Jean-Francois 6SN7 Line Stage photos

[NOSValves]

That is indeed very nice looking !! I bet it sounds every bit as good as it looks. With the workmanship above chassis I would love to see what's underneath.

Craig

[mobile homeless]

Guess what! Working on your site so dont fret (in between posts..heh). I'll fire a link to some more wiring shots.

kh

[Deang]

I just sent Craig about 25 or so shots of the Scott. Not the hi res quality you were probably hoping for, but with the camera I'm using -- it was the best I could do.

Your friend does very nice work.

I don't like REO Speedwagon.

[mobile homeless]

Why not send the shots this way, freak? Thanks for the try. So I take it the guy wouldnt agree to an extra two years of warranty and delayed payment while the pics are being taken? Surprised he didnt snap that one up. You see strange things every day...

I'll send ole Jean-Francois your praise. Just when I was getting ready to call you REOdean, you shoot it down! heh...

kh

[Dale W]

KELLY: How do you pronounce PANTHEON . Your friends is no dout french canadian, so it could go a lot of different ways.

Is it panth-E-on ?

On another note i got your last e-mail and forwarded my address and phone # to you.

[Deang]

Kelly,

Compressed file containing the pictures should be in your mailbox.

Please don't call me 'freak', for some reason, I find the term offensive. Besides, I think you're projecting.

I wonder how Randy is doing with the Jupiters. I'm going to throw some Jensens into the Apollos, as curiosity is getting the best of me.

What is the best way to determine how much power is being delivered to the inputs of the speaker terminals?

[NOSValves]

Dean,

Without a scope you really can't . But I found one thing out as pertains to you using the 4 ohm taps. With tube amps they produce there rated wattage at all taps unlike solid state. The only way the rated output changes is if you hookup a 8ohm load to the 4 ohm tap and create a indepadance mismatch. So if your RF-7 are indeed a 4 ohm speakers hooked to 4 ohm taps on the Apollos or the Scott your actually getting the rated output. Also if it seems like the amp drops over all output using the 4 ohm taps then your RF-7s are not 4 Ohm speakers !

Craig

[mobile homeless]

Happy Holidays and all that stuff....

Another question. What does it matter how much power it's putting out? What if it said 1w? How about 20w? Ultimately, it really doesnt matter what the figure is. As you should know by now, besides ruling out harm, it's virtually meaningless.

Listen to the system. Do what sounds best. Man and Woman doth not live by numbers alone (unless he is lost in a formula).

kh

[mike stehr]

Milliwatts.

[Deang]

Craig,

Leo and myself have had this discussion often. I asked Leo once how much power the Apollos would have on the 4 ohm taps. I asked this question after an anonymous source within Klipsch gave me impedance specifics for the RF-7. The RF-7 does carry a nominal 8 ohm impedance, however -- there are some spots where they dip down pretty low. Here is his Leo's (Leok) take on this.

"Let me see .. I just did this calculation yesterday. Because of the variations in impedance, I started thinking in terms of voltage output figuring I would just use the 4 Ohm tap as a hedge against the low portions of the RF-7 impedance curve. I assume power output specs are real so: if an amp is rated at 10 watts, then into 8 Ohms, using W = V**/R that's 8.9Vrms or 25.3 V p-p. Into 4 Ohms that's 6.3Vrms or 17.9V p-p. However, using that 4 Ohm output into a speaker that is really rated as an 8 Ohm speaker (even though it has 4 Ohm impedance ranges) the amp will be delivering 6.3Vrms into 8 Ohms which will have the amplitude capability of 5 Watts, except the droops at low impedances will be handled better than a 5 Watt amp using an 8 Ohm output (which is what we're looking for; quality, not quantity.)"

...and again...

"Output power = V**/R where R is an ideal 4 or 8 Ohms corresponding to the 4 or 8 ohm tap. A sine wave with 18 Watts of output power has 12Vrms on the 8 Ohm tap and 8.49Vrms on the 4 Ohm tap. (the voltage on the 4 Ohm tap will be voltage at 8 Ohms divided by the square root of 2 or V4 = V8/1.41 or V8*.707. For a given volume, a speaker using the 8 Ohm tap will produce power P8. That same speaker, without changing any volume settings will receive, and produce half the power: P4 = P8/2, or 3dB down connected to the 4 Ohm tap. Remember, as you go from 8 to 4 ohms, the Voltage drops by the sguare root of two. V** drops by two. Power for the same speaker is V8**/spkr-Ohm or V4**/spkr-Ohm. spkr-Ohm is constant in this case so power drops in half. That's why I have begun to see the RF-7 as a 99dB 4Ohm speaker."

There was also this from Mr. Anonymous:

"The way the whole amperage / voltage thing works is this in a nutshell: An amplifier is supposed to be a voltage source because speakers are voltage sensitive devices. If the amp has unlimited current, it can deliver the necessary output voltage (as determined by the volume setting) into any impedance. As impedance drops, more current is demanded to maintain output voltage. Tube amps are typically current limited so when impedance drops the voltage drops and amplitude response changes. Solid state amps are typically capable of higher current output so they can maintain necessary voltage into lower impedances. Killer amps, like Krell etc. cost as much as they do because they have so much current delivery that they can maintain output voltage into even brutally low impedances. High current (think solid state) amps would continue to double output WATTAGE with every halving of the load impedance, but they don't increase output VOLTAGE; they maintain voltage as impedance drops."

The bottom line is this: Since the RF-7 has those low spots, it is best to accomodate them by using the 4 ohm taps. The overall output of the amp is halved, however -- it will deliver the necessary current when the impedance drops without attenuating the frequencies at those positions. At least, that is my understanding at this point.

Running the RF-7's on the 8 ohm taps will generate more current overall, but the frequency response will follow the impedance curve at those instances where the impedance drops.

My question asking if there was a way to tell what was going on at the terminal inputs of the speakers -- was for the purpose of validating the math.

Now, for the paradox. I've been running the Heresies on the Apollos since last night. The Apollos are wired in 4 ohm internally. I can't change them on the fly. I would have to remove parts and then resolder. I get clean output on the Heresies up to 105db. In fact, it sounds very good. There is no sense of strain or evidence of clipping. The sound is dynamic and crystalline. To be honest, compared to the RF-7's, the sound comes forward with less effort, and as far as my ears can tell -- sounds better at 105db than the RF-7s at 100db. At 100db, the RF-7's begin to harden up, and have me grinding my teeth.

So, why do the Heresies generate more output with no strain, then the RF-7's? The really odd thing, is that the Heresies are 98db/w, and the RF-7's are 102db/w. The Heresies, an 8 ohm speaker wired to my 4 ohm taps -- are taking the fullness the Apollos have to offer completely in stride (and according to the information in your post, should be an impedance mismatch, thus choking off the Apollos). The RF-7's OTOH, sound really great until they go over that 95db - 96db barrier, and then they start to sound, well...like $hit. The only way I could get the RF-7's to match the output of Heresies and Apollos, and have them maintain a semblence of integrity in their signature -- was with the Aragon. The Apollos definitely sound better at 95db and under -- but above that, the Aragon delivers a dynamite sound.

I'm just trying to sort some things out here, and will also be emailing Leo about this.

I'm beginning to wonder if some of this might have something to do with sheer mass of drivers in the RF-7, and possibly the additional parts and complexity of the crossover as compared to the Heresy. I don't know. It's odd.

At any rate, I'm looking forward to putting the SET amps on the Cornwalls. It may be that this where they belong. I would then of course put the Scott on the RF-7's -- where I think there might be less problems. Don't know, don't know.

[mike stehr]

The other day I heard a Magnavox SE 6BQ5 job hooked up to a pair of eighties era Sansui PCM100 II's, with a digital cable box for a source/pre.

Mullard output tubes, Tele 12AX7 driver, 5V4 rectifying tube.

The amp's cathode bypass circuit is tweaked to match the vent frequency of the Sansui's at 25hz.

No it couldn't 120 decibel blast beats, so it more than likely won't rototill "Am I evil" through your chest.

But it can do above average moderate listening levels.

(I'd be satisfied listening to Metallica on the setup, and much more.)

The depth of the bass, is what blew me away.

It could get down to 20hz at around 2 watts. you could almost feel it.

It was a clean bass, unless the program material had too much EQ in the lower frequencies, then it would bloat when pushed.

The Output Transformer's are just teeny little things, you would think there just is no way you could get that low with these OPT's. Yet it does, with the Sansui's.

It left me scratching my head.