JJ6V6 in 6L6 amp

[Helmholtz]

Bring your audiology test lab and let's find out.

I thought we were talking about changing sound (perceived frequency response) with different loudness?

There is no doubt, that specific shape and position of each each Fletcher-Munson curve changes from individual to individual depending on influences like age, exposition to high sound pressure etc. But this doesn't necessarily mean that perceived sound changes with loudness. At least it is not possible to read such effect from the typical Fletcher-Munson curves.

[Chuck H]

Could you guys speak up.

[Justin Thomas]

Could you guys speak up.

YEAH! Cuz some of us don't believe in Master Volumes for preamp distortion!

Okay, I'm leaving now til I have something constructive to add...

Justin

[Chuck H]

I've never studied the FM curves. I was surprised when I looked at them because the change doesn't at all represent what I've perceived for decades.?. Now, some of the changes in tone with volume can be attributed to speaker and cabinet behavior, I'm sure, so maybe that's what I've been hearing. Then there are the room dynamics. Certainly different levels of reflectivity/absorption in surrounding objects and surfaces can change the phase relationships that finally hit your ears. So there's that too. FM curves do show a very relevant change in LF from, say, loud speaking level up to the level of a cranked 20W amp. Something like six or seven dB depending on where you place those upper and lower limits. Not a deal breaker for me. I actually don't see a problem with using a different speaker cabinet for low level playing to re-balance that some. Many attenuators include a bright switch, but looking at those circuits I can't see how that would simulate the FM curves very well. More important, and not addressed in the discussion is that loud does sound and feel different from quiet for reasons more apparent, but harder to quantify than the infamous FM curves.

[Helmholtz]

FM curves do show a very relevant change in LF from, say, loud speaking level up to the level of a cranked 20W amp. Something like six or seven dB depending on where you place those upper and lower limits.

But reduces from around 3dB at 200Hz to almost nothing above.

Many attenuators include a bright switch, but looking at those circuits I can't see how that would simulate the FM curves very well.

Neither do bright switches/caps in amps.

[rockon1]

The JJ6V6 will handle and spec'd for 500pv. As long as you can bias them correctly and use use half of the previous impedance setting it should work fine. I ran the JJ's in my Laney AOR at close to 500VDC

[ultra-gain]

The JJ6V6 will handle and spec'd for 500pv. As long as you can bias them correctly and use use half of the previous impedance setting it should work fine. I ran the JJ's in my Laney AOR at close to 500VDC

Thank you sir. I may give it a whirl when I get some extra tube money set aside.