Ampliifers tend to be a little better in immediacy and tonal colours, but loose a little in large scale dynamics, Amplifiers with high transconductance triodes as driver and cokes or interstage transformers in there (mainly gridchokes, IT & DRD Style) all tend to sound a little more delinated but tend towards a slight touch of what I call "whitness" of sound, as if tonal colours are slightly bleached out, but they tend to have a better low frequency impact and handle large scale dynamics better.


Sayonara

Now that's informative, describing the effect rather than 'cussin' dislikes........

 

[Kofi Annan]

I would suggest that the absolutely classic ECC83 (first valve as voltage amplifier, second as phasesplitter) driven circuit similar to the Sansui 500 Circuit using ECL82.

I'd be willing to try either this or the Bevois Valley amp. I have been reading up on the Bevois Valley and I think this is something I can tackle, but if you have a design in mind in line with the Sansui 500 circuit that you mentioned, it would be great if you could post a link.

I have looked at the original Sansui 500 circuit and it looks waaaaaaay too complicated for me. You'd be answering questions from the afterlife on that one.

Well, the "Monkey" may be also called a "signal loop optimised DRD". There where several people messing with DRD style circuits at the time, the DRD is the most famous of the resulting, the "Monkey" is my own take.

Any links to this design would be much appreicated as well. I will be building one of these, but it seems that popular opinion would suggest that I make an attempt at a push-pull first. Since I've never heard one (well, not a good one, anyway) it would behöövenze me to do so. Then I can speak with experience. Or less ignorance, in any event.

Kofi

 

[ThorstenL]

Konnichiwa,

if you have a design in mind in line with the Sansui 500 circuit that you mentioned, it would be great if you could post a link.

I have looked at the original Sansui 500 circuit and it looks waaaaaaay too complicated for me. You'd be answering questions from the afterlife on that one.

Once you boil it down to the actual Amplifier circuit, it's simple, see attached.... You can substitute ECC83 and EL84's, adjust output transformer primary, the actual ECL82(6BM8) is also more than nice and you could use a generic EL34 PP Transformer.


As for the "Two Monkeys on a stick" Amplifier (to give the full name in all it's glory) was discussed here:

http://www.diyaudio.com/forums/showthread.php?s=&threadid=61776

Sayonara

 

[Jaap]

kit ?

If Kofi chooses for a kit he has more time to change our world into a better place.

The Sansui schematic can be bought as a kit here:

http://www.heartaudio.nl/stoetkit/content/stoetkit_junior.html

Of course no family, never been there, etc. I must admit that I have purchased the output transformers of this amp because I like to build it some time in the future myself.
The stoetkit jr. has automatic bias, could be the better option for our secretary general.

 

[jacco vermeulen]

High time you visited Rik Stoet's shop in The Hague, Jaap.

 

[Jaap]

Yes,

And of course Radio Twenthe in the same street.

But Rik is not there anymore, he is now in Zoetermeer I believe.

 

[Kofi Annan]

OK-- as always, I gotta couple of questions:

In looking at the 6BM8, it appears to my stupid, stupid eyes that its a dual tube with one site being a triode and one being a pentode. If that's the case, would I only need two tubes per channel for this design with the triode being the phase splitter and the pentode being the output tube?

Also, since I've never worked with a PP before, I need to ask if the pentode stage is triode strapped-- it appears that it is, but you know how I think, so I'm probably wrong.

Furthermore, in addition, too, also, as well, I got more dumb ones for ya. There's like some funny-lookin' symbol thingee hangin' out in space above the 253V label over the bottom output pentode and I have no idea what this is. My first instinct is to bomb it and install a new regime, but I thought I'd ask first in case its important. So, WHADDIZZAT?!?

Bonus round:

It looks like there's a 500K input pot (see, I can do learnding!), so could this be driven from a preamp by just using a 500K resistor in its place? Oh-- and I'd like to know what the output power is and if this could drive a pair of Fostex FE-103s (~89 - 90dB SPL). I have some 206Es, which are plenty sensitive for SETs, so should be no problem with the PP, but I may wind up donating this to a tube audio-challenged friend.

And... one more...

Can I use one PSU for both channels here or would you strongly recommend two PSUs?

And can I get a cup of coffee for Chrissake?!? JEEZ!

Thanks as always,
Kofi

 

[BHD]

it appears to my stupid, stupid eyes that its a dual tube with one site being a triode and one being a pentode. If that's the case, would I only need two tubes per channel for this design with the triode being the phase splitter and the pentode being the output tube?

Yes.

Also, since I've never worked with a PP before, I need to ask if the pentode stage is triode strapped-- it appears that it is, but you know how I think, so I'm probably wrong.

I don't think so - see Jaap's schematic earlier in the thread. That's a triode strapped pentode. I'd suggest you try ultralinear connection for something different, and a little more power (but you know what going after power gets you, don't you Kofi?).

It looks like there's a 500K input pot (see, I can do learnding!), so could this be driven from a preamp by just using a 500K resistor in its place?

Yes. Shunted to ground.

Can I use one PSU for both channels here or would you strongly recommend two PSUs?

It depends on whether you want a pair of dual mono amps or a single stereo one. One supply is cheaper and should work fine, especially if you're donating it to a friend. It's good enough for 'em.

And can I get a cup of coffee for Chrissake?!? JEEZ!

I don't know about you, but I'm enjoying mine. Roasted the beans myself last night and made the coffee in my 50's vintage Cory vac pot with the glass rod this morning. The coffee never touches anything but glass. Mmmmmm...

 

[Sheldon]

There's like some funny-lookin' symbol thingee hangin' out in space above the 253V label over the bottom output pentode and I have no idea what this is. My first instinct is to bomb it and install a new regime, but I thought I'd ask first in case its important. So, WHADDIZZAT?!?
Kofi

The amp in that schematic is pentode connected. Don't know what that thingee is, but the schematic looks complete without it. I'd go ahead and bomb it. Btw, if you build something like this, you might as well get opt's with UL taps. Then, when you feel that things are slowing down on the conflict front and you're bored, you can compare UL, triode connection, and pentode connection. Also, Kuei said, you can use ECC83 and EL84. One more tube socket is required, but the total number of connections is almost the same. Just one extra heater connection.

Sheldon

 

[SY]

There's like some funny-lookin' symbol thingee hangin' out in space above the 253V label over the bottom output pentode and I have no idea what this is.

You mean the arrow with the k? That would be the voltage source for the screens. You want that source to be very, very well regulated.