Kofi Annan in: "Push and Pull with Me"

[SY]

Just for the record... I wouldn't even consider a single ended design. Just so's you know that affection for those Model Ts is not universal. Too little power, too much coloration for my tastes. Granted, lots of people love that coloration, but I'd rather be able to turn effects on and off at will.

Try both and see what you prefer. A p-p EL84 amp will be cheap, easy, and probably pretty good. To put it in perspective, the cost of my entire EL84 p-p amp was less than a single 300B tube.

[arnoldc]

Kofi,

If you mean this amp



I babysat this amp for about two weeks and found that it sounds too sweet and too slow for my liking.

I believe Thorsten has the most experience in tweaking this design, as has made various posts about this in the Asylum IIRC.

@sy, you must be referring about those WE300Bs? but a TJ mesh can be had for just a little over $100 per pair.

[Kofi Annan]

Just for the record... I wouldn't even consider a single ended design. Just so's you know that affection for those Model Ts is not universal. Too little power, too much coloration for my tastes. Granted, lots of people love that coloration, but I'd rather be able to turn effects on and off at will.

Try both and see what you prefer. A p-p EL84 amp will be cheap, easy, and probably pretty good. To put it in perspective, the cost of my entire EL84 p-p amp was less than a single 300B tube.

Good information. The EL-84 does sound intriguing, but I'm thinking that the sound may be more clinical than the SET. Maybe what I'm noticing is the coloration of the SET?

I believe Thorsten has the most experience in tweaking this design, as has made various posts about this in the Asylum IIRC.

Hmmmm... has anyone had any experience with that amp with Thorsten's tweaks installed?

Man. I'm seriously conflicted here. Push-pull or SET? Unified Iraq or Kurdish, Sunni and Shiite sections?

Grrrr....

Kofi

[Gluca]

This might be an (other) option...

[SY]

Originally posted by Kofi Annan


Good information. The EL-84 does sound intriguing, but I'm thinking that the sound may be more clinical than the SET. Maybe what I'm noticing is the coloration of the SET?

Thinking is a wonderful thing. Building and listening is even better.

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.

[ThorstenL]

Konnichiwa,

Originally posted by SY
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.

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.

This is easily ascertained by anyone given the simple expedient of inserting a 2.2 Ohm to 2.7 Ohm resistor in series with their speakers. This is the output impedance of an SE Amplifier that is well implemented. Try it (not just YOU SY) and see how much the sound really changes, also compare this to the sonic difference a real SE Amplifier produces and you find a huge gap between the two.

I will still propose the simple hyphotesis that Zero Feedback SE Amplifiers do not ONLY sound the way they do because of their production of certain types of distortion (otherwise it would be trivial to produce a cheap SS Amplifier that replicates this behaviour and it is not, I tried - though I admit that a certain amount of "Aphex" is present at very high levels), but because of the absence of certain types of distortion not covered by traditional amplifier specifications.

Of course, a typhical SE Amplifier based system tends to also use speakers that are substantiatively freer from certain types of distortion commonly charaterised in Amplifiers, but omited in speakers, so the combination may very well be one that overall provides a drastically different sonic result.

If it is subjectively closer to reality or not can only be ascertained when testing a recording of a known event in known acoustics (and with a knowledge of the fundamental differences between event and recording) on the system. I found that with a well implemented SE Amplifier based system the gap is reduced. It does not make the recording more real than the actual original event, but it does seem to provide a closer subjective match.

Sayonara

[ThorstenL]

Konnichiwa,

Originally posted by Kofi Annan
Man. I'm seriously conflicted here. Push-pull or SET? Unified Iraq or Kurdish, Sunni and Shiite sections?

Define your aims. Do you want to:

1) Try cheaply "Push-Pull" sound to see if you like it (proceed to EL84PP)

2) Get an "Edge of the Art" high power PP Amplifier to drive these horrible powersinks masquerading as "High End Loudspeaker" (proceed to multiple parallel push-pull KT88, don't cheap out, 4pair Monoblocks are the job)

3) Get the best possible sound within a limited budget for your fairly sensitive speakers (proceed to 300B SE and build the Amp with a certain amount of universality in mind, methinks the DRD/Monkey with a D3a driver is probably best for that)

4) Something else I have not thought off

Sayonara

[mr mojo]

Kofi,

Please believe me-when I say if a monkey like me can build it anyone can.

Really.

I'm a graphic artist by trade and training. Anything more than algebra sends the tachometer in my brain into the red. I've no illusions and no asperations of being anything more than someone who draws pictures for a living but I still enjoy the challenge of restoring and building tube equipment.

My reading has led me to think that the difference between SET and PP are in some ways relatively minor. If either a triode or a pentode is used within the most linear portion of its' characteristic curve they will sound similar. The pleasing distortion of SET will only come into play when the triode is over-driven.

In fact, some friends and I (the friends being quite a bit smarter than I) set up a blind test in which DIY SETs, vintage and DIY PP as well as some EXPENSIVE SS gear were all set up to use the same speakers, source and cables, volume levels of each were matched and while behind a screen one person used a rotary switch to switch between each.

Guess what. We thought they all sounded great and not one of us could consistantly distiguish which was which. We heard some differences-but it depended almost entirely on the source and we found ourselves just as likely to choose the SETs, PP or SS at any given time.

Maybe none in our group possesses the "golden ears" of some audiophiles, but we all recognize and search for great sound to the extent of building or restoring our own tube gear so that has to carry at least a little weight.

My point is, good sound is good sound. It can just as easily come from SET, PP or SS. It sure does look a lot prettier when it comes from tubes, which the artistic side of me enjoys deeply.

I chose PP because I enjoy the beauty of tubes and my experiences with PP amps has led me to the 7591 as the best sounding tube for my ears. I've lived with KT66s, 6L6GCs, 7591s and EL34s, all in fully restored and correctly operating amps and I found the 7591s to have the detail, clarity and bass of the 6L6 family but with the full mid-range of the EL34s.

I think in the end the question really comes down to power, complexity and cost.

A SET is in some ways simpler to build, but on the backside the advantage of simplicity is offset by the cost of building or buying speakers to suit.

A PP is in some ways the exact opposite. The advantage of using less efficent speakers is offset by the more complicated building of a PP amp.

Either one can give great results. The question is which solution works best for you?

Best,
mr mojo

[SY]

It's not a tone copntrol, but it can cause swings of 4dB. Sheesh, this reminds me of the Black Knight.

[ThorstenL]

Konnichiwa,

Originally posted by SY
It's not a tone copntrol, but it can cause swings of 4dB. Sheesh, this reminds me of the Black Knight.

The room can cause 40db swing and is not commonly called tone control.

And I repeat, +/-2db at (say) 50Hz require only a few inch displacement of listener or speaker displacement, so the few db shift caused by using an SE amplifier can usually be adjusted for.

Let us just say that you dislike SE Amplifiers because your worldview is based on the assumption that modern style engineering must invariably be better, so if people still like the old stuff it must be because they "enjoy" distortion.

For me, I have no prejudices on the subject, never had any, so I pragmatically use whatever does the job best for my personal use.

Sayonara