If you indeed have no respect for a voice of experience, why ask?
waltdogg has your answer.
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Reducing output by removing tubes
- Thread starter awilkie84
- Start date
If you indeed have no respect for a voice of experience, why ask?
waltdogg has your answer.
IME linear pots are impractical for volume control. These pots work nearly similar like an On/Off switch, where control is only possible on the amount of overdrive/overload of the signal.
Well, that's assuming that it actually has a linear pot in it. I don't honestly know what type Traynor used for their design. I just know it's REALLY touchy at moderate to high gain.
Ah okay, my mistake. Plate voltage well above the 6V6GT's abilities is, I'm sure the reasoning.
Gain in the preamp is 500K log.
Master is 100K linear.
Master volumes are usually linear.
Gotta watch the B+. If that goes you're asking for a meltdown. There's a reason why Fenders bias cold, high plate voltage, there's a reason why all those early variants of the JTM45 failed, plate voltages were too high. 6V6 and 6L6 amps, respectively.
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Ok, guys. I'm getting seriously conflicting information on which value of pot to use for the effects loop volume control. Local tech says 25-100K...you guys are saying anywhere from 50K to 500-1000K...which do I go with? lol
The master is 100K linear , you are putting something in series with that. A small value isn't going to do much. I would try linear 500K and 1M and see. Adding a pot is going to affect the impedance. You will have to experiment to see what works. I would buy more than one pot and try them.
Traynor suggested that you try a volume pedal. An Ernie Ball has a 500K for passive instruments and a 25K for active instruments. You aren't plugging into a volume pedal so impedance of the instrument isn't an issue. But what I take from this is that Traynor was suggesting something higher, like the 500K in the EB pedal.
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k. I have a 500K kicking around. I'll try that first & go from there.
by all means try it; you'll probably find that it acts like a switch, dropping really fast from full-up.
any legit buffered effects loop needs a low-impedance volume control to sweep evenly from off to full, tubes in the amp have nothing to do with it.
if the amp's master volume really is linear then an audio replacement is the answer!
too many amps do this as kind of a "dirty trick" in the music store, using a linear master volume; the sales guy turns that master volume up a little and says, "wow, listen to how loud it gets when it's just on "3", what a powerful amp!"
meanwhile, you never realize (because you never go that far) that the amp gets no louder past "5" on that knob.
You can take what I say anyway you wish. What I post is based on more that fifty years of working and designing with tubes. Tubes were current technology when I went to Engineer school. Gawd that seems so long ago now!
BTW tube amps are very forgiving of an output impedance mismatch. They'll work until they don't. It's when they stop being forgiving that the fireworks start. If you must run an amp into an incorrect load, endeavour to run into one that is lower than the selected impedance tap. This is opposite to what you would do with a SS unit.
If he already has a master volume, what will adding another pot in series with it accomplish?
Wow, you ARE an old fart. When I got my EE degree in the 80's tubes were already long gone from the curriculum. Of course, I was 38 when I graduated, so I'm right there with ya'!You can take what I say anyway you wish. What I post is based on more that fifty years of working and designing with tubes. Tubes were current technology when I went to Engineer school. Gawd that seems so long ago now!
Hopefully more control over what is in there now with a larger value. The manufacturer suggested the same thing later when they said to try s volume pedal in the effect send and return jacks.
I would guess as the amp's manufacturer did that it will help with the over sensitivity of the unit's master volume at lower output levels.
Sensitivity of ears is directly propotional to a logarithmic process of power. Audio tapers perform logarithmic process every time when turning the level knob up or down. There is no way to mod a linear taper to act as logarithmic processing.
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If the linear doesn't work, give the log a try. It is a simple experiment to see what works best.
I understand what you are saying about the log pot and human hearing. The linear pot is used between the preamp and the power amp as a voltage divider. Designers typically use linear pots for this function.
I understand what you are saying about the log pot and human hearing. The linear pot is used between the preamp and the power amp as a voltage divider. Designers typically use linear pots for this function.
